Fertilizer Effects Of Nitrogen And Phosphorus On Yield And Diagnosis Of Plant Nitrogen And Phosphorus With Remote Sensing Of Dryland Winter Wheat

The yield of crops was limited in rainfined agriculture due to lack of natural precipitation and poor soil fertility.Under the unchangeable natural condition,fertilizer nitrogen（N）and phosphorus（P）are become two main inputs materials to regulate the crop nutrition in the process of winter wheat production for fertilizer modification in soil so as to improving yield.Therefore,it is important to study the fertilizer effects of nitrogen and phosphorus on yield and diagnosis of plant nitrogen and phosphorus nutrition in a rapid way to develop agricultural production with a method of cost saving and reduce fertilizer pollution.For the requirement of less fertilizer and more yield of winter and its nutrition quick and real time diagnosis in Guanzhong plain,one site experiment including five N fertilizer levels（0,75,150,225 and 300 kg N/hm²,marked N0,N1,N2,N3,N4 respcetively）and four P fertilizer levels（0,75,150 and 225 kg P₂O₅/hm² marked P0,P1,P2,P3 respcetively）in all twenty combined treatment was conducted from 2011 to 2017 to study response of light energy use efficiency,fertilizer use efficiency,yield and economic benefit of winter winter to different nitrogen and phosphorus application rate.In addition,the high precision nitrogen and phosphorus nutrition remote sensing monitoring model were established respectively in winter wheat nutrition regulation key growth stages（Jointing stage,booting stage and heading stage）.The aim of this study was to provide a practical experience and scientific basis to efficient field management and dynamic regulation for winter wheat.The main results of this experiment are as follows:（1）Effects of different N and P fertilizers on winter wheat light use efficiencyDifferent combined N and P fertilizer treatments significantly affect photosynthetic productivity（chlorophyll content,photosynthetic rate and shoot dry matter accumulation）and light energy interception（leaf area index,photosynthetically active radiation component）of winter wheat.With the increasing of nitrogen and phosphorus application rate,wheat photosynthetic production capacity showed a trend of increasing firstly and then smoothed,fertilizer rate increased to a level N3 and P2,photosynthetic capacity stabled at a high level;However,the light energy interception ability of wheat group increased with the increase of fertilizing amount,and the leaf area of winter wheat and the photosynthetic effective radiation component of N4 and P3 were significantly higher than that of other treatments.Compared of nitrogen group treatments,grain light use efficiency was no longer increased after N2.Under phosphorus group treatments,the grain light efficiency was maximized at the level of P2.Under the combined treatment of nitrogen and phosphorus,the light energy utilization rate of N2P2 was 0.48%,and the straw light use 0.40%.This fertilizer treatment can synergistically increase the interception and utilization of light energy,the production of photosynthetic products and their transport and accumulation efficiency,and up to the high level in both total light use efficiency and grain light use efficiency.Therefore,recommended 150 kg/hm² of nitrogen fertilizer and 120 kg/hm² of phosphate fertilizer be the appropriate ratios of nitrogen and phosphorus for winter wheat from the perspective of light use efficiency of winter wheat.（2）Effects of N and P fertilizers on winter wheat on fertilizer use efficiencyThe nitrogen and phosphorus fertilizer use efficiency of winter wheat was decreased with the increase of fertilizer application and improved in combined nitrogen and phosphorus fertilizer treatment.Comprehensive analysis of nitrogen and phosphorus fertilizer use efficiency and the accumulation of nitrogen and phosphorus in grain,combined nitrogen and phosphorus treatment N2P2 with a higher nitrogen and phosphorus fertilizer use efficiency and the amount of nitrogen and phosphorus fertilizer input was equal to that of the grain nitrogen phosphorus removal.It can well satisfy the crop growth and development in the process of the demand for nitrogen and phosphorus nutrition and maintain the soil nitrogen and phosphorus nutrient balance,therefore,from the point of view of fertilizer use efficiency,this study recommends the N application rate of 150 kg/hm² cooperate is 120 kg/hm² P fertilizer rates was the high fertilizer use efficiency application rate in this area.