Article

Intercropping of oat and field pea in Alaska: An alternative approach to quality forage production and weed control

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Abstract

Intercropping of legumes with non-legumes is an ancient crop production method used to improve quality and dry matter (DM) yields of forage and grain, and to control weeds. However, there is little information regarding intercropping at high latitudes. The objectives of this field study were to evaluate performance of (1) sole cropped oat (Avena sativa L.) (cultivars Toral and Calibre) and pea (Pisum sativum L.) (cultivars Carneval and Orb) and their intercrop combinations, and (2) inter- and sole-crop responses to weeds. The different cropping systems were studied with different weed treatments (weed-free all season long, weed-free until flowering, and left weedy all season long). In general intercrops of oat and pea produced DM (forage) and grain yields similar to sole oat crops and higher than sole pea crops although the difference was not statistically significant. Furthermore, forage quality [crude protein (CP), acid detergent fiber (ADF) and neutral detergent fiber (NDF)] was improved by intercropping. Most of the variables measured were unaffected by weed treatments, however weed DM was generally lower in sole oat and oat-pea intercropping than sole pea cropping systems. More than 80% of the weed DM was from common lamb's quarters (Chenopodium album L.). The CP of this weed was higher than oat and pea, and ADF and NDF were equivalent to the sole cropped oat. Thus, including weeds as part of the forage is possible. However, if crops are grown for grain, weeds are likely to produce large numbers of seeds that would enter the seed bank. Thus, pea–oat intercrops show potential as an alternative and sustainable approach for optimum yield and high quality forage and weed control under Alaskan subarctic conditions.

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... Another option for producers looking to increase the quality and the quantity of their forages is intercropping, or planting mixtures of cereals and legumes. According to Begna et al., (2011), the intercropping of legumes and non-legumes is a practice that has been around for years as a means of improving the quality and the quantity of forage, as opposed to a monoculture of one species over the other. This sort of practice is common for dairy producers in the northern US and Canada where a higher quality feedstuff is needed to meet high nutrient requirements of milking cattle . ...
... Research has shown that when cropped together cereals and legumes can utilize nitrogen more efficiently than monocultures (Begna et al., 2011). This is because the cereals outcompete the legumes for the inorganic N in the soil (Begna et al., 2011;Lithourgidis et al., 2011;Neugschwandtner and Kaul, 2015). ...
... Research has shown that when cropped together cereals and legumes can utilize nitrogen more efficiently than monocultures (Begna et al., 2011). This is because the cereals outcompete the legumes for the inorganic N in the soil (Begna et al., 2011;Lithourgidis et al., 2011;Neugschwandtner and Kaul, 2015). Along with the forage quantity and quality benefits of intercropping, other positives can include increased yields of the following crop, increased land use efficiency, increased diversity, increased economic gain, and even the potential for controlling weeds, insects, and diseases. ...
Article
Success of integrating annual forages into crop and livestock systems throughout Nebraska may be variable depending on field location, field/forage crop management, and precipitation. There are many different warm- and cool-season annual forage species available for integrating crop and livestock systems at different times of the year. Mixtures of cereal species, such as oats (Avena sativa)) and spring peas (Pisum sativum)), are often used to optimize forage quantity and forage quality. Our two-year, three location study across Nebraska’s precipitation gradient suggested that forage quantity and quality may vary by location due to different precipitation amounts received during the spring growing season. Data also suggested, that in low rainfall environments, including spring peas with oats did not always increase crude protein levels in forages produced. However, this was more likely to occur in higher precipitation areas. If this is the case, the elevated seed cost due to the addition of spring peas may be unwarranted in low precipitation environments with lower forage production. No mixture of oats and spring peas produced significantly more biomass than an oats monoculture. This suggested that if the primary goal was biomass production, adding spring peas may be unnecessary. Data collected from different farms using annual forages for grazing throughout Nebraska suggests that annual grasses, when included in annual forage seed mixtures, will almost always be the greatest producers of biomass compared with other functional groups (i.e., legumes, brassicas, and other). Harvest efficiency of grazing animals was affected by the large amounts of biomass production from annual forages. Our data suggested that harvest efficiency levels may often be low (17-41%), resulting in large amounts of biomass being left within the field as standing biomass or trampled residue. Producers within the study felt that grazing annual forages was economical, but a number of variables may affect forage biomass which is a key factor in the economic sustainability and ecological benefit of including annual forages in integrated crop and livestock systems. Advisors: Mitch Stephenson and Daren Redfearn
... Baklagiller yalın ekildiğinde veya karışımlardaki oranları arttığında verim azalırken, ham protein ve sindirilebilirlik oranı artmaktadır (Droushiotis 1989;Lithourgidis 2006). Dolayısıyla karışımların yem kalitesi yalın ekimlerden daha yüksektir (Todd and Spaner 2003;Carr et al. 2004;Begna et al. 2011). Karışımların biçim zamanları da elde edilen otun kalitesi üzerine oldukça etkilidir. ...
... Uzun and Asik (2012) biçim döneminin ilerlemesiyle protein oranı azaldığı için, en düşük ham protein oranını 3. biçim zamanından elde etmişlerdir. Birçok araştırıcıya göre en yüksek ham protein oranı yalın ekilen bezelyeden elde edilmiştir ve bezelye-tahıl karışımlarının protein oranı yalın yetiştirilen tahıllardan daha yüksektir (Chapko et al. 1991;Begna et al. 2011;Lithourgidis et al. 2011;Pozdisek et al. 2011 Dordas et al. (2012) bezelye-tahıl karışımlarında en yüksek ham protein verimini %80 bezelye + %20 yulaf karışımından (1552 kg/ha), Balabanlı et al. (2010) ise fiğ-tahıl karışımlarında Macar fiği-çavdar karışımından (1.11 t/ha) elde etmişlerdir. Biçim zamanlarının ortalama ham protein verimleri 58.9-56.0 ...
... same letter are not significant at P<0.05 level. B(P): Pea, Y(O): Oat, ÇB(BF): Beginning of flowering, TÇ(FF): Full flowering, BB(PB): Pod binding Çizelge 2. Bezelye ve yulaf karışımlarının bazı verim ve kalite özellikleri (iki yılın ortalaması)Table 2. Some yield and quality characteristics of pea and oat mixtures (elde edildiğini bildirmişlerdir.Begna et al. (2011) yulaf-bezelye karışımlarının kuru madde verimlerinin yalın ekilen yulaftan istatistiksel olarak farksız, yalın bezelyeden ise daha yüksek olduğunu vurgulamışlardır. Bazı araştırıcılara göre de en yüksek kuru madde verimi yalın ekilen tahıllardan elde edilmektedir(Kocer and Albayrak 2012;Lithourgidis et al. 2011). ...
... A possible approach to successfully cultivate peas after shallow ploughing may be the intercropping of peas and cereals such as oat (Avena sativa L.). Pea-oat and other cereal intercrops produce a better weed suppression than pea sole crops (Begna et al., 2011;Corre-Hellou et al., 2011;Kimpel-Freund et al., 1998). Peas and cereals complement one another in the N use with the cereal being competitive to a greater degree in the use of soil mineral N and therefore forcing the pea to depend more on N derived from N 2fixation than in pea sole crops. ...
... As a result, the N use in pea-cereal intercrops is more efficient than in pea sole crops (Hauggaard-Nielsen et al., 2009). These issues of pea-cereal intercropping contribute to the higher total grain yields in intercrops than in pea sole crops and result mostly in better pea, cereal or total intercrop grain quality properties (Begna et al., 2011;Hauggaard-Nielsen et al., 2001, 2008Neumann et al., 2007). ...
... Significantly higher annual weed biomass values were observed in pea sole crops than in pea-oat intercrops and particularly in oat sole crops at both sites and in both years (Fig. 2). These results demonstrate the good weed suppressive ability of pea-oat intercrops, which has been reported for pea-oat and other peacereal intercrops in previous studies (Begna et al., 2011;Corre-Hellou et al., 2011;Hauggaard-Nielsen et al., 2001;Kimpel-Freund et al., 1998). This may be due to a faster canopy development and a greater soil surface shading in pea-cereal intercrops than in pea sole crops (Kimpel-Freund et al., 1998), a release of weed suppressive allelochemicals through oat root exudation (Baghestani et al., 1999;Kato-Noguchi et al., 1994) and a stronger weedcrop competition for water or nutrients in intercrops than in pea sole crops. ...
Article
The effect of ploughing depth and mechanical soil loading on the performance of pea sole crops, oat sole crops and pea–oat intercrops was investigated in field experiments under organic farming conditions at two sites in Germany in 2009 and 2010. The two ploughing depths were short-term shallow ploughing to a soil depth of 7–10 cm and deep ploughing to 25–30 cm. Wheel loads of 26 and 45 kN, which correspond to typical rear wheel loads of field machinery used during sowing operations, were compared to an uncompacted control. Shallow ploughing resulted in a greater penetration resistance in the 14–28 cm soil layer compared to deep ploughing. An increase in mechanical soil loading intensity increased the bulk density and decreased the air capacity in the 10–15 cm soil layer, whereas the penetration resistance was not affected. The annual weed infestation in pea sole crops was higher after shallow than after deep ploughing at both sites. Pea–oat intercrops compensated for the higher weed infestation after shallow ploughing at one site due to their excellent weed suppressive ability. Dependent on oat productivity, pea–oat intercrops produced comparable or higher grain and protein yields than pea sole crops. Intercropped pea yield components and grain protein yields were significantly lower than those of sole cropped peas. The ploughing depth did not affect pea grain yields in either year and oat yields in 2009. Due to a better emergence, the grain and protein yield of sole and intercropped oats were significantly higher after shallow ploughing in 2010. Mechanical soil loading did not have any effect on the yield performance of pea sole crops, oat sole crops and pea–oat intercrops in 2009. In 2010, mechanical soil loading of 26 kN and 45 kN decreased the pea grain yield by 12.1% and 20.8% respectively, regardless of sole or intercropped. Neither the grain yield nor the grain quality of sole and intercropped oats was affected by the mechanical soil loading in 2010. Grain and crude protein yields of total crop stands decreased with increasing mechanical soil loading after deep ploughing, whereas no significant differences were revealed after shallow ploughing. The present study confirms the positive qualities of pea–oat intercrops with regard to weed suppression and plant performance. Shallow ploughing mitigates the risk of a decrease in crop performance caused by heavy field traffic and provides an alternative to deep ploughing even in low weed competitive organically farmed grain legumes.
