Long-term effects of crop residues and fertility management on carbon sequestration and agronomic productivity of groundnut–finger millet rotation on an Alfisol in southern India

The data from long-term management and cropping systems experiments are needed to assess changes in soil quality, organic carbon pool, and agronomic sustainability. Thus, a 13-year-old soil fertility management experiment was used to assess the impact of crop residues carbon (C) inputs on SOC stock in a rainfed groundnut (Arachis hypogeae L.)–fingermillet (Eleusine coracana (L.) Gaertn) rotation in semiarid alfisol. The application of farmyard manure (FYM) alone or in a combination with chemical fertilizers contributed to higher amounts of C inputs and subsequently to build up a higher SOC pool. Application of 10?Mg?ha^?1 of FYM and a recommended dose of chemical fertilizer (25:21.8:20.7 and 50:21.8:20.7?kg?N, P, K ha^?1 for groundnut and fingermillet, respectively) increased soil SOC pool by 41.2% to 73.0?Mg?ha^?1 with an increase of 9.3?Mg?ha^?1 over 13 years. Both SOC pool and rates of its sequestration were positively correlated with cumulative C input and sustainable yield index. A minimal input of 1.62?Mg?C?ha^?1?yr^?1 is needed to maintain SOC pool at the antecedent level. Balanced application of NPK fertilizers is needed to reduce and reverse the depletion of SOC pool.     

Yield and income risk-efficiency analysis of alternative systems for rice production in the Guinea Savannah of Northern Ghana

Risk efficiency of rice grain yield and returns to farm operators' household resources generated from an improved short‐duration cover crop fallow system were compared with (traditional) natural bush fallow, and continuous rice‐cropping systems. The improved fallow system involved maintaining Calopogonium mucunoides, seeded into a natural bush fallow for 2 years before planting to rice. With no chemical fertilizer application, which reflects farmers' practice in the area, average grain yield for continuous rice (1,185 kg/ha) and the cropping sequence incorporating a natural bush fallow (1,175 kg/ha) did not differ, but were higher for the improved fallow system (1,304 kg/ha). This suggests that nutrient contribution from the leguminous cover crop made up for critical crop N requirements in the improved fallow. Stochastic dominance of grain yield distributions from the improved fallow system, relative to the other two cropping systems, was more dramatic with no N fertilizer application compared to treatments with 30 kg/ha N. Average returns were highest for the improved fallow system, followed by the natural bush fallow‐cropping system, and then continuous rice, under the no N fertilizer treatment regime. With 30 kg/ha N fertilizer, income risk efficiency was less clear (compared to treatments with no N fertilizer), especially between continuous rice and the improved fallow treatment, because of faster N mineralization effects on continuous rice. In contrast, the improved cover crop fallow system completely dominated the natural bush fallow treatment under both fertilizer regimes. Rice production systems that incorporated the leguminous cover crop fallow were superior to the natural bush fallow system, based on both grain yield and average farm income risk‐efficiency considerations.     

Push—pull technology: a conservation agriculture approach for integrated management of insect pests,weeds and soil health in Africa

Push—pull technology (www.push-pull.net) is based on a novel cropping system developed by the International Centre of Insect Physiology and Ecology, Rothamsted Research (UK) and national partners for integrated pest, weed and soil management in cereal—livestock farming systems. Stemborers are attracted to Napier grass (Pennisetum purpureum), a trap plant (pull), and are repelled from the main cereal crop using a repellent legume intercrop (push), desmodium (Desmodium spp.). Desmodium root exudates effectively control the parasitic striga weed by causing abortive germination. Desmodium also improves soil fertility through nitrogen fixation, natural mulching, improved biomass and control of erosion. Both companion plants provide high value animal fodder, facilitating milk production and diversifying farmers' income sources. The technology is appropriate to smallholder mixed cropping systems in Africa. It effectively addresses major production constraints, increases maize yields from below 1 to 3.5t/ha, and is economical as it is based on locally available plants, not expensive external inputs. Adopted by over 30,000 farmers to date in East Africa, key factors in its further up-scaling include effective technology dissemination, adaptability of companion plants for climate resilience, capacity building and multi-stakeholder collaboration, integration with livestock husbandry, improvement in input accessibility and creation of a supportive policy framework.     

