[show abstract][hide abstract] ABSTRACT: Black polyethylene (PE) film is used for mulching in processing tomato (Lycopersicon esculentum P. Mill.) in Spain achieving a generally high weed control but causing a serious waste problem. Few herbicides are available for tomato, so that a biodegradable mulching is the desired solution which should provide high yield, high weed control and be economically available. For 3 years, the same field trial was carried out in four areas of Spain using the following mulch materials in processing tomatoes: (1) untreated control, (2) manual weeding, (3) PE, black, 15 μm thick, (4) and (5) two types of biodegradable plastic mulch, black, 15 μm, (6) oxo-degradable plastic mulch, black, 15 μm, (7) paper mulch, black, 85 g m−2, (8) kraft paper mulch, brown, 140 g m−2 and (9) barley straw, 1 kg m−2.. Weed control, yield and economic aspects were analysed. Most frequent weed species were Convolvulus arvensis, Chenopodium album and Amaranthus spp. Here, we showed that despite differences in weed species, soil type and years, weed competition caused a similar yield decrease in all locations. A common regression coefficient could be estimated indicating that weed competition was responsible for a yield decrease of 3.3 to 4.4 t ha−1 for each 10% of efficacy loss. Weed control was high for biodegradable plastics, paper mulches and PE ranging between 80% and 100% for all of them; also, yield was similar for all plastic and paper mulching treatments ranging between 72% and 108% of the yield achieved by PE. Here, we demonstrate that technically viable biodegradable alternatives exist for all four locations. From the economic point of view, PE gave highest benefits, mainly due to its low market price and to high yields despite removal costs, showing that its substitution will depend on prohibition. For locations with low-density weed infestations, manual weeding can be an alternative.
Agronomy for Sustainable Development 08/2013; 32(4). · 3.57 Impact Factor
[show abstract][hide abstract] ABSTRACT: Management practices, geographical gradients and climatic factors are factors explaining weed species composition and richness
in cereal fields from Northern and Central Europe. In the Mediterranean area, the precise factors responsible for weed distribution
are less known due to the lack of data and surveys. The existence of weed survey data of year 1976 in the Zaragoza province
of the Aragón region, Spain, offered us the opportunity to compare present weed species with weed species growing 30years
ago. No detailed comparison of changes in weed species composition in cereal fields in that period of time has been conducted
in the Mediterranean area. Here a survey was conducted in the Aragón region from 2005 to 2007. Weeds were surveyed in 138
winter cereal fields in ten survey areas where winter cereals are the main crops, using the same methodology applied 30years
ago. In the Zaragoza province, 36 fields were chosen in the same municipalities than in the previous survey. Several management,
geographic and climatic variables of each field were recorded and related to weed species with multivariate analysis. Diversity
index were calculated and related to survey area and altitude. Our results show that out of the 175 species only 26 species
were found in more than 10% of the surveyed fields. The main species were Papaver rhoeas, Lolium rigidum, Avena sterilis and Convolvulus arvensis found in more than half of the surveyed fields. L. rigidum was related to dryland, while the other species were found overall. Furthermore, we found that management, geographical and
climatic factors were significantly related to weed species distribution. In particular altitude, survey areas, irrigation
and herbicide use in post-emergence were the most driving factors explaining weed species distribution. Species richness was
higher in survey areas with extensive management practices and increased with altitude excepting a very productive area with
intensive management practices at high altitude where richness was as low as in the irrigated lowlands. The main differences
found between the 1976 and the 2005–2007 surveys were (1) the striking increase of grass weeds, (2) the high decrease of mean
weed species number found in each field declining from 9 to 3 and (3) the frequency decrease of many weed species probably
caused by agriculture intensification in that period of time. The growing importance of other weed species is probably related
to their adaptation to minimum tillage, which is a widespread technique nowadays.
