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

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.