Inadequate nutrient management is one of the major challenges for sustainable soybean production in semi-arid climatic conditions. Hence, a 3-year (2015–2017) field experiment was conducted to assess the effect of foliar application of macro- and micronutrients on the growth, productivity, and profitability of soybean. Eight foliar nutrient sprays at the pod initiation stage—water spray (WS), 2% urea solution, 2% di-ammonium phosphate solution (DAP_2%), 0.5% muriate of potash solution (MOP_0.5%), 2% solution of 19:19:19 nitrogen phosphorus and potassium (NPK_2%), and a 0.5% solution each of molybdenum (Mo_0.5%), boron (B_0.5%), chelated-zinc (Zn _0.5%) and no-foliar nutrition (NFN)—were compared with a basal-applied recommended dose of fertilizers (RDF: 30 kg N, 75 kg P, and 40 kg K ha⁻¹) in a randomized block design (RBD), replicated three times. Foliar-applied chelated Zn@0.5% (Zn_0.5%) at the pod initiation stage resulted in more pods per plants. In addition to Zn_0.5%, urea_2%, NPK_2%, and B_0.5% significantly improved the pods per plant over treatment by no-foliar nutrition (NFN). The RDF-supplied soybean subsequently sprayed with Zn_0.5% produced the highest seed yield, which was 18.5–37.8% higher than that of NFN treatment Yield improvement due to the application of B_0.5%, DAP_2%, and urea_2% varied between 19.2–23.7, 16.6–20.4 and 18.6–20%, respectively. Foliar nutrition showed the largest net returns from Zn_0.5%. The water-use efficiency (WUE) and production efficiency increased by 18.4–37.6 and 34.9–37.5%, respectively, due to Zn_0.5% over the efficiencies from NFN treatment. Monetary efficiency (ME) gains due to Zn_0.5% were 24% higher, while ME efficiency gains due to urea_2%, NPK_2%, and B_0.5% varied between 15–16%. Thus, this study suggested that the foliar application of 0.5% Zn and B, urea, NPK fertilizer, and DAP at 2%, along with RDF. is a profitable nutrient management option for quality soybean production in a semiarid region. However, nutrient partitioning, changes in soil chemical and biological indicators, and environmental aspects need critical examination in future studies.

The energy consumption pattern and greenhouse gas (GHG) emission of any rice production system is important to know the sustainability of varied cultivation and establishment technique. This study was conducted to determine the energy use pattern, GHG emission and efficiency of rice farms in puddled transplanted (PTR, rainfed) and direct-seeded rice (DSR, irrigated) production systems in Karnataka, India. The energy indices and GHG emission of different input and output in a rice production system were assessed by using energy and carbon equivalence. The efficiency of PTR and DSR farms were identified using data envelopment analysis (DEA) and energy optimization was ascertained. The key finding was excessive use of non-renewable energy inputs was observed for the PTR (92.4%) compare to DSR (60.3%) methods. The higher energy use efficiency (7.3), energy productivity (0.3 kg MJ⁻¹) and energy profitability (6.3) were mainly attributed to the large decrease in energy inputs under DSR. The DEA showed efficiency for 26 PTR farms in comparison for 87 DSR farms. The mean technical efficiency value highlighted the scope for saving energy by 6% and 2% in PTR and DSR, respectively and showed an economic reduction of $405.5/ha with PTR versus $163.3/ha with the DSR method if these inefficient farms perform efficiently. The GHG emissions revealed that the total emissions for PTR versus DSR production caused by on-farm emissions were 86% and 65%, respectively. The DSR method also had a higher carbon efficiency ratio and carbon sustainability index (10.1 and 9.1, respectively). Thus, adoption of DSR method is imperative for reduction of energy consumption and GHG emissions to achieve the carbon sustainability.