KeywordsBiodiversity–Canonical correspondence analysis–Rare weeds–Weed diversity
Agronomy for Sustainable Development 04/2012; 31(4):675-688. · 3.57 Impact Factor
[show abstract][hide abstract] ABSTRACT: Field poppy, Papaver rhoeas L., is a very common weed in winter cereals in North-Eastern Spain. Its control is becoming difficult due to expanding herbicide
resistance. To control field poppies there are alternative strategies such as non-chemical control that take into account
the weed emergence period. However, there is a lack of knowledge of P. rhoeas emergence patterns in semi-arid conditions. Thus, here we conducted pot experiments on the emergence of P. rhoeas. We aimed to describe the emergence period and to quantify the emergence of a susceptible and of a herbicide-resistant P. rhoeas population at two locations in Catalonia, Spain, from 1998 to 2001 and until 2004 at one of them. Therefore, pots containing
seeds of both populations were established at the two locations and emergence was recorded monthly. We studied the origin
of the population, the sowing location, the effect of cultivation and the sowing year. First, we found that the main emergence
peaks in our experiments occurred in autumn, accounting for between 65.7 and 98.5% of the annual emergence from October to
December, and only little emergence was recorded in spring. This emergence pattern is different from those found in the literature
corresponding to Northern European countries, where in some cases main flushes occur only in autumn, in spring and winter
or only in spring. The emergence was mainly affected by cultivation, but the effect of light stimulus was observed several
months later. As a consequence, cultivation should be done in early autumn, promoting emergence during the whole autumn and
winter so that emerged seedlings can be controlled before sowing a spring crop. Second, most experiments showed that the emergence
was significantly higher in the first autumn than in the following seasons, e.g. 4.1% emergence in the first year and only
2.1, 2.3, 0.5 and 0.6% new emergence at one of the locations for the second, third, fourth and fifth years. Thus, after having
a severe P. rhoeas infestation causing a big seed rain, emergence should be stimulated by autumn cultivation in the following season and seedlings
controlled by trying to deplete the soil seed bank as much as possible. Despite the fact that emergence will be staggered
throughout several years and that there was a significant relationship between rainfall and emergence, so that dry years will
cause a smaller emergence rate of the weed, these findings define a cultural management strategy to reduce P. rhoeas infestations
and to contribute to integrated weed management strategies combining it with other tools.
emergence period–dormancy–cultivation–seed bank–
Agronomy for Sustainable Development 04/2012; 28(2):207-220. · 3.57 Impact Factor
[show abstract][hide abstract] ABSTRACT: Sprinkler irrigation can reduce the irrigation water needed to grow rice. However, most available information on weed control with herbicides is related to flood irrigated rice because this is the main growing method. Field experiments were conducted at Zaragoza (Spain) during two years to study weed control and tolerance of sprinkler irrigated rice to several herbicides. The main weeds were Atriplex prostrata Bouchér ex DC., Cyperus rotundus L., Echinochloa crus-galli (L.) Beauv. and Sonchus oleraceus L. Rice cv Guadiamar was tolerant to preemergence (PRE) application of clomazone at 0.36 kg ha-1 and oxadiazon at 0.5 kg ha–1. PRE application of pendimethalin at 1.32 kg ha–1 combined with clomazone at 0.36 kg ha-1 decreased rice yield. Postemergence (POST) application of bentazon at 1.6 kg ha–1 + MCPA at 0.25 kg ha–1 did not injure rice but POST application of azimsulfuron at 0.025 kg ha–1 produced visual crop injury. Only treatments that controlled grassy weeds since rice was planted and by more than 80% at harvest time lead to acceptable rice yield (> 5,000 kg ha–1). Clomazone applied PRE at 0.36 kg ha–1 provided good control of grassy weeds (> 80%) and the highest rice yield, so it is recommended as a selective and efficacious PRE treatment for weed control of annual weeds in sprinkler irrigated rice. The perennial purple nutsedge was difficult to control at high plant densities (> 150 plants m–2) and the recommended herbicide is azimsulfuron applied at POST at 0.02 kg ha–1.