... The no-tillage cropping system, on subtropical environments, allows cultivating the oat crop during the winter-spring time and, after its harvest, it is possible to establish the soybean crop (Federizzi et al., 2015). However the oat crop grain yield is decreasing during recent years (Federizzi et al., 2015), in part due to weed competition (Lemerle et al., 1995;Begna et al., 2011). For instance, Lolium rigidum competition reduces oat grain yield by 14% (Lemerle et al., 1995), whereas Chenopodium album interference decreases this crop grain yield by 10% (Begna et al., 2011). ...
... However the oat crop grain yield is decreasing during recent years (Federizzi et al., 2015), in part due to weed competition (Lemerle et al., 1995;Begna et al., 2011). For instance, Lolium rigidum competition reduces oat grain yield by 14% (Lemerle et al., 1995), whereas Chenopodium album interference decreases this crop grain yield by 10% (Begna et al., 2011). ...
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Temperature affects the selectivity of post-emergence herbicides in a complex manner. The objective of this work was to develop a method to estimate the impact of temperature on herbicide selectivity using the white oat (Avena sativa) crop and iodosulfuron-methyl as study models. Greenhouse/growth-chamber experiments were conducted using a completely randomized design with the treatments arranged as a bi-factorial, with three repetitions. The first factor consisted of six temperatures (10, 15, 20, 24, 28 and 32 oC) to which the plants were submitted during one week after the herbicide spray. The second factor corresponded to seven doses of iodosulfuron-methyl (0, 0.2, 0.4, 0.8, 1.2, 5 and 20 g ha-1). For each temperature, regression curves were fitted to the dose-response data. The rate of herbicide efficacy was computed through the method first proposed in this study. The crop tolerance to the herbicide increased proportionally to the temperature, suggesting the product detoxification is improving crop selectivity. In practical terms, it is predicted that white oat crop tolerance to iodosulfuron-methyl increases in regions of the world with high temperatures. The method developed here also can be used to understand the effect of temperature on herbicide efficacy on weeds.
... Recently there is renewed interest in grass/legume intercropping. A number of workers in northern climates have evaluated and recommended pea and oat as a potential forage mix that can be adopted in low-input systems 21,22 . ...
... Studies conducted in North Dakota, Manitoba and Alaska reported DM production of pea/oat similar to the present study 14,21,22 . In conventional systems grasslegume mixtures (i.e. ...
Article
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There is a need to design intensive cropping systems that can reap multiple benefits from annual forages including animal feed, soil fertility and weed control. Considering pea/oat (Pisum sativum cv. 40–10/Avena sativa cv. Legget) as a standard green manure, this study investigated the productivity, weed competitiveness, utilization and nitrogen (N) benefit from grazed and ungrazed green manures to spring wheat (Triticum aestivum cv. Waskada) and fall rye (Secale cereale cv. Hazlet). A set of 3-year experiments was carried out in Carman, Manitoba, Canada in 2009, and was repeated in 2010 and 2011. Green manures were grazed by 2–3 ewes and 2–5 lambs for 24 h (1111–1667 sheep days per ha). Averaged over experiments pea/oat mix, hairy vetch (Vicia villosa L.) and sweetclover (Melilotus officinalis cv. Norgold) above-ground dry matter (DM) production were 5036, 5032 and 4064 kg ha−1, respectively. Lentil (Lens culinaris cv. Indianhead), a mixture of seven species and soybean (Glycine max cv. Prudence) produced the least amount of DM over 3 years; 3589, 3551, 3174 kg ha−1, respectively. Pea/oat and hairy vetch were the most weed-competitive species and, averaged over 3 years, contained less than 15% weed DM. Utilization of green manures by grazing animals varied little among species across years and ranged from 28 to 86% for individual species and years. When combined across experiments grazing increased N availability to the wheat crop. The grazing effect was significant for wheat DM production, N uptake and grain N, but not significant for yield across experiments. Averaged over 3 years, wheat took up 107 kg N ha−1 from grazed plots versus 98 kg N ha−1 from ungrazed plots. A significant species×management interaction for total (wheat+fall rye) N uptake in 2009 indicated that increasing the proportion of legumes in the green manure increased N benefit from grazing. Fall rye productivity was not affected by grazing. We recommend pea/oat and hairy vetch as two green manure species to enhance the overall system performance to achieve high level of DM production, good weed competition, utilization by sheep and provision of N benefit to the following wheat and fall rye crops.
... Cereal forages are commonly used in annual forage mixtures because they have the potential to produce substantial biomass that provides a good source of energy for livestock, but cereal forages can be deficient in CP for nutrient demands of certain livestock classes in some situations (Anil, Phipps, & Miller, 1998). Cereal−legume forage mixtures are often recommended because of the potential to maintain or increase forage production with the cereal crop and increase CP concentrations and nutritive value with a legume (Begna et al., 2011;Carr et al., 2004;Dordas, Vlachostergios, & Lithourgidis, 2012;Han et al., 2013;Hodgson, 1956;Kocer & Albayrak, 2012;Lauriault & Kirksey, 2004). Adjusting the relative ratio of a cereal forage (e.g., oat [Avena sativa L.]) and a legume (e.g., spring pea [Pisum sativum L.]) can allow manipulation of the potential trade-off between forage quantity and quality (Carr et al., 2004;Carr, Martin, Caton, & Poland, 1998). ...
... At HPS in 2018, we observed that as oat biomass production increased, there was less weed biomass present in the total biomass. Cover crops, including cereal grains, have been shown to suppress weed pressure (Begna et al., 2011;Hauggaard-Nielsen, Ambus, & Jensen, 2001), but the competitive advantage of cereal grains to reduce weed biomass is influenced by stand density and cereal forage biomass production (Arlauskiene, Sarunaite, Kadziuliene, Deveikyte, & Maiksteniene, 2014;Petrosino, Dille, Holman, & Roozeboom, 2015). While the use of forages for weed suppression was not directly planned in the objectives of the current study, our results support other research conclusions and suggest that as the proportion of spring pea in the total biomass increased in the forage mixtures there was less ability for the forage to outcompete and reduce weed biomass in situations with heavy weed pressure. ...
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Forage mixtures including oat (Avena sativa L.) and spring pea (Pisum sativum L. spp. sativum) provide opportunities to optimize forage production with increasing forage quality, relative to single species stands. Under different climate scenarios, adjusting seeding rates of these mixtures may produce variable results in forage quantity and quality. We conducted a two‐year study at three study sites to evaluate forage characteristics within mixtures of oat and spring pea stands across a semi‐arid to sub‐humid precipitation gradient. At the western‐most and driest location (219 mm Mar ‐ Jun precipitation), the oat monoculture produced 16 to 19% more total biomass than seeding treatments with mixtures of oat and spring pea. In contrast, at the moderate‐precipitation site (255 mm precipitation), no differences in total biomass were detected for the oat monoculture and seed mixtures of oat and spring pea. Large variation at the wettest site (339 mm precipitation) limited our ability to detect differences for total biomass production across treatments, but weed pressure in year 2 of the study reduced forage production. Typically, crude protein (CP) concentration decreased linearly (P < 0.01) as spring pea decreased in the seeding rate, but CP concentration and total CP yield varied for the seeding rate treatments at the different study sites. Environmental condition may influence the benefit of substituting spring pea into a properly managed oat forage crop to increase forage quality. The contribution of spring pea forage in the total forage biomass of mixtures may be limited, especially in drier conditions. This article is protected by copyright. All rights reserved
... Owing to the low lodging resistance, aeration and harvest of normal-leafed pea crop stands is often problematic. An intercropping with cereals improves the lodging resistance of normal-leafed winter peas (Urbatzka et al., 2011) and the weed suppressive ability of semi-leafless peas (Begna et al., 2011;Corre-Hellou et al., 2011;Poggio, 2005), which deserves special attention in reduced tillage systems under organic management. ...
... Moreover, James-triticale intercrops showed lower weed ground coverage values than James sole crops (Table 5). These results confirm the efficient weed suppressive ability of pea-cereal intercrops that has been shown in previous studies for intercrops of semi-leafless winter as well as spring peas and cereals (Begna et al., 2011;Corre-Hellou et al., 2011;Hauggaard-Nielsen et al., 2001;Urbatzka, 2010). Despite higher weed pressure towards maturity in 2010/11, resulting in higher weed biomass accumulation and N uptake in James sole crops compared to the first experimental year, values in James-triticale intercrops had a comparable level in both experimental years (Table 5, 7). ...
Article
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The performance of organic pea production largely depends on preventive and cultural control strategies for weeds and pests. Field experiments were carried out to study the effect of intercropping a normal-leafed (cv. E.F.B. 33) or a semi-leafless, early-flowering winter pea (cv. James) and triticale on the infestation with annual weeds, pea aphids and moths in comparison to the respective sole crops. Also, shallow ploughing (10 to 12 cm) vs. deep ploughing (25 to 27 cm) was investigated with regard to an infestation with annual weeds. The higher weed suppressive ability of normal-leafed winter pea cv. E.F.B. 33 compared with semi-leafless cv. James was due to a lower light transmission to the weed canopy level. In contrast to E.F.B. 33, intercropping James significantly reduced the weed infestation compared to the respective sole crop. The ploughing system had no significant effect on the weed infestation in crops differing in their ability to suppress annual weeds. Sole crops were found to have higher pea aphid density, incidence and cumulative aphid-days than the corresponding intercrops. Intercropping winter peas and triticale, however, was not beneficial in reducing an infestation with pea moths.
