Soil Fauna Diversity And Soil Health Evaluation In Lycium.Barbarum Plantations In Arid Oasis Region

Lycium barbarum,as an important crop,has been largely planted due to its drought resistance,salinity resistance,cold resistance and barren resistance,as well as high nutritional value and medicinal value in the arid oasis area of Ningxia.Soil fauna are the important biological groups of L.barbarum plantations,which play an important role not only in biodiversity protection and ecosystem maintenance,but also in the process of material cycle,energy flow and information transmission.Indeed,it is an important problem of the sustainable development in L.barbarum plantations to study the impact of L.barbarum plantations growth and development on soil fauna diversity and soil health.To be specific,the aged L.barbarum plantations of 1,4,6,10,13 years were selected as sampling sites,and contrasted with adjacent farmland in spring,summer and autumn of 2021.Besides,the community composition,diversity and functional groups distribution of soil fauna in L.barbarum plantations were investigated.Combining with soil physical and chemical properties,we identified the key environmental factors affecting the distribution of soil fauna,clarified the spatial and temporal distribution of community composition and diversity of soil fauna in L.barbarum plantations,and explained soil health and relationship with soil fauna.In short,these studies provide a basis for the healthy development of L.barbarum plantations in arid oasis areas.The main results are as follows:(1)The abundance and richness of meso-micro soil fauna increased along with aged plantations.At the same time,there were foot of the Shannon-Wieren index and Simpson index in 6-year-old plantation.The abundance and richness of predatory meso-micro soil fauna were significantly lower in L.barbarum plantations than in corn field in the 0-10 cm soil layer(P<0.05).There were some peaks of the abundance and richness of omnivorous meso-micro soil fauna in 13-year-old plantation.Besides,there were peaks of the abundance and richness of saprophytic meso-micro soil fauna in 10-year-old and 13-year-old plantation.The abundance was significantly higher in autumn than in summer with the seasonal timing(P<0.05).The abundance of omnivorous meso-micro soil fauna was significantly higher in autumn than in spring and summer(P<0.05).Meanwhile,the richness was considerably higher in spring and autumn than in summer(P<0.05).Furthermore,the richness of saprophytic meso-micro soil fauna was significantly higher in summer than in autumn in the 10-20 cm soil layer(P<0.05).According to the Pearson correlation analysis results,the meso-micro soil fauna diversity in the surface layer was significantly correlated with soil moisture,electrical conductivity,organic matter,total nitrogen,alkalihydrolyzable nitrogen and clay,while the meso-micro soil fauna diversity in the subsurface layer was merely significantly correlated with the soil moisture.(2)Along with the aged plantations,there was an increasing-decreasing trend of the abundance and richness of ground-active arthropods.Beyond that,the Shannon-Wieren index was significantly lower in L.barbarum plantations than in corn field(P<0.05).The Simpson index was considerably higher in 10year-old plantation than in 1-year-old plantation(P<0.05).There were foots of the abundance and richness of phytophagous ground-active arthropods in 1-year-old plantation.At the same time,the abundance and richness of predatory ground-active arthropods were significantly lower in L.barbarum plantations than in corn field(P<0.05).There were foots of the abundance and richness of omnivorous ground-active arthropods in 4-year-old plantation.There were foots of the abundance and richness of saprophytic ground-active arthropods in 1-year-old and 6-year-old plantation.Nonetheless,the richness and ShannonWieren index were significantly higher in summer and autumn than in spring(P<0.05).The Simpson index was considerably higher in autumn than in spring(P<0.05).The abundance and richness of phytophagous ground-active arthropods were significantly higher in summer and autumn than in spring(P<0.05).The richness of predatory ground-active arthropods was greatly higher in summer and autumn than in spring(P<0.05).The abundance and richness of saprophytic ground-active arthropods was:autumn>summer>spring.As shown by the RDA analysis results,the soil organic matter,silt and available kalium were the main environmental factors that affected the distribution of ground-active arthropod communities.(3)There were peaks of QBS-ar index of meso-micro soil fauna and ground-active arthropod in 13year-old plantation.The QBS-ar index of meso-micro soil fauna was significantly higher in spring than in summer in the 10-20cm soil layer with the seasonal timing(P<0.05).Apart from that,the QBS-ar index of ground-active arthropod was significantly higher in summer and autumn than in spring(P<0.05).The QBS-ar index was considerably positively correlated with the abundance,richness and Shannon-Wieren index of meso-micro soil fauna(P<0.01),and was positively correlated with the Simpson index(P<0.05).In addition,QBS-ar index had a significantly positive correlation with the abundance,richness and Shannon-Wieren index of ground-active arthropod(P<0.01).It can be observed that the increase of meso-micro soil fauna diversity is promoted by the planting of L.barbarum plantations with corn fields,while it exerts a negative impact on the ground-active arthropod diversity.During the growth of L.barbarum plantations,the diversity of meso-micro soil fauna and ground-active arthropod presented an increasing trend.Seasonal changes had little effect on the distribution of meso-micro soil fauna diversity,but had a greater impact on the distribution of groundactive arthropod diversity.Meanwhile,the distribution of ground-active arthropod diversity was higher in summer and autumn.Along with the aged plantations,there was a decreasing-increasing trend of the abundance and richness of omnivorous and sacrificial meso-micro soil fauna,and the abundance and richness of phytophagous,predatory and omnivorous ground-active arthropod increased gradually.Seasonal changes significantly influenced the abundance and richness of omnivorous meso-micro soil fauna,phytophagous and saprophytic ground-active arthropod.There is a trend of deteriorating soil health from corn fields to L.barbarum plantations based on the QBS-ar index.However,the soil health of the 13-year-old plantations reached the best state with the management and growth process of the L.barbarum plantations,which is favorable to the protection of soil biodiversity and the sustainable development of the soil.