Influence of Organic and Inorganic Sources of Nutrients on Soil Physicochemical and Biological Properties under Direct Seeded Basmati Rice

Abstract

Understanding the impact of organic and inorganic fertilizers on soil fertility to boost crop productivity has become crucial. An experiment was conducted with direct seeded rice including various combinations of nutrient sources. The experiment was carried out in a randomized block design with ten treatments viz. T1: control, T2: N75P30K30, T3: N37.5P15K15, T4: biogas slurry (4 t ha-1), T5: N37.5P15K15 + biogas slurry (2 t ha-1), T6: N37.5P15K15 + biogas slurry (4 t ha-1), T7: vermicompost (4 t ha-1), T8: N37.5P15K15 + vermicompost (2 t ha-1), T9: N37.5P15K15 + vermicompost (4 t ha-1), and T10: vermicompost (2 t ha-1) + biogas slurry (2 t ha-1). The application of organic manures either alone, or in combination with chemical fertilizer significantly decreased bulk density and increased organic carbon in soil compared to control. Results revealed that the highest available nitrogen (N) and phosphorus (P) were attain under treatment T6, whereas the available potassium (K) and the biological parameters i.e. microbial biomass carbon (MBC), urease, phosphates, dehydrogenase and geometric mean of enzyme activities were recorded highest under treatment T9, being statistically at par with T6. However, the treatment T9 increased the available N, P, K, MBC, urease, phosphates, dehydrogenase and geometric mean of enzyme activities by 50.7, 57.2, 10.6, 15.2, 20.2, 13.2, 75.0 and 33.9 per cent, respectively over control. The DTPA-extractable micronutrients were increased significantly with application of vermicompost (VC) or biogas slurry (BS) alone or in combination with inorganic fertilizers. Conclusively, the integration of chemical fertilizers (N37.5P15K15) and VC or BS (4 t ha-1) is a promising choice for improving soil health.