| Optimization of water and carbon management modes for paddy fields in different hydrological years based on the DNDC model |
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| DOI：10.7606/j.issn.1000-7601.2020.04.12 |
| Key Words: paddy field water\|saving irrigation straw return soil organic carbon hydrological year yield water productivity DNDC model |
| Author Name | Affiliation | | JIANG Zewei | College of Agricultural Science and Engineering,Hohai University, Nanjing, Jiangsu 210098, China | | YANG Shihong | College of Agricultural Science and Engineering,Hohai University, Nanjing, Jiangsu 210098, China
State Key Laboratory of Hydrology\|Water Resources and Hydraulic Engineering, Hohai University, Nanjing, Jiangsu 210098, China | | DING Jie | College of Agricultural Science and Engineering,Hohai University, Nanjing, Jiangsu 210098, China | | SUN Xiao | College of Agricultural Science and Engineering,Hohai University, Nanjing, Jiangsu 210098, China |
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| Abstract: |
| In order to explore the optimal water and carbon management modes for paddy fields in different hydrological years, the DNDC model was verified and validated based on data from two years of field experiments. Three typical hydrological years were selected to simulate the influences of different irrigation modes and straw\|return levels on soil organic carbon (SOC) and rice yield in the lower paddy field. The results showed that DNDC model well simulated SOC and rice yield dynamics under controlled irrigation. Different irrigation modes affected SOC and rice yield, while the SOC of the 0~10 cm soil layer in the CS treatment was slightly lower than that in FS(0.25%~1.92%), but the rice yield was higher than FS(0.32%~8.13%). With the improvement of straw returning level, the SOC in different hydrological years showed a gradually rising trend, but the results of rice yield and water productivity were different. In the normal year, the “S” curve appeared first rising and then stable, and reached the peak at the level of 6 500 kg·hm-2 of straw returning to the paddy field. In the wet year, straw returning increased rice yield more significantly than that in dry year.Compared with 1 000 kg·hm-2, the rice yield and water productivity of 8 000 kg·hm-2increased by 1.95% and 2.27% in 1964 (dry year), and 4.36% and 4.38% in 1977 (dry year). Therefore, the coupling of water\|saving irrigation and straw returning was a recommended water and carbon management mode. The recommended straw returning levels were 6 000, 6 000, and 7 500 kg·hm-2 in normal, dry, and wet years, respectively. At this time, the SOC and yield reached 99.2% and 89.8% of the potential, respectively, and the water productivity was 43.5% higher than that of flooding treatment. |
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