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Understanding the dynamics of soil phosphorus (P) over extended periods of soil and crop management practices is essential for sustainable P management. This study assessed the impact of four crop rotations [maize-wheat (M-W), maize-wheat-mungbean (M-W-Mb), maize-wheat-maize-chickpea (M-W-M-C), and pigeonpea-wheat (P-W)] each with three levels of nutrient management [control (CT), integrated nutrient management (suboptimal fertilizer+ farmyard manure + crop residue + bio-fertilizers; INM), and sole-chemical fertilizers (CF)] on soil inorganic and organic P (Pi and Po) pools and crop–soil relationships at the end of 15-year cropping. Legume-inclusive rotations resulted in higher labile-P pools, being higher with M-W-M-C and P-W. M-W-M-C rotation had higher moderately labile organic P (Po) in both surface (+23%) and subsurface (+18%) depths over M-W. Di-calcium P (Ca2-P) (+6%) and microbial biomass P (MBP) (+46%) increased in M-W-Mb over M-W, while iron-P (Fe-P) was reduced (−12%) in subsurface soil. INM enhanced bioavailable-P [soluble-P (+17%), labile-Pi (+15%) labile-Po (+12%), MBP (+96%), moderately labile-Po (+22%)] over CF in surface soil, while CF had a higher Fe-P (+16%). Legumes in rotation caused notable changes in the surface-to-subsurface ratio (SSBR) of Ca2-P (1.18–1.50) and occluded-P (1.64–2.78). INM had a higher SSBR of labile-P pools but had a lower SSBR of occluded-P facilitating mobilization of the later in the surface. Hence, in tropical soils, legume-inclusive diversification (particularly with chickpea) and INM involving crop residue recycling could be a sustainable option to improve P use efficiency, crop productivity, and save fertilizer resources. [ABSTRACT FROM AUTHOR]

Evaluating the impacts of high temperature-mediated changes in soil-plant systems is crucial in sustaining the productivity of heat-sensitive crops like chickpea (Cicer arietinum L.). Currently, the impact of a high temperature environment on soil processes and crop nutrition, particularly phosphorus (P), remains uncertain in tropical alkaline soils. Therefore, an open-top chamber-based experiment with ambient temperature [a(Temp)] and elevated temperature [e(Temp)] (+2 °C over ambient) aimed to investigate the impacts of high temperature environment on plant physiology, soilplant P dynamics, and yield of chickpea in a moderately-alkaline Vertisol of sub-tropical climate. The e(Temp) reduced Olsen-P (available-P) and NaHCO3-Pi at the flowering stage by 12% and 32%, respectively, as compared to a(Temp) treatment. The e(Temp) treatment markedly reduced KMnO4-oxidizable carbon (-25% to 42%), but did not alter water-soluble carbon. Alkaline phosphatase and ß-glucosidase activities were reduced under the e(Temp) treatment, while acid phosphatase activity remained unchanged. The elevated temperature had a significant impact on chlorophyll-b content (+18%), stomatal conductance (+5%), transpiration rate (+8%), and photosynthetic rate (-22%). The e(Temp) treatment did not alter total P uptake rather altered its distribution in grain (-16%) and stover (+17%) parts, resulting in a lower internal P use efficiency (-12%) and P harvest index (+15%). The e(Temp) treatment caused 12% yield loss compared to a(Temp) treatment. Therefore, this is concluded that retardation in P-mineralization along with terminal heat stress could impair P nutrition, physiological activity, and yield of chickpea. [ABSTRACT FROM AUTHOR]

