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Soil physical degradation is one of the serious production constraints in the Indo-Gangetic Plain region. The present investigation was undertaken to study the effect of different nutrient management practices involving the use of fertilizer NPK alone or in combination with Farm Yard Manure (FYM), sulphitation pressmud (SPM), or induced defoliation (ID, imposed in pigeonpea through foliar spray of 10% urea solution at physiological maturity) on soil hydrophysical properties of a Typic Haplustepts under pigeonpea-wheat sequence, in a field experiment that continued for 5 years at IARI, New Delhi. Fertilizer NPK at recommended rate to both the crops resulted in a significant increase in macroaggregates, mean weight diameter, geometric mean diameter, water-stable aggregates, and saturated hydraulic conductivity in surface soil. Conjoint use of fertilizers, organic manures, and ID also decreased soil bulk density (0-15 cm) significantly over control. Effectiveness of organics and ID in improving soil physical environment was in the order: FYM > ID > SPM. [ABSTRACT FROM AUTHOR]

The rice-maize cropping system (RMS) is an emerging option for diversification of the prevalent rice-wheat system (RWS) in South Asia. Studies underlined the significance of adequate potassium (K) nutrition for sustainable intensification of the RMS. Although studies on combined effects of tillage, residue retention, and nutrient management on crop yields and nutrient use efficiency for the RWS are plenty, such studies are scarce for the RMS. We, therefore, conducted a 5-year field study on sandy loam (Typic Ustochrept) soil at Modipuram, India to evaluate the effects of tillage and crop establishment, residue management and K fertilization on crop productivity, K use efficiencies, changes in soil K status, and apparent K balance under irrigated RMS in north-western India. Three combinations of tillage and crop establishment methods i.e., puddled transplanted rice (TPR) followed by conventional-till maize (TPR/CTM); conventional-till dry direct-seeded rice (CTDSR) followed by CTM (CTDSR/CTM); and zero-till DSR followed by zero-till maize (ZTDSR/ZTM) were considered as main plots. Sub-plot treatments consisted of two residue management options i.e., removal of residues (-R) of both crops, and partial residue retention (5 Mg ha −1 ) for rice and maize, either at soil surface in zero till (ZT) plots or incorporated into the soil in conventionally-till (CT) plots (+R). The sub-sub plot treatments were no-K application (-K) and 62 kg K ha −1 application (+K) to both rice and maize. Data summed-up for 5 years revealed that rice grain yield and K uptake under TPR were significantly higher ( p <  0.05) compared with CT/ZT DSR, irrespective of residue and K management options. The maize yield and K uptake were highest under the ZTDSR/ZTM treatment. Both rice and maize yields were significantly (p < 0.05) higher with 62 kg ha −1  K application under −R plots, but such effects were not significant under + R plots. Similarly the effect of residue management on yield and K uptake of rice and maize was significant only in the absence of fertilizer K application. Recycling of rice residue in maize had more pronounced effect on K uptake compared with that of maize residue in rice. Agronomic and recovery efficiencies of applied K were lower under +R plots, and agronomic efficiency was further decreased when both rice and maize were grown under ZT conditions (ZTDSR/ZTM). Soil exchangeable K content at 0–0.05 m and 0.05–0.15 m depths was significantly higher ( p <  0.05) under ZTDSR/ZTM compared with that under CTDSR/CTM and TPR/CTM treatments, and the values were greater under +R + K compared with −R−K treatments. Soil exchangeable K under −K−R plots dropped to 102 and 90 mg kg −1 at 0–0.05 m and 0.05–0.15 m depth, respectively vis–a-vis the initial K content (122 and 114 mg kg −1 , respectively). The apparent K balance, computed as K addition less K off-take by rice and maize during the study period of 5 years, was invariably negative in the absence of K fertilizer i.e., −307 kg ha −1 in TPR/CTM (+R−K) to −1483 kg ha −1 in ZTDSR/ZTM (−R−K) treatments. On contrary, the apparent K balance was positive in +R + K plots under different tillage and crop establishment methods. Positive correlation between soil exchangeable K and K input indicated that soil K mining in the RMS could be mitigated to a great extent with adequate supply of K through residue retention and K fertilization. [ABSTRACT FROM AUTHOR]

