The disposal of crop residues from agricultural fields is often seen as a burden due to the difficulties involved. However, this study aims to turn pigeonpea stalks into biochar, which can serve as a fuel substitute and soil amendment to sequester carbon. Different pyrolysis methods were employed to investigate the variations in yield, physicochemical characteristics, and higher heating value (HHV) of biochar produced from pigeonpea stalks. The biochar produced using a muffle furnace exhibited higher fixed carbon and ash content. These characteristics make it beneficial for restoring degraded agricultural soils by enhancing carbon sequestration. In addition, the muffle furnace biochar demonstrated a total potential carbon ranging from 262.8 to 264.3 g of carbon per kilogram of biochar, along with a CO₂ reduction potential ranging from 77.17 to 79.68 CO₂ eq per kg. Both the European Biochar Certificate and the International Biochar Initiative confirmed the agronomic abilities of the biochar and its compliance with the highest quality standards for soil carbon sequestration, with 0.11 H/C and 0.7 O/C ratios. Furthermore, biochar produced by muffle furnace from pigeonpea stalks exhibited superior fixed carbon recovery efficiency (181.66 to 184.62%), densification (5.86 to 6.83%), energy density (1.77 to 2.06%), energy retention efficiency (54.80 to 56.64%), fuel ratio (18.95 to 22.38%), and HHV (30.66 to 32.56 MJ kg⁻¹). Additionally, it had lower H/C and O/C ratios, suggesting its potential as an alternative solid fuel. The results of the characterization of biochar with scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) revealed that the biochar samples prepared with both the methods had carbonyl (C=O), C=C, and aromatic C-H functional groups; however, the biochar prepared in the muffle furnace had more porosity. In summary, this study highlights the potential of using pigeonpea stalks to produce biochar, which can be utilized as a renewable fuel substitute and soil amendment to sequester carbon. The biochar derived from the muffle furnace exhibited desirable physicochemical characteristics, high carbon content, and excellent energy properties, making it a promising option for various applications.

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.

Food grain production has multiplied over the last two decades in India, but natural resources are overexploited in modern farming. Farmers, especially those with small and marginal holdings, are suffering losses more often than not, the cost of production is increasing year after year, and profits are not up to the necessary levels. To address such challenges, there has been a broad recognition of the importance of employing farming system approaches in research. The cultivation of cropping systems with orchard crops and livestock components can play a significant role in the optimal utilization of resources, enhancing energy use efficiency as well as the eco-efficiency index, and reducing carbon footprints. This study was carried out to create a suitable IFS model with high economic and energy efficiency for small-holder farmers in India’s southern plateau and hills with a negligible impact on the environment. The following were the seven models: M₁: Rice − Groundnut; M₂: Rice − Groundnut, Pigeonpea + Sweetcorn (1:3) − Bajra, Bt cotton + Greengram (1:2) − Maize; M₃: Rice − Groundnut, Pigeonpea + Sweetcorn (1:3) − Bajra, Pigeonpea + Maize (1:3) − Sunhemp; Napier grass, Sheep (5 + 1); M₄: Rice − Groundnut, Pigeonpea + Sweetcorn (1:3) − Bajra, Bt cotton + Greengram (1:2) − Maize, Pigeonpea + Maize (1:3) − Sunhemp, Poultry unit; M₅: Guava, Hedge Lucerne, Napier grass, Bt cotton + Greengram (1:2) − Maize, Sheep (5 + 1); M₆: Guava, Bt cotton + Greengram (1:2) − Maize, Rice − Groundnut, Poultry; M₇: Rice − Groundnut, Pigeonpea + Sweetcorn (1:3) − Bajra, Pigeonpea + Maize (1:3) − Sunhemp; Napier grass, Hedge lucerne, Poultry (100), Sheep (5 + 1). Model M₁ was used to represent the local region, and the other models were compared in terms of economics, energetics, greenhouse gas emissions, and employment creation. The M₇ and M₃ models, according to the results, have higher economic efficiency (₹342.3 day⁻¹, ₹263.7 day⁻¹), increase output energy (228,529 and 183,231 MJ) net energy (258,184 and 198,920 MJ), produce net negative emissions (−2842 and −2399 kg CO₂ eq.), and create jobs year-round (112.5 and 110.5 man days year⁻¹), respectively. This is primarily because they have multiple highly efficient components that make them viable for Telangana’s small and marginal farmers.

Conservation agriculture (CA), characterized by reduced tillage, continuous soil cover through mulching or cover cropping, and crop rotation, is established as a sustainable approach for enhancing soil health and agricultural resilience, particularly in cotton-based systems. Several studies indicated that CA in cotton systems played a crucial role in climate mitigation by enhancing soil carbon sequestration and mitigating greenhouse gas (GHG) emissions. CA practices reportedly increased soil organic carbon (SOC) levels, which helped stabilize atmospheric CO₂ Additionally, CA minimized energy-intensive inputs by reducing reliance on machinery, thereby further lowering CO₂ emissions. With reduced tillage, weed management became more challenging but remained essential for productivity, soil health, and sustainability. Research showed that weed management practices in CA systems influenced soil physical, chemical, and biological properties. CA was found to improve physical attributes such as bulk density, soil structure, aggregation, and hydraulic conductivity, which enhanced porosity, root growth, and water infiltration. CA-based weed control helped in stabilizing the soil pH, reducing electrical conductivity, increasing cation exchange capacity, and enhancing SOC, thereby improving nutrient retention. Reliance on herbicides in CA-based cotton systems was shown to impact soil microbial diversity and enzyme activity, varying with herbicide type and frequency of application. Some herbicides temporarily inhibit soil microorganisms and enzyme functions (e.g., dehydrogenase, urease, phosphatases). However, mulching and organic residue retention in CA systems demonstrated positive effects on soil microbial biomass carbon (SMBC) and microbial activity. CA practices gradually stored carbon by sequestering CO₂ in SOC, thereby stabilizing carbon and supporting biodiversity.