| The black soil is a soil with good properties and high fertility.The main crops in Northeast my country are corn and soybeans.This area is the largest commercial grain production base in my country and has an important impact on my country’s food security.The amount of nitrogen fertilizer used in agricultural production in my country is higher than the world average level.Excessive fertilization leads to waste of fertilizer resources and environmental pollution.It is of great significance for the sustainable development of agriculture on black soil to improve the use efficiency of nitrogen fertilizer and optimize the economic benefit under the condition of increasing yield and increasing yield.The research area is located in Dahewan Farm,Zhalantun City,Hulunbeier City,Inner Mongolia Autonomous Region.The research objects are corn and soybeans.Using UAV(Unmanned Aerial Vehicle)remote sensing data and DSSAT(Decision Support System for Agrotechnology Transfer)crop growth model,on the basis of data assimilation,the nitrogen fertilizer management methods of crops are evaluated.The highefficiency utilization of nitrogen fertilizer for crop planting in the black soil region of Northeast China provides technical support,and the main conclusions are as follows:(1)The LAI remote sensing estimation models of maize and soybean under different growth stages were constructed.Through the Relief F contribution analysis,variance inflation factor selection and correlation diagnosis of the selected multispectral vegetation indices,the most suitable vegetation indices for constructing remote sensing estimation models for corn and soybean under different growth stages were screened out.The R~2 of the multiple linear regression model test sets constructed under each growth period of maize was greater than 0.762,and the RMSE was less than 0.282;the R~2 of the multiple linear regression model test sets of soybean under each growth period were greater than 0.780,and the RMSE was less than 0.583.The LAI estimation models of the two crops were better.(2)The crop variety parameters of the DSSAT model suitable for maize and soybean were optimized.Sensitivity parameters for corn are photosensitive period P2,leaf emergence interval characteristic PHINT,soil drainage upper limit SDUL,root growth factor SRGF,soil PH value SLHW;for soybeans are critical short day length CSDL,soil drainage upper limit SDUL,root growth factor SRGF,species specific leaf area SLAVR under standard conditions,organic carbon content SLOC.(3)The nitrogen use efficiency of corn and soybean under different nitrogen fertilizers was simulated and evaluated.Taking LAI as the assimilation index,UAV remote sensing combined with DSSAT model,simulated the yield and nitrogen use efficiency of corn and soybean under three nitrogen fertilizer test treatments,and found that the yield and nitrogen use efficiency of corn and soybean under the application of bio-wax modified water-based coating fertilizer The nitrogen use efficiency was the highest,and the relative value of nitrogen availability evaluation of the two crops under this treatment was also the highest. |