In Indian agriculture, nitrogen (N) and phosphorus (P) fertilizers are predominantly used by the farmers, often ignoring secondary and micronutrients. Significance of boron (B) in nutrient management studies has been increasingly underlined under intensive cropping systems particularly in acid soils. In order to understand the distribution of soil native B in different fractions and their contribution to plant B uptake as influenced by nutrient management, soil samples collected after wheat (2009–2010) from a long-term experiment (LTE) continuing since 1972–1973 on Typic Paleustalf of Ranchi were subjected to sequential fractionation of soil B. Treatments included N alone, NP, NPK, 150% of recommended NPK, NPK + farmyard manure (FYM), NPK + lime, and an unfertilized-control. Five soil B fractions were determined along with hot CaCl2-extractable (available) B. Averaged across the treatments, the soil had low organic carbon (C), pH and cation exchange capacity (CEC), and high free sesquioxides. Total B content was 21.7 mg kg−1. Among different B fractions, residual B was the major contributor to total B and other fractions collectively shared 7% of total B only. Application of N alone depleted readily soluble, specifically adsorbed and organically bound B bringing the contents even below unfertilized-control. Conjoint use of lime or FYM with NPK increased significantly these fractions, whereas a decrease in oxide bound B was noticed under these treatments. Available B was positively correlated with these fractions indicating their significance in controlling B availability in the soil. The study revealed that use of lime or FYM helped modifying the distribution of soil B in different fractions by way of changing soil pH and organic C content, resulting in enrichment of plant available pool. A drastically low available B content in different treatments receiving fertilizers alone, however, suggested the necessity of B fertilization at prescribed rates for maintaining soil B fertility as also high crop yields. [ABSTRACT FROM AUTHOR]

Abstract: In the Indo-Gangetic Plain region, a major deterrent to large scale adoption of the otherwise advantageous pigeonpea–wheat cropping system is the poor crop stand of pigeonpea due to temporary water logging during the rainy (monsoon) season, leading to its low productivity and a smaller residual effect on the succeeding wheat crop. The permanent raised bed (PRB) system of planting, as widely used particularly for wheat in different countries, has seldom been studied in the pigeonpea–wheat system. We, therefore, conducted a field experiment at Modipuram (29°4′N, 77°46′E, 237masl), India, for 3 consecutive years (2001–02 to 2003–04) to evaluate the PRB vis-à-vis the conventional flat bed (FB) system of planting at varying fertilizer NP rates in the pigeonpea–wheat system, in terms of changes in soil organic carbon, nutrient and water use efficiencies, annual productivity and economic returns. Pigeonpea grown on PRB had lower plant mortality (4–7%) and higher yield (1.6–2.1tha−1) as compared to FB with 26–36% mortality and yield of 1.3–1.8tha−1. Pigeonpea on PRB had greater N and P recycling (11–23% N and 8–14% P) through its residue comprising root, stubble and leaf litter. Although wheat yield following pigeonpea under PRB was lower (p <0.05) compared with that under FB, the system productivity in terms of wheat equivalent yield was 8.44% higher under PRB. The economic optimum doses of fertilizer N and P for wheat in the pigeonpea–wheat system were smaller (128kgN and 28kgPha−1) under PRB as compared to FB (152kgN and 30kgPha−1) owing to increased N and P supply, greater P use efficiency and a better crop growth environment under PRB planting. The N use efficiency indices were