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 major challenge of growing soybean, other than unfavorable weather and small farm size, is the non-availability of quality inputs at the right time. Furthermore, in soybean growing regions, crop productivity and soil environment have deteriorated due to the use of traditional varieties and conventional methods of production. Soybean crop intensification or system of crop intensification in soybean (SCI) is an agricultural production system that boosts soybean yields, improves the soil environment, and maximizes the efficiency of input utilization, although the contribution of SCI to crop productivity is not well understood as different genotypes of soybean exhibit different physiological responses. Therefore, a field study was conducted in 2014–2015 and 2015–2016 using three crop establishment methods (SCI at a 45 cm × 45 cm row spacing, SCI at 30 cm × 30 cm, and a conventional method at 45 cm × 10 cm) assisted in vertical strips with four genotypes (Pusa 9,712, PS 1347, DS 12–13, and DS 12–5) using a strip-plot design with three replications. Compared with standard methods of cultivation, the adoption of SCI at 45 cm × 45 cm resulted in a significantly higher stomatal conductance (0.211 mol H₂O m⁻²s⁻¹), transpiration rate (7.8 mmol H₂O m⁻²s⁻¹), and net photosynthetic rate (398 mol CO₂m⁻²s⁻¹). The implementation of an SCI at 30 cm × 30 cm had significantly greater intercepted photosynthetic active radiation (PAR) (1,249 mol m⁻²s⁻¹) than the conventional method system, increasing crop yield from 9.6 to 13.3% and biomass yield from 8.2 to 10.7%. In addition, under an SCI at 30 cm × 30 cm, there were more nodules, significantly larger root volume and surface density, and increased NPK uptake compared with the other methods. Significantly greater soil dehydrogenase activity, alkaline phosphatase activity, acetylene-reducing assay, total polysaccharides, microbial biomass carbon, and soil chlorophyll were found with SCI at 45 cm × 45 cm (13.63 g TPF g⁻¹soil hr.⁻¹, 93.2 g p-nitro phenol g⁻¹soil hr.⁻¹, 25.5 n moles ethylene g⁻¹soil hr.⁻¹, 443.7 mg kg⁻¹soil, 216.5 mg kg⁻¹soil, and 0.43 mg g⁻¹soil, respectively). Therefore, the adoption of an SCI at 30 cm × 30 cm and/or 45 cm × 45 cm could provide the best environment for microbial activities and overall soil health, as well as the sustainable productivity of soybean aboveground.

A field experiment was conducted during the winter season (rabi) of 201112 and 201213 at New Delhi, to find out the impact of irrigation schedules and nutrient management on wheat [Triticum aestivum (L.) emend. Firoi & Paol.] varieties. Two nutrient-management practices, i.e. 100% recommended dose of fertilizer (RDF) and 50% RDF + 50% recommended dose of nitrogen (RDN) through FYM were applied and 3 irrigation schedules i.e. irriga- tion at crown root initiation stage (CRI), CRI + flowering stage and irrigation at all critical stages were allocated to main plots and 4 wheat varieties (HD 2967, WR 544, HD 2987 and HD 2931) were allocated to sub-plots in split-plot design with 3 replications. Application of 50% RDF + 50% RDN through FYM gave significantly higher number of tillers/m2, spike length, number of spikelets/spike, grains/spike, 1,000-grain weight and grain yield. Irri- gations at all critical stages resulted in significantly higher tillers/m2, spike length, spikelets/spike, grains/spike, 1,000-grain weight and gain yield. Leaf-area index (LAI), crop-growth rate (CGR), relative growth rate (RGR) and net assimilation rate (NAR) were found significantly higher under 50% RDF + 50% RDN through FYM and irriga- tions at all critical stages. Among the varieties, HD 2967 gave significantly higher gross returns (77.6 103 /ha) over the other varieties during the first year. However, during the second year the yield was at par with HD 2987. Between irrigations schedules, irrigations at all critical stages and application of 50% RDF + RDN 50% through FYM gave significantly the highest gross returns, net returns and benefit: cost ratio. Root length, volume and dry weight were higher under irrigations at all critical stages and application of 50% RDF + RDN 50% through FYM.

A field experiment was conducted during rainy season of 2009 at the research farm of the Indian Agricultural Research Institute, New Delhi to evaluate the appropriate combination of pre-emergence and post-emergence herbicides in direct-seeded rice (Oryza sativa L.). All the weed control treatments brought significant increase in grain (25-52%) and straw yield (27-58%) as compared to season long crop weed competition. Cyhalofop-butyl residues in soil were found below detectable level indicating safety to soil microbial population and succeeding crop. It may be concluded that weeds can be managed during critical period of competition with the sequential application of pretilachlor (750 g/ha) as pre-emergence followed by post- emergence application of cyhalofop-butyl (60 g/ha) at 30 DAS in direct-seeded rice.