Study On Estimation Of Rice Nutrient Demand And Its Variation Mechanism Of Phosphorus Fertilizer Utilization Rate In Northeast China

The increasing demand for food by a growing population poses serious challenges to agricultural production.However,unreasonable fertilization is becoming more and more serious in the pursuit of high yield,leading to many problems such as waste of nutrient resources and ecological environment pollution.Fertilizer utilization rate is an important indicator for judging the efficient use of fertilizer resources,and is of great significance for guiding recommended fertilization and improving nutrient management.This experiment was based on the field test data of rice"3414"in northeast China from 2006 to 2011,and quantitative estimation of soil phosphorus supply?Ps?by phosphorus effect function.Statistical analysis of yield effect indicators of rice phosphate fertilizer in Northeast China,using the method of correlation analysis to study on the variation of phosphorus fertilizer utilization rate in rice;And apply the QUEFTS model to predicting the nutrient requirement of rice under different target yields in Liaoning Province.And the main finding are as follows:?1?Estimation of nitrogen,phosphorus and potassium nutrient requirements of rice in Liaoning Province by QUEFTS model:the average grain yield of rice in Liaoning Province is7242 kg/ha,which is about 12%higher than the average level of China in 2010?6441 kg/ha?,maintaining stable high yield is still the primary goal of rice planting in Liaoning Province.Useing QUESTS model to fitting nitrogen,phosphorus and potassium nutrient uptake curves under different potential yield and target yield?8000 kg/ha?14 000 kg/ha?.The fitting result is shown as a linear-parabolic-platform curve,when the target yield reached the range of 60%?70%of potential yield,the required nutrients showed a linear increase,at this time,the above ground nitrogen,phosphorus and potassium nutrient requirements of 1000 kg grain yield of rice were the same,that were 16.3 kg,3.5 kg and 18.4 kg respectively,and N:P:K=4.66:1:5.26.And the intrinsic efficiencies?IE?of nitrogen,phosphorus and potassium were 61.2 kg/kg,286.2 kg/kg and 54.4 kg/kg,respectively.?2?Statistical analysis was made on the basic yield and efficiency indexes of phosphorus in rice in Northeast China?Liaoning Province and Jilin Province?from 2006 to 2011:The grain yield of rice in the treatment of phosphorus deficiency in Northeast China was 7.10 t/ha,the average yield of total phosphorus fertilizer treatment was 8.12 t/ha,the yield increased was 1.01 t/ha,the effect of phosphate fertilizer on increasing yield was at medium level.The relative yield?Ry?was 0.87kg/kg.The soil phosphorus supply averaged 146.29kg/ha,as it covers a large planting area,the variation range is large,high frequency distribution between120 and 170 kg/ha,and the average phosphorus application rate at the highest yield was 78.44kg/ha.The agronomic efficiency of phosphate fertilizer is 12.90kg/kg on average,which is within the national average for China.The P fertilizer partial productivity averaged 106.08kg/kg,which was lower than the average level of China's major rice producing areas?98.9kg/kg?144.8 kg/kg?.?3?There are two methods for variation of rice phosphate fertilizer utilization efficiency in northeast China?Liaoning Province and Jilin Province?:rice phosphate fertilizer"hunger"degree?Y0/Ps?and relative phosphorus supply capacity of phosphate fertilizer?Popt/Ps?.A quadratic polynomial regression model was established for the degree of"starvation"of rice phosphate?Y0/Ps?,the relative phosphorus supply capacity of phosphate fertilizer?Popt/Ps?and the agronomic efficiency of phosphate fertilizer?AEp?.The results are as follows:Y=-3.307+0.141X₁+11.672X₂+0.204X₁X₂-9.403X² R²=0.999?Y0/Ps—X₁,Popt/Ps—X₂,AEp—Y?At the same time,it is affected by three factors:soil phosphorus supply?Ps?,crop yield?Y0?and maximum phosphorus application?Popt?,which respectively represent the properties of soil,crop and fertilizer.In view of the variation pathway,the improvement of rice phosphate fertilizer utilization efficiency in northeast China can be summarized as two measures:First,to improve the degree of phosphate fertilizer"hunger"-based management.Second,to improve the relative phosphorus supply capacity of phosphate fertilizer-based management.Third,Y0/Ps and Popt/Ps have independent and interrelated effects on the utilization efficiency of phosphate fertilizer,any unilateral improvement should be completed together with other measures.?4?According to Yopt and AEp,the yield types of phosphate fertilizer in rice growing areas were divided into four types,the high yield range of 7940kg/ha?10080kg/ha and low yield range of 5825kg/ha?8114kg/ha,the high efficiency range of phosphate fertilizer is 12.65kg/kg?22.38 kg/kg,and the low efficiency range is 6.86 kg/kg?13.15 kg/kg.Popt/Ps was the main influencing factor for the variation of phosphate fertilizer utilization efficiency in different yield types,which was consistent with the overall results in northeast China.Suggestions for the improvement of planting and management in each region are given:in low yield areas,the rice planting method and the effectiveness of phosphate fertilizer application should be improved,and the"demand"and"supply"of phosphorus in rice should be coordinated.In the areas with low efficiency of phosphate fertilizer,the"hunger"of rice for phosphate fertilizer can be improved by improving rice varieties and moderately increasing the planting density.At the same time,the relationship between the supply capacity of soil phosphorus and the application of phosphate fertilizer was fully coordinated to improve the effectiveness of phosphate fertilizer.