Waterlogging reduction and wheat yield increase through long-term ditch-buried straw return in a rice-wheat rotation system

Waterlogging stress and rice residue management are two major problems for wheat production in rice-wheat rotation systems. Ditch-buried rice straw return (DB-SR) is designed to incorporate all rice straw residues and has exhibited positive effects on soil carbon sequestration and nitrogen retention. However, little is known about its effects on waterlogging and wheat yield after long-term application. We therefore determined whether DB-SR could reduce waterlogging stress and increase wheat yields through a 6.5-year field experiment. We found that the straw ditches served as hidden drainage channels and could significantly reduce soil moisture content and water potential after rainfall in the wheat fields. However, the drainage effect was dependent on DB-SR burial depths. DB-SR promoted more waterlogging reduction at the depth of 40 cm than 20 cm. Wheat yields began to increase only after DB-SR application for four years. Our results suggest that DB-SR has the potential to solve the problems of waterlogging stress and incorporation of total rice straws, as well as simultaneously maintain or increase wheat grain yield in the rice-wheat rotation system.