Effects Of Combined Application Of N,P And K On Growth And Yield Formation Of Japonica Rice In Cold Region

Rice(Oryza.sativa L.)is an important food crop,which provides food for more than half of the world’s population.N,P and K have a great impact on the growth and development of rice,but unreasonable fertilizer application will not only reduce the yield of rice,but also cause waste of resources,environmental pollution,reduce economic benefits,which is not conducive to the sustainable development of agriculture.Therefore,it is of great significance for high yield and high efficiency cultivation of rice to study the combined application of three fertilizers and determine the optimal application amount of NPK.In this experiment,Dongnong 427,a Japonica Rice Variety in cold region,was used as experimental material to study the effects of combined application of N,P and K Fertilizers on plant height,tillering,leaf area,root morphology and activity,dry matter accumulation and transportation,grain filling characteristics,panicle characters and yield of Japonica rice in cold region by adopting"3414"fertilizer experimental design The optimal amount of fertilizer was used to lay the foundation for rational fertilization of Japonica Rice in cold region.The main results are as follows:(1)Nitrogen fertilizer had the greatest effect on the growth and development of japonica rice in cold region.When the application amount of any two kinds of fertilizer was"2"level,with the increase of the application amount of the other kind of fertilizer,the heading rate decreased,and the leaf area index,root morphological index and root activity increased before heading,but the leaf area index,root morphological index and root activity increased first and then decreased.The effect of combined application of two fertilizers was better than that of single fertilizer application.When the application amount of any fertilizer was"2",the average plant height,tiller number,heading rate,leaf area index,high-efficiency leaf area index at heading stage,high-efficiency leaf area ratio at heading stage,and root system was the most developed.The combined application of three fertilizers was better than the combined application of two fertilizers.N3P2K2 had the highest final plant height and tiller number,the highest heading rate in the treatment without fertilizer,the highest leaf area index and leaf area attenuation rate before heading in the treatment of N3P2K2,and the most developed root system.Leaf area index(LAI)after heading and efficient LAI at heading stage were the highest in N2P2K2 treatment,and root system was the most developed.(2)Nitrogen fertilizer had the best effect on promoting the accumulation of various organs and total dry matter weight.When the application rate of any two kinds of fertilizer was"2",the stem dry matter weight increased gradually with the increase of the application rate of the other fertilizer;the root,leaf,spike and total dry matter weight increased gradually before heading;with the advance of filling process,the root,leaf,spike and total dry matter weight increased first and then decreased.The results showed that the combined application of two kinds of fertilizer had better promotion effect than single application of fertilizer.When the application rate of any fertilizer was"2",the combined application of phosphorus and potassium had the best effect on the dry matter weight of each organ and total dry matter weight.In all fertilization treatments,the stem dry matter weight was the highest in N3P2K2 treatment;the root,leaf,ear and total dry matter weight before heading was the highest in N2P2K2 treatment,and the highest in N3P2K2 treatment after heading.(3)Nitrogen fertilizer had the greatest effect on promoting the production,accumulation and transportation of photosynthetic products.When the application rate of any two kinds of fertilizer was"2",with the increase of the application rate of the other fertilizer,the dry matter transportation of stem and sheath first increased and then decreased;the dry matter transportation of leaves,the transportation rate and the contribution rate of stem and leaf gradually increased;the photosynthetic potential and population growth rate gradually increased before heading,and decreased after heading It increased first and then decreased after heading.When the application rate of any fertilizer was"2",the combined application of the two fertilizers had better promotion effect than the single application of fertilizer.In all fertilization treatments,leaf dry matter transport capacity and transport rate,stem leaf dry matter contribution rate,photosynthetic potential and population growth rate before heading were the highest in N3P2K2 treatment,stem sheath dry matter transport capacity,transport rate and population growth rate after heading were the highest in N2P2K2 treatment.(4)When the application amount of any two kinds of fertilizer was"2",with the increase of the application amount of the other kind of fertilizer,the maximum and average grain filling rate of dominant grains decreased,and the active filling period increased,so as to ensure grain filling fullness;The maximum grain-filling rate and average grain-filling rate of inferior grains increased firstly and then decreased,and the active period increased.The effect of the two fertilizers combined application on the maximum grain filling rate,average grain filling rate and active period of weak grains was better than that of single fertilizer application.Among all fertilization treatments,N3P2K2 treatment had the longest active grain filling period.Fertilization promoted grain filling of inferior grains,increased grain filling rate,prolonged active grain filling period,reduced the gap with superior grains,increased grain weight,and increased grain yield.(5)When the application rate of any two kinds of fertilizer was"2",with the increase of the application rate of the other kind of fertilizer,the number of effective panicles increased,the number of grains per panicle,the length of panicle,the number of branches and the number of grains per branch first increased and then decreased,the seed setting rate decreased,and the change of 1000 grain weight was not significant.When the application rate of any fertilizer was"2",except 1000 grain weight,the panicle character of P and K combined application was the best.In all fertilization treatments,the number of effective panicles was the most in N3P2K2treatment,which was significantly different from other fertilization treatments except for N2P3K2 and N2P2K3;the number of grains per panicle,panicle length,number of branches and grains of branches were the most in N2P2K2 treatment,which was significantly different from other fertilization treatments.(6)When the application rate of any two kinds of fertilizer was"2",the yield increased first and then decreased with the increase of the application rate of the other fertilizer.When the application rate of any fertilizer is"2",the yield of rice is the highest under the combined application of P and K.The results showed that the effect of combined application of three fertilizers was better than that of combined application of two fertilizers,and the yield of N2P2K2 treatment was the highest,which was significantly different from other fertilization treatments.In 2018,the production is 8616.67kg/hm~2,and in 2019,the production is8550.00kg/hm~2.(7)The recommended amount of fertilizer for this soil condition was 131.94kg/hm~2for nitrogen,88.13kg/hm~2for phosphorus and 61.70kg/hm~2for potassium.