Intensive mono-cropping without a balanced supply of nutrients and declining water resources are degrading soil health, and as a consequence, agriculture production is becoming unsustainable and causing environmental degradation. The field experiment was conducted during Rabi season to assess the effect of an irrigation schedule, nutrient management, and wheat (Triticum aestivum L.) varieties on soil microbial biomass carbon (SMBC) and soil enzymes activities. Two nutrient levels, recommended rate of chemical fertilizer (RDF) and 50% RDF + 50% recommended dose of nitrogen (RDN) through farmyard manure (FYM) designated as Integrated Nutrient Sources (INS), and three irrigations levels, one irrigation at crown root initiation (CRI), two irrigations at CRI and flowering stages, and five irrigations at all main stages of the crop (CRI, tillering, jointing, flowering, and grain filling) were allocated to main-plots while four varieties of wheat, HD 2967, WR 544, HD 2987, and HD 2932, were allocated to sub-plots. The results revealed that SMBC and activities of dehydrogenase, alkaline phosphatase enzymes, and acid phosphatase were higher under restricted irrigation (irrigation at CRI stage) than other irrigation schedules. SMBC, dehydrogenase, acid phosphatase, and alkaline phosphatase activities were 73.0 µg g soil⁻¹, 86.0 µg TPF g soil⁻¹d⁻¹, 39.6 µg PNP g soil⁻¹ h¹, and 81.8 µg PNP g⁻¹ soil h⁻¹, respectively, with the use of INS that was higher than RDF. Root weight and root volume followed a similar pattern. Applying single irrigation at CRI left behind the maximum available nitrogen (166.4 kg ha⁻¹) in soil compared to other irrigation schedules and it was highest (149.31 kg ha⁻¹) with the use of INS. Moreover, total organic carbon (TOC) was 0.44 and 0.43% higher with irrigation at CRI stages and the use of INS, respectively. The INS with single irrigation at the CRI stage is important to improve the root growth, SMBC dehydrogenase, alkaline phosphatase, and acid phosphatase enzyme activity in the wheat production system.

Phosphorus (P) and zinc (Zn) are essential plant nutrients, and their deficiency in soils and the antagonistic effect of P on Zn are important concerns world-over. Thus, a two-year (2012–13 to 2013–14) experimentation was carried out to assess grain yield, nutrient uptake and quality parameters of wheat by various levels of P and Zn. The results revealed that 50% recommended dose of P (RDP) through phospho-enriched compost (PEC) + 50% RDP through fertiliser and soil application of 12.5 kg ZnSO₄.7H₂O ha⁻¹ + one foliar spray of 0.5% ZnSO₄.7H₂O recorded significantly higher grain yield (4.81 and 4.61 t ha⁻¹, respectively), straw yield (7.20 and 6.92 t ha⁻¹, respectively) and protein content (11.5% and 11.3%, respectively). The concentrations of Zn in grain (35.6%) and straw (57.3%) were not affected due to organic P application but 100% P through P fertilizer reduced the Zn content in the grains. Both soil and foliar application of Zn were found to be more promising in increasing Zn and Fe concentration in grains (37.5 and 30.9 mg kg⁻¹, respectively) and straw (60.3 and 398 mg kg⁻¹, respectively). Overall, the treatment combination of 50% RDP through PEC + 50% RDP through fertiliser and soil applied 12.5 kg ZnSO₄.7H₂O ha⁻¹ + one spray of 0.5% Zn was beneficial in reducing antagonistic effect of P on Zn and increasing Zn and Fe concentration in wheat grain and, thus, could be used for improving the yield of Zn and Fe enriched wheat grains.

The practices of the System of Rice Intensification (SRI) methodology have been extended to wheat and various other crops with reported good results. To assess such reports with respect to wheat, an experiment was conducted at the Indian Agricultural Research Institute, New Delhi during 2011–2012 and 2012–2013. This experiment compared the performance of wheat under System of Wheat Intensification (SWI) and standard recommended practices (SRPs). In 2011–2012, the SWI yield of 7.93 t ha⁻¹ was 30% higher than for SRP in 2012–2013, climatically a less favorable year, hence SWI performed relatively better with a 46% yield advantage under climate stress. SWI produced 12.5% less in the stressful year, while the reduction for the SRPs ranged from 18% to 31%. Differences in yield attributes and root traits were also observed in favor of SWI. Available N, P, and K in the soil after harvesting was increased with SWI, whereas depletion in nutrients with the SRPs indicated the scope for SWI sustaining soil fertility. Higher yield compensated for higher SWI costs of cultivation. A net return of US$ 1383 ha⁻¹ was obtained with SWI, 35% more than the US$ 1020 ha⁻¹ from SRPs. Overall, SWI outperformed the SRPs in terms of yields, climate resilience, and economics.