... Field crop mixtures are extensively grown in traditional agricultural systems of developing countries (Biabani, 2009). There is also an increasing scientific interest in intercropping systems in temperate regions for developing sustainable farming systems for forage (Anil et al., 1998;Begna et al., 2011) or grain production (Aufhammer et al., 2004;Kübler et al., 2008). Advantages of intercropping have been attributed to greater long-term yield stability, a more efficient utilization of finite resources such as light, nutrients and water, and reduced weed, insect and disease pressure (Musa et al., 2010). ...
Article
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Intercropping is of increasing interest in sustainable arable farming systems in temperate regions. This study was determined to assess the influence of sowing ratio and N fertilization on yield and yield components of oat (Avena sativa L.) and pea (Pisum sativum L.) in intercrops. A two-year field study was carried out on a fertile soil in eastern Austria with oat and pea sown in three substitutive sowing ratios and at different nitrogen levels. Oat was the dominant partner in the mixtures, strongly outcompeting pea. N fertilization increased the competitive ability of oat. Total grain yields were generally lower in intercrops than in pure stands; thus oat–pea intercrops failed to achieve a yield advantage. Sowing ratio and fertilization affected yield component parameters of oat and pea compared to the corresponding pure stands. Oat in intercrops used available environmental resources for increasing panicles plant−1 and grains panicle−1 whereas harvest index and grain weight of pea were negatively affected in the mixtures. In conclusion, oat–pea intercrops could no achieve higher grain yields than corresponding pure stands on a fertile soil.
... Damit stimmen diese Ergebnisse mit einer Vielzahl von Untersuchungen zum Gemengeanbau von anderen Körnerleguminosen, wie z. B. Erbse mit Hafer als Getreidepartner überein (KIMPEL-FREUND et al., 1998;GRONLE und BÖHM, 2011BEGNA et al., 2011). Hervorzuheben ist, dass mit ...
Article
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Seed vetches (Vicia sativa L.) are currently grown mainly in catch crop mixtures. They are characterized by a high biomass production with a good rooting intensity and good weed suppressing effect. However, common vetches can be cultivated as a grain legume, but in this case only as an intercrop together with a supporting crop. The seeds of common vetch have a high protein content and a good amino acid composition, so that it can be used as a high protein, on-farm produced feedstuff. Mechanical weed control is difficult in common vetch cultivation. So the weed suppressing effect of different vetch-oat-mixtures was investigated. Field trials were conducted at the Thünen-Institute of Organic Farming with the vetch cultivars Berninova, Ina, Jaga, Toplesa and Slovena in pure stands and in intercrops with oat in the years 2011 and 2012. The intercrops were sown in three different seed density ratios (75% vetch with 25% oat, 50% vetch with 50% oat, 25% vetch with 75% oat of the respective sole seed density). During the growing season weed biomass was harvested, once at the time of flowering of common vetch and another sample was taken at the time of harvest. The valuation of the two-year results showed interactions between the tested cultivars and the seed density ratios as well as between cultivars and the sampling time. Weed biomass showed in the different mixtures within a cultivar in most cases comparable graduations. The highest weed biomass, with the exception of the cultivar Slovena, was determined in pure stands, the lowest one in the mixture with a share of 75% oat. In pure stands, Toplesa showed due to their less leafy and upright growth type as well as a lower field emergence, the significantly highest weed biomass, followed by the cultivar Ina. The cultivar related differences decreased with increasing amounts of oat in the seed mixture, so that no significant differences were evident in the mixtures with 50% and 75% oat.
... The weak weed suppressive ability of semi-leafless winter peas as well as the low lodging resistance of normal-leafed cultivars may result in difficulties with yield formation or harvesting of sole crops. Intercropping peas and cereals reduces the infestation with weeds (Begna et al., 2011;Corre-Hellou et al., 2011;Hauggaard-Nielsen et al., 2001) and prevents peas from lodging (Kontturi et al., 2011;Urbatzka et al., 2011a). For these reasons, intercropping semi-leafless or normal-leafed winter peas and cereals would be one possible solution to ensure improved weed control, good canopy aeration and light interception, and to facilitate harvest operations and thus to avoid yield losses. ...
Article
Winter peas (Pisum sativum L.) are a promising alternative to spring peas in organic farming. Intercropping winter peas and cereals may be a beneficial way to improve lodging resistance in normal-leafed and weed suppression in semi-leafless winter peas. At the same time, there is an increasing interest in a reduction in tillage intensity, e.g. shallow ploughing. A normal-leafed, coloured-flowered (cv. E.F.B. 33) and a semi-leafless, white-flowered winter pea (cv. James) were cultivated as sole crops or in intercrops with triticale (Triticosecale Wittmarck) on a loam soil under Northern German conditions during two seasons (2009/2010, 2010/2011) and compared for winter survival, lodging resistance, yield performance, grain quality and succeeding winter wheat yield. The two ploughing depths were short-term shallow ploughing to 10–12 cm and continuous deep ploughing to 25–27 cm. Intercropping did not improve winter survival, which depended on pre-winter development. Owing to the low lodging resistance of normal-leafed winter pea E.F.B. 33, sole cropping is not advisable. Intercropping normal-leafed winter pea E.F.B. 33 and triticale resulted in a better yield performance (2.54–3.39 t d.m. ha−1) than the semi-leafless winter pea James sole (0.97–1.79 t d.m. ha−1) or intercrops (2.05–2.86 t d.m. ha−1). E.F.B. 33 had significantly higher grain crude protein, crude fibre and macronutrient contents, whereas the crude fat, starch and sugar content as well as the energetic feed value were higher in James. Wheat yields after E.F.B. 33 sole and intercrops were higher than after the corresponding James sole or intercrops. The biomass production, yield performance and the energetic feed value of winter pea sole and intercrops were comparable between ploughing depths or higher after shallow ploughing. Thus, E.F.B. 33-triticale intercrops provided better results than James sole or intercrops, except for the energetic feed value, and shallow ploughing was a good alternative to deep ploughing for the cultivation of winter peas.
... They improve the quality and yield of grass when used in combination with poaceae (Sleugh et al., 2000). Moreover, they resist weed infestation in cultivation with grains (Begna et al., 2011). Unlike the cool-season grasses, they have a summer dormancy and, therefore, continue to grow, contributing to the prolongation of the grazing season in the system (Nelson and Moser, 1994). ...
... The findings of this research will help them improve productivity and contribute to sustainable intensification of forage or fodder-based cropping systems. Perennial and annual forage/fodder cultivation systems in the UK [41], USA [47,59], Africa [60], and other developing countries [61] have been found beneficial for the sustainability of agroecosystem. ...
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The quantity and quality of forage and fodder crops is the major drawback of the livestock sector in the country. There is a need to bridge the gap between the supply and demand of fodder through the adoption of specific sustainable fodder production strategies. The field experiments were conducted during kharif (rainy, June-October), rabi (post-rainy, October-February), and summer (March-May) seasons of 2018-19 and 2019-20 to identify a sustainable fodder cropping system module in randomized complete block design with fifteen fodder cropping systems in three repli-cations. The main objective of this research was to identify the most productive cereal-legume cropping system, both in terms of quantity and quality of biomass, to reduce the gap between supply and demand of quality livestock feed around the year. Among cropping systems, Bajra-Napier hybrid intercropped with lucerne, cowpea, and sesbania recorded significantly higher green fodder (163.6, 155.2, and 144.0 t/ha/year, respectively) and dry matter yields (32.1, 30.8, and 31.3 t/ha/year, respectively). Similarly, the same perennial systems also recorded higher quality yield and ash content. However, higher crude protein content was noticed in monocrop legumes, with the highest in sesbania (22.32%), while higher ether extractable fat was found in monocrop sesbania (3.78%). The monocrop oats recorded higher non-fiber carbohydrates (36.90%) while a monocrop of pearl millet recorded higher total carbohydrates (80.75%), however they were on par with other monocrop cereal cropping systems. Cultivation of legumes as a monocrop, and their inclusion as an intercrop with cereals resulted in lower fiber fractions and improved crude protein in intercropping systems. Furthermore, this improved the dry matter intake and digestibility of fodder. With higher sustainable yield index values and land-use efficiency, perennial intercropping systems were also found to be sustainable. Thus, cultivation of the Bajra-Napier hybrid with either lucerne, cowpea, or sesbania as an intercrop will help livestock farmers to achieve higher productivity in terms of quantity and quality, and forms a viable option for overcoming livestock feed scarcity.
... benefits of oat intercropping with other crops also reported by many researchers (Malézieux et al., 2009;Naumann et al., 2010;Begna et al., 2011;Chen et al., 2011;Han et al., 2012). ...
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Intercropping is one of the most important and sustaibale cropping practice in agro-ecosystems. The study was conducted under field conditions in the arid Horqine sandy land in Baicheng District, Jilin Province, Northern China in 2011. A randomized complete block design with four replications was used. Treatments comprised different mono cropping and intercropping patterns, TO: sole cropping of oat, TOS-O: oat in the intercropping of oat and soybean, TOG-O: oat in the intercropping of oat and groundnut, TS: sole cropping of soybean, TOS-S: soybean in intercropping of oat and soybean, TG: sole cropping of groundnut, TOG-G: groundnut in the intercropping of oat and groundnut. In intercropping patterns, oat in oat-groundnut had obtained the highest dry matter in all stages. The highest value of protein percentage and organic matter in heading stage, grain filling stage, and grain dough stage was achieved in groundnut in oatgroundnut intercropping. The maximum value of protein percentage and organic matter in booting stage and ripening stage was related to soybean in oat-soybean intercropping. The results of this study clearly indicate that intercropping oat and groundnut affects the growth rate of the individual species in mixtures as well as the dry matter yield and nitrogen accumulation. The highest seed yield was obtained for mono-cropping of soybean, followed by mono-cropping of groundnut and oat. Oat seed yield intercropping of oat and groundnut, and intercropping of oat and soybean were 1208.00 kg/ha, and 832.3 kg/ha, respectively. The highest grain yield was obtained when soybean was grown together with oat, where the higher yield of intercrop is due to the better usage of nutrient, water and light. LER in all intercropping patterns were higher than 1. LER in intercropping of soybean and oat, and intercropping of groundnut and oat were 1.41, and 1.30, respectively. With these LER values, 29.07% and 23.07% of land were, respectively, saved in intercropping of soybean and oat, and intercropping of groundnut and oat, respectively, which could be used for other agricultural purposes. In both intercropping of soybean and oat, and intercropping of groundnut and oat, CI were less than 1, which means that both these two intercropping patterns have positive effects.
