Effects of Mulching Cultivation Practices on Nitrogen Use Efficiency, Soil Carbon Sequestration and Net Ecosystem Economic Budget of Rainfed Summer Maize in Sub‐Humid but Drought‐Prone Regions of Northwest China

ABSTRACT Ridge‐furrow planting with plastic film mulch has been widely applied for improving maize production in sub‐arid and sub‐humid areas around the world, but the effects of various ridge‐furrow patterns and film colors on nitrogen fertilizer utilization, net ecosystem carbon budget, and net greenhouse gas emission intensity remain poorly understood. Field trials were undertaken during 2023–2024 to explore the impacts of six mulching cultivation practices, including flat planting without mulch (FN), flat planting with straw mulch (FS), ridge‐furrow planting with transparent film mulch on the ridge (RP), ridge‐furrow planting with transparent film mulch on continuous ridges (RFCt), ridge‐furrow planting with silver‐black film mulch on continuous ridges (RFCs), and ridge‐furrow planting with black film mulch on continuous ridges (RFCb) on grain yield, nitrogen use efficiency, and soil carbon sequestration of dryland summer maize in the Loess Plateau of China. Relative to FN, the five mulching practices significantly improved grain yield, nitrogen use efficiency, and net ecosystem economic budget, with RFCb exhibiting the largest increases by 51.1% in grain yield, 96.5% in plant nitrogen uptake, 96.5% in nitrogen uptake efficiency, 51.8% in partial factor productivity, 26.5% in nitrogen harvest index, 87.7% in net ecosystem economic budget, and a decrease of 45.9% in soil nitrate residue compared to FN. Compared to FN, FS and RFCb increased net ecosystem carbon budget by 248.9% and 233.3%, decreased net greenhouse gas budget by 637.5% and 286.3%, and reduced net greenhouse gas emission intensity by 639.7% and 179.8%, respectively. Among mulching practices, RFCb was environmentally friendly while obtaining the greatest grain yield, nitrogen use efficiency, and net ecosystem economic budget, and the lowest soil nitrate residue, with its soil carbon sequestration second only to that of FS, which was considered a preferred planting practice for dryland summer maize production in northwest China.