SPANISH JOURNAL OF AGRICULTURAL RESEARCH 04/2011; 9(2):597-605. · 0.66 Impact Factor
[show abstract][hide abstract] ABSTRACT: Lolium rigidum Gaud. is one of the most common weed species in winter cereals in north-eastern Spain, with populations that have evolved resistance to herbicides becoming more widespread since the mid-1990s. Nine trials on commercial fields with herbicide-resistant L. rigidum were conducted during the cropping seasons 2001-2002 to 2003-2004, testing the efficacy of 20 herbicides and mixtures pre- and post-emergence and as sequential applications. Weed populations chosen had different resistance patterns to chlortoluron, chlorsulfuron, diclofop-methyl and tralkoxydim, representative of the resistance problems faced by farmers.
In pre-emergence, prosulfocarb mixed with trifluralin, chlortoluron or triasulfuron was effective on six populations. In post-emergence, iodosulfuron alone or mixed with mesosulfuron gave the best results but did not control three resistant populations. At Ferran 1, none of the herbicide combinations reached 90% efficacy.
The diverse efficacy patterns of the different populations demonstrate the need for detailed knowledge of the populations before using herbicides. Moreover, the unexpected insufficient efficacy of the new herbicide iodosulfuron prior to its field use shows the need to combine herbicides with other non-chemical weed control methods to control resistant L. rigidum in north-eastern Spain.
Pest Management Science 10/2010; 66(12):1380-8. · 2.59 Impact Factor
[show abstract][hide abstract] ABSTRACT: En Zaragoza (España), durante tres años se condujeron investigaciones de campo utilizando diferentes materiales biodegradables como cubiertas en el cultivo de tomate. El objetivo fue evaluar el control de la maleza con varias cubiertas biodegradables como alternativas a la cubierta de polietileno negro (PE). Los tratamientos fueron con paja de arroz, paja de cebada, residuos de la cosecha del maíz, plantas de Artemisia absinthium L., plástico negro biodegradable, papel de estraza, PE, herbicida, deshierbe manual y con un control sin deshierbe. Las evaluaciones se centraron en la maleza y en rendimiento del cultivo. Un estudio de laboratorio mostró que 1 kg/m2 de cubierta orgánica era suficiente para recubrir el suelo en el caso del arroz, la paja de cebada y los residuos de la cosecha del maíz. En el campo, las especies de maleza más abundantes fueron Cyperus rotundus, Chenopidium album, Portulaca oleracea y Digitaria sanguinalis. Se observó un cambio en la composición de la maleza entre los tratamientos y entre años. La mayoría de las especies de maleza fueron controladas por las cubiertas evaluadas, con excepción de Cyperus rotundus, que fue controlada únicamente con la cubierta de papel. Las otras especies fueron bien controladas por el PE y el plástico biodegradable y también por algunos tratamientos con cubierta orgánica. El mejor control y la menor biomasa de maleza, fueron logrados con la aplicación de papel, seguido por el PE y el plástico biodegradable. La mejor cubierta orgánica fue la paja de arroz y el peor control de maleza fue el que resultó del uso de la Artemisia. El rendimiento de tomate claramente está relacionado con el control de maleza, y este fue mayor cuando se usó el PE, seguido por el papel, el deshierbe manual, el plástico biodegradable y la paja de arroz. El papel, el plástico biodegradable y la paja de arroz son substitutos potenciales para el PE y los herbicidas.
[show abstract][hide abstract] ABSTRACT: The effect of soil mulching polyethylene and some biodegradable alternatives on weed control and tomato (Lycopersicum esculentum L.) growth and yield was evaluated. Eight treatments were established in a completely randomized design with four replications. The mulch treatments were rice harvest residues, maize harvest residues, wood sawdust, Kraft paper and silver-black no degradable polyethylene, untreated, hand weeding and herbicide (rimsulfuron+metribuzin). The effect of treatments on weeds and the development and yield of crop were determined. A difference in weed species was observed between treatments. To 63 days after the treatment the smaller cover of the soil by weeds was herbicide (1.92%), followed by hand weeding (1.50%), polythene (4.58%) and paper (14.67%). The vegetal mulches and the wood sawdust obtained values similar to each other, but smaller than polythene and paper. For the plots with vegetal mulches, weed control was similar among them. However, these results were significantly lower from the polyethylene and paper mulches. The best vegetative growth was obtained by plastic and paper mulches. However, biomass dry matter 45 days after transplanting was lower with polyethylene than the organic mulches. The polyethylene mulch gave the highest tomato yield, followed by paper and maize harvest residues mulches. Results show that paper and vegetal mulches could be excellent biodegradable alternatives for weed control and increasing growth and tomato yields in semiarid tropical regions.