... Annual intercrops of cereal-legumes have been reported in previous studies to be more productive and more able to suppress weeds than comparable sole crops (Begna et al., 2011;Corre-Hellou et al., 2011;Gronle et al., 2014;Hauggaard-Nielsen et al., 2001b;Pridham and Entz, 2008;Szumigalski and Van Acker, 2005). However, there is little information regarding the intercropping of brassica and legume species and its impact on weed suppression. ...
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Accroître la compétitivité des cultures vis-à-vis des adventices est un levier essentiel pour concevoir des systèmes de culture moins dépendants des herbicides. Les légumineuses sont des espèces majeures pour diversifier les systèmes mais elles sont réputées peu compétitives vis-à-vis des adventices. Cependant la variabilité entre espèces en particulier pendant la phase précoce a été peu explorée. Ce travail vise à i) étudier, via deux expérimentations en rhizotrons en serre, les traits impliqués dans la croissance et l’acquisition d’azote (N) en début de cycle chez une gamme d’espèces de légumineuse et les conséquences sur la compétition légumineuse-adventice et à ii) quantifier au champ l’intérêt d’associations légumineuse-non légumineuse (colzalégumineuses, maïs-légumineuses pérennes, la légumineuse étant plante de service) sur la croissance et la composition de la flore adventice. Nous montrons qu’il existe une variabilité entre espèces de capture d’N en début de cycle en lien avec les réserves azotées de la semence et l’exploration racinaire. La croissance et l’acquisition d’N de l’adventice sont impactées différemment selon l’espèce de légumineuse pendant la phase précoce. Les essais au champ montrent l’intérêt de combiner des espèces aux traits complémentaires pour l’utilisation des ressources conduisant à un meilleur contrôle des adventices tout en maintenant la productivité de la culture. Cette étude montre aussi que la composition de la flore est modifiée en fonction de la légumineuse insérée dans le système en lien à la fois avec les traits des légumineuses et les traits de réponse des adventices.
... The ultimate goal of intercropping is to promote the complementary use of growth resources (Strydhorst et al., 2008;Mariotti et al., 2012;Ceccon et al., 2013;Iqbal et al., 2018a) by component crops in temporal (using resources at different times) ( Freitas et al., 2015; and spatial (by varied roots or canopy) dimensions (Bedoussac and Justes, 2010;Arshad and Ranamukhaarachchi, 2012;Munz et al., 2014). Intercropping has been reported to yield higher productivity per unit land area owing to better use of soil (Aasen et al., 2004;Bhatti et al., 2008;Begna et al., 2011;Kontturi et al., 2011;Mateus et al., 2016;Iqbal et al., 2018b) and environmental resources compared to sole crops ( Pasynkova and Zavalin, 2010;Vasileva et al., 2017). The sowing of binary mixtures containing blended seeds of component crops having no distinguishable lines, is widely practiced particularly by small land holders in Indo-Pak subcontinent and Africa (Akhtar et al., 2013). ...
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The assessment of competitive performance of mixture components is important for maximizing benefits of intercropping systems. This field study tested binary mixtures of two cereals (sorghum and pearl millet) and three forage legumes (cowpea, cluster bean and soybean), along with their sole crops on competitive indices. Sorghum-cowpea binary mixture resulted in a lower green forage yield of sorghum and cowpea by 9% and 36% respectively, but overall biomass production was increased by 30% and 117% compared to their sole crop equivalents. Partial land equivalent ratios (LER) of all component crops were higher than 0.50, indicating better land use efficiency, except of soybean in binary mixtures with cowpea and cluster bean. However, the highest LER was of sorghum-cowpea (1.55), followed by sorghum-soybean (1.48) and pearl millet-soybean (1.48) binary mixtures. Pearl millet dominated sorghum and all legumes, while cowpea remained a superior competitor among legumes as per aggressivity value index. The highest crowding ratio was exhibited by pearl millet in binary mixture with cluster bean indicating its higher competitive ability in comparison to other mixture components. Observed yield loss data indicated that pearl millet was the most resistant crop to yield loss in all binary mixtures, while soybean had the highest yield reduction. In a short term, the highest area-time equivalent ratio for sorghum-cowpea binary mixture indicated the maximum advantage for this binary mixture compared to other binary mixtures.
... In a meta-analysis, Verret et al. (2017) found that intercropping with a companion crop (i.e., a crop not harvested as a cash crop) resulted in significantly lower weed biomass and often higher crop yield. For example, several studies have shown that intercropping mixtures had better weed suppression than either crop planted alone (Izaurralde et al., 1993;Hauggaard-Nelson et al., 2001;Nelson et al., 2012;Wang et al., 2012) or had comparable weed suppression to the better of the crops planted alone (Poggio, 2005;Deveikyte et al., 2009;Begna et al., 2011). However, the opposite has also been found, for example, intercropped mixtures of maize and climbing bean didn't show any improvement in weed control over the monoculture maize and in some cases decreased crop yield (Nurk et al., 2017). ...
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Intercropping with different crop species and different spatial patterns is suggested to lead to increased competition with weeds and reduced weed abundance and biomass. In this study, our objective was to explore the ability of multi-species annual forage crop mixtures to control weeds while providing productive forage. We utilized field and greenhouse trials to evaluate the impact of different crop mixtures and row spacing on weed control in the semi-arid Brown soil region of southwestern Saskatchewan, Canada. Seven different mixtures of up to eight annual forage crops were grown with row spacing of 15 or 30 cm in a replicated field trial. Weed abundance and biomass were significantly affected by crop species mixtures. Crop mixtures that contained radish and barley generally had higher weed suppression. Row spacing did not significantly impact weed abundance or biomass across the treatments. Results were similar over both years in spite of drastically different precipitation conditions. Forage production was significantly different between cropping mixtures in July in both years. The barley-radish mixture had the highest crop biomass in July, and this early crop production was linked to weed suppression because crop biomass had a significant effect on weed abundance and biomass in July, but not August. A greenhouse experiment was used to further evaluate the crops (i.e., barley and radish) that demonstrated the highest weed suppressive activity in the field trial. Crop identity and row spacing were both significant factors affecting weed and crop biomass production. Radish exhibited stronger control of common lamb's quarters (Chenopodium album) compared to barley, but the binary mixture of the two species produced the highest crop biomass and equivalent weed control compared to the radish monoculture. This research suggests that cropping with multiple species (particularly forage radish) may be an effective way to control weeds in semiarid environments.
... Warm-and cool-season annual grass-type crops (e.g., corn, sorghum-Sorghum bicolor, winter wheat, winter triticale, and barley-Hordeum vulgare) are the commonly used forage crops in dairy feed rations in many parts of the world [3][4][5][6][7] including the SGP. Monocropping of annual grass-type crops produces higher forage yield compared with monocrop annual legumes, but forage quality of grass-type crops is lower than that of annual legumes [3,8,9]. Intercropping of cereal and legume crops can address some of the protein requirements of livestock. ...
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Forage crop–dairy farming is an important agro-industry across the world. This system is intensive with high-input forage crops. In the United States (US) Southern Great Plains, the system is based primarily on high-input annual grass-type crops in monocropping approaches and requires diverse low-input broadleaf crops for strengthening its sustainability. Winter canola (Brassica napus L.) and pea (Pisum sativum L.) have the potential to provide forage crop diversity options with high forage yields of high quality. Winter canola and pea in mono- and mixed-cropping approaches at seeding ratios of canola/pea at 0:100, 25:75, 50:50, 75:25, and 100:0 were studied for yield and quality in 2015 and 2016 in Clovis, New Mexico (NM). Averaged over years, canola–pea at 75:25 and 50:50 seeding ratios produced similar biomass forage yield but higher than mono-pea by 43% and canola–pea at 25:75 and mono-canola cropping by 8%. The land equivalent ratio of all mixed-cropping treatments exceeded 1.0, with canola–pea at the 50:50 seeding ratio recording a land equivalent ratio of 1.15, indicating that mixed-cropping systems are better users of land resources. Total digestible nutrients and relative feed value were higher in canola–pea mixed cropping than in mono-canola and mono-pea cropping. Canola–pea mixed cropping achieved high yields (13.3 to 14.7 Mg·ha−1) with improved forage quality, as well as improved crop and land productivity, with the potential to improve mechanical harvestability of vining pea, and strengthen the diversity and sustainability of forage crop–dairy farming in the Southern Great Plains under limited irrigation input of ~300 mm.
... Thus, N application benefits the cereal crop in a legume-cereal intercropping system, but not the legume (Naudin, Corre-Hellou, Pineau, Crozat, & Jeuffroy, 2010). Additional benefits associated with legume-cereal intercropping include: i) increased biomass and grain yield (Carr, Gardner, Schatz, Zwinger, & Guldan, 1995;Jensen, 1996), ii) higher N content in fodder (Cowell, Bremer & Van Kessel, 1989;Droushiotis, 1989) and better feed value (Begna, Fielding, Tsegaye, Van Veldhuizen, Angadi, & Smith, 2011), iii) more efficient use of limited resources (Spitters, 1983;Wilson, 1988), and iv) weed suppression (Hauggaard-Nielsen, Ambus, & Jensen, 2001). ...
