Long-term tillage and fertilizer experiments were conducted in rice in kharif followed by lentil in dry subhumid Inceptisols at Varanasi and Faizabad; horse gram at Phulbani and linseed at Ranchi in moist subhumid Alfisols in rabi during 2001 to 2010. The study was conducted to assess the effect of conventional tillage (CT), low tillage + interculture (LT1) and low tillage + herbicide (LT2) together with 100% N (organic) (F1), 50% N (organic) + 50% N (inorganic) (F2) and 100% N (inorganic) (F3) on productivity, profitability, rainwater and energy use efficiencies. The results at Varanasi revealed that CT was superior with mean yield of 2389 kg ha−1, while F1 was superior with 2378 kg ha−1 in rice. At Faizabad, CT was superior with mean rice yield of 1851 kg ha−1 and lentil yield of 977 kg ha−1, while F1 was superior with 1704 and 993 kg ha−1 of rice and lentil, respectively. At Phulbani, F2 was superior with rice yield of 1170 kg ha−1. At Ranchi, F2 with rice yield of 986 kg ha−1 and F3 with linseed yield of 224 kg ha−1 were superior. The regression model of crop seasonal rainfall and yield deviations indicated an increasing trend in rice yield over mean (positive deviation) with increase in rainfall at all locations; while a decreasing trend (negative deviation) was found for lentil at Faizabad, horse gram at Phulbani and linseed at Ranchi. Based on economic analysis, CTF1 at Varanasi and Faizabad, CTF2 at Phulbani and LT2F2 at Ranchi were superior.

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.

Agricultural production in southern Africa is constrained by numerous factors, including low soil fertility, frequent droughts and flooding, limited access to fertilizers and the use of unsustainable management techniques that increase soil erosion rates. Conservation agriculture (CA) is based on the principles of minimum soil disturbance, crop residue retention and crop rotations. CA systems have been proposed to alleviate the negative externalities associated with conventional crop management systems. This study was conducted to examine the riskiness of economic returns of CA technologies based on maize grain yield evaluated in 12 target communities in Malawi from 2005–2011. On average, maize grain yields on both CA treatments exceeded the conventional control treatment by 22.1–23.6%, with differences more distinct in low altitude areas with low rainfall and frequent seasonal dry spells. Stochastic dominance analysis suggest that CA technologies would be preferred by risk-averse farmers, with corresponding differences in risk premiums (compared to conventional maize production systems) ranging between US$40 and US$105. However, these rankings are sensitive to the agroecological zones where the experiments were conducted. The risk premiums associated with the CA technologies in low elevation regions are unambiguous. Risk-averse farmers in higher elevations may need substantial incentives to adopt some CA technologies.

We are very sad to say goodbye to Dr Lindsay Innes, OBE, FRSE who is retiring from the post of Book Review Editor that he has held for 15 years. During that time, Lindsay has worked tirelessly to ensure that regular readers of Experimental Agriculture have always been able to find out what books they should be reading, and why, by consulting the Journal's concise, incisive reviews by renowned experts from a bewildering range of fields. Lindsay, whose career description reads like a summary of all the top jobs in International Agricultural Research, always knew the best person to ask to review a book and the result was that we got the best reviews. We will miss him but we thank him sincerely for his work for the journal and we wish Lindsay the best of luck for the future.

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.

Correct placement of side dress nitrogen (N) fertilizer could increase nitrogen use efficiency (NUE) and maize yield production. Field studies were established to evaluate application of midseason (V8 to V10), variable liquid urea ammonia nitrate (28%), N rates (0, 45, 90 and 134 kg N ha−1) and different application distances (0, 10, 20 and 30 cm) away from the maize row on grain yield and NUE at Haskell and Hennessey in 2009, Efaw in 2010 and Lake Carl Blackwell, Oklahoma in 2009 and 2010. A randomized complete block design with three replications was used throughout the study. Results indicated that maize grain yield in sites with adequate rainfall increased significantly (p < 0.05) with N rate, and poor N response was recorded in sites with low rainfall. Across sites and seasons, varying side dress N application distance away from the maize row did not significantly (p < 0.05) influence maize grain yield and NUE even with no prep-plant applied. Environments with adequate rainfall distribution had better maize grain yields when high side dress N rates (90 and 134 kg N ha−1) were applied 0 to 10 cm, and a higher NUE when 45 kg N ha−1 was applied 0 to 20 cm away from the maize row. For low N rates (45 kg N ha−1), increased maize grain yield and NUE were achieved when side dress N was applied 0 to 20 cm away from the maize row at locations with low rainfall distribution. Across sites and seasons, increasing side dress N to 134 kg N ha−1 contributed to a general decline in mean NUE to as low as 4%, 35%, 10%, 51% at Hennessey, Efaw, LCB (2009) and LCB (2010) respectively.

