Effects Of Inter Cropping Grass On Micro Environment,Insect Community And Fruit Quality In Apple Orchard

Inter cropping can provide a large amount of organic fertilizer for the production of forest and fruit industry,reduce the spread of weeds in orchards,improve the ecological environment of orchards,reduce the use of pesticides and has a certain biological control effect.In this study,7different inter cropping treatments were selected according to the random block design,which were Trifolium repens L,Lotus corniculatus L,Vicia sativa L,Onobrychis viciifolia,Trifolium pratense,Lolium perenne L,Dactylis glomerata L.The temperature and humidity of air and surface soil,light intensity in orchard and fruit tree,insect community composition in orchard were measured from May to October in 2021,and the mature fruits and soil in orchard were collected in October and brought back to laboratory for analysis.The influence of orchard raw grass on the temperature and humidity of orchard air and surface soil,soil nutrients,orchard insect community and fruit nutrition quality was clarified,and the best inter cropping grass species were obtained through the main component analysis,in order to improve the orchard small environment,improve the biological control effect and improve the nutritional quality of fruit.The main study results are as follows:（1）In August,all inter cropping treatments could reduce air temperature,and the effect of Lotus corniculatus L treatment was the best（2.11℃）.Compared with the control treatment,the humidity of 15 cm soil layer under inter cropping treatment was increased by 2.35-5.89%,and the humidity of 15 cm soil layer under Trifolium repens L treatment was the highest（22.85%）.In October,all inter cropping treatments could increase air temperature,among which Lolium perenne L treatment had the best thermal insulation effect（0.68℃）.Inter cropping treatment significantly increased humidity in 15 cm soil layer（8.15-10.01%）,and Trifolium repens L treatment had the highest humidity in 15 cm soil layer（29.20%）.（2）The surface of the control plot is bare soil,and its reflectance is only 30%,while the light reflectance of the grass plot is above 60%,and the light reflectance of Trifolium repens L is above 70%.Soil p H was the lowest（7.63）and soil organic matter(23.90 g·kg^-1),alkali-hydrolyzed nitrogen(89.77 mg·kg^-1),available phosphorus(25.67 mg·kg^-1)and available potassium(164.37 mg·kg^-1)were the highest under Vicia sativa L treatment.（3）According to the population structure and function,insects in the orchard can be divided into three categories:pests（17901 insects in 7 orders,50.04%of quantity）,natural enemies（12363insects in 8 orders,34.56%of quantity）.Neutral insects（5503 insects in 3 orders,15.38%number）;Insect species,quantity,shannon-Wiener diversity index（H’）and Margalef’s richness index（E）were the highest under Trifolium repens L treatment.Simpson dominant concentration index（C）and stability index（I₁）were the highest under Lotus corniculatus L treatment.Trifolium repens L treatment could effectively improve insect population and community diversity.（4）The quality of peripheral fruits was significantly higher than that of internal fruits,and no whole red fruits were found in inner fruits under all treatments.However,the colorimetric and nutritional quality of fruits were improved under inter cropping treatments,and the comprehensive evaluation of principal components was best under Trifolium repens L,Lotus corniculatus L and Vicia sativa L treatments.The above results indicate that insect community and fruit quality in apple orchards micro environment has obvious improvement effect by inter cropping,with the Vicia sativa L to the improvement of soil fertility effect is best,Trifolium repens L in water retention capacity and improve the orchard and the fruit tree bore light intensity,improve the quality of the fruit nutrition on the best effect,sward treatment can improve the diversity of insect community structure and stability,It has certain biological control effect on pests in the orchard.