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Intercropping cereal grains and legumes has potential as an alternative cool-season forage cropin low-input farming systems. The objectives of this study were to quantify the effects of density, species proportion and nitrogen (N) supply on the biomass accumulation of field pea and spring oat grown as sole or intercrops. Greenhouse experiments were conducted using an additive series experimental design. Treatments included threefertilizer Nrates and 20 density/proportion combinationsin a randomized complete block with four replications. Sole plant densities included 2, 3, 4, 5 plants of each species pot-1 (16 cm in diameter, 16 cm in height). The species ratios per pot for the intercrop included 1:1, 1:2, 1:3, 1:4, 2:2, 2:3, and 3:5 and their reciprocals. Nitrogentreatments included urea at 0, 0.2, or 1.0 g N pot-1 in a split application. Plants were harvested and oven dried to constant weight at 46 days after planting. As density increased, sole cropped oat and fieldpea biomass increased. In the intercrop, oat showed greater biomass accumulation at higher N levels, whereas field pea biomass was reduced at the highest N level. In both sole and intercrop, oat was more sensitive to intraspecific competition than field pea. Niche differentiation was only observed at the highest N level. At higher N and lower total density, mixtures yielded more than monocultures, indicating that intercropping of field pea and spring oat may be beneficial. Results from this study can aid in future field research to determine optimum density for each species and N rates to be applied in field pea-oat intercropping systems.
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The cultivation of weak weed competitive pea sole crops after reduced ploughing depth may result in weed problems in organic farming. Intercropping peas and cereals is one option to manage weed problems. However, little evidence exists on the weed suppressive ability of pea-cereal intercrops after differing ploughing depths. The effect of crop stand (pea sole crop, pea-oat intercrop and oat sole crop) and ploughing depth (10–12 vs. 25–27 cm) on the annual weed infestation, PAR transmission and weed nitrogen as well as water supply was investigated in field experiments in Northern Germany. In order to determine causes for the differing weed suppressive ability in pea and oat sole or intercrops, a pot experiment and a bioassay were conducted complementary to the field experiments. Crop stand and ploughing depth did not interact with regard to weed infestation. The weed suppressive ability increased from pea sole crops to oat sole crops, whereas shallow ploughing resulted in a significantly higher weed infestation than deep ploughing. While crop-weed competition for light was not essential for the differing weed suppressive ability, competition for water and nitrogen were detected to be key factors. As root exudates of the examined oat cultivar showed a growth inhibiting potential, allelopathy may also contribute to the weed suppression in oat sole and pea-oat intercrops. Results from this study indicate that pea-oat intercropping is not able to compensate for the higher annual weed infestation after shallow ploughing. Nevertheless, owing to their good weed suppressive ability, intercrops with cereals are of particular suitability for the cultivation of weak weed suppressive semi-leafless peas in reduced tilled soils in organic farming.
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This experiment was carried out with annual forage legume-grass mixtures to determine winter catch crop possibilities in Aydın ecological conditions in trial fields of Adnan Menderes University between 2014-2015. Two forage legumes (field pea (Pisum sativum subsp. arvense (L.) Asch.), common vetch (Vicia sativa L.)) and two forage grasses (oat (Avena sativa L.), Italian ryegrass (Lolium multiflorum Lam.)) were selected as crops of experiment material. Mixtures were prepared as %100 forage legume, %100 forage grass, %75 forage legume + %25 forage grass, %55 forage legume + %45 froage grass. Experiment was desinged with 4 replications and mixtures were harvested 2 times. Plant height, green forage yield, dry matter ratio, dry matter yield, ADF, ADL, NDF, CP ratio, CP yield, DDM and RFV were examined in this study. Consequences of the results; forage yield and quality hasn’t been effected by harvest time. The highest forage yield (4140,4 kg/da) was obtained from %100 oat application. The highest crude protein ratio (%28,08) was observed in %100 common vetch treatment. As a result of this study, %75 Common vetch + %25 Oat veya %75 Field pea + %25 Oat were suitable mixtures as winter crop mixtures in the same ecological conditions.
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Current ecological trends for production of forage for livestock indicate a need for small usage of fertilisers while increasing productivity. The study aimed to assess yield and interactions of selected Lolium and Festulolium species grown in mixtures with Trifolium repens and fertilised with NS, regarding mutual interactions based on available indicators. A two-year field study (2016–2017) was carried out in southern Poland and the research objects were designed on degraded chernozems. The highest yield was observed for mixtures: L. multiflorum + T. repens and L. × boucheanum + T. repens sown in the proportion 50 : 50, fertilised with N<sub>50</sub>S<sub>15</sub>. The mean dry matter yield was higher in the 1<sup>st</sup> year of the study, in all variants of fertilisation and types of mixtures. The land equivalent ratio differed for species in individual objects, for individual cuts and study years, and was most often higher than 1.0, which points to a positive interference between species in mixtures. Also, the competitive ratio index was often higher than 1.0, which means that grass species were more competitive than white clover. However, in the second year of study T. repens was dominant in multiple objects.
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Weed population density and biomass production may be markedly reduced using crop rotation (temporal diversification) and intercropping (spatial diversification) strategies. Crop rotation resulted in emerged weed densities in test crops that were lower in 21 cases, higher in one case, and equivalent in five cases in comparison to monoculture systems. In 12 cases where weed seed density was reported, seed density in crop rotation was lower in nine cases and equivalent in three cases when compared to monocultures of the component crops. In intercropping systems where a main crop was intersown with a "smother' crop species, weed biomass in the intercrop was lower in 47 cases and higher in four cases than in the main crop grown alone. When intercrops were composed of two or more main crops, weed biomass in the intercrop was lower than in all of the component sole crops in 12 cases, intermediate between component sole crops in 10 cases, and higher than all sole crops in two cases. The success of rotation systems for weed suppression appears to be based on the use of crop sequences that create varying patterns of resource competition, allelopathic interference, soil disturbance, and mechanical damage to provide an unstable and frequently inhospitable environment that prevents the proliferation of a particular weed species. -from Authors
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In field trials in 1987/88 near Pangbourne, England, wheat (Triticum aestivum) and field beans (Vicia faba) were grown in an organic farming system as sole crops and additive intercrops. The sole crops were grown at 25, 50, 75, 100 and 150% of the recommended density (RD) for conventionally grown crops. The intercrops consisted of all density combinations of wheat and beans from 25 to 100% RD in a factorial experiment. The grain yield of sole cropped wheat and beans increased significantly as their density was increased. The highest yield of both was achieved at 100% RD, indicating that the conventional recommendation was the optimum when applied to organically grown crops. Land equivalent ratio (LER) values for the intercrops were significantly greater than 1·0 when the wheat was sown at > 5% RD and beans at > 50% RD. The highest LER of 1·29 was achieved when wheat and beans were both sown at 75% RD. There was resource complementarity, expressed as relative yield total (RYT) > 1·0, in all of the density combinations. There was a significant decrease in resource complementarity with increasing wheat and bean density. The nitrogen content of the wheat grain and whole plant biomass was significantly increased when the density of beans in the intercrops was increased; this was reflected in a significant increase in grain protein at harvest. The total amount of N accumulated by the wheat, however, decreased with increasing bean density due to a reduction in the biomass of wheat. Beans also showed a significant increase in %N as the density of the other component increased and a decrease in total N accumulation due to reduced biomass. All of the intercrops accumulated more N than the sole cropped wheat, but did not exceed that accumulated by sole-cropped beans. The biomass of weeds was greater under beans than under wheat. Weed biomass in intercrops was significantly reduced when the density of wheat and beans was increased, resulting in a lower weed biomass in the intercrops than was achieved in either the sole cropped wheat or beans. The N content of weeds was significantly reduced with increasing wheat density but was significantly increased with increasing bean density. The total amount of N accumulated by weeds per unit area was reduced significantly by increasing the density of both components. The levels of disease on the wheat were low, but mildew (Erysiphe graminis) increased significantly as bean density increased. The incidence of chocolate spot (Botrytis fabae) increased significantly with increased bean density. The experiment demonstrated that it was possible to harvest the crop with a combine harvester and the wheat and beans can be planted separately mechanically, therefore this system is suited to mechanized agricultural systems.
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Cereals grown for forage are increasing in importance in the rations of ruminants in the UK and have the potential to supply high proportions of energy-rich forage in their diets. However, such diets usually require some degree of protein supplementation. Crop mixtures, generally referred to as intercrops, have the potential to boost the forage protein content of diets as well as having a number of agronomic benefits. In this paper, the growth and utilization of annual intercrops is reviewed with particular reference, where feasible, to temperate regions. General agronomic and feeding issues associated with cereal intercrops are outlined together with the practicalities of field-scale management of intercrops in highly mechanized systems. A number of cereal-based intercrop combinations are also considered, concentrating specifically on their value for forage production. The future potential for different combinations is discussed and research recommendations made.
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Field pea has been shown to benefit from the use of rhizobium inoculation and seed-applied fungicides under intensive production. The objective of this research was to determine the effect of seed- or soil-applied rhizobium (Rhizobium leguminosarum bv. viciae) inoculants and seed-applied fungicides on field pea (Pisum sativum 'Carneval') production on fields with no previous history of the crop. The study was conducted at seven locations in Saskatchewan in each of 2 yr. Fungicide treatments were Apron FL (metalaxyl), Apron FL + Thiram 75WP (dithiocarbamate) and an untreated check in 1997 and a fourth treatment, Thiram 75WP, was added in 1998. Rhizobium treatments were seed-applied liquid inoculant, soil-applied granular inoculant and a non-inoculated check. Inoculation with rhizobium increased nodulation (5 of 10 sites), seed yield (6 of 13 sites), and protein content (3 of 8 sites), but occasionally appeared to reduce emergence (3 of 14 sites). Granular inoculant had more beneficial effects than the liquid inoculant. Fungicide treatments had few positive effects on production, and occasionally negative effects such as reduced emergence. Interaction effects were rare between seed-applied fungicide and seed-applied liquid or soil-applied granular rhizobium inoculants, which indicated compatibility of these products. Variability in the effects of inoculant types and fungicides suggests that responses are dependent on local soil and environmental conditions.
