Plastic film-mulched ridges and straw-mulched furrows increase soil carbon sequestration and net ecosystem economic benefit in a wheat-maize rotation

Abstract

The application of soil mulching has been widely used to increase crop production in arid, semi-arid, and sub-humid areas, with plastic film-mulched ridges and straw-mulched furrows (RFPS) proving to be more effective as compared with other soil mulching practices. However, few research studies have comprehensively assessed the impacts of RFPS on greenhouse gas (GHG) emissions, grain yield, net ecosystem carbon budget (NECB), and net ecosystem economic budget (NEEB) compared against the single practices of either plastic film mulching or straw mulching. A three-year field experiment was conducted on a wheat (Triticum aestivum L.)-maize (Zea mays L.) rotation field in the southern Loess Plateau, China. Four treatments were evaluated: (1) conventional flat planting without mulching (CK), (2) flat planting with plastic film mulching (PM), (3) flat planting with straw mulching (SM), and (4) RFPS. All mulching practices significantly increased wheat and maize yields as well as the seasonal cumulative carbon dioxide (CO2) emissions from soil respiration (Rs) and ecosystem respiration (Re) compared with CK. RFPS had the greatest annual grain yield and the greatest Rs for wheat seasons. The average annual NECB values for CK and PM were − 1.47 and − 1.05 Mg CO2-eq ha−1 yr−1, respectively, where the negative values indicated that the soil in CK and PM acted as a carbon (C) source. SM and RFPS acted as C sinks because of the straw C input, having average annual NECB values of 1.46 and 1.74 Mg CO2-eq ha−1 yr−1, respectively. PM, SM, and RFPS significantly increased the average annual NEEB by 31.4%, 70.5%, and 60.3%, respectively, compared with CK. Although RFPS had greater C input and grain yield income, it also had greater Rs, harvest removal C loss, and agricultural input costs, resulting in similar NECB and NEEB to what was observed with SM. Considering that the greatest grain yields were obtained with RFPS, this production practice should be a promising method for maintaining greater, more stable crop production, while increasing soil C sequestration and NEEB for the wheat-maize cropping system in dry semi-humid regions such as the southern Loess Plateau of China.