目标树经营初期对柏木人工林土壤线虫群落的影响

为研究目标树经营初期对柏木人工林土壤线虫群落的影响,对遂宁市安居区处于竞争生长阶段的柏木林进行3种不同密度目标树经营,共计样地12个(目标树密度为6株/667 m~2、9株/667 m~2、12株/667 m~2以及对照各3个)。在目标树经营1年后,采集春、夏、秋、冬4个季节样品共252个,采用改进的Baermann湿漏斗法分离土壤线虫,共鉴定出土壤线虫59科143属。其中Prionchulus为优势属,食细菌性线虫38属,食真菌性线虫12属,植食性线虫36属,杂食/捕食性线虫57属。土壤线虫生活史策略以c-p 4类群为主,占总数的44.33%,其中目标树密度为9株/667 m~2整个样地(9N)的c-p 4占比最大。目标树经营增加了土壤线虫的数量,目标树密度为9株/667 m~2的目标树单株(9C)线虫密度达到最大;目标树经营处理中均以杂食/捕食性线虫数量最多,其中9C杂食/捕食性线虫数量均高于其他处理;目标树经营提高了多样性指数(H′)、均匀度指数(J)、线虫营养多样性指数(TD)、线虫成熟度指数(MI),目标树经营改善了土壤线虫群落结构,其中目标树密度为9株/667 m~2样地的土壤线虫群落结构最优。研究结果表明,采用目标树经营有利于提升土壤线虫群落多样性,使柏木人工林生态系统向更稳定的方向发展,其中目标树密度为9株/667 m~2的效果最为显著。

Effects of early crop-tree release on soil nematode communities in a Cupressus funebris plantation

To study the impact of crop-tree release on the soil nematode community in a Cupressus funebris plantation, 12 plots were selected from the cedar forest of Anju District, Suining City (crop tree density 6 trees/667 m², 9 trees/667 m², and 12 trees/667 m², and a control group for each of the three), 252 samples from four seasons (spring, summer, autumn, and winter) were collected, and a total of 143 genera belonging to 59 families were identified. Among them, Prionchulus was a dominant genus, Bacterivores were represented by 38 genera, fungivores by 12 genera, plant parasites by 36 genera, and omnivores/predators by 57 genera. The soil nematode colonizer persister was dominated by c-p 4 groups, accounting for 44.33% of the total. Among these, the whole plot with crop tree density of 9 trees/667 m² (9N) had the largest proportion of c-p 4.The crop-tree release increased the number of soil nematodes. Among these, the crop trees with a crop tree density of 9 trees/667 m² (9C) had the maximum nematode density. The number of omnivore/predator nematodes was highest in the crop-tree release, and the number of 9C omnivore/predator nematodes was higher than that of the other treatments. The crop-tree release increased the Shannon-Wiener index (H''), Pielou evenness index (J), Trophic Diversity (TD), and Maturity index (MI), which showed that the crop-tree release increased the diversity of soil nematode communities, and the crop tree density 9 had the best soil nematode community structure. The results showed that the use of crop-tree release was conducive to the enhancement of the diversity of soil nematode communities and the development of a Cupressus funebris plantation ecosystem to a more stable direction. Among these, the crop tree density of 9 trees/667 m² had the most significant effect.