Revista de la Facultad de Agronomia 06/2010; 28:71-90. · 0.13 Impact Factor
[show abstract][hide abstract] ABSTRACT: Torra J, Cirujeda A, Recasens J, Taberner A & Powles SB (2010). PIM (Poppy Integrated Management): a bio-economic decision support model for the management of Papaver rhoeas in rain-fed cropping systems. Weed Research50, 127–139.SummaryA bio-economic model for Papaver rhoeas designed for dry-land cropping systems in Spain was developed. The model included four seed bank layers to simulate seed movement in the soil profile resulting from tillage, with different emergence rates and seed bank mortalities depending on soil cultivation and burial depth. Users of Poppy Integrated Management (PIM) might specify the crop sequence and any feasible combination of 38 different weed management practices (herbicide and non-herbicide options) each year over 10 or 20 years. Weed treatment options included selective herbicides (14), non-selective herbicides (1), non-herbicide treatments (11) and user-defined treatments (1). PIM represented weed and seed bank population dynamics, weed–crop competition, weed treatment impacts, agronomic practices and financial details. The bio-economic model could be used to evaluate weed management scenarios by investigating the implications of different tillage, fallow and cereal rotational sequences and of constraints on herbicide availability. Model validation combined available data from literature with our own data, to show that PIM was sufficiently accurate for predicting P. rhoeas population dynamics. Sensitivity analyses indicated that economics associated with fuel, fertiliser and seed costs, as well as grain yield and price, were primary drivers of management decisions, whereas seedling emergence and initial seed bank size were of secondary importance.
Weed Research 03/2010; 50(2):127 - 139. · 2.05 Impact Factor
[show abstract][hide abstract] ABSTRACT: Corn poppy is the most important broad-leaved weed in winter cereals in southern Europe. It is an increasing problem due to the appearance of herbicide-resistant biotypes. Experiments were conducted in north-eastern Spain with three corn poppy populations to determine the level of resistance to 2,4-D and tribenuron using seed-germination tests. Field experiments were conducted at sites from where the tested populations had been collected to test the effectiveness of various herbicides applied pre-emergence (PRE) or post-emergence (POST) in winter cereals. In the seed-germination tests, two populations were found to be 2,4-D-resistant and one resistant to both 2,4-D and tribenuron. In field trials, the efficacy of 2,4-D at 900 g a.i. ha−1 ranged from 25 to 76% of reduction of plant densities, depending on season and population, indicating that all populations were 2,4-D-resistant in field conditions. Moreover, at 15 g a.i. ha−1 tribenuron, one of the three populations (CU2) was only reduced by 65% in two seasons, indicating also the presence of resistance to tribenuron in this population in addition to 2,4-D. Florasulam at 6.25 g a.i. ha−1 + 2,4-D at 300 g a.i. ha−1 resulted in poor control (75–85%) in CU2 suggesting possible cross-resistance to this triazolopyrimidine. On average, all the other herbicides provided 90–100% control of corn poppy. Only PRE herbicides and the mixture 150 g a.i. ha−1 bromoxynil + 150 g a.i. ha−1 ioxynil + 450 g a.i. ha−1 mecoprop in POST performed consistently well (>90% control). The results of this study indicate that 2,4-D and tribenuron-resistant corn poppy populations in winter cereals can be controlled by application of PRE or POST herbicides with alternative modes of action.