Gliricidia sepium Carbon Inputs and Soil Carbon Pools in a Costa Rican Alley Cropping System

Alternative land management practices, including agroforestry, help to maintain levels of soil organic matter (SOM) and can facilitate soil carbon (C) sequestration for mitigating atmospheric CO₂ emissions. This study quantified C inputs and determined the changes of the soil C pool in a 19-year-old Gliricidia sepium alley cropping system, studied at two fertiliser levels (tree prunings only [? N], and tree prunings plus chicken manure [+ N]), and was compared to a sole crop system. Carbon input from tree prunings ranged from 455 to 457 g C m^{? 2} y^{? 1}, whereas C inputs from crop residues were similar between alley- and sole crops ranging from 121 to 159 g C m^{? 2}y^{? 1}. The soil organic C (SOC) pool in the alley crop was 16–23% higher than the sole crop. In the 19th year of alley farming, SOC was significantly higher (p < 0.05) in the alley crop (3.2%) compared to the sole crop (2.4%), and was also greater compared to that at the time of establishment of the agroforestry system (2.8%). Gross SOC turnover to a 20-cm depth ranged from 12 to 14 years in the + N and ?N alley crops compared to 49 and 50 years in the + N and ?N treatments for the sole crops. Residue stabilisation efficiency in the alley crops was 39% and 55% in + N and ?N treatments respectively.     

矮牵牛快繁技术研究

以重瓣矮牵牛的不同外植体为试验材料，诱导不定芽，产生再生植株；分别用叶片、茎段、茎尖和花蕾作为外植体进行培养，结果表明茎尖最易诱导产生幼苗，出苗率为90％；继代培养基以MS BA2 NAA0．1最有利于不定芽的产生，用于重瓣矮牵牛的快繁生产。     

On-Farm Nutrient Balance Studies in the Dry Zone of Myanmar

On-farm experiments to study soil fertility depletion—one of the biophysical factors limiting crop production—were conducted in six villages of central Myanmar during 1997 to 1999. Systematic socioeconomic surveys and analysis of socioeconomic and crop production factors aided the selection of farmers.

Topsoil mineral nitrogen content at the start of the cropping season was high (10–25 mg N kg^?1). Available phosphorous was around the threshold level for most crops, but exchangeable potassium was low. The predominant continuous cropping system of sole groundnut was on average positive for P (0.24 kg ha^?1 y^?1) and K (7.05 kg ha^?1 y^?1) and negative for N (?32.4 kg ha^?1 y^?1). A negative balance for N in the groundnut/pigeonpea (?58 kg ha^?1 y^?1) and mung bean/pigeonpea (?56 kg ha^?1 y^?1) intercropping systems was noted. The nutrient balances were positive in early sesame—late sesame (29 kg N ha^?1 y^?1, 8 kg P ha^?1 y^?1, 33 kg K ha^?1 y^?1) and early sesame/pigeonpea (8 kg N ha^?1 y^?1, 15 kg P h^?1 y^?1, 44 kg K ha^?1 y^?1) production systems while sole sorghum system resulted in positive balance for N (23.8 kg ha^?1 y^?1) and negative balance for K (?3.8 kg ha^?1 y^?1).     

森林凋落物研究进展

对森林凋落物的概念、凋落物组成、研究方法、影响凋落量的因子进行了阐述,并对凋落物收集器面积、凋落物分解速率、凋落量时空动态等问题进行了综合分析。得出森林凋落物目前的研究进展,阐明目前凋落物研究的动态;总结了当前存在的问题,并对凋落物研究方向进行了展望。     

Feasibility of conservation agriculture in the Amu Darya River Lowlands,Central Asia

