Effects Of Different Fertilization Patterns On Yield And Nutrient Loss In One-Season Rice

As the most important food crop in China,nitrogen and phosphorus loss caused by long-term excessive or improper fertilization in rice cultivation is one of the main sources of agricultural non-point source pollution.The application of controlled-release compound fertilizer and organic fertilizer has a certain promoting effect on achieving stable crop yield increase and reducing agricultural non-point source pollution.The application of organic fertilizer can also improve soil environment.After two years of field experiments,we have had an in-depth understanding of four fertilization modes:non-fertilization（CK）,conventional fertilization（CF）,controlled release compound fertilizer reduction（CRF）and organic fertilizer replacement（OM）.Find the effects of four fertilization modes on nitrogen and phosphorus concentration in field water,nitrogen and phosphorus runoff and leakage loss,rice yield and fertilizer use efficiency,the main results were as follows:Under different fertilization modes,the peak value of TN concentration in field surface water（two-year average）was different.The modes of CF,OM and CRF were 85.79,56.47and 40.31 mg﹒L^-1,respectively.The concentration stays the same for seven days after it reaches its lowest level.Compared with the CF model,the peak concentration of TN in OM and CRF models（two-year average）decreased by 30.52%and 56.36%,respectively.the concentration of TP,DP and PP in each fertilization modes reached a peak on the first day after fertilization,with the maximum concentration being 2.46-12.59 mg﹒L^-1,1.16-5.94 mg﹒L^-1,0.16-2.83 mg﹒L^-1in 2017 and 2.15-11.02 mg﹒L^-1,1.01-5.20 mg﹒L^-1and 0.14-2.48mg﹒L^-1in 2018,Compared with CF,the peak TP concentration in CRF and OM modes decreased by 29.26%and 72.33%,respectively.Under different fertilization modes,the cumulative runoff TN loss under CF,OM and CRF modes were 14.14,11.95 and 9.41 kg﹒hm^-2,respectively.The cumulative TN loss of CK mode was 34.95%-52.55%of that of other fertilization modes,indicating that fertilization significantly increased nitrogen runoff loss.The cumulative TP loss of CK,CF,OM and CRF models was 0.43,2.21,1.29 and 0.81 kg﹒hm^-2,respectively.The maximum average TP loss in CF mode was 1.11 kg﹒hm^-2,Compared with CF mode,the average TP loss in OM mode and CRF mode decreased by 41.48%and 63.49%,respectively.The cumulative loss of TP in CK mode was only 7.27%～19.75%of that in the other three fertilization modes.Two years’experiment results showed that the seepage of total nitrogen concentration in different growing stages of rice showed similar regularity CF>OM>CRF>CK.Compared with CF mode,TN peak concentration（two-year average）of OM mode and CRF mode decreased by 16.37%and 51.46%respectively.The change trend of TN in CK mode is not obvious,indicating that fertilization could increase the possibility of TN leaking into the ground.The average concentration gradient of TP in soil seepage solutions was CF>OM>CRF>CK,Both CRF mode and OM mode could significantly reduce the average TP concentration in soil seepage,compared with CF model,it was reduced by 43.18%and30.33%,respectively.The N and P utilization rates were 37.74%～45.96%and 21.32%～24.34%respectively under different fertilization modes（2-year average）.The utilization ratio of nitrogen and phosphorus was the highest in CRF mode,and the nitrogen utilization ratio was 8.19%and8.69%higher than OM mode and CF mode,respectively,and the phosphorus utilization ratio was 2.97%and 2.88%higher,respectively.The results showed that the rice yield in the CF,OM and CRF models was significantly higher than that in the CK model in two years.This indicated that fertilization could significantly increase rice yield,the rice yield of CRF mode was significantly higher than that of CF and OM mode in two years,Although the yield difference between OM mode and CF mode is not significant,the yield of OM mode is higher than CF mode in two years with the same amount of fertilizer applied.To sum up,the controlled-release compound fertilizer Single-Season Rice appropriate reduction can obviously improve the utilization rate of nitrogen,phosphorus,increase the yield of rice,organic alternative mode of paddy fields to reduce nutrient loss and stable production has a role in promoting,but the effect of controlled release nitrogen fertilizer on mode better,The economic benefit and environmental benefit of rice production were both achieved.