Effect Of Shelterbelt On Large And Medium Soil Animals Community In Farmland

In recent years, the health and stability of agro-ecosystem had been regard as the main problem to human’s life quality with the increasingly serious environmental issue. As the ecological barrier in agro-ecosystem, shelterbelt played the important role in regulating ecological balance. Soil animal, the important consumer and decomposer, controls the nutrient cycling and energy flow of underground ecosystem. Moreover, soil animal is also the important biological indicator of soil fertility, health and pollution. However, knowledge was litter about effects of shelterbelt on soil animal in adjacent farmland. Thus, mixed shelterbelt, poplar shelterbelt, alder shelterbelt, and cypress shelterbelt were selected as the study shelterbelt, and no shelterbelt farmland was selected as the reference site. This study investigated the soil animal communities in shelterbelt and adjacent farmland. The main object was to analyze the influence of shelterbelt on soil animal community and to research the main environmental factors affect to soil animals. The main results were as follows.(1) In this research,4196 soil animals were captured, which belonged to 4 phyla, 11 classes,23 orders and 60 families. The dominant groups were Oligochaeta (23.49%), Porcellio Department (15.25%), Chrysomelidae (16.66%). The common groups were Carabidae, Geophilomorpha, Lycosidae, Salticidae, Millipede, Gryllidae, Histeridae, Scolopendrellidae, Formicidae,31.55% of the total. There were 47 types of rare species,13.05% of the total community. The number of large and medium-sized soil animals in mixed shelterbelt was largest, followed by the poplar shelterbelts, alder shelterbelts, cypress shelterbelts. The soil animal number in reference was the smallest. Group number and density was the same trend.(2) The maximum of diversity index (H’), richness (D’) and evenness (E) appeared in mixed shelterbelt, and the value were 1.83,5.19,0.81 respectively. There had the significant difference on H’and D’of soil animal between mixed shelterbelt and other treatments (P<0.05). The biomass of soil animal changes with the follow trends:H>Q>Y>B>CK. Moreover, the number of predator, herbivore, detritivore were largest in mixed shelterbelt among treatments. However, the number of omnivore was largest in poplar shelterbelt. The reference had the lowest soil animal density.(3) Large and medium-sized soil animals on the horizontal distribution is shown as:with the increase of distance the less soil animal density and the number of groups. Vertical distribution shown as the number of individuals and groups of soil animals will follow deepness of soil deepen gradually reduced.(4) Oligochaeta had the largest niche breadth in different shelterbelt. Gryllidae had the smallest niche breadth among all common soil animals, but it’s niche breadth was largest in mixed shelterbelt. The mixed shelterbelt had the largest soil animal’s niche breadth compared to the other shelterbelts and reference. The niche overlap value of different functional group was highest in mixed shelterbelt and lowest in reference. This results showed that mixed shelterbelt treatment had the highest soil animal density.(5) The similarity of soil animal community between treatments was increased with the increasing distance between shelterbelt. The similarity value was lowest between mixed shelterbelt and reference in different distance. The similarity between cypress shelterbelt and reference, however, was largest. This result suggested that the influence of shelterbelt was weakened with the increasing of distance to shelterbelt, and the cypress shelterbelt had the lower effects on soil animal community among all treatment.(6) The diversity index of soil animal was significant negatively correlated with pH value. However, there was significant positive correlation between diversity index and soil total N, soil SOM, and shrub and herb coverage. The richness of soil animal was significant positively correlated with soil water content, total N, SOM, and shrub and herb coverage. The individual number of soil animal was significantly correlated with soil water content, sol SOM and shrub and herb coverage.(7) Redundancy analysis showed that different soil environmental factors and different shelterbelt will influence on soil animals. Among oligochaeta and formicidae omnivorous soil animals and soil total nitrogen (TN), organic matter (SOM), water content (SW) and mixed forests were positively correlated The tarantula spider, salticidae, section plate, earwig secco predatory soil animals and soil available phosphorus (AP), available potassium (AK), pH has good correlation, and the more suitable living environment for their mixed shelterbelt. The principal component analyze and hierarchical cluster analyze showed that the environmental factors were divided into two group. One group was regard as the forest factor, which including tree height, shrub and herb coverage, canopy density, and diameter at breast height. The other group was regard as soil factor, which including soil SOM, soil TN, soil water content, soil AP.The results suggested that the group number, density, diversity and biomass of soil animal were more accumulated in mixed forests treatment. However, the cypress shelterbelt had the little effects on soil animal community. Thus, the shelterbelt management should be conducted on pure cypress shelterbelt in the future.