Human-driven land degradation threatens economic and environmental sustainability of irrigated agricultural production such as in Central Asia. Many current challenges can be eased by implementing Conservation Agriculture (CA), with however unknown financial consequences under the predominating irrigated conditions. We applied the linear programming to compare costs and benefits of four CA production systems, which are cotton-based rotation systems including (i) cotton-cotton and (ii) cotton-wheat-maize rotations under conventional tillage (CT), as well as (iii) cotton-cover crop-cotton, and (iv) cotton-wheat-maize rotations with mulch cover (crop residue retaining) and both rotations under permanent-bed planting (PB) with minimum tillage. All systems were subjected to six levels of land quality and a series of crop pricing schemes. Data were extracted from empirical research on CA in Uzbekistan, complemented with data on input and output prices from surveys. The findings underpinned the financial advantages of more diversified cropping systems (cotton-wheat-maize) over the crop monoculture (cotton-cotton-based system). Crop cultivation on marginal land was unprofitable under CT. In contrast, crop production under PB could generate profits even on croplands with a lower productivity level considered. It is argued that PB with crop residue retaining and applied in cotton-wheat-maize rotation shows most promise for improving crop yields and income.     

Characterization of urban and peri-urban agroecosystems in three West African cities

Systems of urban and peri-urban agriculture (UPA) take many forms in terms of integration of different activities, production intensities and production orientations. The present study is aimed at a refined characterization of the diversity in terms of production orientation, resource endowments and production strategies of the different types of farm households involved in urban and peri-urban agriculture in three West African cities. A total of 318 UPA households were surveyed using a standardized semi-structured questionnaire in the West African cities Kano (Nigeria), Bobo Dioulasso (Burkina Faso) and Sikasso (Mali). Through categorical principal component analysis and two-step cluster analysis, six distinct household clusters were identified based on resource endowments and the degree of integration of vegetable, field crop and animal production. Three clusters appeared in all three cities; the remaining three were specific for one of the cities each and comprised (i) commercial gardening plus field crop–livestock (cGCL) keeping, (ii) commercial livestock plus subsistence field cropping (cLsC), (iii) commercial gardening plus semi-commercial field cropping (cGscC), (iv) commercial gardening plus semi-commercial livestock (cGscL) keeping, (v) commercial field cropping (cC) and (vi) commercial gardening (cG). Production constraints were similar across the cities, that is, high costs of inputs, water shortages and lack of fertilizers in the garden and field crop production systems, while feeding constraints and animal diseases were the main constraints in livestock production. UPA remains an important economic activity to livelihood strategy for urban and peri-urban farmers. Appropriate policies should be formulated that efficiently target the site-specific constraints for improving the quality and sustainability of UPA production systems.     

Diversity of Mexican diets and agricultural systems and their impact on the land requirements for food

Mexico is a megadiverse country with large agroclimatic diversity and socioeconomic inequality. These two factors result in strong diversity in diets and agricultural systems within the country. In this paper, we assess the impact of Mexican diets and production systems on the per capita land requirements for food. We estimate it for the extremes: from the very basic diet of the poorest share of the population to the affluent diet of the richest share of the population; and for extensive and intensive systems, with irrigation as the indicator of the intensity of the system. We show that the basic diet produced in rainfed systems requires 1620 m²/cap/yr and produced in irrigate systems requires 700 m²/cap/yr. The affluent diet produced in rainfed systems requires 2540 m²/cap/yr and produced in irrigated systems requires 1230 m²/cap/yr. Hence, differences in diets result in a requirement for 80% or 60% more land for an affluent diet; and differences in production systems result in more than twice the amount of land for extensive than for intensive systems. In 2050, it would be possible to feed the entire population with affluent diets only if all the present area of crop land had the productivity of intensive systems. In contrast, it would be possible to feed all people with a basic diet even if all present crop land area had only the productivity of extensive systems.     