[show abstract][hide abstract] ABSTRACT: Lolium rigidum Gaud. is one of the most common weed species in winter cereals in Northeastern Spain. Herbicide resistance has been growing since the mid 90's and exclusive herbicide use is not enough in many cases, so that it is nec-essary to combine as many control tools as possible. Six field trials have been conducted during the cropping seasons 2001-02, 2002-03 and 2003-04 on winter cereal infested with herbicide resistant L. rigidum in Northeastern Spain testing differ-ent cultural control strategies. Sowing delay was conducted at five fields, mouldboard ploughing at four fields, the combination of sowing delay and ploughing at two fields, increasing the cereal sowing density and combined with sowing delay at one field. Sowing delay was confirmed to have an irregular efficacy depending on the L. rigidum emergence dur-ing the delay period. In the trials, weed emergence was reduced up to 88% in the best case but there was no effect in two cases. Ploughing had a more constant efficacy and reduced weed emergence between 50 and 80% although stoniness impeded in one occasion a correct soil inversion causing a very low efficacy. Increasing the cereal sowing rate did not reduce the weed population. The combination of the different methods did not increase significantly the individual effica-cy, and one method was clearly more effective than the other, depending on the trial. In fields with high L. rigidum densi-ty, these methods are not effective enough and need to be combined with other methods, which are discussed in the text. Additional key words: cereal density, integrated weed management, mouldboard ploughing, sowing delay.
SPANISH JOURNAL OF AGRICULTURAL RESEARCH 01/2009; 7:146-154. · 0.66 Impact Factor
[show abstract][hide abstract] ABSTRACT: Seeds of three Spanish Papaver rhoeas populations (two resistant to both tribenuron-methyl and 2,4-dichlorophenoxyacetic acid and one susceptible to both herbicides) were buried at 2, 8 and 20 cm depth in Lleida (Catalonia, Spain). At various intervals up to 77 months they were exhumed and tested for germination in an agar medium and for viability in a tetrazolium test. A similar annual dormancy cycle was found for each population in 3 years. Maximum germination occurred between September and December. Practically no seeds germinated between February and May. Burial depth influenced the germination cycle in the first 16 months after burial, and higher germination was found to occur in the seeds that were buried at 2 or 8 cm, but no consistent effect was observed thereafter. In a second study, burial depth had no effect on the loss of dormancy of P. rhoeas seeds in the first 2 months after burial. Viability of the buried seeds decreased slowly throughout the 77-month experimental period and, at the end of this period, it was 53, 72 and 61% for seeds buried 2, 8 and 20 cm respectively. No significant differences were observed between the three populations.
Weed Research 07/2006; 46(4):327 - 334. · 2.05 Impact Factor
[show abstract][hide abstract] ABSTRACT: Twelve field trials were conducted in Catalonia (North-Eastern Spain) between 1998 and 2003 on different winter cereal fields highly-infested with Papaver rhoeas L. or, in two cases, with mixed dicotyledoneous weeds. Trials were conducted in semi-arid conditions in order to find out which are the real limitations of harrowing in those circumstances. A tine harrow was used in a single pass as the only weed control method at 4–6 km h and on four occasions again later in post-emergence. Weed size, crop soil cover and climatic conditions were significantly correlated with initial efficacy so that small weeds, low crop soil cover allowing good harrowing and dry conditions enhanced weed control. Despite soil moisture not being significantly correlated with initial efficacy, it was significantly related to other factors like weed size, thus having an indirect influence on initial control. Initial efficacy ranged between 18 and 93% and was not correlated with final weed control at crop elongation, which was highly related to natural weed mortality. Efficacy increases in time were significant in four cases but decreases due to new germination flushes were not significant. Repeating harrowing later in post-emergence does not seem to be generally convenient as efficacy did in fact not decrease but increased only in one out of four cases. The results show how initial efficacy is highly dependent on small weeds, which are at the same time related to dry soils, dry climatic conditions and low crop soil cover. As harrowing was conducted as soon as possible in the trials, the real main limitation was thus climatic, i.e. having dry soils. Later natural weed mortality can increase significantly initial weed control but this did not occur in all cases. Thus, in Mediterranean conditions, harrowing should be conducted as early as possible as wet winter periods can also impede correct timing.
