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| DOI：10.13522/j.cnki.ggps.2019299 |
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| The Effects of Soybean-maize Intercropping on N2O Emission from Soil |
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CHEN Jinsai, WANG Guangshuai, ZHANG Yingying, GAO Yang, LIU Kun
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1.Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences/Key laboratory of Crop Water Requirement and Regulation, Ministry of Agriculture and Rural Affairs, Xinxiang 453002, China;2. Graduate School of Chinese Academy of Agricultural Sciences, Beijing 100081, China;3.College of Economics and Management of Shanghai Ocean University, Shanghai 201306, China
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| Abstract: |
| 【Background】Nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) are three main greenhouse gases emitting from soils that have important implications for global warming. N2O emission from soil accounts for 72% of total N2O emanating from agricultural production, and increasing nitrogen use efficiency is thus critical to reducing N2O emission. Previous studies had revealed that intercropping could improve water and nutrient use efficiency, but most of them focused on yield and resource use efficiency while overlooking its consequence for the environment. It remains obscured that if intercropping could reduce bioavailability of nitrogen to microorganisms and enhance its uptake by crops, thereby reducing N2O emission.【Objective】The purpose of this paper to experimentally investigate how maize-soybean intercropping affects their competition for water and nutrients in soil and the consequence for N2O emission.【Method】The experiment consisted of four treatments: Monoculture of maize with nitrogen application at 120 kg/hm2 (SM120), monoculture of maize with nitrogen application at 240 kg/hm2 (SM240), monoculture of soybean with nitrogen application at 120 kg/hm2 (SS), and maize-soybean intercropping with nitrogen application at 120 kg/hm2 (IMS). During the experiment, we measured soil moisture, temperature, inorganic nitrogen and N2O emission in each treatment.【Result】①There was a significant difference in water-filled pores and soil temperature in the 0~10 cm soil between the treatments (P<0.05), with their values in SM120 significantly higher than that in other treatments. ②The inorganic nitrogen content in 0~20 cm soil was lower in IMS than in SS, SM120 and SM240, by 20.4%, 5.3%, and 29.3% (P<0.05) respectively. ③IMS reduced the average N2O emission by 31.98%, 39.16% and 47.80% (P<0.001) respectively, compared with SM120, SM240 and SS. The average cumulative N2O emission in IMS was significantly lower than that in other treatments (P<0.001).【Conclusion】Intercropping soybean and maize could improve nitrogen uptake by the crops, thereby reducing soil inorganic nitrogen content and N2O emission. |
| Key words: : intercropping; maize; soybean; N2O; global warming potential |
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