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 m~2, 9 trees/667 m~2, and 12 trees/667 m~2, 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 m~2(9 N) 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 m~2(9 C) had the maximum nematode density. The number of omnivore/predator nematodes was highest in the crop-tree release, and the number of 9 C 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 m~2 had the most significant effect.