Evaluation of managing nutrient supply to soybean crop on calcareous soil

Calcareous soils, common in arid and semi-arid regions, are characterised by high calcium carbonate content, alkaline pH, and limited availability of macro and micronutrients. These constraints often reduce crop performance, particularly in soybean (Glycine max L.), which is sensitive to nutrient imbalances and iron chlorosis. This study investigated the effect of integrated nutrient management strategies combining inorganic fertilizers, sulphur application, organic amendments, and foliar nutrient sprays on soil properties in calcareous soils. It was aimed to study effect on nutrient management on soybean on calcareous soil using a Completely Randomized Design (CRD) comprised of seven treatments viz; T₁-Absolute control, T₂- RDF (50:75:45 N: P₂O₅: K₂O kg ha^-1), T₃- RDF + two foliar spray of [19:19:19 (1%) + Phule liquid micro-grade II (0.5%)] at 30 and 55 DAS, T₄- RDF (50 kg N through SCU + 75:45 P₂O₅: K₂O kg ha^-1) + two foliar spray of [19:19:19 (1%) + Phule liquid micro-grade II (0.5%)] at 30 and 55 DAS, T₅- RDF + 40 kg S ha^-1 + two foliar spray of [19:19:19 (1%) + Phule liquid micro-grade II (0.5%)] at 30 and 55 DAS, T₆- RDF + soil application of micro-grade I at sowing @ 25 kg ha^-1 + two foliar spray of 19:19:19 (1%) at 30 and 55 DAS and T₇- RDF + 40 kg S ha^-1 + soil application of micro-grade I at sowing @ 25 kg ha^-1 + two foliar spray of 19:19:19 (1%) at 30 and 55 DAS replicated 3 times. Post-harvest soil analysis revealed improved soil available nutrients viz., available N (148 kg ha^-1), available P (17.33 kg ha^-1), available K (286 kg ha^-1) and available S (12.21 mg kg^-1), higher organic carbon (0.45%), and a reduction in calcium carbonate content (11.21%). The findings highlight that balanced nutrient supply, incorporating both macro- and micronutrients through combined application methods, can effectively overcome the limitations of calcareous soils, improve soybean productivity and sustain soil health.