Although the application of small quantities of nitrogen (N) fertiliser has improved cereal yields on low-input farms in semi-arid Zimbabwe, the practice is reported to be laborious and time-consuming by farmers. In an effort to make micro-dosing less labour-intensive and more precise, an ammonium nitrate (AN) tablet, the equivalent of a micro-dose of prill AN (28 kg N ha−1) applied per maize plant, was developed by International Crops Research Institute for the Semi-Arid Tropics in collaboration with Agri-Seeds, Zimbabwe. This study characterized the physical stability, chemical (N% and solubility) and agronomic performance of AN tablets compared with prill AN. Only 10% of tablets broke when dropped from 2 m, showing that they are physically stable and can handle rough treatment. The N content in the tablets (33.3%) was comparable to that in prill AN (34.6%). However, the tablet formulation took twice as long to dissolve than prill AN when placed on a wet soil. Despite this difference in solubility, simple leaching column experiments suggest that less than 2% of the total AN applied was lost due to leaching. Agronomic trials were superimposed on the paired-plot demonstrations used to promote micro-dosing and the conservation agriculture tillage technique of planting basins from 2005 to 2008. Each tillage (plough and basins) plot was subdivided into three sub-plots on which no AN, prill AN and tableted AN treatments were superimposed. Maize was planted and management of plots was left to farmers. Micro-dosing with either prill or tableted AN significantly (p < 0.001) increased maize grain yield by over 40% in all seasons for planting basins. However, on the ploughed plot there was no yield benefit to using either AN formulation in the season with the lowest rainfall (2006–2007). There was no significant difference in grain yield and agronomic N use efficiency between prill and tableted AN formulations except for the 2005–2006 season in planting basins. During this season, in planting basins, tableted AN had significantly (p < 0.001) higher rainwater productivity than prill AN, which translated into greater grain yield. In addition, the maximum benefit to micro-dosing was observed to accrue when combined with water harvesting techniques such as planting basins. An observation supported by the host farmers, who in the second and third seasons chose to apply available basal soil fertility amendments to the basin plots over the flat plots. Thus, AN tablets if available at an affordable price can be used by smallholder farmers to more precisely apply N fertiliser. Future work should focus on the labour issues of micro-dosing, and making cost-effective tablets available to resource-poor farmers and also addressing other limiting soil nutrients.

Field experiments were conducted on a Typic Hapludoll (Mollisols) soil in the Indo-Gangetic Plains of India during the 2008 and 2009 rainy seasons to (1) find out the effect of irrigation schedules and plant spacing on physiological parameters, yield and water productivity of two rice cultivars under System of Rice Intensification (SRI), and (2) compare the performance of SRI with conventional transplanting (CT). Treatments under SRI included 12 combinations of three irrigation schedules, viz. irrigation at 1, 3 and 5 day(s) after disappearance of ponded water (DADPW), two spacing intervals (20 × 20 cm and 25 × 25 cm) and two cultivars (‘Pant Dhan 4’ and ‘Hybrid 6444’). The two control treatments were the CT of each cultivar. The experiment was set in a factorial randomized complete block design replicated thrice. The net photosynthetic rate (NPR) of the topmost fully expanded leaf at tillering and that of flag-leaf at flowering stage was affected significantly by irrigation schedules. Irrigating rice crop at 1 or 3 DADPW, being at par with each other, recorded significantly higher NPR than 5 DADPW. The increase in NPR at 1 and 3 DADPW was 17.1% and 8.4% at tillering and 13.6% and 6.1% at flowering stage, respectively, compared with that at 5 DADPW (tillering: 12.78 μmol CO2 m−2 S−1, flowering: 16.01 μmol CO2 m‑2 S−1). At closer spacing (20 × 20 cm) the cultivars did not differ significantly for NPR; however, at wider spacing (25 × 25 cm), ‘Hybrid 6444’ showed significantly higher NPR than ‘Pant Dhan 4’. Between two methods, SRI recoded higher NPR. Dry matter accumulation (DMA) in leaves and grains declined with delay in irrigation from 1 to 5 DADPW. Wider spacing significantly enhanced DMA in stems and grains. ‘Hybrid 6444’ showed higher DMA in all plant parts than ‘Pant Dhan 4’. Grain yield was not affected significantly by irrigation schedules in 2008, while in 2009, irrigation at 1 and 3 DADPW resulted in 12.8% and 8.0% higher grain yield, respectively, than 5 DADPW (5.84 t ha−1). Wider spacing was superior to closer spacing. SRI improved grain yield by 16.9% and water productivity by 18.5% over CT.

