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Agriculture in central Tibet: an assessment of climate, farming systems, and strategies to boost production

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Abstract

In the south of the Tibet Autonomous Region of China there is a network of valleys where intensive agriculture is practiced. Although considered highly productive by Tibetans, farm incomes in the region are low, leading to a range of government initiatives to boost grain and fodder production. However, there is limited information available on current farming practices, yields, and likely yield constraints. The present paper uses available data and farmer interviews to describe the agro-climate and current systems of crop and livestock production, and considers possible strategies to boost production. Although winters in Tibet are cold and dry, summer and autumn provide ideal conditions for crop growth. Cropping systems are characterised by heavy tillage, frequent irrigation, high seeding rates and fertiliser applications, some use of herbicides, and little stubble retention or mechanisation. Spring barley and winter wheat are the predominant crops, followed by rapeseed, winter barley, and minor fodder and vegetable crops. Average yields for the main grain crops are around 4.0t/ha for spring barley and 4.5t/ha for winter wheat, significantly lower than should be possible in the environment. Farmers typically keep five or six cattle tethered near the household. Cattle are fed diets based on crop residues but are generally malnourished and rarely produce beyond the needs of the family. It is suggested that research and extension in the areas of crop nutrition, weed control, irrigation, seeding technology, and crop varieties should enable significant increases in grain yield. Increases in cattle production will require increases in the supply of good quality fodder. Cereal/fodder intercrops or double crops sown using no-till seed drills might enable the production of useful amounts of fodder in many areas without jeopardising food grain supply, and allow more crop residues to be retained in fields for improved soil health.

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... The study area (28 • 20 ~31 • 20 N, 89 • 00 ~92 • 35 E) was the Brahmaputra River and its two tributaries in the Tibet Autonomous Region (BRTT) of China, which covers 18 counties (6.65 × 10 4 km 2 ) in the Lhasa, Lhoka, and Shigatse Prefectures (Figure 1). The climate on the plateau is characterized by low temperatures, with average annual temperature varying between 4.7 • C and 8.3 • C. The average annual precipitation varies between 252 to 580 mm and falls mainly between May and September [41]. There is a precipitation gradient that decreases from southeast to northwest and is strongly controlled by topography [42]. ...
... The climate on the plateau is characterized by low temperatures, with average annual temperature varying between 4.7 °C and 8.3 °C. The average annual precipitation varies between 252 to 580 mm and falls mainly between May and September [41]. There is a precipitation gradient that decreases from southeast to northwest and is strongly controlled by topography [42]. ...
... The blue shaded bar showed a discrepancy between croplands and woodlands in September or October. Croplands were in lower greenness and water content with low VIs values during the harvest phase while woodlands were still in higher greenness and water content [9,41]. tation did not exhibit this dramatic variation in phenology during the growing season ( Figure 5). ...
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The Tibetan Plateau (TP), known as “The Roof of World”, has expansive alpine grasslands and is a hotspot for climate change studies. However, cropland expansion and increasing anthropogenic activities have been poorly documented, let alone the effects of agricultural activities on food security and environmental change in the TP. The existing cropland mapping products do not depict the spatiotemporal characteristics of the TP due to low accuracies and inconsistent cropland distribution, which is affected by complicated topography and impedes our understanding of cropland expansion and its associated environmental impacts. One of the biggest challenges of cropland mapping in the TP is the diverse crop phenology across a wide range of elevations. To decrease the classification errors due to elevational differences in crop phenology, we developed two pixel- and phenology-based algorithms to map croplands using Landsat imagery and the Google Earth Engine platform along the Brahmaputra River and its two tributaries (BRTT) in the Tibet Autonomous Region, also known as the granary of TP, in 2015–2019. Our first phenology-based cropland mapping algorithm (PCM1) used different thresholds of land surface water index (LSWI) by considering varied crop phenology along different elevations. The second algorithm (PCM2) further offsets the phenological discrepancy along elevational gradients by considering the length and peak of the growing season. We found that PCM2 had a higher accuracy with fewer images compared with PCM1. The number of images for PCM2 was 279 less than PCM1, and the Matthews correlation coefficient for PCM2 was 0.036 higher than PCM1. We also found that the cropland area in BRTT was estimated to be 1979 ± 52 km2 in the late 2010s. Croplands were mainly distributed in the BRTT basins with elevations of 3800–4000 m asl. Our phenology-based methods were effective for mapping croplands in mountainous areas. The spatially explicit information on cropland area and distribution in the TP aid future research into the effects of cropland expansion on food security and environmental change in the TP.
... Except for the major urban areas (Xigazê, Lhasa, and Nêdong), the river valleys of south-central Tibet are intensively cultivated and produce 55% of Tibet's cereal production . Historically barley Hordeum vulgare of the spring type (planted March-April and harvested August-September) has been the major grain cultivated, and to this day remains Tibet's major food crop, occupying between 50% (Paltridge et al. 2009) and 70% (Zeng et al. 2015) of croplands. Wheat Triticum aestivum is the other major crop and includes both spring wheat (planted March-April and harvested August-September) and winter wheat (planted in October and harvested August-September). ...
... Wheat Triticum aestivum is the other major crop and includes both spring wheat (planted March-April and harvested August-September) and winter wheat (planted in October and harvested August-September). Minor field crops include rapeseed Brassica rapa, B. napus, and B. juncea, field peas Pisum sativum, and tubers (potatoes Solanum tuberosum and turnips Raphanus sativus; Paltridge et al. 2009). Approximately 65% of the cultivated lands are irrigated (Li et al. 2013) and are almost exclusively in bottomlands of river valleys. ...
... Whereas the widespread use of irrigation in autumn and spring are critical to winter wheat production (Paltridge et al. 2009), warmer temperatures on the wintering grounds, especially warmer minimum temperatures, may increase the availability of winter wheat for Bar-headed Goose consumption. In a series of field warming experiments examining winter wheat growth and yield, Zheng et al. (2016) found a significant increase in winter wheat seed germination rate caused by warming. ...
Article
Four of China’s six wintering populations of “grey” geese Anser spp. declined during the last decade. In contrast, the Bar-headed Goose A. indicus wintering population in China’s Tibet Autonomous Region more than doubled. During six surveys in Tibet over a 27-year period (1991/92 to 2017/18 winters) we documented an annual growth rate of 6.8% in the Bar-headed Goose population – an increase from approximately 10,100 to 68,100 birds. We propose that in addition to the cessation of hunting, the population growth of Bar-headed Goose is being driven by changes in agricultural land use patterns in Tibet, the establishment of protected areas on the wintering and breeding grounds, and the impacts of climate change across the Tibetan Plateau. Consistent with this hypothesis, the sown area of winter wheat in Tibet has increased and geese have shifted from primarily feeding in crop stubble to planted winter wheat fields. We also found that the most rapid population growth coincided with a 1998 climate regime shift across the Tibetan Plateau resulting in warmer temperatures, an increase in net precipitation, the appearance of new lakes and changes in the water levels and surface area of historical lakes. We suggest that warmer temperatures and high-quality forage on the south-central Tibet wintering grounds may be enhancing over-winter survival, while on the breeding grounds the expansion of lakes and wet meadows is augmenting breeding and brood-rearing habitat.
