荒漠区柠条锦鸡儿灌丛土壤线虫群落研究

Study on Soil Nematode Community of Caragana Korshinskii Shrub in Desert Area

本文比较了荒漠区柠条锦鸡儿灌丛内外不同土层土壤线虫群落特征。结果表明:(1)灌丛内的土壤线虫总数、物种数和Shannon-Wiener指数大于灌丛外;土壤深度仅对线虫总数影响显著,表现出明显的表聚性。(2)灌丛增加了食细菌类群的相对丰度而降低了植物寄生类群的相对丰度;随着土壤深度的增加,灌丛内外食细菌类群相对丰度逐渐降低,但捕食杂食类群相对丰度逐渐增加。(3)灌丛内土壤线虫PPI/MI指数低于灌丛外,表明灌丛内的土壤环境更稳定,受干扰程度更小。(4)灌丛内外30~40cm土层土壤线虫CI指数小于50,其他土层CI指数均大于50,表明30~40cm土层土壤食物网分解途径以细菌分解途径为主,其他土层以真菌分解途径为主。(5)灌丛内外不同土层SI和EI组合样点全部分布在D象限,表明灌丛虽然对荒漠环境有一定的缓冲作用,但仍受较高程度的干扰。(6)冗余分析表明,速效钾是影响土壤线虫群落的主要环境因子。

In this paper, the characteristics of soil nematode communities inside and outside Caragana korshinskii shrub and different soil layers were compared in desert areas.The results showed that:(1) The total number of soil nematodes, species number and Shannon-Wiener index in the shrub were larger than those outside the shrub;The soil depth only had a significant effect on the total number of nematodes, showing obvious surface aggregation.(2) Shrubs significantly increased the relative abundance of bacterial feeders and decreased the relative abundance of plant parasitic groups.With the increase of soil depth, the relative abundance of the bacterial feeders inside and outside the shrub gradually decreased, but the relative abundance of the predatory omnivorous groups gradually increased.(3) The PPI/MI index of soil nematodes inside the shrub was lower than that outside the shrub, indicating that the soil environment in the shrub was more stable and less disturbed.(4) The CI index of soil nematodes in the 30~40 cm soil layer inside and outside the shrub was less than 50,but they in other soil layers was greater than 50,indicating that the decomposition method of the soil food web in the 30~40 cm soil layer was mainly through bacterial decomposition, and the other soil layers were mainly through fungal decomposition.(5) The SI and EI combinations in three soil layers inside and outside the shrub were all distributed in the D quadrant, indicating that although the shrub had a certain buffering effect on the harsh desert environment, it was still subject to a high degree of interference.(6) Redundancy analysis showed that available K was the main environmental factor affecting soil nematode communities.