Effects of different nutrient supply options on system productivity, nitrogen use efficiency and soil enzyme activities in maize - wheat cropping system cropping system

The field experiments were conducted during during kharif and the following rabi seasons of 2011-12 and 2012-13 with five different treatments in maize (Zea mays L.) and wheat (Triticum aestivum (L.) emend Fiori & Paol.) cropping systems. Application of 50% RDF + 50% RDN recorded maximum WEY of maize (3.23 and 4.58 t/ha) and system productivity (8.20 and 9.03) over rest of the treatments, but remained statistically similar with other treatments except control during 2011-12 and 2012-13, respectively. The highest ANUE (5.07 and 15.36 kg grain yield increase/kg N applied) of maize crop was recorded at 50% RDF + 25% RDN + BF, followed by 50% RDF + 25% RDN during both the years. The highest ANUE (17.64 and 17.18 kg grain yield increase/kg N applied) of wheat crop were recorded from 37.5% RDF + 37.5% RDN + BF during both the years, respectively. Application of 50% RDF + 50% RDN to maize resulted in increased the value of MBC (18.0 and 18.4%), DH (22.9 and 18.6%), alkaline phosphatase (33.3 and 29.6%) and urease (37.1 and 37.8%) over control during 2011 and 2012, respectively. An increased value of MBC (38 and 34.6%), DH (29.2 and 29.8%), alkaline phosphatase (37.2 and 34.9%) and urease (30.1 and 25.6%) was recorded with the application of 37.5% RDF + 37.5% RDN + BF to wheat over control during both the years, respectively. Bangladesh J. Bot. 53(3): 429-438, 2024 (September)