... Most studies focused on the impacts of climate change on alpine grassland in the TP Fan et al., 2010;Yu et al., 2010;Shen et al., 2011). However, it is still unclear how warming affects alpine agriculture in the TP (Paltridge et al., 2009). The cropland in the TP is mainly located in the central Tibet Autonomous Region (Tibet for short, hereafter), so-called the drainage basin of the middle reaches of Brahmaputra River and its two Tributaries (BRTT), including Lhasa River and Nyang Qu River in Tibet (Paltridge et al., 2009(Paltridge et al., , 2011b. ...
... However, it is still unclear how warming affects alpine agriculture in the TP (Paltridge et al., 2009). The cropland in the TP is mainly located in the central Tibet Autonomous Region (Tibet for short, hereafter), so-called the drainage basin of the middle reaches of Brahmaputra River and its two Tributaries (BRTT), including Lhasa River and Nyang Qu River in Tibet (Paltridge et al., 2009(Paltridge et al., , 2011b. The area of BRTT is about 6.65 × 10 4 km 2 , only accounting for 5.53% of the total area of Tibet; however, its cropland area (2295.70 km 2 ) accounts for 45% and its cereal production accounts for 55.27% in Tibet. ...
... The area of BRTT is about 6.65 × 10 4 km 2 , only accounting for 5.53% of the total area of Tibet; however, its cropland area (2295.70 km 2 ) accounts for 45% and its cereal production accounts for 55.27% in Tibet. Therefore, BRTT is the most important agricultural production area in Tibet and called "Plateau Granary" (Paltridge et al., 2009(Paltridge et al., , 2011b. Agriculture in BRTT was single cropping system (with seeding in spring or previous winter) in 1980s (TPCSECAS, 1984). ...
Article
Effects of global warming on agriculture have attracted lots of attention; however, agricultural response to climate change has been hardly documented in alpine regions. The Tibetan Plateau (TP) has a low agricultural portion, but it is an increasing minority, which plays an important role in regional food security due to growing population. The region of Brahmaputra River and its two tributaries in Tibet Autonomous Region (BRTT) is the main alpine agricultural area in the TP. Rapid warming has substantially affected agro-climate resources there and altered cropland pattern as well as cropping intensity. In this study, we explored how climate warming affected cropping intensity in past decades in BRTT. The potentially spatial distributions of single and double cropping systems in different decades (1970s, 1980s, 1990s and 2000s) were simulated based on a cropping suitability model, considering climatic, terrain and water factors. The results showed a significant increase of cropping intensity in some regions, in response to climate warming. The area suitable for single cropping increased from 19 110 km2 in 1970s to 19 980 km2 in 2000s, expanding from the downstream valleys of Lhasa River and Nyang Qu River of the tributaries of Brahmaputra to upstream valleys. The area suitable for double cropping gradually increased from 9 km2 in 1970s to 2015 km2 in 2000s, expanding from the lower reaches of Brahmaputra River in Lhoka Prefecture to the upper ones, as well as the Lhasa River tributaries. The upper limit elevation suitable for single cropping rose vertically from 5001 m above sea level (ASL) to 5032 m ASL from 1970s to 2000s, meanwhile that of double cropping rose from 3608 m ASL to 3813 m ASL. Overall, increased cropland area and cropping intensity due to climatic warming could increase food production in BRTT to some extent. Further investigation about potential uncertain effects from warming is still needed for regional agricultural adaption to climate change.
... QTP has undergone a much faster (i.e., about three-times) warming trend (~0.447 • C per decade) than the global average (0.15-0.20 • C per decade) in the past fifty years according to the observations and the climate models [1,14,15]. The growing threats, including accelerated permafrost thawing [16] and glacier melting [7], extended drought [17], the speed-up of biodiversity loss [18], ever-growing human population and activities [19], and increased food insecurity [20], constitute superior challenges to scientists and managers. ...
... However, the agricultural outputs of most QTP farmlands are low because the farmlands are surrounded by rolling mountains and are vulnerable to erosion [54]. To complement the low income from agricultural production, farmers and herdsmen often make earnings from other non-cropping activities such as livestock farming [20,55]. Since 2000, the national environmental protection policies have been ...
... Agricultural land reduction was mainly a result of conservation policies and, to a lesser extent, expansion of urban areas. Different from the flat cultivated land in eastern China, the agriculture in the southeastern QTP can be called "valley agriculture" because most (65%) of the cultivated lands occur in the high-elevation (>2500 m) river valley plains (i.e., Huangshui River, Minjiang River, Dadu River, and Brahmaputra River) [20]. These valleys meet the temperature and the light required for crop growth, as well as the topographical condition for tillage and irrigation. ...
Article
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The Qinghai-Tibet Plateau (QTP) is among the most sensitive ecosystems to changes in global climate and human activities, and quantifying its consequent change in land-cover land-use (LCLU) is vital for assessing the responses and feedbacks of alpine ecosystems to global climate changes. In this study, we first classified annual LCLU maps from 2001–2015 in QTP from MODIS satellite images, then analyzed the patterns of regional hotspots with significant land changes across QTP, and finally, associated these trends in land change with climate forcing and human activities. The pattern of land changes suggested that forests and closed shrublands experienced substantial expansions in the southeastern mountainous region during 2001–2015 with the expansion of massive meadow loss. Agricultural land abandonment and the conversion by conservation policies existed in QTP, and the newly-reclaimed agricultural land partially offset the loss with the resulting net change of −5.1%. Although the urban area only expanded 586 km2, mainly at the expense of agricultural land, its rate of change was the largest (41.2%). Surface water exhibited a large expansion of 5866 km2 (10.2%) in the endorheic basins, while mountain glaciers retreated 8894 km2 (−3.4%) mainly in the southern and southeastern QTP. Warming and the implementation of conservation policies might promote the shrub encroachment into grasslands and forest recovery in the southeastern plateau. While increased precipitation might contribute to the expansion of surface water in the endorheic basins, warming melts the glaciers in the south and southeast and complicates the hydrological service in the region. The substantial changes in land-cover reveal the high sensitivity of QTP to changes in climate and human activities. Rational policies for conservation might mitigate the adverse impacts to maintain essential services provided by the important alpine ecosystems.
... Zhang et al. (2008) surveyed households in eastern Tibet to explore livelihood diversification. Related to this study, Paltridge et al. (2009) undertook a small preliminary survey of agricultural households to build on the previously limited information to provide a broad description of the farming systems for their examination of crop strategies. ...
... Given the dynamic forces that have bought about change within these household systems, however, additional insights can be gained through the modelling of farm households to explore different farming systems and alternate policy, market and technological scenarios. This study draws on information contained in both the Paltridge et al. (2009) and Fan (2007) surveys. The modelling also requires very specific and detailed information on household and farming systems, however, that requires in-depth case studies of farm households to identify and synthesize the many model parameters. ...
... Information was obtained from agronomists and animal production and nutrition scientists from Tibet Agricultural Research Institute (TARI) and Tibet Livestock Research Institute (TLRI) of the Tibet Academy of Agriculture and Animal Sciences as well as overseas scientists involved in collaborative research with these institutes (see, for instance, Wilkins and Piltz, 2008). Information from previous research and surveys such as that in Paltridge et al. (2009) was also drawn upon while general information on feed nutritional contents and energy and protein requirements was drawn from sources such as NRC (2001). However, as Paltridge et al. (2009) noted there is a significant difference between potential and actual crop yields in Tibet while lactation curves, livestock productivity and feed nutritional contents are also region specific. ...
