Response of Labile Organic Matter Fractions to Plastic Film Removal During Maize (Zea Mays L.) Growth in Semiarid Farmland Soil

Abstract

Understanding the differences of labile soil organic matter between plastic film mulching at all growing stages (FM) and plastic film removal after the silking stage (RM) is essential to identify changes in soil quality and N availability. Compared to the FM treatment, the RM treatment significantly decreased the microbial biomass C (MBC) content, water soluble organic C content in the 0-20 cm layer and extractable organic C content in 2011 at milk stage (R3); however, it significantly increased the MBC content at planting time (PT) or the 6th leaf stage (V6) of the next growing season. Moreover, compared with the FM treatment, the RM treatment significantly increased the microbial biomass N content from silking stage to physiological maturity (R6) in the 0-20 cm layer and extractable organic N (EON) content at R6 in 2012; however, it significantly decreased the water soluble organic N (WSON) content at R3 and the WSON and EON contents at PT or V6 of the next growing season. Thus, plastic film mulching with film removal during the maize reproductive stages could be an excellent option for maintaining soil quality and improving soil N availability in the temperature-and rainfall-limited regions of northwest China.