基于SPOT/VGT数据的中国北方耕地物候提取研究

耕地物候的空间格局综合反映了作物种植在环境因子及人类活动双重作用下的空间差异性,因此耕地物候识别成为农业遥感应用的热点之一。研究利用SPOT的植被指数产品开展我国北方耕地作物种植制度空间分布的遥感识别并分析耕地种植制度空间分布特征。首先使用非对称高斯函数拟合法对时间序列植被指数进行重构,然后采用多项式和谐波函数拟合数据来确定耕地的生长季个数,最后通过比例阈值法提取耕地的生长季开始期和结束期。在上述过程中结合先验知识引入波峰阈值并通过对NDVI时间序列数据进行"掐头去尾"处理来保证耕地种植制度识别以及物候信息获取的准确性。基于SPOT/VGT数据对我国北方15省的耕地种植制度进行了识别,并在此基础上分别提取了不同生长季的耕地物候信息并分析了其空间格局特征。结果表明,适当引入先验知识有利于正确识别耕地种植制度和准确获取耕地物候信息,2005年我国北方耕地的种植制度以一年一熟为主,一年二熟制主要分布在北纬40°以南的平原地区。其中第一生长季的空间格局差异比第二生长季更加明显,同时生长季结束期分布的时间范围比开始期更为集中。总之我国北方耕地物候的空间格局与种植制度密切相关,受到自然资源和人类活动的共同影响。     

Diversification economies and specialisation efficiencies in a mixed food and coffee smallholder farming system in Papua New Guinea

Smallholder farming systems in Papua New Guinea are characterised by an integrated set of cash cropping and subsistence food cropping activities. In the Highlands provinces, the subsistence food crop sub-system is dominated by sweet potato production. Coffee dominates the cash cropping sub-system, but a limited number of food crops are also grown for cash sale. The dynamics between sub-systems can influence the scope for complementarity between, and technical efficiency of, their operations, especially in light of the seasonality of demand for household labour and management inputs within the farming system. A crucial element of these dynamic processes is diversification into commercial agricultural production, which can influence factor productivity and the efficiency of crop production where smallholders maintain a strong production base in subsistence foods.
In this study we use survey data from households engaged in coffee and food crop production in the Benabena district of Eastern Highlands Province to derive technical efficiency indices for each household over two years. A stochastic input distance function approach is used to establish whether diversification economies exist and whether specialisation in coffee, subsistence food or cash food production significantly influences technical efficiency on the sampled smallholdings.
Diversification economies are weakly evident between subsistence food production and both coffee and cash food production, but diseconomies of diversification are discerned between coffee and cash food production. A number of factors are tested for their effects on technical efficiency. Significant technical efficiency gains are made from diversification among broad cropping enterprises.     

A Participatory Simulation to Facilitate Farmers' Adoption of Livestock Feeding Systems Based on Conservation Agriculture in the Uplands of Northern Vietnam

In the mountain areas of northern Vietnam, extensive husbandry of large-ruminants is limited by the lack of natural forage. Since 2000, the Mountain Agrarian System Program has been concerned with this issue and has evaluated technical alternatives aimed at sustainable integration of crop-livestock systems. One alternative consists of feeding systems for largeruminants based on cropping systems with plant cover. Diffusion of information about the new system is supported by a set of interactive communication tools for use between farmers and researchers. A participatory simulation method was developed that combines a compartmental model of the village territory with five technical innovations. Farmers simulate the adoption of the innovations they choose among food-forage cropping systems in rotation or in association, and urea-treated straw. They evaluate the quantity of forage that can be grown for their herd using the chosen set of techniques.

Simulations revealed farmers' constraints and objectives in adopting sustainable cropping systems on the hillsides while maintaining a small animal husbandry system. The results obtained by each farmer provide a useful basis for discussion about the implementation of innovation. This participatory simulation method could be more widely used to facilitate the diffusion of innovations such as integrating livestock feeding systems with conservation cropping practices.     

A novel approach for assessing the contribution of agricultural systems to the sustainable development of regions with multi-scale indicators: Application to Guadeloupe