Continuous rice–wheat (RW) cropping with intensive tillage has resulted in land degradation and inefficient use of water in Indo-Gangetic Plains (IGP) of South Asia. Replacement of rice with less water requiring crops such as soybean in RW system and identification of effective strategies for tillage management could result in sustainable cropping system in IGP. A field experiment was conducted for five years on an annual soybean–wheat (SW) rotation in the northwest IGP of India to evaluate effect of tillage, raised bed planting and straw mulch on yield, soil properties, water use efficiency (WUE) and profitability. In soybean, straw mulch reduced soil temperature at seeding depth by about 2.5 °C compared with no mulch. Straw mulch also resulted in slightly reduced water use and slightly higher WUE relative to their respective unmulched treatments. During wheat emergence, raised beds resulted in higher soil temperature by 1.6 °C compared with flat treatments. Bulk density and cumulative infiltration were greater in no-tillage compared with conventional tillage. Soil organic carbon in surface layer increased significantly after five years of experimentation. Soybean and wheat yields were similar under different treatments during all the years of experimentation. Soybean and wheat planted on raised beds recorded about 17% and 23% higher WUE, respectively, than in flat layout. The net returns from SW system were greater in no-tillage and permanent raised beds than with conventional tillage. Both no-tillage and permanent raised bed technologies can be adopted for sustainable crop production in SW rotation in northwest IGP. However, more studies are required representing different soil types and climate conditions for making recommendations for other regions of IGP.

In a context of understanding the physiological mechanisms and cultivar traits which could improve durum wheat (Triticum durum) yield in water limited conditions, the paper focuses on the contribution of stored assimilates to grain growth and yield. A conceptual model describing the different fluxes of assimilate during the grain filling period is used together with a dataset from field experiments made in northern Tunisia during two growing seasons and under different conditions of water and nitrogen supply. Three types of behaviour have been encountered in relation to the balance between demand for assimilate and supply. Remobilisation of stored assimilates provides a buffer enabling grain growth to be maintained. Conditions at anthesis play an important role in determining the type of fluxes of assimilates. Grain number also plays a major role in short- or long-term remobilisation and grain number per ear increases short-term remobilisation. In rain-fed conditions, short-term remobilisation allows faster grain growth.

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.

Cotton–wheat (CW) is the second most important cropping system after rice–wheat in South Asia. Sowing of wheat after cotton is usually delayed due to late pickings coupled with time needed for seedbed preparation, resulting in low wheat yield. Lack of suitable machinery is a major constraint to direct drilling of wheat into the heavy cotton stubbles. An innovative approach with much promise is the ‘2-wheel tractor-based self-propelled relay seeder’ with seed-cum-fertilizer attachment. On-farm trials were conducted at four locations during 2009–2010 and at 10 locations during 2010–2011 to evaluate the following four wheat establishment methods in CW-dominated areas of south-western Punjab, India: (1) zero till seeding in standing cotton using a self-propelled relay seeder, (2) relay seeding in standing cotton with a manual drill without prior tillage (2010 only), (3) relay broadcast seeding in standing cotton following light manual tillage and (4) conventional sowing of wheat after cotton harvest (conventional tillage and sowing with a seed–fertilizer drill). Planting of wheat under conventional practice was delayed by 20–44 days compared with relay seeding. Seed cotton yield was also significantly higher with relay seeding due to opportunity for one additional picking. Yield of wheat sown with the self-propelled relay seeder was 41.2% and 11.8% higher than with conventional practice in 2009–2010 and 2010–2011 respectively. The increase in wheat yield under relay seeding of wheat was primarily due to higher spike density and more grains per spike. The net income from the CW system was 28.2% higher for the self-propelled relay seeder than with conventional sowing.

