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| Effects of cultivar-fertilizer interactions on nitrogen and phosphorus loss risks in paddy field surface water |
| Received:January 09, 2025 |
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| KeyWord:rice cultivar;controlled-release fertilizer;nitrification inhibitor;surface water;nitrogen and phosphorus loss |
| Author Name | Affiliation | E-mail | | XU Changxin | China National Rice Research Institute, Hangzhou 311401, China | | | FENG Jinfei | China National Rice Research Institute, Hangzhou 311401, China | | | FANG Fuping | China National Rice Research Institute, Hangzhou 311401, China | | | LI Fengbo | China National Rice Research Institute, Hangzhou 311401, China | lifengbo@caas.cn |
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| Abstract: |
| To investigate the interactive effects of rice cultivars and fertilizer types on rice yield, nitrogen-phosphorus loss risks in paddy field surface water. A randomized block design with split plots with three replications was used. The main plots comprised three fertilizer types：conventional fertilization（CK）, controlled-release fertilizer（CRN）, and urea combined with a nitrification inhibitor（DMPP）. The split plots included three rice cultivars：Zhongzheyou 8（ZZY8）, Yongyou 1540（YY1540）, and Zhehexiang 2（ZHX2）. The results showed that under all fertilization treatments, the concentrations of total nitrogen（TN）and nitrate nitrogen（NO3--N）in paddy field surface water reached their peak levels at 1 day and 7 days after fertilization, respectively, while ammonium nitrogen（NH4+-N）peaked within 1-3 days after fertilization, followed by a continuous decline. The application of different fertilizer types significantly influenced peak nitrogen concentrations and speciation distribution in paddy field surface water. The TN peak concentration under the CRN treatment was comparable to that of the half-fertilized CK while all nitrogen forms in the CRN treatment showed slower reduction rates, with TN decreasing to 5 mg · L-1 prior to mid-season field drying. Integrated analysis of nitrogen speciation dynamics following basal and supplemental fertilization revealed that the 7-day period post-application constitutes the critical window for mitigating nitrogen losses in paddy field surface water. Across all fertilization regimes, NH4+-N dominated the dissolved nitrogen pool, with the CRN treatment exhibiting the highest NH4+ - N / TN ratio（61.36% - 65.43%）. The cultivation of different rice cultivars significantly influenced nitrogen content dynamics in surface water of paddy fields. Cultivating YY1540 significantly reduced TN, NH4+-N, and NO3--N concentrations by 12.19%, 16.50%, and 11.15%, respectively. The interaction between YY1540 and CRN resulted in the lowest average concentrations of all nitrogen forms in surface water, while simultaneously achieving significantly higher grain yield, nitrogen partial factor productivity（NPFP）, and phosphorus partial factor productivity（PPFP）compared to other treatments. Application of CRN fertilizer demonstrated substantial reductions in total phosphorus（TP）and dissolved inorganic phosphorus（DIP）concentrations, with reduction rates reaching 29.45% and 21.65% respectively. However, no significant interaction effect between rice cultivar and fertilizer type was observed on phosphorus content dynamics in surface water. In summary, cultivating indica-japonica hybrid rice（YY1540）and applying CRN had the best effect on rice yield increase and the risk of nitrogen and phosphorus loss in paddy field surface water. |
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