Vol. 10, Issue 9 (2021)

Author(s):
Priyanka Kumari, Shailja Kumari, Rajeev Padbhushan, Anshuman Kohli, Yanendra Kumar Singh, Sanjeev Kumar Gupta, Mainak Ghosh, Sudhanshu Singh and Ashish Kumar Srivastava

Abstract:
The present investigation was carried out in an on-going fertigation experiment involving rainfed rice based cropping systems initiated in June, 2014 at the farm of Bihar Agricultural University, Sabour, Bhagalpur, Bihar, India. This study was conducted during the sixth cycle of the system (Kharif, 2019). The sample for analysis was taken from two depths of soil (0-15cm and 15-30cm). Split plot design was taken having 12 treatments which replicates thrice. Top soil as well as subsoil nitrogen availability was found more to be a function of the fertilizer addition and crop uptake rather than biological nitrogen fixation by legumes. The highest fertigation regime resulted in significantly higher nitrogen availability in the surface soil at the time of rice crop establishment but this did not persist till the harvest of the rice crop, when significantly higher nitrogen availability in the surface soil was found in the lowest fertigation regime. After rice harvest, ammonical and nitrate nitrogen content was also found to significantly higher in the lowest fertigation regime in the top soil and in the highest fertigation regime in the sub soil. Top soil nitrogen availability seems to directly influence the nitrogen uptake by rice from the sub soil which has significance for the system sustainability.