The physiological performance of four cacao clones was examined under three artificial shade regimes over the course of a year in Ghana. Plants under light shade had significantly higher photosynthetic rates in the rainy seasons whereas in the dry season there was a trend of higher photosynthetic rates under heavy shade. The results imply that during the wet seasons light was the main limiting factor to photosynthesis whereas in the dry season vapour pressure deficit was the major factor limiting photosynthesis through stomatal regulation. Leaf area was generally lower under heavier shade but the difference between shade treatments varied between clones. Such differences in leaf area allocation appeared to underlie genotypic differences in final biomass production in response to shade. The results suggest that shade for young cacao should be provided based on the current ambient environment and genotype.

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.

This study was conducted to investigate the physiological response of sugarcane genotypes to drought and its consequence for stalk yield. Sugarcane genotypes IACSP94-2094, IACSP96-2042 and SP87-365 were subjected to water deficit during the initial growth phase by withholding water. Resistance and sensitivity patterns were defined by the impact of drought on the stalk yield and content of soluble solids in the stalk juice. IACSP94-2094 and SP87-365 were considered drought-resistant genotypes, as the stalk dry matter production and yield of soluble solids were not reduced by the water deficit. Although drought caused reductions in leaf gas exchange in all the genotypes, IACSP96-2042 was most affected when considering the cumulative reduction in photosynthesis throughout the experimental period. This photosynthetic impairment of IACSP96-2042 was related to both non-stomatal and stomatal limitations, whereas photosynthesis in SP87-365 and IACSP94-2094 were only stomatally limited under drought. In general, a reduced photosynthetic sensitivity to water deficit was an important physiological trait for dry matter production in sugarcane plants, and the concentrations of soluble carbohydrates, sucrose, starch and proline in the leaves did not reveal consistent differences between the patterns of resistance and sensitivity. Even though IACSP96-2042 was severely affected by water shortage, this genotype presented a similar stalk yield under drought and the highest stalk yield under well-watered conditions when compared to the other genotypes. This response to variable water conditions is interesting for regions with seasonal drought, whereas the pattern of drought resistance is more appropriate for regions in which drought occurs for long periods during the crop season. Our findings are also discussed from the point of view that increases in sugarcane yield and sustainable agriculture may be reached by choosing the best genotype for each specific environmental condition.

The distribution of dry matter among the fractions of cotton boll (the bur, the fibre and the seed) may have significant impact on fibre biomass per boll, and consequently on lint yield. Little is known on how cotton boll allocates available photosynthetic assimilates to its components. A two-year field study was conducted to ascertain the difference in boll dry matter production and partitioning among three cotton genotypes differing in boll size and lint percentage. The dynamics of dry matter production in all fractions of cotton boll against boll age followed a logistic pattern. The final dry weights of all components were largely due to the duration of dry matter exponential accumulation, and less correlated with the maximal rate of exponential accumulation. Partitioning biomass to the bur differed significantly among these genotypes at 10 days post-anthesis (DPA). The genotypic difference in partitioning biomass to the fibre was originally observed at 24 DPA in 2009, while in 2010, this was observed at 17 DPA. The genotypic difference emerged rather late for the seed ratio compared with the fibre ratio and the bur ratio, which was first observed at 45 DPA in 2009 and at 31 DPA in 2010. These results indicate that management practices may need to be applied to cotton plants prior to 31 DPA to ensure optimal boll size and partitioning. Large boll genotype MM-2 consistently maintained higher seed ratio and lower fibre ratio than two other genotypes (2870 and AX) due to more developing ovules in its boll. These differences contributed to significant difference in lint percentage and less difference in fibre mass per boll between MM-2 and 2870 and AX.

