Effects of plastic mulch and nitrogen fertilizer on the soil microbial community, enzymatic activity and yield performance in a dryland maize cropping system

Abstract Farming practices that integrate plastic film mulching and nitrogen (N) fertilization have been extensively used to enhance crop productivity. However, the interactive effects of mulching and N application on soil microbial properties and crop yields have received little attention. A 2‐year field experiment was carried out in the Loess Plateau to investigate the independent and combined effects of plastic mulch and N application rate on the soil microbial population, enzymatic activity and grain yield. From 2016 to 2017, two mulching patterns (i.e., plastic mulching and no mulching) were exposed to five different N application rates (0 (N 0 ), 80 (N 80 ), 160 (N 160 ), 200 (N 200 ) and 240 (N 240 ) kg N ha −1 ). N application significantly affected the soil microbial community composition, as suggested by significant increases in soil total bacteria, cellulose‐decomposing bacteria and the bacterial‐to‐fungal ratio with N rates. In contrast, the mulching pattern significantly affected soil extracellular enzyme production. Furthermore, there were significant effects of mulching, N application and their interaction on grain yield. The highest grain yield (11,728 kg N ha −1 in 2016 and 12,350 kg N ha −1 in 2017) in both growing seasons was consistently obtained under plastic mulching with a N level of 200 kg N ha −1 . Our study showed that plastic mulching significantly affected extracellular enzyme production, and N fertilizer application significantly affected the composition of the soil microbial community. Highlights Independent and coupled effects of mulching and N application on soil biological properties and grain performance were explored. N application significantly influenced soil microbial community composition. Mulching pattern rather than N application independently and significantly affected soil extracellular enzyme production The combined application of plastic mulching with 200 kg N ha −1 should be seem as an optimum crop production pattern in this area.