Occurrence of physical dormancy or hard seed coat prevents proper utilization and conservation of wild species of Cajanus and Rhynchosia, which offers a source of many useful traits. Hence, an attempt has been made to understand the variability in hardseededness and the pretreatments (hot air treatment for 3, 5, 7, and 14 days; hot air treatment for 30 and 60 min; sulfuric acid scarification for 2 and 5 min; partial incision on seed coat) to overcome it in 44 accessions of 10 wild pigeon pea species. The level of hardseededness varied from 36% to 100% with an average of 76.5%. Likewise, time to 1% germination or time taken to initiate germination (T1), time to 50% germination (T50), and mean germination time (MGT) varied between 16.18–249.9 h, 94.7–607.7 h, and 37.5–153.2 h, respectively. Overall, all the treatments reduced hardseededness and improved germination over the control, with partial incision on seed coat being the best treatment for all the species recording 70%–98% germination, except for Rhynchosia aurea (30%) and Cajanus cajanifolius (59%). The hot water treatment for 30 and 60 min was the best treatment for C. cajanifolius recording germination of 66%–70% as compared to 11% in control. The sulfuric acid scarification for 2 min was the best pretreatment for overcoming dormancy and improving germination in Rhynchosia bracteata, Rhynchosia rothii, and Rhynchosia rufescens. The result indicated a significant inter‐ and intraspecific variation in the effectiveness of pretreatments in overcoming physical dormancy, suggesting that the optimum pretreatment for overcoming hardseededness should be standardized for each accession. Also, the dormancy‐breaking pretreatments not only reduced hardseededness and improved final germination percent but it also reduced time for T1, T50, and MGT, suggesting that use of such pretreatments before sowing could result into higher, uniform, and rapid germination. Core Ideas: Wild relatives offer a source of many useful traits for pigeon pea improvement.Occurrence of dormancy in wild Cajanus and Rhynchosia prevents its proper utilization and conservation.Result indicated significant inter‐ and intraspecies variation to pretreatments in overcoming hardseededness.Overall, partial incision on the seed coat was the best dormancy‐breaking pretreatment. [ABSTRACT FROM AUTHOR]

Soil-test crop response (STCR) approach is aiming to precise adjustment of fertilizers under varying soil-test values for targeted-yield, presently gaining recognitions for sustainable nutrient management. The study aimed to envisage the precision scale of STCR targeted-yield models in maize-lentil rotation in alkaline Fluvisol under sole-fertilizer and integrated nutrient management (with farmyard manure). Fertility-gradient, test-crop diagnostic, and validation trials were conducted following STCR technical program. Soil fertility gradient and variable fertilizer doses had caused a large variation in grain yield of maize (0.99–4.94 t ha−1, CV = 30%) and lentil (1.11–2.02 t ha−1, CV = 13%). Lentil had increased potential to utilize soil nutrient pools; in contrast, maize was highly responsive to fertlizer nutrients. Multivariate-regression analysis revealed that fertilizers N, P, and S had a strong and direct influence on maize yield; where fertilizer-P was the primary yield-determining variable for lentil. Both sole-fertilizer and integrated STCR-based treatments attained the targeted-yields in maize. However, STCR treatments could not attain the targeted-yields in lentil (17–29% deviation), but had yield advantage over the blanket recommended fertilizer dose. Hence, in tropical-alkaline soils, integrated STCR targeted-yield approach could be the sustainable nutrient management option(s) for improving the productivity of the maize-lentil system. [ABSTRACT FROM AUTHOR]

Sustainability of rice-wheat rotation is questioned with soil degradation and depleting natural resources. The study aimed to assess the long-term impact of four crop rotations [rice-wheat, rice-wheat-mungbean, rice-chickpea, rice-wheat-rice-chickpea (2-year rotation)], each consisted of three nutrient treatments [control, integrated nutrient management (INM), and chemical fertilizers (RDF)] on soil carbon pools, soil microbial, and biochemical properties. Mungbean inclusion in rice-wheat rotation increased soil organic carbon (SOC) and microbial biomass carbon (MBC) by 17% and 27%. Rice-wheat-mungbean rotation increased soil enzymes activities over rice-wheat rotation, prominent on arylsulfatase (41%), dehydrogenase (38%), and phosphatases (32%). Rice-chickpea rotation had higher alkaline phosphatase (10%), β-glucosidase (13%), and protease (6%) activities over rice-wheat rotation. Rice-wheat-mungbean rotation increased the MBC/SOC and reduced MBC/MBN ratio over rice-wheat rotation, which indicates increased lability of soil carbon and enhanced nitrogen cycling rate. The INM treatment increased SOC (20%), MBC (53%), soil respiration (9%), and enzymes activities over RDF treatment, which was primarily attributed to higher organic matter input through farmyard manure and residues recycling. The higher SOC and microbial activity in legume-inclusive rotations influenced the base-crop (rice) productivity. Thus, the inclusion of grain legume and INM could improve microbial activity and biochemical functions in tropical rice soils. [ABSTRACT FROM AUTHOR]

