Design And Experiment Of Wolfberry Orchard Target-oriented Fertilizer System

Rational fertilization could improve soil nutrition,it’s also an important way to ensure the wolfberry productivity and quality.The traditional wolfberry orchard fertilization technology has the problems of inefficient fertilization,labor intensity,low accuracy of fertilizer amount and labor shortage.To solve these above problems,this paper offers a target-oriented fertilization system witch equipped with orchard strip-ditching fertilizer applicator,the system mainly includes the orchard hole-fertilizer distributor and the target-oriented variable-rate fertilization controller.The system experiment platform was built to do tests in laboratory and equipped with different model orchard strip-ditching fertilizer applicator to do field verifying experiments.This paper mainly contents and conclusions are as follows:(1)Based on infrared photoelectric sensor,an orchard dual model target-oriented precision fertilization method is provided and an orchard target-oriented fertilization control system is designed.This paper designs a dual model wolfberry tree detecting method based on infrared photoelectric sensors in two main fertilization periods.The two main fertilization periods is the germination period in spring and the fruiting period in autumn.The dual model detecting method includes the Trunk Detection Model(TDM)and the Canopy Detection Model(CDM),witch working in spring and autumn respectively.In TDM,the system gets the tree location by detecting the trunk,meanwhile,excludes the signal disturbed by dropping canes.In CDM,the system gets the center location of wolfberry tree by detecting the canopy,meanwhile,identifies the different signals effected by the gap in one tree and the gap between two adjacent tree,continuous canopy and discontinuous canopy.Based on the above method,the dual model fruit tree central target-oriented algorithm is designed.The algorithm not only could detect orchard trees and read the Fertilizer-Volume and Tree-Width settings for target-oriented variable rate fertilization,but also could monitor the fertilizer dropping and alert the operator when detecting incorrect fertilization.(2)A blade rotation dropping fertilizer induction method is provided,and an orchard toward-target variable-rate fertilizer distributor supporting fault alarming is designed.The fertilizer outlet sectional area and fertilizer dropping speed experiment was done based on high-speed photography(HSP)technique.Intermittent rotating mechanism makes quantitative hole fertilization.The fertilizer fault monitoring device is designed based on the blade rotation dropping fertilizer induction method.The orchard hole fertilizer precision distributor is finally designed.(3)The laboratory experiment platform was built.The fertilizer ejecting fault monitoring device performance test was conducted,the results showed that the monitoring device at least could get the on-off signal 2 times in each fertilizer ejecting process,and the accuracy of fault alarm was 100%.The Hole fertilizing amount accuracy test was conducted,the results showed that when the application setting was one of the 1~5 grades,the maximum error between the average amount of ejected fertilizer and theoretical amount was 10 g,with the maximum coefficient of variation of 4.6%;the range of average fertilizer length was 20.2~40.9cm.In TDM laboratory experiments,the system could ignore the signals from canes when their diameters were less than 16 mm,the maximum fertilizer position offset error was 6.2cm.In CDM laboratory experiments,the controller could determine the gaps within a tree when they were less than 21 cm,the average center offset distances on the condition of discontinuous canopies and continuous canopies is 13.1cm and 9.1cm respectively.(4)The system was carried on the different types of tractor to do field experiments in spring and autumn.In germination topdressing period,the results showed that the accuracy of fertilizer ejecting was 97% in selected 100 wolfberry trees.In young fruit fertilizer period,the system did 95 times fertilization with 50 kg granular fertilizer(Bulk density is 0.97g/cm3),the results showed that the accuracy of fertilizer volume was 90.3%.The results indicated that the dual-model detection method could be used for Wolfberry trees or other trees with similar canopy change at different growth stages.