The cotton–wheat production system (CWPS) occupies an important place in the agricultural economy of several South Asian countries. The instability of the CWPS has increased particularly during the post-transgenic hybrids phase mainly because of these hybrids calling for intensive crop management being cultivated under all situations, especially in resource-poor conditions leading to violent fluctuations during adverse years and thereby affecting the socio-economic status of these developing countries. A study was conducted to evaluate and quantify the effect of the two-tier intercropping of cotton and peanut with the substitution of a 25–50% recommended dose of nitrogen (RDN) of cotton by farmyard manure (FYM) on productivity, profitability and nitrogen economy in the CWPS at New Delhi during 2006–08. To quantify the residual effects of previous crops and their fertility levels, a succeeding crop of wheat was grown with varying rates of nitrogen, viz. 0, 50, 100 and 150 kg ha−1. Wheat equivalent productivity was significantly more with the inclusion of peanut in the CWPS (21–26%) with a high net return (US$288) than a pure stand of cotton in the CWPS. The substitution of 25% RDN of cotton by FYM being on par with no substitution recorded a higher wheat equivalent yield, nitrogen, phosphorus and potassium uptake, net return and nitrogen use efficiencies. Nitrogen economy in wheat was 22 kg ha−1 due to inclusion of peanut in the CWPS and 13 kg ha−1 due to substitution of the 25% RDN of cotton by FYM. The study suggested that for the success of the CWPS in South Asian countries, escalating prices of N fertilizers with environmental issues and the instability of transgenic hybrids can be overcome by using wider rows of cotton by peanut intercrop with the integrated use of both organic and inorganic sources of nitrogen.

This study presents farmers’ evaluations of the performance of winter-sown chickpea technology developed by ICARDA relative to traditional spring planting, and assesses impacts of this technology on farmers’ livelihoods in Syria. Ascochyta blight, insects and weeds were the most important factors affecting productivity of winter-sown chickpea, according to 480 farmers. Among package components, crop varieties were widely adopted and most farmers adopted other components. The winter-sown chickpea area is expanding, particularly in drier regions that do not traditionally grow chickpea. Adoption was higher for better-off farmers – poorer farmers generally prefer to see positive effects first. Adoption over time is accelerating, with obvious benefits: yields have increased by 18% in drier areas and 32% elsewhere in Syria. Winter-sown chickpea technology increased incomes for all adopting households with greatest impact among poorer farmers. All gains are important because chickpea contributes 22% of total household income and should increase with further increases in package adoption.

Conservation agriculture (CA) has been promoted as a strategy to cope with deterioration in soil fertility, but its adoption on smallholder farms in tropical areas remains limited. In Madagascar, livestock production is facing shortages in forage especially during the dry season. The value of cover crops used in CA as livestock feed could be an incentive to make this form of agriculture more acceptable in rural areas. To do so, farmers must find a trade-off between the use of biomass from cover crops for animal production and its maintenance on the soil to meet CA's criteria. In this study, we evaluated the impact of biomass flows (cover crops and manure) between cropping and cattle production in crop–livestock farms in the Lake Alaotra region. Surveys among crop–livestock farmers were used to calculate feed concentrate and mineral fertilizer equivalents. Our results show that on average 42, 22 and 10% of biomass production (dry matter basis) of Brachiaria spp., Stylosanthes guianensis and Vicia villosa, respectively, are used for livestock feeding. The economic benefit in feed concentrate equivalent is between €73 and €723/year per farm. The use of manure contributes, just as CA, to improve soil fertility without using external fertilizing resources. The economic benefit in mineral fertilizer equivalent is between €116 and €2365/year per farm. The integration of CA and livestock production shows, beyond the agronomic advantages, an obvious economic benefit, which is essential to secure the Malagasy agricultural systems. Moreover, this economic benefit is another argument for the dissemination of CA practices in rural areas.

