Effect of continuous cropping of banana on soil nematodecommunity structure and diversity

To study the effect of long-term banana continuous cropping on soil ecosystem, nematode classification methods were adopted to study the changes of soil nematode community structure and diversity under different continuous cropping years (l a, 3 a, 5 a, 7 a, 10 a and 15 a). The results indicated that 45 nematode genera were identified during the whole banana growing season. The abundance of total nematodes and bacterivores decreased with the increase of continuous cropping years at seedling stage, and exhib-ited low to high to low trend with the increase of continuous cropping years at jointing and booting stages. The abundance of fungi-vores decreased with the increase of continuous planting years at seedling and booting stages, and exhibited low to high to low trend with the increase of continuous planting years at jointing stage. The abundance of plant parasites exhibited low to high to low trend with the increase of continuous planting years at four growing stages. The abundance of omnivores-predators was decreased with the increase of continuous cropping years at seedling, jointing and ripening stages. The abundance of total nematodes was higher at seed-ling and booting stages than that at the jointing and ripening stages. The abundance of fungivores at seedling stage and plant parasitesat jointing stage was lower than that at the other stages. The abundance of omnivores-predators was lower at seedling and jointing stages than that at booting and ripening stages. The values of dominance (λ) exhibited low to high to low trend at seedling, jointing and booting stages with the increase of continuous cropping years. The values of plant parasite index (PPI) increased with the in-crease of continuous cropping years at four growing stages while Wasilewska (WI) exhibited a reverse pattern at seedling, jointing and booting stages. The values of diversity (H′ ) increased with the increase of continuous cropping years at the seedling stage, while a reverse pattern was exhibited at other stages. The values of nematode channel ratio (NCR) increased with the increase of continuous cropping years at jointing and booting stages, while the values of maturity index (MI) exhibited a reverse pattern at jointing and rip-ening stages. The values of H′ increased with the increase of growing stages while λ exhibited a reverse pattern. The values of MI were higher at booting and ripening stages than that at seedling and jointing stages. The values of WI were higher at jointing and booting stages than that at seedling and ripening stages. It indicated that soil nematode community structure could be a useful bio-logical indicator to evaluate the status of soil health under banana continuous monocropping system in China.