The assessment of agriculture at a regional scale is necessary to better guide regional agricultural planning. To improve the contribution of agriculture to sustainable regional development, assessments must take account of the locations and diversity of cropping systems. We have therefore developed a method based on a set of multi-scale indicators to assess the contribution of agriculture to the sustainable development of regions, and its evolution over time. This method can identify: i) sustainability issues, ii) relevant indicators that will provide information on impacts at the field scale, iii) a method to aggregate indicators, iv) data on cropping systems, and v) a database containing spatial units to analyse the whole region. Application of this method to Guadeloupe (2004–2010) enabled the definition of ten issues and 16 indicators, with three procedures to aggregate information from 36 cropping systems allocated to 11,908 fields between 2004 and 2010. Economic, social and environmental sustainability was poor in 2004, with high dependency on subsidies (47.3 M€ yr⁻¹), low agricultural added value (48.5 M€ yr⁻¹), low employment (only 1799 workers), significant risks of crop contamination and pressure on water quality. The total value of subsidies and the risks of river pollution tended to decrease between 2004 and 2010 because of a reduction in intensive banana cropping systems. In parallel, we were able to see that sugar cane, the most widespread crop in Guadeloupe, made only a small contribution to employment and food self-sufficiency during the studied period. The spatial representation revealed that improvements have been seen in southern Guadeloupe due to reductions in banana cultivation. This method was therefore helpful in identifying the most critical agricultural development issues and helping to highlight areas where relevant agricultural land use policies could be formulated.     

Measuring the sustainability and economic viability of tropical farming systems: a model from sub-Saharan Africa

New technologies must be developed in sub-Saharan Africa which are sustainable and economically viable. This paper discusses a methodology for measuring the agricultural sustainability and economic viability of tropical farming systems for new technology evaluation. The approach is based on the concept of interspatial and intertemporal total factor productivity, paying particular attention to valuation of natural resource stock and flows. Agriculture is a sector which utilizes natural resources (e.g. soil nutrients) and the stock and flows of these resources affect the production environment. However, in many cases, the stock of these resources is beyond the control of the farmer and must be accounted for in an agricultural sustainability and economic viability measurement. For example, soil nutrients are removed by crops, erosion or leaching beyond the crop root-zone, or other processes such as volatilization of nitrogen. Agricultural production can also contribute to the stock of some nutrients by leguminous plants such as agroforestry systems. Using a data set available at the International Institute of Tropical Agriculture, we compute the intertemporal and interspatial total factor productivity indices for four cropping systems in southwestern Nigeria using stock of major soil nutrients as the natural resource stock. Results show that the sustainability and economic viability measures are sensitive to changes in the stock and flow of soil nutrients as well as the material inputs and outputs. Where the contribution of natural resource stock and flows are important (such as in the case of alley cropping), the measures provide markedly different results from conventional TFP approaches. The advantage of this approach is that interspatial and intertemporal total factor productivity measures are computed using only price and quantity data, thus eliminating the need for econometric estimation.     

Economic analysis of different options in integrated pest and soil fertility management in maize systems of Western Kenya

The major biotic constraints to the production of maize, the major staple food in Western Kenya, are field pests such as Striga and stem borers, and low soil fertility. To counter these constraints, new cropping systems have been developed, including “push‐pull,” rotations with promiscuous soybean varieties and green manure crops, and imidazolinone resistant‐ (IR‐) maize. To analyze the technical and economic performance of these technologies, both with and without fertilizer, on‐farm researcher‐managed long‐term trials were implemented over six seasons in two sites each in Vihiga and Siaya districts of Western Kenya. The economic results, based on marginal analysis using a multioutput, multiperiod model, show that the new cropping systems with fodder intercropping (push‐pull) or soybean rotations were highly profitable. Push‐pull is more profitable but requires a relatively high initial investment cost. Green manure rotation, IR‐maize, and fertilizer all increased yields, but these investments were generally not justified by their increased revenue. We argue that research on rotation and cropping systems to tackle pest and soil fertility problems in Africa deserve more attention. This will require increased collaboration between agronomists and economists to set up long‐term experiments with new cropping systems to develop proper economic models.     

Farm-level adaptation to climate change in Western Bangladesh: An analysis of adaptation dynamics,profitability and risks