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Field pea (Pisum sativum L.) acreage has expanded rapidly in the past 10 yr in the Peace River Region of Alberta as well as western Canada. Understanding nitrogen dynamics of Rhizobium inoculants and applied N will provide farmers opportunities to improve N nutrition of field pea. Field experiments were conducted (a) to compare the effects of soil inoculation using granular inoculant, and seed inoculation using peat powder and liquid inoculants with an uninoculated check, on field pea nodulation and N2 fixation, and (b) to determine whether starter N is required by field pea to enhance N2 fixation. The effects of inoculant formulation on nodule number, N accumulation and N2 fixation were in the order: granular > peat powder >liquid = uninoculated. Field pea, from soil-applied inoculant, accumulated more N prior to and during podfilling than field pea with seed-applied inoculant. Fertilizer N application rates < 40 kg N ha-1 had no significant effects on biomass N at flatpod, indicating that starter N was not necessary. Application rates greater than 40 kg N ha-1 reduced nodulation, but the total amounts of N accumulated by plants did not vary. The close proximity of a highly concentrated band of N fertilizer had a greater impact on nodulation and subsequent N2 fixation than the residual soil N level. Under field conditions, soil-applied inoculant improved N nutrition of field pea compared to seed-applied inoculation, with or without applied urea-N.
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Alfalfa (Medicago sativa L.), red clover (Trifolium pratense L.), yellow sweet-clover (Medicago officinalis L.), fababean (Vicia faba L.), lentil (Lens culinaris Medik.), pea (Pisum sativum L.), and white lupin (Lupinus albus L.) were evaluated as annual crops in central Alaska on neutral and acid soils for their potential herbage productivity and N accumulation. Herbage dry matter yields were high on the neutral soil, with an overall average yield of 6927 kg ha ⁻¹ . Yields were much lower at the cooler, acid soil site with an overall average yield of 3743 kg ha ⁻¹ for inoculated legumes. Herbage N concentrations ranged from 14 to 36 mg g ⁻¹ . Amounts of N-fixation, as estimated by the total N difference method, ranged from < 50 kgha ⁻¹ for some legumes on the acid soil to > 200 kg ha ⁻¹ for fababean on the neutral soil. Inoculation resulted in increases in nodulation, growth and apparent N-fixation on the acid soil where legumes had not previously been grown, but were usually not significant on the neutral soil where legumes had been grown for many years. Liming the acid soil resulted in significant increases in soil pH and in nodulation, herbage yield, and herbage N yield. Key words: Forage legume crops, Alaska, liming, N-fixation
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(1) The hypothesis that intercrops have fewer, smaller weeds than their component sole crops was tested by sowing pure and mixed crops of barley and field pea at commercial densities and at double these densities in two fields near Ithaca, New York, U.S.A. The effect of these cropping systems on the species composition of associated weeds was also investigated. (2) For both sole crops and intercrops weed productivity decreased and crop productivity increased with higher crop density. (3) Crop treatments had no effect on weed numbers relative to unplanted control treatments. (4) For both high- and low-density treatment series, weed productivity decreased in the order unplanted controls > pea sole crops > intercrops > barley sole crops. Weed productivity in the high-density intercrop, formed by sowing together the two low-density sole crops, was not significantly different from weed productivity in the low-density barley sole crop. (The estimated difference ± S.E. was 0.77 ± 21.8 g m-2.) (5) Weed suppression by barley may have resulted from competition for soil moisture since weeds which grew in barley sole crops or barley/pea intercrops had lower predawn water potentials than weeds in unplanted controls or in pea sole crops. (6) Within both density series, above-ground crop productivity decreased in the order barley > intercrop > pea. Yield of the high-density intercrop was nearly equal to the sum of yields of the two low-density sole crops. (7) Relative abundance of the major weed species differed among crop treatments. In general, the most dominant weed species was more suppressed than other species as crop productivity increased. This response is explained in terms of a dominance hierarchy.
Article
In semiarid climates, appropriate management of the previous crop stubble in combination with seeding method is important to improve growing conditions for the subsequent crop. To determine the effects of standing stubble of various heights on the microclimate and on the growth and yield of pulse crops, we seeded desi chickpea ( Cicer arietinum cv. Cheston), field pea ( Pisum sativum cv. Grande) and lentil ( Lens culinaris cv. Laird) directly into cultivated, short (15-18 cm), and tall (25-36 cm) spring wheat ( Triticum aestivum ) stubble. The study was conducted in Swift Current, Saskatchewan, Canada, in 1996-98 and 2000. Standing stubble changed the microclimate near the soil surface by reducing soil temperatures, solar radiation, wind speed and potential evapotranspiration throughout the life cycle of these crops. Microclimate effects were much more pronounced for tall versus short stubble. The three pulses responded similarly to increasing stubble height. Vine len gth increased as stubble height increased, but the plants did not stand more erect. However, there was a tendency for plant height to increase as stubble height increased. Tall and short stubble increased the overall average grain yield by 13 and 4% compared to cultivated stubble. Crop water use was not affected by stubble height so the increased grain production was due to increased water use efficiency. Tall and short stubble increased the overall average water use efficiency by 16 and 8% compared to cultivated stubble.
Article
Italian and Westerwolds ryegrasses (Lolium multiflorum Lam.), Persian clover (Trifolium resupinatum L.), red clover (T. pratense L.), alfalfa (Medicago sativa L.), and birdsfoot trefoil (Lotus corniculatus L.) were grown in monocultures and in ryegrass-legume mixtures as summer annual forages. Ryegrass monocultures were fertilized with NH 4 NO 3 at 75 kg N/ha at plant emergence, and at the same rates after cuts 1 and 2. The forage legumes in order of productivity were Persian clover > red clover > alfalfa > trefoil when grown in monoculture. Growing legumes in mixtures with ryegrass increased the dry matter (DM) yields from 15 to 52% over legumes grown in monocultures. The DM yields of mixtures were intermediate in relation to yields of legume monocultures and N fertilized ryegrasses. Inclusion of ryegrasses with legumes increased the DM production at the establishment phase and in the fall. Total N and in vitro digestibility of DM were lower for Westerwolds ryegrass-legume mixtures than for legume monocultures and Italian ryegrass-legume mixtures.Key words: Lolium multiflorum Lam., Trifolium resupinatum L., Trifolium pratense L., Medicago sativa L., Lotus corniculatus L.
Article
In Canada, lamb’s-quarters (Chenopodium album L.) occurs in disturbed habitats in every province, the Yukon and the Northwest Territories. A key is provided separating two other closely related weedy species, C. berlandieri Moq. ssp. zschackei (Murr.) Zobel and C. strictum Roth var. glaucophyllum (Aellen) Wahl from C. album. The biology of C. album, the most common weedy species in the genus, is discussed.
Article
Barley (Hordeum vulgare L.) and oat (Avena sativa L.) have been intercropped with field pea [Pisum sativum subsp. sativum var. arvense (L.) Poir.] to increase forage yield and quality. Our objective was to evaluate the effects of two barley and two oat cultivars and seeding rates of cereal-pea intercrop on forage production, crude protein (CP) concentration, and N yield. A field experiment was conducted in 1993 and 1994 under dryland management in both fallowed and continuously cropped, no-tillage environments. 'Bowman' and 'Horsford' barley, and 'Dumont' and 'Magnum' oat, were each sown at 93, 185, and 278 kernels m-2 with 'Trapper' pea at 40, 80, and 120 seeds m-2, in all possible rate combinations. The cereal cultivars also were sown alone at 185 kernels m-2. Cultivars developed for forage production (Horsford, Magnum) produced as much or more forage than cultivars developed for grain production (Bowman, Dumont) across sole-crop and intercrop plots (P ≤ 0.05). Forage yield was unaffected by intercropping when the cereal crop was sown at the sole-crop or greater rate. Less forage was produced by intercrops when the cereal component was sown at half the sole-crop rate. Forage yield was not affected by the pea seeding rate, but CP concentration increased with increasing seeding rate of pea in three of four environment-years. Forage N yield was unaffected by intercropping. These data indicate that the cereal component in barley-pea and oat-pea mixtures should be sown at a sole-crop or greater seeding rate for maximum forage production. Forage CP concentration can be increased as the relative proportion of pea seed to cereal kernels sown in a mixture is increased, but forage N yield may not be affected, since the cereal component contributes more to yield than the pea component.
Article
Forage yield and several quality parameters of oat (Avena saliva L.) have been addressed in the literature, but the effect of N fertilizer rate on forage yield and quality of oat cultivars, and the possibility of cultivar by N interactions, has received little attention. The objective of this study was to evaluate oat cultivar responses to N fertilization when harvested as forage at heading. Nine adapted oat cultivars ranging from early to late in heading date were grown in four field environments from 1982 to 1984 with five N application rates (0, 28, 56, 84, and 112 kg ha⁻¹). Nitrogen application rates up to 84 or 112 kg ha⁻¹ increased forage yield and increased N concentration in two of three environments. Increasing N application rate increased neutral detergent fiber (NDF) 46 g kg⁻¹ in one environment but decreased it slightly otherwise. In three of four environments, forage yield at heading increased (r² = 0.66−0.94) linearly with later heading date. Nitrogen concentration generally decreased and NDF, acid detergent fiber, and acid detergent lignin concentrations increased with later heading date. The difference in NDF between the earliest and latest cultivars could affect forage utilization by affecting forage intake. In situations where high quality is important, early maturing oat cultivars might be preferable because they produce higher quality forage. Early harvest would also alleviate competition with an underseeded perennial legume earlier in the season. Application of 84 to 112 kg ha⁻¹ of N produces maximum yields and increases N concentration with generally small effects on fiber concentrations and without increasing lodging. Contribution of the Dep. of Agron., Univ. of Kentucky and Univ. of Wisconsin. Article no. 89-3-73. Please view the pdf by using the Full Text (PDF) link under 'View' to the left. Copyright © . .
