Effect Of Long-term Fertilization On Soil Nematodes Community Structure In Black Soil Area

In farmland ecosystems, soil animal has been soil ecological process indispensable constitutent part, it bears the decomposition and nutrient mineralization functions. Soil nematode in soil as the largest number, the most abundant species of animals, their life process and evolution history of diversity, feeding type differ in thousands ways, in ecological system, they play an mportant role. Soil nematodes are a huge number, their shapes and habits difference, various kind and distri-bute widely, they have very important position in groups of soil organisms.Black soil zone in heilongjiang province is a major grain producing areas,black soil is famous for its good soil quality and provide high cereal yield. We focus on the effects of nematode community on soil quality, the effects of long-term fertilization on the change of soil microbe. It is possible that we find the factors affecting mollisol microbial community and we take some measures to keep and improve soil fertility.The soils were sampled in long-term mollisol experiment station established in 1979 (Harbin, E126°35", N45°40"). The nematode species and numbers were detected by sampling, isolation and identification. The results show that the nematode species ranged from 10 familia and 13 genus to 16 familia and 19 genus. The nematode numbers increase followed the plant growth. At the stage of harvesting, the numbers of nematode genus in the order:CK (18 genus)> N application (15 genus)> organic manure (14 genus)> NPK application (12 genus). In addition, the nematodes show different response to the environment, e.g. soil bacterivorous nematodes respond sensitively to environment, however, soil fungivorous nematodes and omnivore/predator nematodes don't respond sensitively to environment. Furthermore, the dominant species in nematode community show different abundance, e.g. helicotylenchus is the dominant species in plant-parasitic nematodes and acrobeloides nanus is the dominant species in bacterivorous nematodes. In soil profile, soil nematode numbers and species decrease along the depth. Fungivorous nematodes lived in the depth of 0 to 40 cm. Plant-parasitic nematodes distributed in the depth of 0 to 60 cm. Bacterivorous nematodees and omnivore/predator nematodes were found in the depth of less 60 cm. We found that soil nematode species and distributions correlated to soil moisture. In certain range, soil nematode numbers increase as the moisture increasing. Furthermore, the abundance of bacterivorous nematode increased as the increase of the concentration of soil organic matter, total nitrogen, total phosphorus and available phosphorus. Plant-parasitic nematodes decrease as the increase of the concentration of soil organic matter, total nitrogen, total phosphorus and available potassium.