Trade-offs between high yields and soil CO2 emissions in semi-humid maize cropland in northern China

Abstract

Optimizing yields while reducing soil CO2 emissions in cropping systems has become the focus of agricultural study. To explore effective ways to achieve the balance, short-term field experiments (2018–2020) were conducted in North China Plain. Three replications of three-factor combinations of two tillage systems (i.e., no-tillage and conventional tillage), two straw management (i.e., no straw and straw mulch), and two nitrogen fertilization levels (i.e., medium nitrogen of 180 kg N ha1 and high nitrogen of 210 kg N ha1) were arranged in a randomized complete block design. It was discovered that soil CO2 emissions were mainly dominated by soil temperature. No-tillage decreased soil CO2 emissions by 7.3% than conventional tillage, straw mulch promoted soil CO2 emissions than no straw, and high fertilization increased CO2 emissions by 21.8% compared to medium fertilization. However, maize yields were not significantly affected by above treatments. The combinations of agricultural practices that achieved the highest maize yields were medium nitrogen in combination with straw mulch under no-tillage and conventional tillage. The combination of no-tillage, straw mulch, and medium nitrogen decreased soil CO2 emissions intensity by 11.5%. It was concluded that the combination of no-tillage, straw mulch amendment, and medium nitrogen achieved a balanced yields and soil CO2 emissions, which should be recommended for local farmers in North China Plain.