（3）Effects of N and P fertilizers on winter wheat yield and economic benefitThe increasing of panicle number and spike number resultd in the increasing of yield under the nitrogen and phosphorus fertilizer treatment,and the panicle per unit area increasing was the greatest contributor to the increase of yield,and the number of spike grains followed.The wheat yield,the number of panicles and panicles was increased firstly and then decreasd with the increasing of nitrogen and phosphorus application rate,reached maximum（8553kg/hm²ï¼‰under N2P2 treatment,and also achieve maximum economic benefits（11533yuan/hm²ï¼‰.To establish the dual effect equation of nitrogen fertilizer and phosphorus concentration on yield and economic benefit,obtained 203 kg/hm² N fertilizer and 117kg/hm² P fertilizer under the dual effect equation of yield and 188 kg/hm² N fertilizer coupled106 kg/hm² P fertilizer was most appropriate fertilizer amount.（4）N nutrition remote sensing diagnosie for winter wheatThe relevance sensitive area between winter wheat canopy spectral NDVI and plant nitrogen content were basically consistent at different growth stages,it is mainly concentrated in near infrared（780¹330 nm）,visible light（750⁷70 nm）region,red edge（640⁷00 nm）region and visible light（450⁵00 nm）region.NDVI（748,787）was selected during the jointing stage and the fitting equation is y=-5.353x²+15.228x-2.3245,fitting accuracy R² is0.8667;NDVI（756,782）was selected at booting stage and the fitting equation is y=-0.723x2+0.2456x+2.0878,the fitting accuracy R² was 0.8947;The NDVI（765,780）was selected at the heading date.The fitting equation was y=-7.343x²+12.484x-2.4536,and the fitting accuracy R² was 0.8531.The fitting model of establishing plant nitrogen content at different growth stages has a higher accuracy and stability,and can be used for prediction of plant nitrogen nutrition in winter wheat.The relevance sensitive area between winter wheat canopy spectral NDVI and plant nitrogen content were basically consistent at different growth stages,it is mainly concentrated in near infrared（780¹330 nm）,visible light（750⁷70 nm）region,red edge（640⁷00 nm）region and visible light（450⁵00 nm）region.Based on the vegetation index of different sensitive bands,this experiment established and verified the total nitrogen content estimation model of winter wheat plant with nitrogen nutrition sensitivity but insensitive to phosphorus in different reproductive stages.NDVI（748,787）was selected during the jointing stage.The fitting equation is y=-5.353x²+15.228x-2.3245（R²=0.8667）;NDVI（756,782）is selected at booting stage,fitting equation is y=-0.723x²+0.2456x+2.0878（R²=0.8947）;NDVI（765,780）was selected at the heading stage,the fitting equation was y=-7.343x²+12.484x-2.4536,（R²=0.8531）.The fitting model for establishing nitrogen content in different growth stages has high accuracy and stability,and can be used for prediction of plant nitrogen nutrition in winter wheat.（5）P nutrition remote sensing diagnosie for winter wheatThe correlation between NDVI and plant P content in winter wheat canopy spectral range was less stable than that in nitrogen,and the trend of variation at different growth stages was less stable.The bands with higher sensitivity were mainly concentrated in NIR（780¹330nm）.Visible light（450⁶80 nm）and visible light（750⁷70 nm）regions,the coefficient of determination is approximately 0.6⁰.87;The coefficient of determination at the jointing stage is the highest in the different growth stages,the lowest in the booting stage,followed by the heading stage,and the nitrogen stress（N0）Non-nitrogen stress treatment（N2）plants overlapped in the total P sensitive area.Based on the NDVI vegetation index at different sensitive bands,this experiment established and validated a model for estimating total phosphorus content in winter wheat plants that was not sensitive to nitrogen but sensitive to phosphorus during different growth stages.NDVI was selected during the jointing stage（742,443）.The fitting equation is y=-9.347x²+16.228x-2.6276（R²=0.6167）,NDVI（745,445）is selected at booting stage,and the fitting equation is y=-0.023x²+0.2036x+2.0318（R²=0.6597）.NDVI（780,465）is selected at the heading date.The fitting equation is y=-8.357x²+13.485x-2.1276（R²=0.6637）.The established diagnostic model is stable and can be used to better estimate the phosphorus content of plants,and is more suitable for the interaction of nitrogen and phosphorus.Comprehensive,the winter wheat in 150²00 kg/hm² nitrogen application rate coupled P application of 100¹20 kg/hm² grew well,showed a high light energy use efficiency and nutrient use efficiency,achieved high yield and economic benefit.Constructed hyperspectral remote sensing technology of nitrogen and phosphorus nutrition monitoring model has good stability and reliability which can provide a reference for the development and application of nitrogen and phosphorus nutrient management technology in dryland winter wheat...