Heat stress caused due to increasing warming climate has become a severe threat to global food production including rice. Silicon plays a major role in improving growth and productivity of rice by aiding in alleviating heat stress in rice. Soil silicon is only sparingly available to the crops can be made available by silicate solubilizing and plant-growth-promoting bacteria that possess the capacity to solubilize insoluble silicates can increase the availability of soluble silicates in the soil. In addition, plant growth promoting bacteria are known to enhance the tolerance to abiotic stresses of plants, by affecting the biochemical and physiological characteristics of plants. The present study is intended to understand the role of beneficial bacteria viz. Rhizobium sp. IIRR N1 a silicate solublizer and Gluconacetobacter diazotrophicus, a plant growth promoting bacteria and their interaction with insoluble silicate sources on morpho-physiological and molecular attributes of rice (Oryza sativa L.) seedlings after exposure to heat stress in a controlled hydroponic system. Joint inoculation of silicates and both the bacteria increased silicon content in rice tissue, root and shoot biomass, significantly increased the antioxidant enzyme activities (viz. superoxidase dismutase, catalase and ascorbate peroxidase) compared to other treatments with sole application of either silicon or bacteria. The physiological traits (viz. chlorophyll content, relative water content) were also found to be significantly enhanced in presence of silicates and both the bacteria after exposure to heat stress conditions. Expression profiling of shoot and root tissues of rice seedlings revealed that seedlings grown in the presence of silicates and both the bacteria exhibited higher expression of heat shock proteins (HSPs viz., OsHsp90, OsHsp100 and 60 kDa chaperonin), hormone-related genes (OsIAA6) and silicon transporters (OsLsi1 and OsLsi2) as compared to seedlings treated with either silicates or with the bacteria alone. The results thus reveal the interactive effect of combined application of silicates along with bacteria Rhizobium sp. IIRR N1, G. diazotrophicus inoculation not only led to augmented silicon uptake by rice seedlings but also influenced the plant biomass and elicited higher expression of HSPs, hormone-related and silicon transporter genes leading to improved tolerance of seedling to heat stress.

Initial evaluations of the System of Rice Intensification in India and elsewhere focused mainly on its impacts on yield and income, and usually covered just one or two seasons. Researchers at the ICAR-Indian Institute of Rice Research have conducted a more comprehensive evaluation of SRI methods over six years (six wet and six dry seasons), comparing them with three alternatives: modified, partially mechanized SRI (MSRI) to reduce labor requirements; direct-seeded rice (DSR) as an alternative method for growing rice; and conventional transplanting of rice with flooding of fields (CTF). Grain yield with SRI methods was found to be about 50% higher than with CTF (6.35 t ha⁻¹ vs. 4.27 t ha⁻¹), while the MSRI yield was essentially the same (6.34 t ha⁻¹), 16% more than with DSR (5.45 t ha⁻¹). Water productivity with SRI methods was 5.32–6.85 kg ha-mm⁻¹, followed by 4.14–5.72 kg ha-mm⁻¹ for MSRI, 5.06–5.11 kg ha-mm⁻¹ for DSR, and 3.52–4.56 kg ha-mm⁻¹ for CTF. In comparison with CTF, SRI methods significantly enhanced soil microbial populations over time: bacteria by 12%, fungi by 8%, and actinomycetes by 20%. Biological activity in the rhizosphere was also higher as indicated by 8.5% greater dehydrogenase and 16% more FDA enzymes in soil under SRI management. Similarly, an indicator of soil organic matter, glucosidase activity, was 78% higher compared to CTF. SRI enhanced the relative abundance of beneficial microbial-feeding nematodes by 7.5% compared to CTF, while that of plant-pathogenic nematodes was 7.5% lower under SRI. Relative to conventional methods, SRI management reduced GHG emissions by 21%, while DSR reduced them by 23%, and MSRI by 13%, compared to standard rice-growing practice. Economic analysis showed both gross and net economic returns to be higher with SRI than with the other management systems evaluated. While the six-year study documented many advantages of SRI crop management, it also showed that MSRI is a promising adaptation that provides similar benefits but with lower labor requirements.

