The Effects of Irrigation Amount and Method on Soil CO2 Emission and Yield of Summer Maize

Abstract

【Objective】 Maize is an important staple crop in central and northern China, and during certain seasons, its cultivation needs irrigation. This paper studied]s the intertwined effect of irrigation amount and method on soil CO2 emissions and the yield of summer maize. 【Method】 The field experiment compared two irrigation methods: conventional drip irrigation (DI) and alternating drip irrigation (ADI). For each irrigation, there were two irrigation amounts: 36 and 27 mm. In each treatment, we measured CO2 emission using the Li-8100A. We also measured soil enzymatic activity, soil water content and temperature, and grain yield, from which we analyzed the dependence of soil CO2 emission on soil water-filled porosity (WFPS) and soil temperature. 【Result】 Compared to DI, ADI reduced cumulative soil CO2 emission by 12% to 17%. Increasing irrigation amount from 27 mm to 36 mm increased cumulative soil CO2 emissions, despite the increase depending on irrigation method. A notable correlation was found between soil CO2 emission and WFPS and soil temperature in the 0~10 cm soil layer. The impact of soil water and temperature on CO2 emission was intertwined. Irrigation amount and method both affected soil enzyme activity via their effect on WFPS and soil temperature, which serve as a regulatory mechanism impacting soil CO2 emissions. Irrigation amount and method also significantly affected maize yield. Compared with DI with irrigation amount of 36 cm, ADI with irrigation amount of 27 mm reduced the yield by 8.7%, but it reduced the cumulative CO2 emission by 19%. 【Conclusion】 ADI with 27 mm of irrigation was most effective to ensure maize yield while reducing soil CO2 emissions. It is a water-saving and emission-reducing irrigation method and can be used as an improved agronomic practice for maize production in the studied region.

Keywords

• maize
• alternate drip irrigation
• co2 emissions
• soil enzymatic activity
• yield