Sustainability of cereal-based cropping systems remains crucial for food security in South Asia. However, productivity of cereal–cereal rotations has declined in the long run, demonstrating the need for a sustainable alternative. Base crop, that is, common crop in different crop rotations, productivity could be used as a sustainability indicator for the assessment of different long-term crop rotations. This study aimed to evaluate the impact of grain legume inclusion in lowland rice–wheat (R-W) and upland maize–wheat (M-W) rotation on system's base crop (rice in lowland and wheat in upland crop rotations) productivity and sustainability and also in soil fertility. Mung bean (April–May) inclusion in R-W rotation increased rice grain yield by 10–14%. In upland, mung bean inclusion in M-W rotation increased wheat grain yield by 5–11%. Replacing wheat with chickpea in R-W rotation increased rice grain yield by 5–8%. Increased base crop productivity in legume inclusive rotations was attributed to significant improvement in panicle (rice) or spike (wheat) attributes. Increased soil organic carbon and available nitrogen and phosphorus in the legume inclusive rotations significantly influenced the base crop productivity in both the production systems. Among the crop rotations, R-W-Mb (in lowland) and M-W-Mb (in upland) rotations had the highest system productivity and net return. Therefore, intensification/diversification of cereal–cereal rotations with grain legume could improve soil fertility and sustain crop productivity. [ABSTRACT FROM AUTHOR]

In this experiment, weed management was studied in zero tillage (ZT) and conventional tillage (CT) wheat with and without crop residue and nitrogen (N). The treatment ZT with crop residue retention (R) and 75% of required N plus GreenSeeker™ (GS)-aided N management (ZTRNGS) resulted in a reduction of density and dry weight of weeds compared to CT and ZT without residue. Sequential application of pendimethalin and sulfosulfuron (PMT-SSF) reduced the weed density and dry weight compared to the weedy check (WC). Importantly, the richness and diversity indices were high in ZTRNGS and in WC treatments. Greater wheat grain (5.11 t/ha) and biomass yield (13.31 t/ha) were observed in ZTRNGS than CT without residue and blanket split application of N (CTN). The treatment ZTRNGS recorded 14.1% and 16.9% higher gross and net returns, respectively, over CTN. This study demonstrates that surface retention of crop residue in ZT is more useful than residue incorporation under CT for effective weed control, improving crop yield and profitability. [ABSTRACT FROM AUTHOR]

Root–knot nematodes (Meloidogyne spp.) are the sedentary endoparasites that cause severe yield losses in chickpea. Chemical nematicides are widely used to control root–knot nematodes. These toxic chemicals pollute the soil and water environments and affect human health. The present study aimed to identify a potential bio–organic approach of management of M. javanica in chickpea. A two–year field experiment (2013–2015) was conducted to evaluate the efficacy of organic amendments (neem cake, neem seed powder and vermicompost), bio–control agent (Trichoderma harzianum), and chemical nematicides (carbofuran 3G, carbosulfan 25DS) for managing M. javanica in chickpea. The population of M. javanica in control treatment was 6.6 infective juveniles cc−1 soil. Organic amendments and bio–control agent reduced nematode population considerably in comparison to control treatment. Results showed that root galls and gall index were reduced in all the treatments over control, and the maximum reductions were observed in carbofuran 3G and neem cake treatments. Neem cake and carbofuran 3G reduced the root galls by 59% and 62% and gall index by 45% and 58% over control. Neem cake, carbofuran 3G and carbosulfan 25DS treatments resulted in the higher yield of chickpea over control treatment, which was primarily attributed to an increase in plant biomass and number of pods per plant. Chemical nematicides reduced the nodulation as compared to other treatments. Hence, neem cake could be an alternative to toxic chemical nematicides and recommended as eco–friendly management of M. javanica in chickpea. • Root-knot nematodes cause severe yield losses in chickpea. • Bio-organic products and bio-control agent suppressed the nematode infestation (M. Javanica). • Chemical nematicides affected nodulation in chickpea. • Nematicidal effect of neem cake (0.5 t ha−1) treatment was comparable to carbofuran 3G. [ABSTRACT FROM AUTHOR]