Article
Integration of green manuring as fallow replacement in dryland cereal production requires selection of well-adapted legumes. The objectives of this study were to (i) analyze vegetative growth of annual legumes and (ii) assess the relative merits of each legume as shortterm green manure crop. Inoculated black lentil (Lens culinaris Medikus), Tangier flatpea (Lathyrus tingitanus L.), chickling vetch (Lathyrus sativus L.), and feedpea (Pisum sativum L.) were tested on an Orthic Brown Chernozem soil (Aridic Haploborolls) at Swift Current, SK, Canada, from 1984 to 1990. Legume species and years differed significantly in dry matter (DM) production of shoots, roots, and nodules; DM partitioning; growth habit; relative growth rate; and weediness. Total legume DM ranged from 601 to 3961 kg ha⁻¹, with 6- yr means of 1669 kg ha⁻¹ for black lentil, 1486 for Tangier flatpea, 2230 for chickling vetch, and 3008 for feedpea. Nodulation was most abundant with chickling vetch and least with Tangier flatpea; nodule DM ranged from 2 to 329 kg ha⁻¹. Coefficients of determination between nodule and legume DM were r² = 0.93*** for chickling vetch and r² = 0.78*** for feedpea, indicating their ability to benefit from symbiosis with Rhizobium. Nodulation was greatly influenced by soil mineral N and soil water. Average DM allocation to roots as a percentage of total legume biomass averaged =7% for chickling vetch and feedpea and 12% for black lentil and Tangier flatpea. Feedpea canopy height was double to triple that of black lentil. The degree of decumbency (stem length/canopy height) was 1.09 for black lentil, 1.19 for chickling vetch, 1.21 for feedpea, and 1.29 for Tangier flatpea. Growth rate analysis identified chickling vetch as an early-developing legume. Feedpea and chickling vetch were definitely more suited to green manuring in semiarid climates than black lentil and Tangier flatpea. Feedpea has good growth habits and greatest DM production. Chickling Please view the pdf by using the Full Text (PDF) link under 'View' to the left. Copyright © . .
Article
Z. 2004. Yield potential and forage quality of annual forage legumes in south-ern Alberta and northeast Saskatchewan. Can. J. Plant Sci. 84: 143–155. There is limited information on the adaptability of small and medium-seeded annual legumes in Western Canadian cropping systems. Pea (Pisum spp.), vetch (Vicia, Lathyrus spp.), medic (Medicago spp.), alfalfa (Medicago spp.), berseem clover (Trifolium alexandrinum L.), arrowleaf clover (T. vesiculosum L.), Persian clover (T. resupinatum L.), balansa clover [T. michelianum Savi. var. balansae (Boiss.) Azn.], rose clover (T. hirtum All.), crimson clover (T. incarnatum L.) and black lentil (Lens culinaris Medik.) were grown at Lethbridge and Brooks, Alberta, and at Melfort and Nipawin, Saskatchewan over a 2 or 3 yr period to assess their forage yield potential under irrigation and dry-land conditions. Measurements included plant height, stand establishment, flowering date, forage yield and forage quality. Peas, winter and hairy vetch, and berseem clover were the top yielding species across locations (5452-6532 kg ha –1). Berseem clover, hairy vetch, winter vetch, Nitro alfalfa, and Persian clover yielded in excess of 9000 kg ha –1 under irrigation at Brooks. Hairy and winter vetches, Magnus pea, chickling vetch (Lathyrus sativus L.) and berseem clover yielded over 4300 kg ha –1 in dryland and rainfed locations at Lethbridge, Melfort and Nipawin. These entries had an upright growth habit, established quickly and were nor-mally harvested twice. Crude protein concentration and yields were higher in legumes at irrigated locations in Alberta than rain-fed locations in central Saskatchewan. Burr medic at the Brooks irrigated location produced the highest crude protein yield of 2495 kg ha –1 . Berseem clover, Persian clover, Nitro alfalfa, hairy and winter vetches show promise as legumes in short term rotations, as green manures and intercrops for increasing forage quality in silage or late season grazing in Western Canada.
Article
The effect of mixed intercropping of field pea (Pisum sativum L.) and spring barley (Hordeum vulgare L.), compared to monocrop cultivation, on the yield and crop-N dynamics was studied in a 4-yr field experiment using 15N-isotope dilution technique. Crops were grown with or without the supply of 5 g 15N-labeled N m-2. The effect of intercropping on the dry matter and N yields, competition for inorganic N among the intercrop components, symbiotic fixation in pea and N transfer from pea to barley were determined. As an average of four years the grain yields were similar in monocropped pea, monocropped and fertilized barley and the intercrop without N fertilizer supply. Nitrogen fertilization did not influence the intercrop yield, but decreased the proportion of pea in the yield. Relative yield totals (RYT) showed that the environmental sources for plant growth were used from 12 to 31% more efficiently by the intercrop than by the monocrops, and N fertilization decreased RYT-values. Intercrop yields were less stable than monocrop barley yields, but more stable than the yield of monocropped pea. Barley competed strongly for soil and fertilizer N in the intercrop, and was up to 30 times more competitive than pea for inorganic N. Consequently, barley obtained a more than proportionate share of the inorganic N in the intercrop. At maturity the total recovery of fertilizer N was not significantly different between crops, averaging 65% of the supplied N. The fertilizer N recovered in pea constituted only 9% of total fertilizer-N recovery in the intercrop. The amount of symbiotic N2 fixation in the intercrop was less than expected from its composition and the fixation in monocrop. This indicates that the competition from barley had a negative effect on the fixation, perhaps via shading. At maturity, the average amount of N2 fixation was 17.7 g N m-2 in the monocrop and 5.1 g N m-2 in the intercropped pea. A higher proportion of total N in pea was derived from N2 fixation in the intercrop than in the monocrop, on average 82% and 62%, respectively. The 15N enrichment of intercropped barley tended to be slightly lower than of monocropped barley, although not significantly. Consequently, there was no evidence for pea N being transferred to barley. The intercropping advantage in the pea-barley intercrop is mainly due to the complimentary use of soil inorganic and atmospheric N sources by the intercrop components, resulting in reduced competition for inorganic N, rather than a facilitative effect, in which symbiotically fixed N2 is made available to barley.
Article
Field pea (Pisum sativum L.) and spring barley (Hordeum vulgare L.) were intercropped and sole cropped to compare the effects of crop diversity on productivity and use of N sources on a soil with a high weed pressure. 15N enrichment techniques were used to determine the pea–barley–weed-N dynamics. The pea–barley intercrop yielded 4.6 t grain ha−1, which was significantly greater than the yields of pea and barley in sole cropping. Calculation of land equivalent ratios showed that plant growth factors were used from 25 to 38% more efficiently by the intercrop than by the sole crops. Barley sole crops accumulated 65 kg soil N ha−1 in aboveground plant parts, which was similar to 73 kg soil N ha−1 in the pea–barley intercrop and significantly greater than 15 kg soil N ha−1 in the pea sole crop. The weeds accumulated 57 kg soil N ha−1 in aboveground plant parts during the growing season in the pea sole crops. Intercropped barley accumulated 71 kg N ha−1. Pea relied on N2 fixation with 90–95% of aboveground N accumulation derived from N2 fixation independent of cropping system. Pea grown in intercrop with barley instead of sole crop had greater competitive ability towards weeds and soil inorganic N was consequently used for barley grain production instead of weed biomass. There was no indication of a greater inorganic N content after pea compared to barley or pea–barley. However, 46 days after emergence there was about 30 kg N ha−1 inorganic N more under the pea sole crop than under the other two crops. Such greater inorganic N levels during early growth phases was assumed to induce aggressive weed populations and interspecific competition. Pea–barley intercropping seems to be a promising practice of protein production in cropping systems with high weed pressures and low levels of available N.
Article
Biological nitrogen (N2) fixation is an important aspect of sustainable and environmentally friendly food production and long-term crop productivity. The amount of N2 fixed is primarily controlled by four principal factors: (1) the effectiveness of the rhizobia–host plant symbiosis, (2) the strength of the sink, i.e., the ability of the host plant to accumulate N, (3) the amount of available soil N and (4) environmental constraints to N2 fixation. Much of the N fixed by grain legumes is removed at harvest, the remainder becomes available to subsequent crops following mineralization, may be incorporated into the soil organic matter, or as with fertilizer N, may be lost from the cropping system.This paper reviews some of the agronomic management practices that affect N2 fixation by grain legumes, asking whether grain legumes can provide an overall net N benefit to the soil when grown in rotation with other crops. A survey of long-term trends in N2 fixation by selected grain legumes is included, and some possible explanations for the observed stagnation in efforts to increase N2 fixation under field conditions are presented.
Article
Management of cropping systems and conservation of water resources requires a knowledge of crop evapotranspiration (ET). Yet, ET from field-grown crops and the association among yield, ET, and water stress are virtually unknown in the subarctic region of North America. Irrigated and nonirrigated barley (Hordeum vulgare L.) treatments were established in 1989 at Delta Junction and 1990 at Fairbanks, Alaska, to ascertain yield-ET relations and to validate a model which simulates relative yield (relative to potential yield) based on the transpiration (T) to potential transpiration (Tp) ratio. Barley development, soil water content (by neutron attenuation), pan evaporation, precipitation, air temperature, relative humidity, and global radiation were monitored at each location. Regression analysis indicated that grain yield increased 26 kg·ha−1 for every mm of water evapotranspired over a range of 180 to 260 mm in seasonal ET. Modeled and measured available water in the soil profile and relative yield were in good agreement. Based on 9 years of measured barley yield and climate data at Fairbanks, modeled ET ranged from 120 to 250 mm and yield decreased as the modeled transpiration deficit () increased. This study indicated that water stress occurs frequently in the subarctic.
