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| Straw incorporation affects the annual nitrogen and phosphorus runoff risk from paddy fields in the lower Yangtze River,China |
| Received:May 03, 2020 |
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| KeyWord:straw incorporation mode;N fertilizer application rate;N and P runoff risk;yield |
| Author Name | Affiliation | E-mail | | ZHANG Gang | Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
Changshu Agroecological Experimental Station of the Chinese Academy of Sciences, Changshu 215555, China | | | ZHANG Shi-jie | Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
Changshu Agroecological Experimental Station of the Chinese Academy of Sciences, Changshu 215555, China | | | WANG De-jian | Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
Changshu Agroecological Experimental Station of the Chinese Academy of Sciences, Changshu 215555, China | djwang@issas.ac.cn | | YU Yuan-chun | College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China | | | ZHANG Lei | Institute of Yuanhui Planning and Design of Yanzhou District, Jining, Yanzhou 272000, China | |
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| Abstract: |
| To clarify the effects of straw incorporation and nitrogen(N) application rate on the annual N and phosphorus(P) runoff risk in paddy fields, we regularly monitored the concentrations of N and P in the surface water of a paddy field in rice season and the runoff water in wheat season. The effects of five treatments:recommended N fertilization rate without straw incorporation(N1), with wheat straw incorporation(WN1), with rice straw incorporation(RN1), with both wheat and rice straw incorporation(WRN1), and conventional N fertilization rate with both wheat and rice straw incorporation(WRN2), on the annual N and P runoff risk in a paddy field in the lower Yangtze River were studied. The results showed that all straw incorporation modes increased the annual yield of wheat and rice by 9.03%~18.5%, among which the WRN1 and RN1 treatments had a significantly higher annual yield compared to that of the WN1 treatment. Compared with the WRN2 treatment, the WRN1 treatment maintained the field's high yield. Under the recommended N fertilizer rate, straw mulching reduced the dissolved total N(DTN) concentration in surface water in the rice season and runoff water in the wheat season by 5.17%~14.9% and 12.3%, respectively, and reduced the risk of N runoff from the paddy field. Additionally, it increased the dissolved total P(DTP) concentration by 6.67%~33.3% and 30.0%, respectively, as well as increased the risk of P runoff. Among the three straw incorporation models, the concentrations of DTN and DTP in the surface water during rice season under the RN1 model were lower than those under the WRN1 and WN1 models, and there was no significant difference in DTP concentration between the RN1 and N1 treatments. Under the double season's straw incorporation, the WRN1 treatment significantly reduced the DTN concentration in surface water by 12.4% but had no significant effect on the DTP concentration relative to that of the WRN2 treatment. Therefore, the "rice straw incorporation in wheat season + recommended N fertilizer rate" model is recommended for rice-wheat rotation farmland in the lower Yangtze River region, which could maintain a paddy field's high annual yields and effectively reduce its annual N runoff risk but has no significant impact on the P runoff risk. This is a farming model that considers the benefits of grain production and the ecological environment. |
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