Using long-term district-level climate data and a case study from a drought-prone village in western Bangladesh, this research explored trends in climate change, and analysed farmers’ adaptation dynamics, profitability and risks. This is the first study of its kind for drought-prone areas in Bangladesh.Farmers perceived climate changes included increases in temperature and decreases in rainfall which were as consistent with the trends of Chuadanga climate records. Farmers’ adaptation measures included changes in cropping systems, cropping calendars, crop varieties, agronomic practices, crop diversification and improved animal husbandry. Reducing environmental stress, ensuring self-sufficiency in staple crops (mainly rice) and other crop production practices, and enhancing economic viability of farm enterprises have underpinned these adaptations. Off-farm and non-farm wage employment, temporary migration, self-employment and educating children, constituted the core non-farm adaptation strategies.Emerging cropping systems like maize/cucumber and maize/stem amaranth/rice were economically more viable than the traditional rice/rice and rice/maize systems. Despite some uncertainties, farming was preferred to off-farm work, generating higher returns to labour for all cropping systems. Limited access to stress-tolerant varieties, extension services and affordable agricultural credit, combined with high production costs, variability in crop yields and output prices, are the main barriers to adaptation. Stronger agricultural research and support services, affordable credit, community-focussed farming education and training are critically important for effective adaptation to climate change.     

基于NDVI时序数据的华北地区耕地物候参数时空变化特征

[目的]耕地物候作为农业生态系统的重要特征之一,是进行农作物长势监测与估产、田间管理、农作物合理布局等的重要依据。利用遥感方法提取大区域尺度耕地物候参数和种植制度的时空变化特征,有助于从整体上掌握农业资源的空间分布情况,为农业生产决策和区域粮食安全评价提供服务。[方法]文章基于1999年和2013年的SPOT/VGT NDVI逐旬时间序列数据,采用TIMESAT软件集成的非对称高斯函数拟合法对数据进行平滑重构,通过比例阈值法提取了华北地区耕地物候参数(生长季开始期和结束期),分析其时空分布特征,并依据年内NDVI变化曲线峰值数目来确定耕地的生长季个数,识别耕地种植制度。[结果]华北地区作物生长开始期和结束期都存在明显的空间差异,15年来河北北部、北京、天津等地区,第一季作物返青/出苗期变化不大。而河南南部和中部地区,2013年第二季作物出苗期明显提前,由1999年6月下旬7月上旬,提前至6月上旬。我国华北地区种植制度仍以一年两熟制为主,华北地区北部受热量资源制约,仍旧保持一年一熟制不变。与1999年相比,华北地区2013年两熟制种植面积下降了21.1%,而一熟制种植面积增加了38.7%。[结论]华北地区耕地物候的时空变化与种植制度密切相关,同时也受到自然资源和人类活动的共同影响。     

A Family of Differential Input Demand Systems with Application to Greek Agriculture

This paper develops a family of input demand systems via alternative parametrisations of Theil's differential model. Each member of this family is as flexible as any other locally flexible functional form. More importantly, selection among the competing family members is possible via simple parameter restrictions. The family of differential input demand systems is applied to the agricultural sector in Greece for the period 1961–96. Formal tests suggest that the model with the CBS-type effects dominates the alternative models. Divisia and price elasticities are calculated from the selected model and a decomposition of changes in the demand for inputs into technical change, total input volume, substitution, and residual effects is performed. The empirical results are quite reasonable. Overall, the analysis in this paper indicates that, in certain cases, the differential approach may provide an attractive alternative to the dual approach in modelling production behaviour.     

Strategies for sustainable intensification in East African highlands: labor use and input efficiency

Strategies for poverty alleviation and sustainable natural resource management usually focus on land use options for improving yields. Increasing the returns to critical factors requires possibilities for input substitution. Inadequate timing of input applications or nonavailability of complementary factors can seriously hinder this substitution. Such constraints particularly apply in less‐favored areas where soil organic matter content is too low for enabling efficient nutrient uptake and soil structure limits water infiltration and moisture retention. This article focuses attention on the importance of labor for crop management activities and input applications that enhance input efficiency in highland area cropping systems of Northern Ethiopia. Given the inherent complementarities between labor and nutrient supply during critical phases of the plant growth process, input efficiency strongly depends on labor use. We present a semiparametric bioeconomic modeling approach to analyze the available options for improving input efficiency in agricultural production. Input response equations are used that consider the returns per unit of land and labor as a function of specific combinations of material inputs and management practices. Critical trade‐offs may arise when opportunity costs for labor are considered or when complementary factors appear as binding constraints. The model enables assessment of feasible pathways for enhancing sustainable intensification and poverty alleviation in typical settings of the East African highland region.