Effect Of Special Controlled Release Blended Phosphorus Fertilizer For Rice In Jiangsu Province

At present,one-time fertilization technology of controlled release blended fertilizer for machine-transplanted rice has a good application effect in rice yield et al.,among which the controlled-release blend fertilizer technique is mostly focused on the study of nitrogen fertilizer and less on phosphorus content.In addition,there are differences in fertilization levels and soil types in different regions of Jiangsu Province,which makes the available phosphorus content in the soil different,resulting in excessive fertilization under the premise of available phosphorus content to meet the needs of rice growth.Therefore,based on onetime fertilization technology of controlled release blended fertilizer for machine-transplanted rice,combined with the precise fertilization technique and the controlled-release blend fertilizer technology.This experiment was carried out in rice growing areas of soils with different basal available phosphorus contents in Jiangsu province(low P in Dafeng District,medium-low P in Rudong County,medium-high P in Xinghua City,and high P in Danyang City)in 2019 and 2020.Set up unfertilized(N0),local conventional high-yield and graded fertilization(CK1),the conventional high-yield fertilization rate of 75%(CK2),controlledrelease blend fertilizer without P(0%P-BBF),50%of phosphorus controlled-release blend fertilizer(50%P-BBF)and controlled-release blend fertilizer(100%P-BBF),controlledrelease blend fertilizer with common phosphate for polyurethane diammonium phosphate(CBBF).The application amount of controlled-release blend fertilizer in 4 treatments was consistent with that of CK2.A total of 7 treatments.To compare the effects of optimize controlled-release blend phosphate fertilizer on rice yield and quality formation,nutrient absorption and utilization and ammonia volatilization,and to explore the appropriate phosphorus ratios of controlled-release blend fertilizer for different ecosites of soil types.The main findings are as follows:1.The yield of 50%P-BBF treatment was different at the ecosite,and P fertilizer could be reduced in medium-high and high P soil.The rice yield increased with the increase of P ratio in controlled-release blend fertilizer,but the increase amplitude of rice yield was different in different soil with basic available P.In low and medium-low P soil,with the increase of P ratio in controlled-release blend fertilizer,the increase amplitude of rice yield increased gradually.In the medium-high and high P soils,the increase amplitude of rice yield decreased between 50%P-BBF and 100%PBBF.Overall,100%P-BBF significantly increased panicles,and ensured the leaf area index and the leaf length and leaf width of the top 3 leaves at the heading stage,thus maintaining the higher dry matter accumulation and making the rice yield the highest.Compared with the CK1 and CK2,50%P-BBF maintained or increased rice yield.In the medium-high and high P soils,while the yield of the low and medium-low P soil decreased.The yield of 0%P-BBF and C-BBF treatments was lower than that of other treatments due to the weak growth of rice population,the decrease of total spikelets and filled grains.2.Different ecosites and treatments had significant effects on rice quality,and 100%PBBF treatment had the best quality.The content of protein and amylose decreased with the increase of phosphorus ratio in controlled-release blend fertilizer,but the trend of taste value was opposite.Compared with the CK1 and CK2,100%P-BBF has a higher taste value,and 50%P-BBF is not significantly different from its taste value.0%P-BBF reduces the taste value of rice,which is mainly manifested in a significant increase in protein content.Compared with the CKi and CK2,CBBF significantly reduced the protein and amylose content in low P and medium-low P content soil,and made the taste quality better than other treatments.In addition,with the increase of the ratio of phosphorus in the controlled-release blend fertilizer,the improvement of rice starch and taste value gradually increased in the low and medium-low P content soil.In medium-high and high P soil,the increase amplitude in rice starch and taste value has a decreasing trend between 50%P-BBF and 100%P-BBF,and the difference between them was not significant,which was related to the content of soil basic available P.There was a problem of excessive application of P fertilizer in the medium-high and high-P soils.In general,100%P-BBF and 50%P-BBF showed better rice quality in medium-high and high P content soil.3.The fertilizer recovery efficiency of rice is different with controlled-release blend P fertilizers,and P fertilizer could be reduced in medium-high and high P soil.With the increase of the ratio of P in controlled-release blend fertilizer,the increase amplitude of NRE of rice in soils with different basal available P content was different.With the increase of the ratio of phosphorus in the controlled-release blend fertilizer,the improvement of rice NRE gradually increased in the low and medium-low P content soil.In medium-high and high-phosphorus soil,the increase amplitude in rice NRE has a decreasing trend between 50%P-BBF and 100%P-BBF.The nitrogen absorption of 100%P-BBF was higher than that of other treatments during the panicle initiation stage and later,which mainly increased the leaf area index at the panicle initiation stage and heading stage,as well as the leaf length and width of the top 3 leaves at the heading stage,and finally increased the NRE.Nitrogen absorption of 50%P-BBF in the low and medium-low P content soil at the panicle initiation stage and heading stage was significantly lower than the CK1 and CK2,but in medium-high and high P content soil,it was higher than the CKi and CK2,thus affecting the NRE.The NRE of 0%P-BBF was significantly lower than the CKi and CK2,mainly due to the weaker growth of the 0%P-BBF population of rice,which affected the nitrogen absorption of rice at various stages.At the maturity stage,the overall nitrogen uptake level of C-BBF was lower than 50%P-BBF,but higher than that of CK2,mainly because of the difference in leaf nitrogen content between the panicle initiation and the heading stage,which affected the nitrogen absorption of rice.With the increase of P ratio in controlled-release blend fertilizer,the amount of P absorbed by rice increased,but the PRE of 50%P-BBF was significantly higher than that of other treatments.100%P-BBF has the highest phosphorus accumulation in the mature stage,which was mainly related to the high phosphorus accumulation at the tilling-panicle initiation stage and the panicle initiation-heading stage.However,its phosphorus application rate was higher,and the final PRE was lower than 50%P-BBF.The performance of C-BBF was different in two years,which may be related to rainfall,which affected the absorption of phosphorus by rice,leading to insufficient supply of P fertilizer in the later period.But the phosphorus absorption was lower than that of the CK1 and CK2 and 100%P-BBF,resulting in lower PRE.4.Controlled release phosphate fertilizer can reduce ammonia volatilization loss in paddy field,and 50%P-BBF ammonia volatilization flux is the least.There was a significant negative correlation between cumulative ammonia volatilization flux and NRE.The cumulative ammonia volatilization flux was CK1>CK2>0%P-BBF>C-BBF>100%P-BBF>50%P-BBF.Due to the weak nitrogen uptake by 0%P-BBF in each growth stage,resulting in its absorption of nitrogen is significantly lower than other treatments,so the cumulative ammonia volatilization flux is significantly higher than 50%PBBF,100%P-BBF and C-BBF.C-BBF reduced the soil urease activity in the early stage,and the ammonia volatilization was less,but the ammonia volatilization increased significantly in the later stage,and finally it was higher than 50%P-BBF and 100%P-BBF.Through regression analysis,it was found that the concentration of ammonium nitrogen had the greatest influence on ammonia volatilization in paddy field.Based on the above results,comprehensively considering the yield,quality and fertilizer utilization of rice,it is not suitable to reduce phosphate fertilizer in low and medium-low P content soil,and 100%P-BBF should be applied.At the medium-high and high P content soil,the application of phosphorus fertilizer can be reduced.The choice of controlled release phosphate fertilizer can better promote the absorption and utilization of nutrients,reduce the loss of nitrogen and improve the NRE of rice compared with ordinary phosphate fertilizer.