[show abstract][hide abstract] ABSTRACT: A field trial on winter barley, containing a large infestation of a herbicide resistant Papaver rhoeas population, was established in North-eastern Spain during the cropping seasons 1998–99, 1999–00 and 2000–01. After decades of minimum tillage, ploughing was conducted in Winter 1998, Winter 2000 or in both 1998 and 2000 in part of the field as a preventive weed control strategy. Plant density assessments and quantification of the seed bank at the end of 3 years were taken. Less P. rhoeas emerged in the ploughed plots and the effect was still visible 2 years after ploughing. In the twice ploughed plots, emergence was higher than in the once ploughed plots but lower than in the non-ploughed treatment. Harrowing conducted post-emergence as an annual control method in part of the plots caused a remarkable reduction of the weed population in all three years. The effect caused by the harrowing was more important than the ploughing treatments. However, the combination of single ploughing and harrowing induced the lowest weed plant emergence. The depth distribution of P. rhoeas seed was similar for all treatments but there was a higher total seed bank in the twice ploughed plots. Occasional ploughing was found to be an effective method for placing P. rhoeas seeds in non-optimal germination situations. When the initial weed seed bank is very high as in this field trial, the reduction achieved by ploughing is not sufficient and an additional weed control method should be conducted.
[show abstract][hide abstract] ABSTRACT: A qualitative seed-based method useful for the detection of resistance to the herbicide tribenuron-methyl in Papaver rhoeas L. is described. Seeds were germinated on 35 mL of a 1.3% agar medium containing 2 g KNO3 L–1 in 8.5 cm Petri dishes in a growth chamber under 20 μmol s–1 m–2 of fluorescent light. When 0.24 μM tribenuron-methyl or more was added, growth in susceptible plants stopped after the cotyledon stage and they turned chlorotic. The resistant plants continued developing new leaves. The same effect was achieved when 0.2 g gibberellin (GA3) L–1 and 7.68 μM tribenuron-methyl or 0.5 g GA3 L–1 and 61.44 μM tribenuron-methyl were added. Germination percentage rose with gibberellin in the presence or absence of the herbicide. Plants developed rapidly, with only about 14 d needed to finish the test but sometimes root growth was reduced because of the addition of gibberellin. In the absence of gibberellin but in the presence of the herbicide, plants grew more slowly and developed smaller leaves with a 17-d evaluation period requirement. The test was validated with pot experiments in a greenhouse and also with field trials. The best combination was found to be 0.2 g GA3 L–1 and 7.68 μM tribenuron-methyl, assuring homogenous germination and testing of dormant seeds but avoiding root inhibition associated with too much gibberellin.
Weed Research 12/2001; 41(6):523 - 534. · 2.05 Impact Factor
[show abstract][hide abstract] ABSTRACT: Purple nutsedge (Cyperus rotundus L.) is a serious weed capable of piercing polyethylene (PE) plastic mulch used in horticulture. A biodegradable plastic, PE and four different papers were tested for 2 years in fields highly-infested with C. rotundus in Zaragoza (Spain). All four papers were able to withstand all weed species. C. rotundus plants penetrated the biodegradable plastic mulch most, possibly because this material had least resistance to slow perforation. Differences in weed biomass between mulching materials were lower because of small size and weight of C. rotundus. Therefore all mulching treatments had a similar impact on weed biomass reduction 63 days after transplanting; biodegradable plastic had most biomass and papers the least, the differences being significant some years, only. Tomato yield was very similar for all mulching treatments and significantly higher than in the non-mulched plots. No effect of treatment was observed on fruit quality parameters. Commercial paper used as mulch without special additives can satisfactory control C. rotundus in processing tomato provided that climate is appropriate to maintain the paper dry during most of the time. Also the crop needs to cover the soil fast enough before the buried part of the mulch degrades allowing wind to lift and tear the mulch.