Effects of crop residue incorporation on soil‐biodegradable mulch film degradation in a broccoli‐sorghum rotation system

Abstract

Soil‐biodegradable mulch films are designed to be incorporated into the soil at the end of the crop cycle, to be degraded by soil microorganisms. Despite scientific community's growing interest, open field studies on these mulch films are rare, with most research conducted in laboratories. We performed an open‐field trial to evaluate the effect of combining a commercial soil‐biodegradable mulch film with incorporation of broccoli and sorghum crop residues over two cropping seasons. The mulch film was sampled after broccoli harvesting and placed inside mesh bags that were buried horizontally or vertically at different depths. Film biodegradation was assessed by direct (CO2 emissions) and indirect indicators (film mass and area loss). Three experiments were conducted to evaluate a) how incorporating crop residues affect mulch film degradation; b) temporal changes of soil microbial activity after incorporation of crop residues and mulch films; and c) possible bias in measurement of soil CO2 emissions due to horizontal mesh bag orientation. Incorporation of crop residues enhanced mulch film degradation and significantly increased soil esterase activity. However, abundances of soil fungi and bacteria in bulk soil were not enhanced by mulch film presence. Mesh bag orientation did not alter the soil CO2 efflux or affect the degradation degree of mulch films. Film in mesh bags buried at 15 cm depth showed greater degradation than that buried at 5 cm. Future in‐field studies are necessary to evaluate the effects of different crop residues incorporation and of other management practices such as different soil tillage regime.This article is protected by copyright. All rights reserved