论文部分内容阅读
以土壤线虫为指示生物,研究了大豆不同耕作系统土壤线虫群落结构、生态指数和食物网指数的变化特征,以期明确大豆长期连作对土壤生物多样性和土壤食物网结构的影响。结果表明:大豆轮作土壤线虫属最丰富,大豆长期连作25年后土壤线虫属水平种类最少。大豆轮作和大豆短期连作3年土壤线虫群落组成Jaccard相似性最高(0.81),大豆轮作和大豆长期连作25年Jaccard相似性最低(0.66)。大豆短期连作3年土壤中植物寄生线虫的数量最高,显著高于大豆轮作和大豆长期连作25年。食真菌线虫在大豆长期连作25年土壤中较丰富,显著高于大豆轮作和大豆短期连作3年。大豆长期连作25年植物寄生线虫成熟度指数(PPI)高于大豆短期连作3年和大豆轮作。土壤线虫的通路指数(CI)在3个处理中均小于50,土壤腐蚀食物网的降解以细菌降解通路为主。大豆短期连作3年处理位于富集指数(EI)和结构指数(SI)食物网特征图的A象限,大豆轮作和长期连作25年位于食物网特征图的B象限。结果表明,大豆长期连作改变了土壤线虫的群落结构,降低了属的多样性,食物网结构向成熟稳定的方向恢复。
Soil nematode as indicator organism was used to study the characteristics of soil nematode community structure, ecological index and food web index in different tillage systems so as to clarify the effect of long-term continuous cropping on soil biodiversity and soil food web structure. The results showed that the soils of soybean were the most abundant in soil nematode, and the species of soil nematodes was the least after 25 years of continuous cropping. The Jaccard similarity of soil nematode community was the highest (0.81) in the three years of soybean rotation and short-term soybean-soybean intercropping, and the 25-year Jaccard similarity of soybean rotation and soybean was the lowest (0.66). The number of plant parasitic nematodes was the highest in soils shortly cropping for three years, significantly higher than that of soybean rotation and soybean for 25 years. The fungus nematodes were more abundant in the soils that were inoculated with soybean for 25 years and were significantly higher than that of soybean rotation and soybean for 3 years. The 25-year long-term plant-borne nematode maturity index (PPI) of soybean was higher than that of soybean short-term continuous cropping for three years and soybean rotation. The path index (CI) of soil nematodes was less than 50 in all three treatments, and the degradation of soil corrosion food web was dominated by bacterial degradation pathways. Soybean was short-term for 3 years to process the quadrant A of the food web, which is located in the food richness index (EI) and structural index (SI) food webs. The results showed that long-term continuous cropping of soybean changed the community structure of soil nematode, reduced the genus diversity, and the food web structure restored to mature and stable direction.