江苏省不同种植年限的西/甜瓜农田土壤线虫群落特征

在江苏省主要西/甜瓜产区,采集不同种植年限的西/甜瓜农田土壤,采用线虫形态学的鉴定方法,分析了不同种植年限西/甜瓜农田土壤线虫的数量、群落结构及相关生态指数的变化。结果表明:所有调查样点中,共发现土壤线虫54属,平均682条·100 g^-1干土,其中原杆属线虫、拟丽突属线虫和矮化属线虫在不同种植年限的西/甜瓜农田土壤中均为优势属;随着种植年限的增加,土壤线虫的总数量虽无显著变化,但其中食细菌类线虫和杂食-捕食类线虫数量显著减少,而植物寄生类线虫数量显著增加;植物寄生类线虫中的矮化属、根结属线虫数量不断增加;随着种植年限的增加,土壤线虫的多样性指数(H)、瓦斯乐斯卡指数(WI)、自由生活线虫成熟度指数(MI)显著降低,线虫通道指数(NCR)、植物寄生线虫成熟度指数(PPI)、PPI/MI显著升高,其他指数无显著变化;相关性分析结果显示,土壤线虫数量与土壤pH、速效磷、有效锌和有效硼均呈显著正相关;土壤p H、有机质、全氮、速效钾、有效硼和有效锌对土壤优势属线虫的影响较大;连续种植西/甜瓜会增加土壤植物寄生类线虫数量,进而可能造成西/甜瓜连作障碍的发生;连续种植6～1...

Community characteristics of nematodes in agricultural soil of watermelon and melon with different cultivation years in Jiangsu Province.

This study aimed to explore the effects of cultivation years on the community structure of nematodes in agricultural soils of watermelon/melon. Soils from cropland planted with watermelon/melon for different cultivation years were collected in the main watermelon/melon production area of Jiangsu Province. We examined the populations,community structure and ecological index of soil nematodes. Results showed that 54 genera of soil nematodes were recorded,with an average abundance of 682 per 100 g dry soil. The dominant genera were Protorhabditis,Acrobeloides,and Tylenchorhynchus. While nematode populations did not change with increasing cultivation years,the abundance of bacterivores and omnivores-predators significantly decreased and that of plant-parasites increased significantly. The populations of Tylenchorhynchus and Meloidogyne gradually increased. With increases of cultivation years,Shannon index(H),Wasilewska index(WI) and free-living nematode maturity index(MI) decreased significantly,while the nematode channel ratio(NCR),plant parasitic index(PPI) and PPI/MI increased significantly.Results of correlation analysis showed that nematode populations were positively correlated with soil pH,available phosphorus,available zinc and available boron. The dominant genera of soil nematodes were largely affected by soil p H,organic matter,total nitrogen,available potassium,available boron and available zinc. The comprehensive analysis suggested that continuous planting of watermelon/melon can increase the abundance of plant-parasites in the soil,which may result in continuous cropping obstacle. Soils continuously planted with watermelon/melon for 6-10 years had a lowest diversity and a worst stability of nematodes,leading to soil deterioration.