An attempt was made to quantify soil properties using hyperspectral remote-sensing techniques and machine-learning algorithms. In total, 100 soil samples representing various locations and soil-nutrient statuses were collected, and the samples were analyzed for soil pH, EC, soil organic carbon, available nitrogen (AN), available phosphorus (AP), and available potassium (AK) by following standard methods. Soil had a wide range of properties, i.e., pH varied from 5.62 to 8.49, EC varied from 0.08 to 1.78 dS/m, soil organic carbon varied from 0.23 to 0.94%, available nitrogen varied from 154 to 344 kg/ha, available phosphorus varied from 9.5 to 25.5 kg/ha, and available potassium varied from 131 to 747 kg/ha. The same set of soil samples were subjected to spectral reflectance measurement using SVC GER 1500 Spectroradiometer (spectral range: 350 to 1050 nm). The measured spectral signatures of various soils were organized for developing a spectral library and for deriving various spectral indices to correlate with soil properties to quantify the nutrients. The soil samples were partitioned into 60:40 ratios for training and validation, respectively. In order to select optimum bands (wavelength) from the soil spectra, we have employed metaheuristic algorithms i.e., Particle Swarm Optimization (PSO), Moth–Flame optimization (MFO), Flower Pollination Optimization (FPO), and Battle Royale Optimization (BRO) algorithm. Further partial least square regression (PLSR) was used to find the latent variable and to evaluate various algorithms for their performance in predicting soil properties. The results indicated that nutrients could be quantified from spectral reflectance measurement with fair to good accuracy through the Battle Royale Optimization technique with a $R^2$ value of 0.45, 0.32, 0.48, 0.21, 0.71, and 0.35 for pH, EC, soil organic carbon, available-N, available-P, and available-K, respectively.

Rainfall deficits and erratic dry spells pose major challenges in rainfed ecosystem. In-situ moisture conservation practices (MCP) like ridge–furrow methods, improve soil moisture but are inadequate during 2–3 week dry spells at critical crop stages (flowering and maturity), leading to yield loss. Supplemental irrigation (SI) using an ex-situ rainwater harvesting (RWH) pond can mitigate these effects, but optimizing the pond design is challenging due to limited runoff and storage losses. This study aims to design RWH pond for small farm holders with a 1.0 ha area and evaluate its efficient use for SI during intermittent dry spells and critical crop stages. The design volume was estimated using the SCS-CN method based on daily rainfall data (1974–2010) for the northeast monsoon. A pond with a capacity of 487.5 m³, constructed for a 1 ha micro-watershed, was used to observe the runoff for design validation. The harvested runoff can be used as SI for a cultivable area of 0.4 ha, based on the watershed-to-cultivable area ratio. Statistical analysis of observed and estimated runoff data from 2011 to 2023 revealed a strong correlation (r = 0.87), confirming the pond design. Harvested rainwater, applied through micro-irrigation (rain gun) at a depth of 50 mm during moisture stress periods, significantly improved cotton productivity. The combined use of harvested rainwater and MCP increased yield in the range of 3.8 to 25.3%, improved rainwater use efficiency (1.52 to 3.13 kg ha⁻¹ mm⁻¹), and had a higher benefit-cost ratio (1.15 to 2.43) over a 13-year period. This study concludes that integrating in-situ MCP with ex-situ RWH with micro-irrigation significantly improves rainfed crop productivity in vertisols.

Long term manure fertilizer experiments provide valuable information on the impact of long term adoption of nutrient management systems with varying sources, types and combinations of plant nutrient inputs on soil fertility and productivity. A Permanent Manurial Experiment (PME) under rice monoculture is in operation since 1975 at the central farm of the Agricultural College and Research Institute, Madurai. The present study was taken up to evaluate the effects of different manure – fertilizer schedules on certain properties of the soil, available nutrient status, total microbial population and enzyme activities of the soil. In this experiment, four main plot treatments involving three organic manures viz., FYM, GLM and UC @ 12.5 t ha^-1 with a no manure control and eight sub plot treatments viz., control N,P,K,NP,NK,PK and NPK. The 57th rice crop (Var ADT 49) was raised during rabi 2016 with NPK recommended dose of 150:50:50 kg N, P₂O₅ and K₂O respectively. The maximum total bacterial population (128 x 10⁶ CFUg^-1 of dry soil), total fungal population (70 x 10⁴ CFUg^-1 of dry soil) and total actinomycetes population ( 84 x 10³ CFUg^-1 of dry soil) were registered in the plots that received integrated application of GLM @ 12.5 tha^-1 and 100% recommended NPK (150:50:50 kgha^-1 during this season). However compared to the bacterial population, the inorganic fertilizers did not have much influence on the fungal population as that of the organic manures. Integrated application of GLM @ 12.5 tha^-1 along with N fertilizer with or without P and K registered the maximum dehydrogenase activity, during tillering stage of rice crop. The maximum yields of rice grain and straw (4790 and 8701 kg ha^-1) respectively was recorded in the treatments that received GLM and NPK and it was evident that the inclusion of FYM or GLM or Urban compost along with NPK, N, NP, and NK fertilizers recorded significantly higher yields than their individual applications and unmanured and unfertilized control.

