Study On The Relevance Of Occurrence Of Underground Pests To Soil Fertility In Corn And Wheat Fields Of Shandong Province

To explore the relationship between the occurrence of soil pests and soil fertility,this study selected eight regional(Five Types of Soil)in Shandong Province(brunisolic soil,cinnamon soil,saline-alkali soil,fluvo-aquic soil,shajiang black soil),underground pest survey and soil fertility survey were conducted simultaneously in corn and wheat fields using a checkerboard sampling method,cleared spatial distribution and soil factors of soil pests in Shandong Province,at the same time,combined with the historical occurrence data collected from 1990 to 2015,after preprocessing,the random forest algorithm based on R language was used to analyze,and the correlation between the three major underground pests and soil factors was explored.Designed to provide technical support and new ideas for monitoring and early warning,green prevention and control of underground pests in corn and wheat fields of Shandong Province.The main results are as follows:1.By selecting 560 survey samples across the province,a total of 5024 samples were obtained,including 4447 underground biological samples and 949 underground pest samples.The laboratory identified that Pleonomus canaliculatus,Anomala corpulenta and Holotrichia parallela were the main underground pests in Shandong Province,and they showed a trend of "low coastal occurrence and high inland occurrence".The overall occurrence of underground pests in corn fields is more serious than that in wheat fields.The occurrence of underground pests in shajiang black soil area is larger than that of the other four soil types.The occurrences of underground pests in the other soil types are cinnamon soil,fluvo-aquic soil,brunisolic soil,and saline-alkali soil.2.The dominant populations of underground pests in the areas surveyed in Shandong Province were identified: Pleonomus canaliculatus are dominant populations of underground pests in Lanshan District of Linyi City,Xintai City of Tai'an City,and Pingyin County of Jinan City;Anomala corpulenta is the dominant population of underground pests in Lingcheng of Dezhou city,Zoucheng of Jining City;Agriotes subrittatus is the dominant population of underground pests in Fushan of Yantai city;and the Mazadera Ovatula is the dominant population of underground pests in Dongying city.3.The monitoring and early warning models of Pleonomus canaliculatus,Anomala corpulenta and Holotrichia parallela were established,the relationship between the occurrences of Pleonomus canaliculatus,Anomala corpulenta and Holotrichia parallela and9 soil factors such as organic matter and pH was analyzed.The OOB estimate of error rate are tested,and the model accuracy rates can reach 90.83%,87.12% and 93.75% respectively.After the model outputs the Gini coefficient and ranks the importance of the independent variables,it was shown that "pH" and "exchangeable magnesium" are main soil factors affecting the occurrence of Pleonomus canaliculatus;"Total phosphorus" and "organic matter content" are main soil factors affecting the occurrence of Anomala corpulenta;"pH" and "organic matter content" are main soil factors affecting the occurrence of Holotrichia parallela.The results of this study indicate that,the impact of soil pH,organic matter content and phosphate fertilizers on the occurrence of underground pests in each region will be fully taken into account in actual farmland management.By improving the application of fertilization and medicine,the yield of acres can be increased while reducing the amount of underground pests.This has important guiding significance for actual production life.In addition,the construction of the monitoring and early-warning model for the Pleonomus canaliculatus,Anomala corpulenta and Holotrichia parallela in this paper can also provide theoretical and technical support for the monitoring and early-warning of other underground pests.