Integrated mulching and nitrogen management strategies influence carbon footprint and sustainability of wheat production on the Loess Plateau of China

Context: Ridge-furrow with plastic film mulching (RPM) has been promoted to improve water use efficiency and crop productivity. However, limited information exists regarding the effects of substituting adding irrigation (AI) with the RPM on economic benefit, carbon footprint (CF) and the sustainability of wheat (Triticum aestivum L.) production, especially under optimizing nitrogen (N) fertilization on the Loess Plateau of China. Objectives: An eight-year field experiment was conducted to evaluate the economic feasibility, soil organic carbon (SOC) sequestration and the CF for wheat production under shifting the adding irrigation with a higher N application rate to the water-efficient field management strategies with a lower N application rate, and to assess the sustainability of wheat production under different N application rates and planting patterns. Methods: A factorial experiment was arranged in a split-plot design with four replications. The main plots were two N levels (i.e., 120 and 240 kg N ha(-1)), while four planting patterns [i.e., conventional rainfed flat planting (CRF), AI, RPM, and straw mulching (SM)] were assigned to subplots. After measurement of plant-derived biomass and SOC analysis, we evaluated wheat grain yields and economic performance, and calculated SOC sequestration rate (C-seq rate) and the CF during the eight-year experiment periods. Finally, considering the aspects of crop yields, economic benefit, SOC concentration, and GHG emissions, the integrated sustainable evaluation index (SEI) of each field management strategy was calculated. Results: Reducing the N application rate significantly decreased grain yields (4.3%), C-seq rate (31.6%), the intensity of CO2-eq emissions produced per unit of grain yields (CFGY, 26.6%) and per unit of economic profit (CFEP, 26.4%), while had no significant effect on economic profit and SEI. Compared with the CRF, the RPM significantly enhanced grain yields (11.2%) and C-seq rate (48.1%), and SEI (10.6%), while exerting no significant effect on economic profit, CFGY and CFEP. The RPM significantly reduced grain yields (7.2%), CFGY (13.9%) and CFEP (26.7%), but increased the SEI (8.5%) relative to the AI. The SEI value was also enhanced by 7.2% under RPM than that under SM. Conclusions: The integrated strategies of plastic film mulching in combination with a low N application rate might enhance grain yields, economic profit, and soil C sequestration, ultimately achieving sustained wheat production in the studied region.

Automated summary

This study conducted an eight-year field experiment and found that substituting high irrigation levels with water-efficient plastic film mulching strategies can improve the economic feasibility, soil organic carbon sequestration, and carbon footprint of wheat production on the Loess Plateau of China, ultimately achieving sustainable wheat production.