Understanding the growth dynamics of fine roots and their contribution to soil organic carbon and nutrient pools is crucial for estimating ecosystem carbon and nutrient cycling and how these are influenced by climate change. Rubber is cultivated in more than 10 million hectare globally and the area under rubber cultivation is fast expanding due to socio-economic reasons, apart from the importance given to this species for eco-restoration of degraded lands. An experiment was conducted to quantify fine root production, fine root turnover and carbon and nutrient cycling through fine roots in rubber plantations with different soil nutrient status and rainfall pattern. Fine root production was estimated by sequential coring and ingrowth core methods. Fine root decomposition was determined by the litter bag technique. Carbon and nutrient contents in fine roots were determined and their turnover was computed. Fine root biomass in the top 0–7.5-cm soil layer showed significant seasonal fluctuation and the fluctuations were particularly wide during the transition period from the dry season to the rainy season. Fine root production estimated by the different methods was significantly higher at the lower fertility site and during the higher soil moisture stress year. Fine root turnover ranged from 1.04 to 2.29 year−1. Root carbon and nutrient status showed seasonal variation and lower status was observed during the rainy season. The annual recycling of C, N, P, K, Ca and Mg through fine roots ranged from 590 to 1758, 30 to 85, 3 to 12, 13 to 31, 11 to 35 and 6 to 13 kg ha−1, respectively. Substantial quantities of carbon and nutrients were recycled annually in rubber plantations through fine roots. When soil moisture and nutrient stress were more severe, fine root production, turnover and carbon and nutrient recycling through fine roots were higher.

Little is known about the adaptability of longan (Dimocarpus longan) to acidic soils high in aluminum (Al). A two-year field study was conducted to determine the effects of various levels of soil Al on dry matter production, plant growth and nutrient content in shoots of four cultivars of longan. Soil Al and cultivars were statistically different for all variables measured in the study. Total leaf, petiole, stem and root dry weights significantly decreased at soil Al concentrations ranging from 5.1 to 12.1 cmol kg−1 but this reduction was of a smaller magnitude in roots than in other organs. Increments in soil Al resulted in a significant reduction in the concentration of leaf Ca and a significant increase in leaf Al in all cultivars. Shoot content of N, P, K, Ca, Mg, Fe, Mn and Al declined with increase in soil Al. The result of this study demonstrates that longan is highly susceptible to acid soils.

Ten endophytic bacteria were isolated from different sugarcane varieties growing in the Crop Research Centre, Pantnagar on nitrogen-free medium. Plant growth-promoting potential of the isolates was reported in terms of indole acetic acid (IAA) production, phosphorus solubilization, siderophore production and antagonistic action against the pathogen Colletotrichum falcatum, which causes red rot disease in sugarcane in vitro. All the isolates were able to produce IAA (4.8–9 μg ml−1); three isolates (H3, H5 and H14) solubilized insoluble phosphorus on Pikovaskaya's agar; two isolates (H10 and H14) showed siderophore production on Chrome-azurol S (CAS) agar and antagonism against C. falcatum was exhibited by two isolates (H14 and H15) in a dual plate assay. 16 S rRNA sequencing identified isolates H3 and H12 as Pseudomonas spp., and H8, H14 and H15 as Bacillus spp. A field experiment on sugarcane was conducted with five plant growth-promoting bacterial endophytes Pseudomonas spp. (H3 and H12) and Bacillus spp. (H8, H14 and H15) along with standard strains of Gluconacetobacter and Azospirillum spp. Plant height, chlorophyll content, total nitrogen and cane length were significantly higher in almost all inoculated plants compared with the uninoculated control. An increase of 40% in cane yield over the control was obtained after inoculation with isolate H15 (Bacillus spp.). This was statistically on par with the standard endophyte Gluconacetobacter diazotrophicus, which resulted in 42% increased cane yield. Identification of new diazotrophs and their promising results towards improving plant growth in the field suggest their use as inoculants in future.

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.