Article
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Purpose The purpose of this paper is to investigate the impact on household and farming systems of government efforts to modernise production, build scale and develop specialisation in the Tibet dairy industry. Design/methodology/approach An overview of policy strategies and industry developments is used to frame detailed micro-level analysis of household and farming systems where impacts on households are explored from both a comparative static and dynamic perspective. Findings Specialisation and intensification improve household returns but elicit major changes in the farming and household systems and engagement with external markets. For instance, scaling up from three to ten improved cows increases returns from farm activities by one-half but shifts households from a state of food self-sufficiency to one where they need to sell two-thirds of their dairy products and buy three-fifths of their livestock feed. Research limitations/implications The diversity among Tibetan farm households and the dynamic changes occurring in farm productivity, product markets and agrarian systems means that the empirical results are used as illustrative rather than definitive. Originality/value Relative to the large attention on the Chinese dairy industry with regard to food safety and industry development, the impacts of dairy specialisation on smallholders especially in western China have been overlooked. The case highlights several issues relevant to agrarian transition and development including changing labour use, risk exposure and engagement with external markets.
... Livelihoods are based heavily on the production of barley (Hordeum vulgare L.), wheat (Triticum aestivum L.) and some livestock products, but with farm size typically <1 ha, food security is low and incomes in rural areas average <$US 2 day −1 (Tashi et al. 2002; TSY 2007). Though progress has recently been made in describing Tibetan farming systems (Paltridge et al. 2009; Tashi et al. 2002), there remains a large knowledge gap with respect to the soils that support Tibetan agriculture and their capacity to maintain the nutritional status of crops. Most of Tibet's agricultural land is associated with the Yalongzangpo River system, which runs from west to east across southern Tibet. ...
... The winters in Tibet are cold and dry, but summer and autumn provide ideal conditions for crop growth, with plentiful sunlight and warmth, reliable rainfall and the potential to irrigate much of the land. Despite winter wheat crops in research trials in Tibet regularly yielding over 8 t ha −1 , and crops in a similar environment in nearby Qinghai Province yielding even more (Sinclair and Bai 1997), farmer yields in Tibet average around 4.5 t ha −1 for winter wheat and 4.3 t ha −1 for barley crops (Paltridge et al. 2009; Sinclair and Bai 1997). ...
Article
Little is known about the soils that support agriculture in Tibet. The aim of this paper is to investigate the physical and chemical properties of Tibet’s agricultural soils, the nutritional status of wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) crops, and the sustainability of current soil management practices. Physical descriptions of Tibet’s agricultural soils were based on soil pits dug at three locations across Tibet’s agricultural zone. Chemical analyses were conducted on soils from seven sites across the zone. Nutritional constraints to agriculture were identified through leaf tissue tests on wheat and barley crops from 23 fields. These results, combined with published information on farm inputs and yields, provided insight into the sustainability of current nutrient practice. Soils were found to be silty or sandy clay loams with alkaline reaction, low organic content and low K and Zn status. Leaf analysis revealed one third to one half of cereal crops were marginal or deficient for K, Zn and Mg. Most farmers export grain and import only nitrogenous and phosphatic fertilizers leading to a nutrient imbalance. A balanced fertilizer program is required to halt nutrient depletion and increase grain production. Reduced tillage and crop residue retention are needed to improve soil health. KeywordsAgriculture–Wheat–Barley–Potassium–Zinc–Magnesium
... In particular, the Three Rivers (Yarlung Tsangpo river, Tibetan river and Nyang Qu river) basin of southern Tibet is an important grain-producing area on the Tibetan plateau ). The rotational forage-crop system is not only an efficient way of producing forages and increasing grain production, but provides a means of protecting and improving soil condition, thereby increasing productivity (Jin 2005;Paltridge et al. 2009). Not only are forage-crop rotations an efficient way of increasing agricultural diversity and production on large-scale farms, but they can equally well be adapted for smaller areas of farmland (Bieba 2006;Sun et al. 2006). ...
Article
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The Tibetan plateau is the source of most of the major rivers of Asia and has a huge impact on the livelihoods of the population, who have for centuries engaged in traditional herding practices. Sustainable management of the plateau is of critical importance not only for maintaining livelihoods but also because of its vital ecological function. The major problem of sustainable development in these grassland-livestock systems is the conflict between forage and livestock production. Despite considerable investment of manpower, material resources and capital over many years, attempts to resolve the problem have not been successful. The magnitude of conflict between forage and livestock is addressed by presenting 19 resolution strategies based on numerous research data. Each of these strategies is evaluated in terms of how it can be implemented, its potential benefits for livestock production, current progress and the requirement for further research. The 19 strategies have been divided into four topic categories, namely; grassland-forage, livestock, economy and market, society and culture, which cover the basic elements of sustainable development in this pastoral region. It is argued that improved planning and implementation of the proposed strategies must be based on the background investigation of natural and social status of the pastoral region. Particular attention needs to be given to genetic resources and technology in order to ensure the successful implementation of these proposals. In addition to expanding the use of 18 currently practiced strategies, the authors propose a further novel strategy of replacing the current intensive form of ecological migration with a model incorporating two semi-permanent settlements. The objective of this novel strategy is to retain the nomadic element of pastoral husbandry while increasing the temporal and spatial scale of rotational stocking to reduce pasture degradation on the Tibetan plateau. It is argued that these proposals should be urgently incorporated into two national plans for the pastoral livestock industry, and the construction of an ecologically safe shelter zone on the Tibetan plateau, while ensuring a sustainable livelihood of its pastoral residents. Ensuring a successful implementation of these strategies in resolving the conflict between grassland and livestock, and promoting sustainable development on the Tibetan plateau, requires willing support at the level of national investment and policy commitment and from the herdsmen.
... Apart from the knowledge gained through their research work, the Tibetan scientists work closely with farmers and so have a lot of local knowledge to place the technical information in context. • Technical and some socio-economic information was drawn from previous studies including work done on associated projects (see, for instance, Paltridge et al. 2009, andPiltz 2008). ...
Article
Full-text available
In its ongoing efforts to identify more socially inclusive forms of development that target households in rural areas of Tibet, the Chinese central government has begun to focus more attention and resources on agricultural modernisation and development. Although agriculture continues to play a pivotal role in rural areas of Tibet, the nature of agriculture and rural society is changing.3 This paper first highlights some of the macro‐level changes that are occurring and some of the underlying drivers behind these changes. It then describes a model used to understand farm household systems at a micro‐level for the main agricultural areas of the Yalong river and its tributaries . The models explore the impact of agricultural innovations and changing agricultural practices on household consumption, resources, and economic returns. Although the model and analysis are still in a preliminary stage, they reveal detailed insights about the role of agriculture in the livelihoods of Tibetan farm households.
... The Tibetan Plateau, also known as the Third Pole, plays an important role in Asian and global hydrological, ecological, and climatic systems. However, crop growth and yields are limited by low and erratic precipitation, strong soil evaporation, and low-temperature stress due to the high altitude, which could be exacerbated by climate change and the increasing population (Piao et al., 2010;Zhang et al., 2013) and threaten local food security and agricultural sustainability (Paltridge et al., 2009). ...
