Effects Of Different Fertilization Management On Rice Nutrients Absorption And Nitrogen And Phosphorus Loss In Paddy Fields

In the field pot experiment,four treatments,including BK(no fertilization),CK(conventional compound fertilizer),FT1(organic and inorganic compound fertilizers reduce nitrogen by 20%and phosphorus by 12.5%),and FT2(organic and inorganic biological fertilizers reduce nitrogen by 20%and phosphorus by 12.5%)were set up to study the effects of rice yield,changes of soil nutrient content and dynamic changes of nitrogen and phosphorus concentrations in the surface water under several different fertilization modes.In the field plot experiment of the Chaohu Paihe small watershed,four treatments,including CK(conventional compound fertilizer),ST1(organic and inorganic biological fertilizer replacing 30%nitrogen fertilizer),ST2(loss-of-control fertilizer replacing 30%nitrogen fertilizer),and ST3(organic and inorganic biological fertilizer and loss-of-control fertilizer replacing 15%nitrogen fertilizer respectively)were set up to study the effects of rice yield,changes of soil nutrient content,dynamic changes of nitrogen and phosphorus concentrations in the surface water,nitrogen and phosphorus loss in the runoff,under several different fertilization modes.There are the fllowing results.(1)After the rice is harvested,the soil nutrient indexes of the treatment FT1 and the treatment FT2 are higher than the soil basic nutrient values,but they are all lower than that of the treatment CK,which shows that the application of organic and inorganic compound fertilizer(less Nitrogen 20%,phosphorus reduction 12.5%)and organic and inorganic biological bacterial fertilizer(nitrogen reduction 20%,phosphorus reduction 12.5%)will not cause soil nutrient deficiency,but the effect of improving soil fertility will not be better than conventional fertilization.The soil nutrient indexes of the treatment ST1,the treatment ST2,and the treatment ST3 are higher than the soil basic nutrient values,and they are all higher than that of the treatment CK.Among them,the total nitrogen,total phosphorus,the contents of available phosphorus and organic matter of the treatment ST1(organic and inorganic biological fertilizer replacing 30%nitrogen fertilizer)are higher than other treatments,and the effect of improving soil fertility is better than other treatments.(2)Compared with treatment CK,the average concentrations of total nitrogen in the surface water of treatment FT1 and FT2 decreased by 14.83%,17.41,the average concentrations of total phosphorus in the surface water decreased by 17.39%and 26.08%,respectively.That is,compared with conventional fertilization,the application of organic and inorganic compound fertilizer(reduced nitrogen 20%,reduced phosphorus 12.5%)and organic and inorganic biological bacterial fertilizer(reduced nitrogen 20%,reduced phosphorus 12.5%)can reduce the nitrogen and phosphorus concentration of field water,thereby reducing the potential for nitrogen and phosphorus loss.Compared with treatment CK,the average concentrations of total nitrogen in the surface water of treatment ST1,ST2,and ST3 decreased by 12.2%,6.5%,5.3%,respectively,the average concentrations of total phosphorus in the surface water decreased by 26.7%,15.6%,and 13.3%,respectively,the total loss of total nitrogen in the runoff of treatment ST1,ST2,and ST3 decreased by 35.0%,30.8%,and 25.5%,the total loss of total phosphorus in the runoff of treatment ST1,ST2,and ST3 decreased by 16.3%,21.9%,and 22.5%,respectively.That is,compared with conventional fertilization,the substitution of organic and inorganic biological bacterial fertilizer for 30%nitrogen fertilizer,controlled loss of fertilizer for 30%nitrogen fertilizer,organic and inorganic biological bacterial fertilizer and controlled loss of fertilizer for 15%each can reduce the potential of nitrogen and phosphorus loss in field water and reduce the loss of total nitrogen and total phosphorus in surface runoff effectively.(3)Compared with treatment CK,the effective panicle number,grain number per panicle,grain yield,and grain phosphorus accumulation of treatment FT1 were reduced by 1.17%,1.59%,2.75%,4.70%,respectively,the total accumulation of phosphorus in the aboveground parts of rice treated with treatment FT1 and treatment FT2 decreased by 15.41%and 15.62%,respectively.The above shows that,compared with the the conventional compound fertilizer,the application of organic-inorganic compound fertilizer(nitrogen reduction 20%,phosphorus reduction 12.5%)and organic and inorganic biological bacterial fertilizer(nitrogen reduction 20%,phosphorus reduction 12.5%)can reduce the loss of nitrogen and phosphorus in field water Potential,but it will reduce the total amount of phosphorus accumulation on the ground part of rice,and the application of organic and inorganic compound fertilizer(reduced nitrogen by 20%,reduced phosphorus by 12.5%)will also reduce rice grain yield by 2.75%.Compared with treatment CK,the grain yield of treatment ST1 and ST3 increased significantly by 7.8%and 6.5%,respectively.The yield of treatment ST2 decreased by 2.18%compared with treatment CK.Considering the two factors of rice yield and the control effect of nitrogen and phosphorus loss in paddy fields,the two fertilization modes of organic and inorganic biological bacterial fertilizer replacing 30%nitrogen fertilizer,organic and inorganic biological bacterial fertilizer and loss-control fertilizer combined to replace 30%nitrogen fertilizer are better.The research results provide a theoretical basis for the prevention and control of non-point source pollution in rice fields of Chaohu Basin.