Deep sowing (15 cm) on sands in the dry season is a practice used in post-rice sowing of legumes without irrigation, designed to increase moisture access for germination, growth and crops yield. However, with such deep sowing there can be a penalty for emergence and growth if there is abundant water stored in the upper soil profile during the growing season. Hence, there is a need to define the soil water regimes under which deep sowing is advantageous for different legumes. To investigate the adaptation of legume crop species to deep sowing, we studied their emergence, growth and yield on three deep soils (3–16% clay) with shallow water tables during two years in northeast Thailand. At site 1 and 2, peanut, cowpea, mungbean and soybean were sown shallow (~5 cm) or deep (~15 cm). At site 3, only cowpea and peanut were shallow or deep sown. Shallow water tables maintained soil water content (0–15 cm) above permanent wilting point throughout the growing season. Deep sowing of all legumes delayed emergence by 3–7 days at all locations. Shoot dry weight of legumes after deep sowing was mostly similar or lower than weight after shallow sowing. Yield and harvest index of legumes did not differ meaningfully among sowing depths. Therefore, deep sowing was not beneficial for dry season cropping without irrigation when there was a shallow water table and sufficient water for crop growth throughout soil profiles in the growing season. Taken together with previous studies, we conclude that shallow rather than deep sowing of legumes was preferred when the soil water content at 0–15-cm depth remained higher than permanent wilting point throughout the growing season due to shallow water table.

In a field experiment initiated in 1991 kharif season (April–October) on an acidic soil in the Western Himalayas of India, 25% and 50% of the recommended doses of nitrogen were substituted through different organics, viz. farmyard manure (FYM), wheat cut straw and Sesbania aculeata (as green manure) in rice, followed by use of chemical fertilizers in wheat each year. The aim of this work was to study the long-term integrated effect of organics and chemical fertilizers on grain yield of rice–wheat system and soil quality. Based on five years’ moving average values, continuous cropping without fertilization or manuring (control) gave the lowest grain yields of both rice and wheat. Application of 50% N through FYM plus 50% NPK through chemical fertilizers to rice followed by 100% NPK through chemical fertilizers to wheat (T3) maintained the highest productivity of rice and wheat at about 3.4 Mg ha−1 and 3.3 Mg ha−1, respectively, as found from the pooled grain yield over the years. The highest values of organic carbon, cation exchange capacity and available N, P, K were also recorded under this treatment (T3). Soil pH was marginally affected by different treatments, while Diphenyl Triamine Penta Acetic acid extractable micronutrient cations increased over control when chemical fertilizers were applied in conjunction with different organics.

This experiment was conducted to study the long-term effect of soil management treatments on crop yields, sustainability yield indices (SYI) and soil fertility in rainfed semi-arid tropical Alfisol at Hayathnagar Research Farm, Hyderabad, India, during the period 1995 to 2009. The experiment was conducted in a split–split plot design with conventional tillage (CT) and minimum tillage (MT) as main factors, surface application of sorghum stover @ 2 t ha−1 (SS), fresh Gliricidia loppings @ 2 t ha−1 (GL) and ‘no’ residue (NR) as sub-factors and levels of N viz. 0 (N0), 30 (N30), 60 (N60) and 90 (N90) kg N ha−1 as sub–sub factors in a castor–sorghum two-year rotation. On an average, CT maintained 30.4 and 57.0% higher grain yields of sorghum and castor, respectively, over MT. Between two residues, GL performed well in both the crops. The highest yields of sorghum (1425 kg ha−1) and castor (876 kg ha−1) were recorded at 90 kg N ha−1. CT maintained higher SYI of 0.44 compared to MT (0.38) and higher agronomic efficiency (AE) of 13.5 and 6.76 kg grain kg−1 N for sorghum and castor crop, respectively. Use of crop residue as mulch had an advantage in increasing the yield of both the crops with increase in rainfall under CT even without N application (control), probably by making the soil more receptive to water infiltration, better moisture storage and by reducing the evaporative losses. Using response functions, the optimum fertilizer N requirement was also computed for a given set of tillage and residue combinations. The revised optimum fertilizer N doses for sorghum and castor varied from 45 to 56 kg ha−1 and 46 to 74 kg ha−1, respectively, under different tillage and residue combinations and could be recommended depending upon the soil management practices.