Article
Droughts, intense soil evaporation, and poor soil structure with low water holding capacity and nutrients restrict agricultural production in the Qaidam Basin on the Tibetan Plateau. Excessive chemical fertilizers have been applied to increase the yields of wolfberry (Lycium barbarum L.), a significant economic crop in northwest China, which has further degraded soils. Biomaterial amendments and ridge–furrow mulching are effective measures for increasing soil water availability, crop yields, and water use efficiency (WUE). However, the combined effects of biomaterial amendments and ridge–furrow mulching on soil hydrothermal conditions, crop growth, and yield in this area are unknown. A field study was undertaken in 2018 and 2019 to investigate their combined influences on soil moisture and temperature, crop growth, yield characteristics, and WUE on the Tibetan Plateau. The experiment comprised four treatments: flat planting with film mulching (FM), flat planting with film mulching and biomaterial amendment (FMBA), ridge–furrow planting with film mulching (RM), and ridge–furrow planting with film mulching and biomaterial amendment (RMBA). The biomaterial amendment and ridge–furrow mulching treatments increased soil water content in the 0–120 cm soil layer, especially at 0–60 cm soil depth at early growth stages, compared with FM. Furthermore, the ridge–furrow mulching treatments had significantly higher soil temperatures than the FM treatment at the sprout stage. The RMBA treatment produced favorable soil hydrothermal properties, which significantly increased mean plant height, ground diameter, and root length density (RLD). The RMBA treatment also produced the highest crop yield, WUE, and berry quality in both growing seasons. Compared with FM, the RMBA treatment increased mean yield and WUE by 23.0% and 28.6%, respectively, across the two growing seasons. We conclude that the RMBA treatment is an effective and promising cultivation pattern for alleviating water scarcity and improving soil hydrothermal conditions, yield, and WUE on the Tibetan Plateau.
... Agricultural production and ecosystems throughout the TP are strongly constrained by low temperature due to the high altitude, which causes a short growing season (Piao et al., 2006;Paltridge et al., 2009). An extended growing season can affect agricultural production and ecosystems throughout the TP. ...
Article
Based on daily mean temperature measurements at 54 meteorological stations throughout the Tibetan Plateau (TP) from 1960 to 2009, the trends in the thermal growing season were investigated. The thermal growing season was defined as the period beginning on the last day of the first 6-day period with a daily mean temperature greater than 5 °C after the last spring frost (daily mean temperature <0 °C) and ending on the first day of the first 10-day period with a mean temperature of less than 5 °C. The results showed that during last 50 years, the regional average growing season length presented a significant increasing trend at the rate of 3.29 days/decade. The majority of this change was attributed to an earlier start of the growing season (−1.82 days/decade). Significant increasing trends in the growing season length were mainly observed in the southern valley as well as the southeastern and northern regions of the TP. During the period of 1980–2009, the regional average growing season indices (i.e., the start, end and length of the growing season) showed significant changes due to increasing air temperatures. The variations in the growing season indices throughout the TP during the last 50 years had been strongly correlated with the elevation.
... Zhang et al. (2013b) also indicated that cropland expanded from downstream valleys to upstream valleys. Certain valleys with cold climates and high altitudes are suitable for agriculture and human settlement (Paltridge et al. 2009). These valleys are distributed along the Huangshui River, the Minjiang River, the Dadu River, and the Yalongzangpo River and its tributaries (the Nyachu River and the Lhasa River). ...
Article
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The Tibetan Plateau (TP) has experienced rapid warming since the 1980s. Previous studies, mainly based on theoretical models and remote sensing interpretation at regional scales, have revealed cropland expansion in high-altitude areas on the TP and identified the agro-pastoral transition zone as the major cropland expansion area. However, few studies have investigated whether farmers and herders reclaim cropland and which factors affect their reclamation decisions. This study aimed to investigate the impact of climate change on the decisions of farmers and herders regarding cropland reclamation in the eastern TP, with Zamtang County considered in a case study. By adopting the participatory rural appraisal method, data were collected from interviews with 169 households in Zamtang County, and the determinant factors of cropland reclamation decisions were examined with the assistance of a probit model. The results showed that (1) cropland reclamation increased from agricultural villages and agro-pastoral villages to pastoral villages with increasing altitude under the effects of climate warming and population pressure. Thus, this case study confirmed the findings of previous studies based on theoretical models and remote sensing interpretation. (2) The perception of changes in precipitation and spring frost, borrowed money, and government subsidies imposed significant negative effects on the reclamation decisions of farmers and herders. The income obtained from gathering Cordyceps fungi, distance from residence to town, and number of plots attained significant positive correlations with reclamation decisions. This study provides a reference for local governments regarding the implementation of measures to promote the livelihood transition of farmers and herders, which could help relieve population pressure and reduce the ecological risks related to cropland reclamation.
... Low and erratic precipitation and serious soil degradation severely restrict agricultural productivity on the Tibetan Plateau . Drought stress significantly aggravates soil water deficit, causes soil desiccation, and limits crop growth, thereby reducing wolfberry yields and WUE in this area (Paltridge et al., 2009;Tang et al., 2020). Soil amendments can increase soil water holding capacity and rainwater infiltration, reduce soil evaporation, and thus improve SWS throughout the growing season (Busscher et al., 2007;Celik et al., 2010). ...
Article
Water scarcity and low soil fertility severely constrain crop growth and sustainable agricultural productivity on the Tibetan Plateau. Organic amendments and ridge–furrow mulching system (RFMS) are widely used to improve soil moisture, soil structure, and crop production in arid and semi-arid areas. However, their combined effects on soil physicochemical properties and economic benefits of wolfberry (Lycium barbarum L.) on the Tibetan Plateau remain unclear. A two-year field experiment was undertaken to evaluate the combined effects of organic amendments and RFMS on soil water, soil structure, soil saturated hydraulic conductivity, soil organic carbon (SOC), total nitrogen (TN), and economic benefits on wolfberry. Four cultivation practices were established: traditional flat plot with mulching (FP), traditional flat plot with mulching and organic amendment (FPOA), ridge–furrow planting with mulching (RF), and ridge–furrow planting with mulching and organic amendment (RFOA). The organic amendment and RFMS treatments had higher soil water storage (SWS) and soil desiccation index (SDI) than the FP treatment in both growing seasons, especially at 20–60 cm soil depth. In addition, organic amendment significantly decreased soil bulk density by 6.4% and increased soil saturated hydraulic conductivity by 16.8% in the 0–60 cm soil layer, respectively, and improved the proportion of larger soil aggregates (0.02–2 mm) by 10.8% in the 0–40 cm soil layer. Furthermore, the RFOA treatment significantly improved SOC and TN contents at 0–60 cm soil depth by 47.7% and 19.4%, respectively, relative to FP. The measured soil properties were highly correlated with wolfberry yield and water use efficiency over 2 years. In particular, the RFOA treatment had higher crop yield and economic benefit than the other treatments due to the more favorable soil environment. Therefore, the RFOA treatment could be a sustainable and efficient cultivation practice for alleviating drought stress, improving soil properties, and increasing economic benefit on the Tibetan Plateau.
... Barley (Hordeum vulgare L.), wheat (Triticum aestivum L.), pea (Pisum sativum L.), and rape (Brassica campestris L.) are the main cash crops. Farm size is generally less than 1 ha, and historically, crop yields have been low (4.5 t/ha for winter wheat and 4.3 t/ha for barley) and incomes in rural areas average <2 USD per day (Sinclair and Bai, 1997;Tashi et al., 2002;TSY, 2007;Paltridge et al., 2009). In recent years, agrochemicals have been used increasingly to improve crop yields and hence economic benefit. ...
