Effect of integrated nutrient management on physico-chemical parameters of soil in rice-wheat system

Abstract

A field experiment was conducted to assess the effects of combined application of organic manure through biogas slurry in the form of bio gas slurry (BGS) and inorganic NPK fertilizers on soil physico-chemical properties of soil in rice, wheat or stevia. Laboratory analysis on the soil samples collected (October 2013) from an on-going long-term field experiment (in progress since Kharif 2009–10) was made. The organic manure through BGS @ 6 t ha−1 was incorporated along with nitrogen fertilizer (N @ 80 and 120 kg ha−1), phosphorus fertilizer (P @ 30 kg ha−1) and potassium fertilizer (K @ 30 kg ha−1) to the rice crop. In the wheat crop, nitrogen fertilizer (N @ 120 kg ha−1), phosphorus fertilizer (P @ 0, 30 and 60 kg ha−1) and potassium fertilizer (K @ 30 kg ha−1) were applied without addition of organic manure. Results showed that the application of organic manure through BGS along with inorganic fertilizers decreased the soil pH and electrical conductivity (EC), whereas, the increased content of soil organic carbon (OC), available nitrogen (N), phosphorus (P) and potassium (K) was found in these treatments. On the other hand, among the physical properties, the bulk density (Db) and particle density (Dp) were found to decrease, whereas the water holding capacity (WHC) and porosity increased with the addition of organic manure along with chemical fertilizers under rice-wheat system.