Research On Suitable Spectral Index Dynamics And Regulation Factor Model Of Fertilizer Period In Rice

Nitrogen is an important element for the growth and development of crops.Excessive nitrogen input is not conducive to high yield and high quality production of crops,but also leads to a decline in the utilization rate of nitrogen fertilizer,resulting in certain environmental pollution and resource waste.In this paper,the optimal spectral index which can reflect the growth status of rice in the whole growth period is studied systematically,and the dynamic model of the appropriate spectral index in the whole growth period of rice is constructed.At the same time,through the period of n,n application rate and production relations,the quantitative research in the process of rice growth in different periods of topdressing nitrogen effect,build the rice with nitrogen fertilizer effect factor model in different periods,provides reference for rice n precise control.Through three years of field test data on test(2 test sites,4 varieties,2 planting methods)of rice nitrogen fertilizer experiment,the constructed under different nitrogen levels and different fertilizing period of rice population.The portable active spectrometer(RapidSCAN cs-45)was used to test the spectral index of rice from the whole growth period after transplantation,and the corresponding agronomic data(LAI,Dry matter weight,Nitrogen accumulation,etc.)of the corresponding period were obtained synchronously.Agronomic parameters and spectral correlation analysis results show that the whole growth period under the best overall correlation index NDRE and agronomy parameters,the whole growth period NDRE present "Growth-peak-fall" normal distribution model,gaussian functions available on the simulation,RAGDD is a function independent variable and NDRE is a dependent variable,Function expression to y=y0+A×e-(?-?c)2/2×w2.In the model,there are four parameters including y0,A,?c and W,respectively.y0 is the early-stage trough spectral value,which is regarded as the background value or threshold value of soil around;the parameter A value is the image amplitude,that is,the difference between the maximum spectral index and the lowest spectral index in the whole rice breeding period.The parameter y0+A is the peak value of the image.Corresponding to the maximum spectral index value of the full growth period under different treatments,where the maximum spectral index value of the whole growth period is taken as the time process(DAT or RAGDD)value required for the model to reach the peak value;W as the shape parameter,as the image of half wave,W=FWHM/(?).The analysis shows that y0+A has A good correlation with the final yield,so the rice grain yield estimation model is constructed based on the model parameter y0+A.A given target under the condition of production,using yield estimation model,calculation of parameter y0 and A value,so as to realize based on the output of target of rice growth period is suitable for spectrum index dynamic simulation.Fertilizer effect factors of different nitrogen recovery periods were studied by the change of fertilizer application time forward,retardation and deficiency.After tillering fertilizer,spikelet-promoting fertilization was applied every 10 days(a),a total of five times until spikelet-protecting fertilization(b),each processing notes for T+10,T+20 T+30,T+40 T+50,Among them,T+30 is the deficiency of spikelet-protecting fertilizer,T+50 is the deficiency of spikelet-promoting fertilizer.Lead a/b value between 0 and 1.Due to fertilizer effect factor by light,temperature,water,gas,etc,and the type of soil and structure,and other environmental factors,therefore,respectively by Ni and N2 processing parameters of grain yield and nitrogen gradient y0+A value,the highest peak of the MAX distance(i.e.,the maximum yield)to 1,and other various processing will fall in it,by other processing compared with MAX range of the ratio of the total distance for the processing effect factors,Finally established the time scale for RAGDD rice whole growth period of fertilizer effect factor change model,the test results showed that the fertilizer effect factor changing with time series presents a yuan quadratic equation Y=aX2+bX+c parabolic changes,in tillering stage RAGDD about 0.35-0.40 times,rice is sensitive to fertilizer level,the largest fertilizer use efficiency is highest.This research at the early stage of the predecessors' research rice flower index on the basis of dynamic development to build the whole growth period of rice spectral index dynamic model,and for different production targets,carried on the quantitative study of model parameter,for the whole growth period of rice growing diagnosis to provide the basis.At the same time,the dynamic model construction of fertilizer effect factors under the dynamic time series of rice full-growth period provides the technical support for the accurate fertilizer application of rice in the future.