Article
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Home courtyard agriculture is an important model of agricultural production on the Tibetan plateau. Because of the sensitive and fragile plateau environment, it needs to have optimal performance characteristics, including high sustainability, low environmental pressure, and high economic benefit. Emergy analysis is a promising tool for evaluation of the environmental-economic performance of these production systems. In this study, emergy analysis was used to evaluate three courtyard agricultural production models: Raising Geese in Corn Fields (RGICF), Conventional Corn Planting (CCP), and Pea-Wheat Rotation (PWR). The results showed that the RGICF model produced greater economic benefits, and had higher sustainability, lower environmental pressure, and higher product safety than the CCP and PWR models. The emergy yield ratio (EYR) and emergy self-support ratio (ESR) of RGICF were 0.66 and 0.11, respectively, lower than those of the CCP production model, and 0.99 and 0.08, respectively, lower than those of the PWR production model. The impact of RGICF (1.45) on the environment was lower than that of CCP (2.26) and PWR (2.46). The emergy sustainable indices (ESIs) of RGICF were 1.07 and 1.02 times higher than those of CCP and PWR, respectively. With regard to the emergy index of product safety (EIPS), RGICF had a higher safety index than those of CCP and PWR. Overall, our results suggest that the RGICF model is advantageous and provides higher environmental benefits than the CCP and PWR systems. © 2016, Zhejiang University and Springer-Verlag Berlin Heidelberg.
... The projects were conducted in collaboration with the Tibetan Academy of Agricultural and Animal Sciences. For further information seePaltridge et al (2009), McNeil et al (2014 andSpiegel and Costa (2014).2. The components form a DPSIR framework that is commonly applied to ecological and social systems (see for exampleFisher et al 2013Fisher et al : 1102Rapport and Friend 1979;Rounsevell et al (2010).3. ...
Article
With small land sizes, precarious food balances, and a changing institutional landscape, farmers in Central Tibet have had to be resilient and adaptive in their livelihood strategies. Rural Tibetans retain a base in semi-subsistence agriculture from which to pursue other major opportunities that have arisen in the 2000s, including off-farm work and caterpillar fungus collection. As reported in this paper, farmers have been given a further boost in recent years through buoyant food markets, and after decades of neglect, increased policy attention to agriculture. This has increased household wealth and reduced vulnerability, but with very low surpluses has had a limited effect on cash income, the vast majority of which must still be sourced off-farm. Thus, semi-subsistence agriculture provides a 'pathway out of poverty' including into the non-farm sector, but the transition will not be linear and will be influenced by a complex combination of forces. The paper documents the way that these forces have played out at the household level in the case study township of Duopozhang in Shannan Prefecture between 2010 and 2015. Analysis is based on an agricultural-economicbiophysical household model populated by detailed household surveys, and contextualized and cross-verified with detailed primary and secondary data at township up to autonomous region levels. This may shed light on recent developments in agricultural areas of Central Tibet that are not easily accessible or widely reported.
Article
Powerful forces of agrarian change are at work in western China while the government has stepped up efforts to “modernize” agriculture. Major components of the modernization process are to disseminate improved crop and livestock breeds and adjust changing agricultural structures including a shift from staple food crops to more specialized crop-livestock systems. This paper explores the changing role of agriculture and the impacts of new agricultural structures on household livelihoods through a detailed model of farm households. The model aids understanding of the complex dynamics and choices faced by farm households that consume much of their own food production but who are under great pressure to specialize and engage in more commercial activities both on- and off-farm. The model draws on detailed information and case studies in Tibet, a region that reflects the marginal productivity, ethnic diversity, rudimentary market systems and development challenges of much of western China. The model results demonstrate that even in the context of agrarian change, agriculture continues to play a significant role in the livelihoods of these Tibetan farm households. They also highlight how mooted specialization paths, despite significantly increasing household returns, fundamentally change the nature of these farm and household systems and risks faced by these households. The detailed modelling enables identification of tight labour constraints, feed gaps and other changes to farm and household systems brought about by the specialization. Such information is crucial in guiding refinements to marketing systems and institutional and policy settings needed to strengthen and smooth out the process of agrarian transition in western China.
Article
Smallholder livelihoods in agricultural areas in Tibet Autonomous Region, China (Tibet for short) have traditionally been based on subsistence mixed crop-livestock systems. Like many parts of China and the developing world, rural Tibet is undergoing rapid change in agricultural development, boosted by links with the off-farm sector. However, the agricultural transition process in Tibet has not been linear, is affected by policies particular to the region, and varies significantly for different categories of rural actors. This paper analyses heterogeneity of household types in agricultural areas of southern Tibet and how household structures and characteristics result in different agricultural development pathways. Data is drawn from a stratified random survey of 144 households in three townships in southern Tibet and analysed through three methods: cluster analysis, bio-economic modelling, and analysis of household perceptions and attitudes to change. The analysis allows for the identification of three key household types — semi-subsistence, pluriactive and semi-commercial — organised along a continuum of intensification, commercialisation, specialisation and productivity. The study demonstrates the diversity of household farming systems in Tibet which in turn highlights the need for disaggregated analysis and tailored development policies and strategies. However, the analysis also reveals commonalities in development paths between groups, where all farm types are more interested in pursuing income and livelihood goals through an increase in productivity than through an increase in scale. Farmers in all systems choose to retain agriculture as a base from which to pursue livelihood strategies, especially through off-farm activities. Accounting for this household heterogeneity is important on several levels. First, it provides more granular detail on the process of development in rural areas of Tibet that have been very difficult to access in English literature especially in recent years. Second, the characteristics of the case study in agricultural areas of Tibet — especially the mixed agricultural-pastoral systems, high levels of seasonality, heavy state investment and increased integration with the other regions of China — may contribute to the broader agricultural development study. Third, policymakers in the central and local governments may be interested in how the household heterogeneity may affect — or be affected by — policies to increase agricultural productivity, intensify systems, change the composition of crop-livestock systems, promote rural-urban transformation and pursue environmental objectives, especially grassland degradation.
Article
In the river valleys of central Tibet, farming households are active in both crop and livestock production. The emphasis is mostly placed on optimizing grain production for subsistence purposes, with little emphasis on forage production to meet livestock diets. Temperatures and rainfall favor crop growth from April to October and, with crops harvested in July or August, sufficient moisture, heat, and light resources remain unused after forage harvest. Here we report data from crop-forage intercrop experiments that evaluated the role of using vetch (Vicia sativa L.) and lucerne (Medicago sativa L.) established by either broadcast or seeding in inter-row spaces of cereal crops. Broadcasting vetch in early July into maturing winter sown wheat (Triticum aestivum L.) allows useful amounts of vetch forage (3 Mg ha(-1)) produced for little extra work with minimal grain yield penalty. The approach of sowing vetch in the inter-row space of widely spaced winter wheat or barley (Hordeum vulgare L.) was a reliable way of establishing this forage crop. However, grain yield losses (P <= 0.05) of approximately 16, 22, and 37% were associated with the wider row spacing (66, 50, and 33% wheat) when vetch was grown in the inter-row space. Based on land equivalent ratios (LERs) alone, the 33% cereal density was most productive (P <= 0.05). However, improved understanding of forage, dairy products, and grain markets, and of the household economy on typical Tibetan farms, will be required before judgments can be made about whether farmers can profit from such intercropping approaches.