significantly greater (p <0.05) in wheat under FB compared to those under PRB. By contrast, P use efficiency was greater under PRB, particularly in treatments that received both N and P fertilizers. Compared with FB, the root mass density (20–46%) of wheat was also greater under PRB in surface and sub-surface soil layers. PRB favored saving of irrigation water by 9.5–13.4hacm and improved the irrigation application efficiency by 9.5–13.4% and the irrigation use efficiency by 19–28kghacm−1 over FB. The post-wheat harvest nitrate N (NO3-N) at 20–40cm soil depth in plots fertilized with 120 or 180kgNha−1 was greater under FB planting (10.25–13.81mgkg−1) compared to PRB (7.33–8.42mgkg−1), suggesting that PRB planting might reduce NO3-N leaching to deeper soil layers. Similarly, in the treatments that received both N and P, NO3-N in soil below 20cm depth was lower compared to those receiving N or P alone. After three crop cycles, soil OC and the Olsen-P content in the 0–20cm depth were increased compared to the initial content under both planting techniques but the magnitude of increase was greater under PRB. Compared with FB, the annual net returns of the pigeonpea–wheat system were greater by US$ 210ha−1 under PRB, and the crop also required less specific energy (1.99MJkg−1) compared with the FB planting (3.18MJkg−1). [Copyright &y& Elsevier]

The rice-wheat system (RWS), managed over 10.5 Mha in the Indo-Gangetic Plains of India suffers from production fatigue caused by declining soil organic matter, multi-nutrient deficiencies and diminishing factor productivity. We, therefore, conducted a long-term field experiment (1998–1999 to 2017–2018) in Modipuram, India to study the effect of continuous use of farmyard manure (FYM) as an organic fertilizer (OF), mineral fertilizers applied alone (RDF) and their combination (IPNS), as well as the inclusion of forage berseem (IPNS+B) or forage cowpea (IPNS+C) on crop yield, soil health and profits. The long-term yield trends were positive (p < 0.05) in all treatments except the control (unfertilized) in rice, and the control and RDF in wheat. Although the yields of rice, wheat and RWS were highest under IPNS treatments (IPNS, IPNS+B, IPNS+C), the maximum annual yield increase in rice (9.2%) and wheat (13.7%) was obtained under OF. A linear regression fitted to the yield data under different IPNS options revealed a highly significant (p < 0.001) annual yield increase in rice (5.1 to 6.6%) and wheat (6.8 to 7.7%) crops. Continuous rice-wheat cropping with RDF brought an increase in soil bulk density (Db) over the initial Db at different soil profile depths, more so at depths of 30–45 cm, but inclusion of forage cowpea or berseem in every third year (IPNS+B or C) helped to decrease Db, not only in surface (0–15 cm) but also in sub-surface (15–30 and 30–45 cm depth) soil. Whereas soil organic carbon (SOC) increased under OF, IPNS and IPNS + legume (B or C) treatments, it remained unaffected under RDF after 20 RW cycles. The inclusion of legumes along with IPNS not only helped to trap the NO3–N from soil layers below 45 cm but also increased its retention in the upper soil (0–15 cm depth). On the other hand, RDF had a higher NO3–N content in the lower layers (beyond 45 cm depth), indicating downward NO3–N leaching beyond the root zone. A build-up of Olsen-P was noticed under RDF at different time intervals. The soil exchangeable K and available S contents were maximal under OF and IPNS options, whereas a decline in DTPA extractable-Zn was recorded under OF. Overall, RWS economics revealed that OF treatment involved the maximum cost of cultivation (US$1174 ha−1) with the least economic net return (US$1211 ha−1). Conversely, IPNS + legume (B or C) had lowest cost of cultivation (US$707 to 765 ha−1) and a significantly higher (p < 0.05) net return (US$2233 to 2260 ha−1). The study, thus, underlines the superiority of IPNS over RDF or OF; the inclusion of legumes gives an added advantage in terms of production sustainability and soil health. Further studies involving IPNS ingredients other than FYM is needed to develop location-specific IPNS recommendations. [ABSTRACT FROM AUTHOR]