Cyanobacteria represent promising organic inputs in rice–wheat cropping system, as they contribute towards accretion of N and C, besides secreting growth-promoting substances which influence plant productivity and soil fertility. The present study focused towards using a combinatorial approach for evaluating field-level colonization of cyanobacteria in soil and their effect on soil microbiological and plant parameters, employing agronomic and molecular tools. A consortium of cyanobacterial strains (BF1, Anabaena sp., BF2, Nostoc sp., BF3, Nostoc sp. and BF4, Anabaena sp.) was employed in different three-and four-member combinations along with 75% N + Full dose of P and K fertilizers. A significant enhancement in microbial activity and plant growth/yields and savings of 25% N in the wheat–rice cropping sequence were recorded, especially in treatments involving 75% N + Full dose of PK+BF1+BF2+BF4 and T5, i.e. 75% N + Full dose of PK+BF1+BF2+BF3. Such treatments were significantly higher or statistically at par with fertilizer controls – 75% N + Full dose of PK fertilizers. The use of DNA-based markers further helped to establish the colonization of the inoculated cyanobacteria, especially BF2 and BF3 strains. Our study clearly illustrated the establishment of inoculated cyanobacterial strains and their role in enhancing the crop productivity and soil health of the rice–wheat cropping system.

The effects of leaves cut during fibre harvesting of Attalea funifera under contrasting irradiance availability were evaluated, studying defoliation-induced changes in photosynthetic and growth characteristics and fibre production in adult individuals of A. funifera growing under full sun and forest understorey. Fibre harvesting was performed with or without (control plants) leaf removal twice in a 12-month interval. Maximum measured values of net photosynthesis (A), stomatal conductance and transpiration were higher in full sun defoliated palms than in non-defoliated palms in the same environment or in understorey palms of the two treatments. Non-defoliated palms from the two environments emitted more leaves than defoliated palms in the same evaluation period. The increment in the leaf-level rate of carbon assimilation following defoliation did not lead to high production of fibre, suggesting that the photosynthetic compensation for leaf removal was not effective, at least during the period of evaluation. The results indicate that leaf removal during harvesting did not represent an advantage for fibre production and may even lead to decreases in leaf and fibre production.

Regression models for the prediction of grain yields of non-irrigated winter wheat in a semi-arid Mediterranean environment were developed based on drought variability. Twenty-five years (1980–2004) of climate data and yield data from four soils (sandy loam, clay, clay loam and sandy clay loam soil) in northern Greece were used for this purpose. Two variables were selected as explanatory variables of the models: (a) the monthly precipitation versus the monthly reference evapotranspiration ratio (P/ETo), which describes the monthly drought and consequently the water deficit conditions during the wheat-growing season and (b) the mean observed yield (y) of each soil, which indirectly describes the intrinsic fertility of the soils. A resampling technique using subsets of the data (bootstrapping) was applied to estimate the coefficients of the models, to assess the uncertainty of the selected explanatory variables and to validate the models. The models showed adequate predictive ability of wheat yields, defining the time and intensity of drought effects. The most crucial period for winter wheat was found to be primarily the vegetative-reproductive stage period between late winter and mid-spring (i.e. February to April). Soil clay content was found to be the most representative parameter in describing most of the physico-chemical parameters and properties of the soils and consequently the mean yield, indicating that yield is non-linearly correlated with most soil properties. With the proposed models, yield gap (YG) predictions between two growing seasons of the selected soils presented 84% accuracy in all years in the identification of the correct signal (+ or −) of yield increase or decrease, respectively, and adequate performance in the prediction of the mean YG.

Using computer simulation model as a management tool requires model calibration and validation against field data. A three-year (2008–2009 to 2010–2011) field study was conducted at the Postgraduate Agricultural Research Station of the University of Agriculture, Faisalabad, Pakistan, to simulate wheat grain yield production as a function of urea fertilizer applications using Crop Environment REsource Synthesis (CERES)-Wheat model. The model was calibrated using yield data for treatment of urea fertilizer application at the rate of 247 kg-urea ha−1 during growing season 2009–2010 and was validated against independent data sets of yield of two years (2008–2009 and 2010–2011) for a wide variety of treatments ranging from no urea application to 247 kg-urea ha−1 application. The model simulations were found to be acceptable for calibration as well as validation period, as the model evaluation indicators showed a mean difference of 8.9%, ranging from 0.05 to 15.38%, root mean square error of 356 having its range from 242 to 471 kg ha−1, against all observed grain yield data. The scenario simulations showed maximum grain yield of 4100 kg ha−1 for 350 kg-urea ha−1 in 2008–2009; 4600 kg ha−1 for 300 kg-urea ha−1 in 2009–2010 and 5200 kg ha−1 for 340 kg-urea ha−1 in 2010–2011. Any further increase in urea application resulted in decline of grain yield function. These results show that model has the ability to simulate effects of urea fertilizer applications on wheat yield; however, the simulated maximum grain yield data need field-based verification.