Article
Mulching combined with a ridge-furrow system (MRFS) has been regarded as a suitable management method for alleviating the hydrothermal limitation of crop production in semiarid regions. However, whether this practice can be extended to high altitude alpine agricultural regions remains unclear. In order to evaluate the effectiveness of MRFS in improving soil hydrothermal properties, crop yield and water use efficiency (WUE) in alpine regions, a field experiment was conducted on the Tibetan Plateau (TP) with three treatments including: mulching with ridge-furrowing (MR), mulching with flat planting (MF), and bare soil with flat planting as a control (CK). The results indicated that MR performed best in terms of increasing soil water content within a depth of 10–50 cm after irrigation and precipitation at the sprout stage, and in maintaining significantly higher (P < 0.05) soil water storage (SWS) in the 50–110 cm soil layer throughout the whole growth period. Thermal performance in the 20 cm soil depth was also best in MR, with an average temperature increase of 1.1 °C compared to CK. Evaporation was significantly lower (P < 0.05) in MR compared with CK, although the highest evapotranspiration rate was observed in MR. Higher values for plant height, ground diameter, leaf area index (LAI) and fine root length density (FRLD) were found in MR. In comparison with CK, yield was 16 % higher, WUE was improved by 3 % and benefit was improved by 11.7 %. These results suggested that MR represents an efficient planting pattern for improving soil hydrothermal properties and crop yield on the TP.
Article
Expanding livestock production is widely promoted as a way of improving livelihoods of smallholder farmers. However the rudimentary, insular and relatively small size of markets in which many smallholders operate means that rapid livestock industry expansion can have an adverse impact on prices and livelihoods. The link between market integration, livestock industry development and smallholder livelihoods is examined in the case of ruminant livestock industry expansion in Tibet. The analysis finds some transmission between Chinese and Tibetan sheepmeat prices and that this integration with the broader Chinese market and its favourable medium term outlook is crucial to any livestock industry expansion given the current low margins for sheep for Tibetan farmers. While Tibet milk prices exceed eastern China prices, and evidence of transmission is less pronounced, the outcome for smallholder Tibetan dairy farmers in doubling their cow numbers is better in an integrated market than in an insular market. Thus the analysis highlights the importance for ruminant livestock industry expansion in Tibet of integration with broader Chinese markets while also highlighting the need to consider market integration when assessing livestock industry development strategies for smallholder farmers. [EconLit Citations: Q12, Q13]
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The chapter traces the life and livelihood of the people along the Yarlung Tsangpo-Siang-Brahmaputra-Jamuna River basin.
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This report on the Yarlung-Tsangpo-Siang-Brahmaputra-Jamuna River Basin, is a first attempt at documenting the Brahmaputra as a one river system and presenting a multi-layered, holistic perspective of the entire river basin from the perspectives of the four riparian countries. The genesis of the report is the stakeholders from the riparian countries themselves, who highlighted the need for one comprehensive, fact-based document that provides information on the various aspects of the entire river basin and that comprehensively captures the viewpoints of those from all riparian countries. It was felt that a document of this type would be important for supporting the dialogue process and policy discussions on cooperative river basin management. It is natural to expect that such a document should be co-written by various stakeholders across the basin, along with other international experts. The authors are pleased that the report includes contributions from over ninety authors, which is a powerful expression of cooperation in and of itself. The report consolidates the existing wealth of knowledge and information on the river system. At its heart, however, are the riparian’s perspectives and insights that reflect how the river is deeply embedded in the cultures and the lives of the people living within it. The report portrays the inextricable interlinkages between those living in the countries that share the river system: even though they are divided by international borders, they are tightly connected through the basin’s water resources.
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A long-term rotation experiment was established in 2001 to compare conservation tillage techniques with conventional tillage in a semi-arid environment in the western Loess Plateau of China. We examined resource use efficiencies and crop productivity in a spring wheat (Triticum aestivum L.)–field pea (Pisum arvense L.) rotation. The experimental design included a factorial combination of tillage with different ground covers (complete stubble removal, stubble retained and plastic film mulch). Results showed that there was more soil water in 0–30 cm at sowing under the no-till with stubble retained treatment than the conventional tillage with stubble removed treatment for both field pea (60 mm vs. 55 mm) and spring wheat (60 mm vs. 53 mm). The fallow rainfall efficiency was up to 18% on the no-till with stubble retained treatment compared to only 8% for the conventional tillage with stubble removed treatment. The water use efficiency was the highest in the no-till with stubble retained treatment for both field pea (10.2 kg/ha mm) and spring wheat (8.0 kg/ha mm), but the lowest on the no-till with stubble removed treatment for both crops (8.4 kg/ha mm vs. 6.9 kg/ha mm). Spring wheat also had the highest nitrogen use efficiency on the no-till with stubble retained treatment (24.5%) and the lowest on the no-till with stubble removed treatment (15.5%). As a result, grain yields were the highest under no-till with stubble retained treatment, but the lowest under no-till with no ground cover treatment for both spring wheat (2.4 t/ha vs. 1.9 t/ha) and field pea (1.8 t/ha vs. 1.4 t/ha). The important finding from this study is that conservation tillage has to be adopted as a system, combining both no-tillage and retention of crop residues. Adoption of a no-till system with stubble removal will result in reductions in grain yields and a combination of soil degradation and erosion. Plastic film mulch increased crop yields in the short-term compared with the conventional tillage practice. However, use of non-biodegradable plastic film creates a disposal problem and contamination risk for soil and water resources. It was concluded that no-till with stubble retained treatment was the best option in terms of higher and more efficient use of water and nutrient resources and would result in increased crop productivity and sustainability for the semi-arid region in the Loess Plateau. The prospects for adoption of conservation tillage under local conditions were also discussed.
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An analysis of the dynamics of green area index (GAI), dry matter (DM), relative growth rate (RGR) and crop growth rate (CGR) based on growing degree days (GDD) is presented for a historical series of wheats commercially released in Western Australia. Relative to the old cultivars, modern wheats were characterized by a greater RGR during the vegetative phase. This was achieved at a lower initial GAI, which persisted as the season progressed and was associated with a higher CGR at anthesis and greater grain yield at the end of the season. In the old cultivars, a greater GAI during the mid season declined rapidly as temperatures and soil moisture stress increased in spring, resulting in a lower GAI at anthesis. Together with lower CGR at anthesis this resulted in less dry matter and grain yield at final harvest. The higher grain yield of modern wheat cultivars was achieved with a high RGR during the vegetative phase and greater CGR from ear emergence to harvest.
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A field experiment was carried out at Lumle Agricultural Research Centre (LARC) farm, Nepal, during the winter seasons of 1992/93 and 1993/94 in order to study the profitability of intercropping wheat ( Triticum aestivum L.) with tori ( Brassica campestris var. toria ) and pea ( Pisum sativum L.). A sole crop of wheat planted at 120 kg seed ha ⁻¹ was compared with sole crops of tori and of pea planted at 8 kg ha ⁻¹ and 60 kg seed ha ⁻¹ , respectively, wheat+tori mixed-intercropped at 120[ratio ]6, 120[ratio ]4 and 120[ratio ]2 kg seed ha ⁻¹ and wheat+pea at 120[ratio ]45, 120[ratio ]30 and 120[ratio ]15 kg seed ha ⁻¹ . Results over the two seasons showed that the intercropping of wheat+pea was profitable in terms of overall grain yield, land advantage, monetary advantage, economic return and meeting the dietary requirements of the subsistence farmers, although the sole crop of pea gave the highest net return. Mixing pea with wheat did not reduce wheat yields in either year except when pea was sown at 45 kg seed ha ⁻¹ , which reduced wheat yield significantly in the first season. For wheat+pea intercropping, sowing pea at 30–45 kg ha ⁻¹ was the most profitable. The wheat+tori intercrop did not perform as well and was not as profitable as either sole crop. Intercropping of tori had a negative effect on wheat yield at all seed rates in the first year.