Article
Two field experiments were conducted to investigate effects of soil conditions and crop genotypes on canopy relations and yield responses of two crops (barley and field pea) and a weed (white mustard) sown in trispecific mixtures. Treatments involved variations in nitrogen supply, water supply and pea genotype.Photosynthetic surface area and seed yield of pea were increased by increasing water supply, but were unaffected or diminished by increasing nitrogen supply. ‘Century’ pea produced about four times more surface area than ‘Alaska’ pea. Under irrigated, low-nitrogen conditions, seed yields of the two pea varieties were similar, but under high-nitrogen conditions, seed yield of the smaller variety declined significantly. Under high-nitrogen conditions, the larger ‘Century’ pea constituted a large proportion of the upper levels of the mixed-species canopies, while the smaller ‘Alaska’ pea was overtopped and shaded by mustard.Increasing nitrogen or water supply increased photosynthetic surface area of barley, but most of these increases occurred at canopy levels where only small amountse of photosynthetically active radiation (par; or Qpa) were available. Increasing nitrogen supply had a much stronger positive effect on barley seed yield than did increasing water supply. Use of ‘Century’ pea rather than the smaller ‘Alaska’ pea decreased barley's photosynthetic surface area, access to Qpa, and seed yield; these effects were particularly pronounced under low-nitrogen conditions.In terms of canopy development, Qpa interception, and yield, nitrogen fertilizer benefitted mustard much more than it did either crop species. Averaged across irrigation regimes, pea genotypes, and years, application of N increased mustard biomass by 472%, but increased total crop seed yield only 31%. Increasing water supply had much less effect than nitrogen fertilizer on mustard's production of photosynthetic surface area and biomass. Use of ‘Century’ pea rather than the smaller ‘Alaska’ pea resulted in increased shading and decreased growth of mustard.Results of the experiments indicate that soil conditions, the relative values and desired yields of the different component crops, and the degree of priority placed on weed suppression should all bear on the choice of appropriate crop varieties for intercropping systems. When the snaller ‘ALaska’ pea was used in the intercrop/weed mixtures, a large total amount of crop seed (pea + barley) was produced under high-water, low-nitrogen conditions. Total crop seed yield was greatest, however, when the larger ‘Century’ pea was used in the mixtures and nitrogen fertilizer was applied. Mustard produced very little biomass under the former conditions, but produced a substantial amount of biomass under the latter conditions.
Article
Intercropping systems influence yield variables of the component crops, such as harvest index, hundred seed weight, number of reproductive organs and number of seeds, within each reproductive unit. Two experiments were carried out at each of two sites during 1993 and 1994. The first experiment investigated the effects of seeding soybean or lupin alone or in combination with one of three forages (annual ryegrass, Lolium multiflorum Lam.; perennial ryegrass, Lolium perenne L.; red clover, Trifolium pratense L.) with corn on the yield components of corn, soybean and lupin. The second experiment examined the effects of seeding date (simultaneous with corn or 3 weeks later) and number of rows of large seeded legumes (one or two) seeded between the corn rows. Corn grain yield was generally not affected by any intercrop treatment, although in 1993 some simultaneously seeded treatments resulted in decreased yields. Soybean grain yield was decreased by most treatments, although some simultaneous seedings produced yields similar to soybean monocrops. Lupin grew poorly as an intercrop component, producing little or no grain. Corn harvest index was not affected by any intercrop treatments. Seeding corn and large-seeded legumes simultaneously resulted in decreases in corn hundred seed weights by as much as 6.6 g compared with the monocropped corn. In 1993 (a year with normal precipitation levels), the hundred seed weight and number of seeds per soybean pod were decreased by intercropping, although the harvest index was not affected. In a high precipitation year (1994), the soybean harvest index was decreased by intercropping, but not the seed components. The underseeded forages, annual ryegrass, perennial ryegrass and red clover, had no effect on yields or yield components of the other intercropped species.
Article
Grain legumes, especially peas, could play a key role in organic cropping systems. They could provide nitrogen (N) to the system via N2 fixation and produce grain rich in protein while improving soil N for the succeeding crop. Thus, maximising N2 fixation and optimising grain N production together with N contribution to soil is a challenging issue for organic pea crops. However, pest, disease and weed infestation are less easy to control in organic systems than in conventional systems. Therefore, the effects of weed infestation and pea weevil (Sitona lineatus L.) attacks on N nutrition and N2 fixation of organic pea crops were examined by on-farm monitoring over two years. The magnitude of the net contribution of the crops to the soil N balance in relation to their productivity was also assessed. In many situations, weed infestation together with pea weevil damage severely limited the nitrogen nutrition and grain yield. Percentage of N derived from fixation (%Ndfa) increased with weed biomass because weeds appeared more competitive than peas for soil N. But %Ndfa decreased with pea weevil leaf damage score. The interaction between these two biotic factors affected N yields and the net contribution of the crops to soil N. This latter ranged from −133 kg N ha−1 to 69 kg N ha−1 depending on %Ndfa and nitrogen harvest index (NHI). Optimising both grain N and net balance would require a reduction in root nodule damage by weevil larvae in order to maximise %Ndfa and a reduction in the NHI through the choice of cultivar and/or suitable crop management.
Article
There is a need to standardize the NDF procedure. Procedures have varied because of the use of different amylases in attempts to remove starch interference. The original Bacillus subtilis enzyme Type IIIA (XIA) no longer is available and has been replaced by a less effective enzyme. For fiber work, a new enzyme has received AOAC approval and is rapidly displacing other amylases in analytical work. This enzyme is available from Sigma (Number A3306; Sigma Chemical Co., St. Louis, MO). The original publications for NDF and ADF (43, 53) and the Agricultural Handbook 379 (14) are obsolete and of historical interest only. Up to date procedures should be followed. Triethylene glycol has replaced 2-ethoxyethanol because of reported toxicity. Considerable development in regard to fiber methods has occurred over the past 5 yr because of a redefinition of dietary fiber for man and monogastric animals that includes lignin and all polysaccharides resistant to mammalian digestive enzymes. In addition to NDF, new improved methods for total dietary fiber and nonstarch polysaccharides including pectin and beta-glucans now are available. The latter are also of interest in rumen fermentation. Unlike starch, their fermentations are like that of cellulose but faster and yield no lactic acid. Physical and biological properties of carbohydrate fractions are more important than their intrinsic composition.
Alternative grain and oilseed crops for Interior Alaska
  • C W Knight
Knight, C. W. (1994). Alternative grain and oilseed crops for Interior Alaska. Agric. Exp. Station Bulletin No. 32. University of Alaska, Fairbanks.
Intercropping corn with soybean, lupin, and forages: yield component responses Inoculant formulation and fertilizer nitrogen effects on field pea: Nodulation, N 2 fixation and nitrogen partitioning Intercropped oat and fababean in Alaska: Dry matter production, dinitrogen fixation
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  • B Prithiviraj
  • Q Fe
  • D Cloutier
  • R C Martin
  • D L Smith
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  • G W Clayton
  • W A Rice
  • N Z Lupwayi
  • A M Johnston
  • G P Lafond
  • C A Grant
  • F Walley
Forage and nitrogen yield of barley-pea and oat-pea inter-cops. Agronomy Journal, 90, 79Á84. Carruthers, K., Prithiviraj, B., Fe, Q., Cloutier, D., Martin, R. C., & Smith, D. L. (2000). Intercropping corn with soybean, lupin, and forages: yield component responses. European Journal of Agronomy, 12, 103Á115. Clayton, G. W., Rice, W. A., Lupwayi, N. Z., Johnston, A. M., Lafond, G. P., Grant, C. A., & Walley, F. (2003). Inoculant formulation and fertilizer nitrogen effects on field pea: Nodulation, N 2 fixation and nitrogen partitioning. Canadian Journal of Plant Science, 84, 79Á88. Cochran, L. V. & Schlentner, S. F. (1995). Intercropped oat and fababean in Alaska: Dry matter production, dinitrogen fixation, nitrogen transfer, and nitrogen fertilizer response. Agronomy Journal, 87, 420Á424.
Harvest management effects on yield and quality of small-seeded annual legumes in Western Montana
  • M P Westcott
  • L E Welty
  • M L Knox
  • L S Prestbye
Westcott, M. P., Welty, L. E., Knox, M. L., & Prestbye, L. S. (1991). Harvest management effects on yield and quality of small-seeded annual legumes in Western Montana. Montana Agricultural Research, 8, 18Á21.
Intercropping Á its importance and research needs. Part 1. Competition and yield advantages. Field Crops
  • R W Willey
Willey, R. W. (1979). Intercropping Á its importance and research needs. Part 1. Competition and yield advantages. Field Crops, Abstract, 32, 1Á10. 244 S.H. Begna et al. Downloaded by [Anadolu University] at 16:03 20 December 2014
Temperate intercropping of cereals for forage: a review of the potential for growth and utilization with particular reference to the UK. Grass and Forage Science The biology of Canadian weeds. 32. Chenopodium album L
  • L Anil
  • R H P Park
  • F A Miller
  • H H Janzen
Anil, L., Park, R. H. P., & Miller, F. A. (1998). Temperate intercropping of cereals for forage: a review of the potential for growth and utilization with particular reference to the UK. Grass and Forage Science, 53, 301Á317. Bassett, J. I. & Crompton, C. W. (1978). The biology of Canadian weeds. 32. Chenopodium album L. Canadian Journal of Plant Science, 58, 1061Á1078. Biederbeck, V. O., Bouman, O. T., Looman, J., Slinkard, A. E., Bailey, L. D., Rice, W. A., & Janzen, H. H. (1993).
Crop rotation and intercropping strategies for weed management Weed productivity and composition in sole crops and intercrops of barley and field pea Nutrient requirements of beef cattle
  • M Liebman
  • E Dyck
  • á122 Mohler
  • C L Liebman
Liebman, M. & Dyck, E. (1993). Crop rotation and intercropping strategies for weed management. Ecological Applications, 3, 92Á122. Mohler, C. L. & Liebman, M. (1987). Weed productivity and composition in sole crops and intercrops of barley and field pea. Journal of Applied Ecology, 24, 685Á699. National Research Council (1996). Nutrient requirements of beef cattle. 7th rev. edn. Washington, DC: National Academy Press.
Berseem clover in binary mixtures with oats, triticale or barley for silage and late season grazing
  • S M Ross
  • J R King