Maize-soybean intercropping reduces greenhouse gas emissions from the fertilized soil in the North China Plain

• Published in: Journal of soils and sediments 2024-08, Vol.24 (8), p.3115-3131
• Main Authors: Raseduzzaman, Md, Dong, Wenxu, Gaudel, Gokul, Aluoch, Stephen Okoth, Timilsina, Arbindra, Li, Xiaoxin, Hu, Chunsheng
• Format: Article
• Language: English
• Subjects: Agricultural ecosystems; Agricultural practices; Carbon dioxide; Carbon dioxide emissions; Cereal crops; Continuous cropping; Corn; Cropping systems; Denitrification; Earth and Environmental Science; Emissions; Emissions control; Environment; Environmental Physics; Fertilizers; Fluxes; Greenhouse gases; Intercropping; Manures; Moisture content; Monoculture; Nitrification; Nitrogen; Nitrous oxide; Sec 5 • Soil and Landscape Ecology • Research Article; Soil; Soil moisture; Soil Science & Conservation; Soil temperature; Soil treatment; Soils; Soybeans; Synergistic effect; Urea; Ureas; Water content
• ISSN: 1439-0108; 1614-7480
• DOI: 10.1007/s11368-024-03859-x

Background and Aim Continuous monocropping with high nitrogen (N) fertilizer input substantially increases greenhouse gas (GHG) emissions in maize-based agroecosystems in the North China Plain (NCP). Introducing soybeans as an intercrop with maize and partially substituting urea with manure might effectively decrease GHG emissions. The aim of this study was to quantify the synergistic effect of maize-soybean intercropping and manure on soil GHG emissions. Methods A two-year field experiment with three cropping systems (maize monocrop, soybean monocrop, and maize-soybean intercrop) and four N treatments (control, urea, manure, and manure + urea) was carried out at Luancheng Agro-Ecosystem Experimental Station in the NCP. All N treatments, except the control, received 150 kg N ha −1 season −1 , either full dose as a basal application or two equal split applications. Results Results showed that all treatments contributed as a net source of N 2 O and CO 2 fluxes but acted as a net sink of CH 4 fluxes. In both cropping seasons, intercrops had significantly lower N 2 O emissions compared to monocropping systems, with 38% and 14% less emissions than maize monocrops in 2018 and 2019, respectively. Additionally, maize monocrops had significantly higher soil CO 2 emissions than other systems, while maize-soybean intercropping had 12% and 13% less CO 2 emissions than maize monocrops in 2018 and 2019, respectively. Among fertilized treatments, manure-treated soils emit notably lower N 2 O fluxes compared to sole urea treatments. In this study, N 2 O and CO 2 fluxes had a strong positive correlation with soil mineral N concentrations, soil temperature, and moisture content. Possibly due to more efficient N utilization, intercrop soils exhibited significantly lower NH 4 + and NO 3 − concentrations, leading to reduced nitrification and denitrification in the system, resulting in lower N 2 O emissions from maize-soybean intercrops. Conclusion Our findings indicate that intercropping maize and soybean reduces soil NH 4 + and NO 3 – concentrations, as well as significantly decreasing soil N 2 O and CO 2 emissions when compared to traditional maize monoculture. Therefore, due to its potential for reducing soil GHG emissions, maize-soybean intercropping can be regarded as an effective alternative cropping system to the prevailing maize-dominant monoculture to develop a sustainable agroecosystem in the NCP region.