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Conservation agriculture (CA), defined as minimal soil disturbance (no-till) and permanent soil cover (mulch) combined with rotations, is a more sustainable cultivation system for the future than those presently practised. The present paper first introduces the reasons for tillage in agriculture and discusses how this age-old agricultural practice is responsible for the degradation of natural resources and soils. The paper goes on to introduce conservation tillage (CT), a minimum tillage and surface mulch practice that was developed in response to the severe wind erosion caused by mouldboard tillage of grasslands and referred to as the American dust bowl of the 1930s. CT is then compared with CA, a suggested improvement on CT, where no-till, mulch, and rotations significantly improve soil properties (physical, biological, and chemical) and other biotic factors, enabling more efficient use of natural resources. CA can improve agriculture through improvement in water infiltration and reducing erosion, improving soil surface aggregates, reducing compaction through promotion of biological tillage, increasing surface soil organic matter and carbon content, moderating soil temperatures, and suppressing weeds. CA also helps reduce costs of production, saves time, increases yield through more timely planting, reduces diseases and pests through stimulation of biological diversity, and reduces greenhouse gas emissions. Availability of suitable equipment is a major constraint to successful CA, but advances in design and manufacture of seed drills by local manufacturers are enabling farmers to experiment and accept this technology in many parts of the world. Estimates of farmer adoption of CA are close to 100 million ha in 2005, indicating that farmers are convinced of the benefits of this technology. The paper concludes that agriculture in the next decade will have to produce more food, sustainably, from less land through more efficient use of natural resources and with minimal impact on the environment in order to meet growing population demands. This will be a significant challenge for agricultural scientists, extension personnel, and farmers. Promoting and adopting CA management systems can help meet this complex goal.
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Experiments were conducted during the winter seasons of 1992–93 and 1993–94 at the Lumle Agricultural Research Centre and its off-station research site at Lopre in Nepal to study the agronomic performance and profitability of barley (Hordeum vulgare) and peas (Pisum sativum) mixed intercropping (that is, without any row arrangement) in the subsistence farming systems of the Nepalese hills. Sole crops of barley (cv. Bonus and Local) at 100kg seed ha−1 were compared with a pure stand of peas (cv. Tikot Local) sown at 60kg seed ha−1 and with peas intercropped with both varieties of barley at 100:40 or 100:20 kg seed ha−1. Results across two locations for two seasons showed that the barley+peas intercropping was advantageous in terms of overall grain yield, land equivalent ratio (LER), monetary advantage, economic return and dietary provision in the subsistence farming system. It also provided yield stability under adverse climatic conditions. Barley genotypes differed in their suitability for intercropping with peas. The yield of Local barley was reduced when peas were intercropped with it at both seed rates but this was not so with Bonus. The most appropriate combinations to realize the maximum advantage from intercropping were Bonus barley+peas at 100:20 kg seed ha−1 and Local barley+peas at 100:40 kg seeds ha−1. A combination of Bonus barley and peas at 100:20 kg seed ha−1 enabled farmers to harvest an additional 400 kg grains ha−1 from peas without significantly reducing the grain yield of barley. The study also verified through formal experimentation that the traditional practice of mixing barley and peas is advantageous.
Article
This article reports on a multi-year study of the impact of China's reform policies since the early 1980s on rural change in the Tibet Autonomous Region. The study was conducted with 780 households in 13 villages, using qualitative and quantitative methods.
Article
Rural Tibet is in the throes of a major paradigm shift from a predominately subsistence agricultural economy to a new mixed economy in which non-farm income plays a dominant role. This paper examines this change, comparing longitudinal data collected through direct fieldwork in rural Tibet in 1997-98 and 2006-07.
Article
This article reports on a multi-year study of the impact of China's reform policies since the early 1980s on rural change in the Tibet Autonomous Region. The study was conducted with 780 households in 13 villages, using qualitative and quantitative methods.
Article
After 20 years of central government efforts that include generous state subsidies, the Tibet Autonomous Region remains China's poorest administrative unit. Growth rates over the past decade have exceeded the national average, while the average Tibetan is better fed and clothed than in the past. However, development has been extensive, resulting from higher subsidies, rather than intensive. Economic rates of return are low and dropping, raising fears that the TAR is becoming more dependent on external aid. There are also questions about the distribution of benefits between both Han versus Tibetans and urban versus rural dwellers; the impact of development projects on the environment; and their deleterious effects on traditional Tibetan culture.
Article
Spring barley (Hordeum vulgare L.) is well adapted to the cool and short growing season of interior Alaska but little is known about thermal requirements for development and maturation of barley at such latitudes. Air temperature and barley development were monitored over the course of six growing seasons at Fairbanks (65°N) and Delta Junction (64°N), Alaska. These data were used to assess the base temperature (Tb) in the linear, thermal-unit model using the least variable, x-intercept, and regression coefficient methods. These methods indicated a range in Tb from 0°C to 1.5°C. At a Tb of 0°C, barley required nearly 1100°C d to mature. The phyllochron differed between early and late sowings and averaged 75°C d leaf−1. Sowing date appeared to influence the phyllochron during early vegetative growth due to differences in daylength as well as temperature.
Article
Natural systems agriculture is based on an understanding that natural systems are self-sustaining due to regulatory mechanisms and processes that help to ensure the long-term maintenance of the ecosystem. An agroecosystem modeled after nature should encompass greater stability and biodiversity at all levels of organization than an agroecosystem based on conventional agricultural practices. The main objective of this study was to determine whether agroecosystems modeled after nature exhibit advantages over conventional agroecosystems. Five treatments were examined: winter wheat (Triticum aestivum L.) monoculture, alfalfa (Medicago sativa L.) monoculture, strip-cropped alfalfa and wheat, and two alfalfa–wheat intercrops (one no-till and one conservation-till). Indicators of ecosystem function studied included primary productivity, soil fertility, plant nitrogen (N) concentration, and abundances of arthropod pests and predators. No fertilizers or pesticides were used prior to or during this investigation. Monoculture, strip-crop and conservation-till treatments produced significantly higher yields than no-till intercropped alfalfa and wheat. Although yields from the no-till intercrop were low, wheat protein values were comparable to other treatments. Soil N concentrations tended to be high in treatments containing alfalfa. Insect pests preferred alfalfa and were, therefore, often more abundant in treatments containing high percentages of alfalfa, as were predators such as spiders. Researching alternatives to monoculture agroecosystems, such as the intercrop systems in this study, may provide us insight into a true natural systems agriculture.