Intensive agriculture is the chief cause of soil degradation, particularly in regions with low soil organic carbon status, such as semi-arid southern India. In the quest to attain sustainable yield and improved soil quality, conservation agriculture (CA) is being advocated and adopted globally, including in India. In this experiment, CA was implemented to investigate the synergistic impacts of tillage and weed management on soil quality index and system yield and to identify a remunerative treatment combination that can sustain system yield and enhance soil quality. Contrasting tillage practices (main plots) included the T₁: conventional tillage with cotton–conventional tillage with maize–fallow, i.e., no Sesbania rostrata (Farmers’ practice), T₂: conventional tillage with cotton–zero tillage with maize–zero tillage with Sesbania rostrata and T₃: zero tillage with cotton + Sesbania rostrata residues–zero tillage with maize + cotton residues–zero tillage with Sesbania rostrata + maize stubbles. Weed management tactics (sub-plots) were W₁: chemical weed control, W₂: herbicide rotation, W₃: integrated weed management and W₄: single hand-weeded control in a split-plot design with cotton–maize–Sesbania cropping system over 3 years, in a split-plot design. Principal component analysis (PCA) was performed using the soil quality index (SQI)-CAL Version 1.0 software tool to extract minimum datasets from measured soil properties. A total of 40 soil variables were analyzed at 60 DAS and after the maize harvest, then subjected to principal component analysis (PCA) and subjected to PCA in soil quality index (SQI)-CAL software as to choose variables, minimum dataset and obtain soil quality index. The following soil properties, soil organic carbon (SOC), silt fraction, available soil zinc (Zn), iron (Fe), potassium (K), nitrogen (N), pH, electrical conductivity (EC), soil carbon to nitrogen (C:N) and cation exchange capacity (CEC), were selected as indicators based on correlations, calculated PCA and adept opinions on texture and lime concretions of experimental soil. The soil quality index improved by 23.34% in the T₃W₄ compared to T₁W₁. The system yield was 51.79% higher with the adoption of T₃W₃ compared to T₃W₄ combinations. Therefore, considering both system yield and soil quality index, T₃ and W₃ were remunerative and the best treatment combination among all others to sustain both soil and crop productivity in this region.

Arbuscular mycorrhizal Fungi (AMF) are essential in agriculture and are often inter-linked with glomalin-related soil protein (GRSP) production which supports binding of aggregates, enhanced SOC and biological attributes. However, conservation agricultural practices in agroecosystem may have significant impact on AMF diversity, GRSP and soil quality-related parameters (SQRPs). This current experiment was implemented to gauge AMF conization percentage (AMF-CP), GSRP and significant changes on critical SQRPs, and to investigate the linkages between AMF-CP, GRSP and SQRPs as influenced by synergistic tillage and weed management in CA. Contrasting tillage practices (Main plots) included the T₁:Conventional tillage with cotton- Conventional tillage with maize-fallow i.e., No Sesbania rostrata (Farmers’ practice), T₂:Conventional tillage with cotton- Zero tillage with maize- Zero tillage with Sesbania rostrata and T₃: Zero tillage with cotton + Sesbania rostrata residues- Zero tillage with maize + Cotton residues- Zero tillage with Sesbania rostrata + Maize stubbles. Weed management tactics (Sub plots) were W₁: Chemical weed control, W₂: Herbicide rotation, W₃: Integrated weed management and W₄: Single hand-weeded control. The roots and soil samples were collected at 60 DAS of maize. Analysis of examined parameters was done duly following standard protocols. The observed results indicated that 22.50 % of AMF-CP, 16.50 % of EE-GRSP and 12.08 % of T-GRSP was significantly higher in conservation tillage compared to T₁ (Farmers practice). SQRPs followed similar trend in the case of tillage. Significantly higher SMBC and β-galactosidase (β-GaA) was exhibited by W₄ and W₃. A highly significant positive correlation of AMF-CP and T-GRSP pool with SOC (r = 0.951∗∗ and 0.756∗∗), SMBC (r = 0.872∗∗ and r = 0.761∗∗), β-GaA (r = 0.916∗∗ and r = 0.832∗∗) and WSA_1–2mm (r = 0.888∗∗ and 0.882∗∗), respectively was also observed. Generally, AMF-CP and GRSP, and SQRPs correlated positively and significantly. The following parameters; T-GRSP, SOC, WSA_1–2mm, SMBC and β-GaA were selected as potential indicators to gauge the soil quality based on calculated principal component analysis (PCA). In general, the examined parameters in the study are highly supported by zero-till + crop residues, and can be considered indicators for monitoring agroecosystem.