Study On Droplets Penetration Prediction Model Based On Layered Porosity Of Plant Canopy

The spray utilization rate of plants and the deposition status inside the plant canopy have been widely concerned as the measuring index of spray quality,which have been studied from different aspects by experts and scholars from home and abroad,and the spray utilization rate of the plants is ultimately affected by the deposition of liquid on the canopy of the plant.In the process of spray,the liquid is penetrated from the top to the bottom of the plant through the pores between the branches and leaves,and deposited on the leaves of each layer.Therefore,the premise of the liquid deposition of the plant interior is liquid penetration.The amount penetration of fog droplets is determined by porosity and its distribution in plant canopy,and the amount of liquid deposition in the inner and lower branches and leaves of the plant canopy is determined by the amount of penetration.This is particularly significant in the plants with high canopy density,with dense branches and leaves,less pore,the medicinal liquid is not easy to penetrate,and the liquid decreases in turn from the upper layer to the lower layer.This situation leads to the liquid medicine is difficulty to obtain in the ranches and leaves of the below plants,at the same time,making the overall deposition situation extremely uneven.It is of great significance to study the distribution and size of pore in plant canopy,and the relationship between pore size and penetration for studying the deposition of medicinal liquid on branches and leaves.In this study,cotton at flowering and boll stage was taken as the research object to explore the relationship between canopy porosity and penetration of high canopy density plants.Based on the Gauss Process,the prediction model of porosity of stratified sub-regions to penetration under different stratification and partition forms is constructed,then the reliability of the model is verified.The main work has been completed as follows:(1)Measurement and statistics of porosity in canopy each layer and regionFour plants were selected to form a rectangular area and divided into three separate layers evenly.The porosity of each layer was measured by laser ranging principle,and the size and distribution of the porosity of each layer were obtained by regional division.(2)Measurement of droplet penetration in each layer of plant canopyAccording to the method of plant canopy stratification,the partition is placed between the two layers to receive the droplets,and the penetration amount of the droplets crossing the plant canopy is measured.(3)Prediction of total penetration in different layers of plant canopyTaking the porosity of different zones of plant canopy as input and the total regional penetration as output,the prediction models of the total regional penetration of each layer were constructed and established by regression fitting through Gauss process.The prediction results of each model were more accurate.The average relative error of the upper layer was 1.31%,the middle layer was 1.46%,and the lower layer was 6.10%.(4)The penetration prediction of partitions in different layers of plant canopyBy dividing the penetration of each layer into different regions,the penetration distribution of two and four zones can be obtained.Similarly,the prediction model of regional penetration can be obtained by using different porosity zones.It is concluded that the average relative error of prediction models in each layer of the two regions is less than 10%.,while the maximum relative error of the four regions penetration prediction model is about 30%.It has obvious physical significance for the prediction of regional total penetration,and the prediction effect is the best.The prediction effect of the two regions’ penetration is the second.This is due to the interaction of transverse flight and transport of fog droplets between the two regions,which has a certain impact on the prediction results.This phenomenon is more obvious in the prediction of the penetration volume in the four regions.It shows that the size of the prediction area will affect the prediction effect of its prediction model.When the prediction area is too small,the penetration volume in each region will be greatly affected by the penetration volume in other regions.It shows that the rationalization of regional selection is the precondition of accurate prediction.In this paper,the distribution of stratified porosity in plant population has been measured,considering the influence of agronomic parameters on the porosity,the relationship between porosity distribution and droplet penetration was established.prediction model by Gauss Process Regression was constructed to predict the droplet penetration through porosity,and the reliability of the model was verified.The model can accurately predict the penetration of plant canopy.It can provide theoretical support for the subsequent study of plant internal deposition and the change of high canopy porosity by means of auxiliary airflow to increase the deposition of medicinal liquid in plant internal.