Article
Gansu Province in north western China contains a large portion of China's rural poor. Within this province we compared extant farming systems in lower and higher rainfall areas of the Loess Plateau. The farming systems were dominated by subsistence winter wheat production in the higher rainfall more productive area (Qingyang), and subsistence spring wheat in the lower rainfall less productive area (Dingxi). Once household grain production is satisfied, remaining land is allocated to cash crop and livestock enterprises. Similar farm sizes (ca. 1 ha) in both areas meant that farmers in the more productive Qingyang area were easily able to meet household food needs and produce more cash income from sale of produce. They have reinvested this into their farms and are now developing new enterprises, particularly livestock and co-operative trading arrangements. This has allowed many of these farmers to move away from subsistence grain production, such that 72% of household income is now derived from sale of farm produce. However, many farmers in Qingyang indicated a lack of technical agronomic support and limited access to reliable markets as barriers to diversification. In Dingxi, many farmers struggle to grow sufficient grain for household use and generate very little cash income, often insufficient to provide basic needs such as education. Potatoes, pea and oilseeds are the most common cash crops here, but livestock enterprises are poorly developed. In this area only 28% of household income is generated on farm, and young males often leave the farm to work in larger cities, leaving farming decisions to the elderly, women, and children, who are left behind to manage the farm. High illiteracy rates in this group reduce assimilation of new information. Farmers in Dingxi indicated that restricted access to capital, lack of technical agronomic support and little access to trading markets were serious impediments to the development of more profitable enterprises.
Article
Increased land degradation and shortage of forage resources for animal production over-winter have accentuated the need for alternative cropping systems in northeast China. While short frost-free period and cool temperatures are major limitations to cereal grain production in the northern regions of China (45°N, 122°E), crop varieties that are able to produce food and feed in short growing season and tolerant to low temperature may extend the total cropping period. Three hulless oat (Avena sativa L.) lines, Baiyan 9015, Baiyan 9017 and Baiyan 9044, were bred and tested for 3 years (2004–2006) to determine their suitability for summer seeding in a double cropping system. The new lines were sown both in the spring and summer to provide growers with opportunities to harvest two grain-crops in a year. Averaged across 3 years, Baiyan 9044 produced 2.5 and 1.6 Mg ha−1 yr−1 grain yield when sown in spring and summer, respectively. The new lines seeded in 20th or 21st July and harvested in early October allowed utilization of an average of over 1500 growing degree days (GDDs). For grain yield alone, the net income for two oat crops a year was up to 1390 Chinese yuan (RMB) ha−1, more than that of growing a single oat crop in 3 years, or in most cases, equivalent to monocultured corn (Zea mays L.) production, the dominant crop in the region. In addition, an average of 5 Mg ha−1 of oat straw was produced as valuable forage fodder for the livestock industry, which was in great demand for over-wintering animals. Furthermore, in the traditional single small grain cereal cropping system, bare ground after harvest leads to severe water and wind erosions. Our results indicate that the new oat lines could be a potential crop for summer seeding, particularly when spring-seeded crops fail due to abiotic (hail, drought, etc.) or biotic (e.g. insects) stresses. The double cropping system provides growers with a potential opportunity to facilitate the farming strategy of food, cash crops and control soil erosion in the region.
Article
CropSyst is a multi-year, multi-crop, daily time step cropping systems simulation model developed to serve as an analytical tool to study the effect of climate, soils, and management on cropping systems productivity and the environment. CropSyst simulates the soil water and nitrogen budgets, crop growth and development, crop yield, residue production and decomposition, soil erosion by water, and salinity. The development of CropSyst started in the early 1990s, evolving to a suite of programs including a cropping systems simulator (CropSyst), a weather generator (ClimGen), GIS-CropSyst cooperator program (ArcCS), a watershed model (CropSyst Watershed), and several miscellaneous utility programs. CropSyst and associated programs can be downloaded free of charge over the Internet. One key feature of CropSyst is the implementation of a generic crop simulator that enables the simulation of both yearly and multi-year crops and crop rotations via a single set of parameters. Simulations can last a fraction of a year to hundreds of years. The model has been evaluated in many world locations by comparing model estimates to data collected in field experiments. CropSyst has been applied to perform risk and economic analyses of scenarios involving different cropping systems, management options, and soil and climatic conditions. An extensive list of references related to model development, evaluation, and application is provided.
Article
Previously published as an Appendix to the World development report. Incl. users guide, list of acronyms, bibl., index. The Little data book is a pocket edition of WDI
Article
In predicting wheat (Triticum aestivum L.) phenology, logic suggests that basing thermal unit accumulation on near-surface soil temperature should give a better representation of shoot apex thermal unit accumulation than air temperature until internode elongation raises the apex above the soil surface. A study was undertaken to determine if predictions of winter wheat phenology are improved when based on measured near-surface soil temperature rather than air temperature. Air temperature 1.5 m above the soil surface and soil temperature at crown depth (the position of the shoot apex before stem elongation) were collected for 23-site-years across the U.S. Central Great Plains representing a range of cultivars, soils, management practices, and climates. Seven site-years from different sites were randomly selected to calculate the mean thermal units from both seeding and 1 January to specific growth stages based on both air and soil temperature. These means were used to predict occurrence of growth stages for the remaining 16 site-years. In no instance did soil temperature significantly improve prediction of winter wheat phenology. From these results, we conclude that the additional effort and expense of using soil temperature in predicting winter wheat phenology are not justified.
Article
Growing winter cereal grain/forage legume intercrops can provide multiple benefits to cropping systems in the North Central USA. Intercropping red clover (Trifolium pratense L.) with winter cereal grains can provide forage and a green manure crop. Seeding rate recommendations for sole crops may not optimize intercrop system productivity if interactions exist. This study was conducted during the 2002-2003 and 2003-2004 growing seasons to determine optimum cereal grain and red clover forage seeding rates for maximum returns using partial budget analyses. In March, red clover was frost-seeded at 0, 300, 600, 900, 1200, and 1500 seeds m-2 into winter wheat (Triticum aestivum L.) and triticale (X Triticosecale Wittmack) seeded at 100, 200, 300, and 400 seeds m-2 the previous October. Triticale and wheat maximized returns at seeding rates of 300 and 400 seeds m-2. No cereal grain by red clover seeding rate interactions were detected for red clover dry matter production (DM). Red clover plant densities after cereal grain harvest were 10 to 22% of the original seeding rates. Red clover DM production and return was maximized at 3.49 Mg ha-1 with 900 seeds m-2 in 2003 and 6.67 Mg ha-1 with 1200 seeds m-2 in 2004. Winter cereal/red clover intercrops in the North Central USA can maximize return using a cereal grain seeding rate between 300 and 400 seeds m-2 and red clover seeding rates between 900 and 1200 seeds m-2.
Article
Grain yields of over 14 Mg ha−1 were reported in 1978 for spring wheat (Triticum aestivum L.) grown in Northwest China. Understanding the circumstances under which this record yield was achieved may be useful in defining the key factors that lead to high grain yields and in determining the limits to wheat yield. A relatively simple, mechanistic model was used in an effort to simulate the record yield. The model was used as a framework in which various crop traits could be adjusted to match the observed crop growth. The weather that was characterized by cool temperatures and high levels of solar radiation, proved to be especially important in allowing a full-season crop to achieve record yields. Variables defining plant development in the model also had to be set to describe the high yielding cultivar grown in China. Leaf development was defined by the length of a phyllochron, which was set equal to 78 TU (thermal units, base temperature equal to 0°C) based on independent data. The description of grain fill had to be defined to match simulation results with the observations. Two variables, length of the grain-fill period and the grain growth rate, were set in response to the unique traits of this cultivar and the low temperatures during grain development. These simulations led to important suggestions for examining the interaction between cool temperature regimes and developmental traits of wheat cultivars.
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