A field experiment was conducted during 2022–23 to 2024–25 at the AICRPDA Research Farm, Tamil Nadu Agricultural University, Kovilpatti, India, to evaluate climate-smart agri-horti systems integrating aonla (Phyllanthus emblica Gaertn.) and custard apple (Annona squamosa L.) with annual intercrops under rainfed conditions. The experiment, laid out in a split-plot design with three replications, included fruit tree species as main plots and blackgram (Vigna mungo L.), greengram (Vigna radiata L.), clusterbean (Cyamopsis tetragonoloba L.), and foxtail millet (Setaria italica L.) as sub-plot treatments. Custard apple–based systems consistently produced higher fruit yield (2674–3306 kg ha⁻¹), intercrop biomass, and blackgram equivalent yield (1337–1653 kg ha⁻¹) than aonla-based systems (1980–2538 kg ha⁻¹ of fruit yield), and 891–1142 kg ha⁻¹ of blackgram equivalent yield of intercrops, respectively), primarily due to improved light availability and favourable canopy architecture. Clusterbean and foxtail millet recorded the highest intercrop yields, whereas pulse intercrops enhanced tree growth, soil nitrogen availability, and system sustainability through biological nitrogen fixation. Maximum rainwater use efficiency and land equivalent ratio were achieved under custard apple + clusterbean and aonla + foxtail millet combinations, indicating superior resource-use efficiency. Relative economic efficiency peaked in aonla + foxtail millet (341.2%), while the highest system profitability was recorded in custard apple + foxtail millet (₹352.4 ha⁻¹ day⁻¹). Soil fertility improved significantly over the study period, with increases in soil organic carbon (1.05–1.76 g kg⁻¹), available nitrogen (9–11 kg ha⁻¹), and potassium (8–14 kg ha⁻¹), particularly under pulse-based systems, whereas available phosphorus in soil remained unchanged. The study demonstrates that integrating short-duration legumes and millets with perennial fruit trees enhances productivity, profitability, rainwater-use efficiency, and soil health, providing a resilient and sustainable strategy for intensifying rainfed agroecosystems.

Multi nutrient deficiencies in soil have been reported with increasing frequency over the past two decades on a worldwide scale, is considered as an important factor that reduces yield and affects the quality of harvested products. Nutrient cycling and transformation of in soil is influenced by microbes and the availability of organic and inorganic nutrients to plants and microbes can both be controlled through enzyme activities. Keeping this in view a field experiment was conducted at O. Alangulam village of Thiruparankundram block, Madurai district, Tamil Nadu during 2016-18 to evaluate the influence of organic and inorganic sources of nutrients on soil microbial population and enzyme activities and optimize the sulphur requirement of Jasmine (Jasminum sambac) which plays a key role in enhancing the yield and quality of flowers. The significantly higher bacterial population of 124 × 10⁶ CFU g^-1 was observed in the treatment that received pressmud as sulphur source @ 60 g sulphur/plant/year along with RDF (recommended dose of fertilisers were applied @ 60:120:120 g of N:P₂O₅:K₂O/plant/ year in the form of urea, SSP and MOP).This was followed by the treatment that received pressmud @ 40 g sulphur/plant/year along with RDF (111 × 10⁶ CFU g^-1). Application of inorganic NPK fertilizers without organics decreased the activities of dehydrogenase and aryl sulphatase enzymes. The flower yield hectare^-1 ranged from 3.8 to 15.4 tonnes ha^-1as influenced by various nutrient sources. Application of RDF along with Gypsum @ 60 g sulphur/ plant/year recorded significantly higher yield followed by the treatment that received RDF along with Pressmud @ 60 g sulphur/plant/year.

Influence of establishment methods and seed coating techniques on the performance of direct seeded rice (Oryza sativa L.) under Periyar Vaigai command area of Tamil Nadu Journals are one of the best online open access journal site in the field of publishing research articles in Agricultural, animal, dairy, food, home, legume Research Journals on a Global platform.