关键词: 毛竹害螨, 危害指数, 竹盲走螨, 爆发成因

Abstract: The study on the contents and distribution patterns of N, P and K in Phragmites australis wetland ecosystem in Jiuduansha shoal of Shanghai showed that horizontally, the contents of soil total and available N, P and K were the lowest at the middle section of the shoal, and increased gradually from the middle to the upper and lower sections of the shoal, being most notable for the available nutrients. Vertically, the contents of soil total nitrogen (TN) and potassium (TK) decreased in the order of upper layer>lower layer>middle layer, total phosphorus (TP) was in the order of middle layer>upper layer>lower layer, and available nitrogen (AN) was in the order of upper layer>middle layer>lower layer. Soil available phosphorus (AP) content was the highest in upper layer but differed in middle and lower layers in different wetlands, while available potassium (AK) content was the lowest in middle layer and changeful in upper and lower layers in different wetlands. The differences of soil available nutrient contents in different wetlands were greater than those of total nutrient contents. At the soil depth of 0-60 cm, both total and available nutrients were in the order of K>N>P. The nutrients content in plants was the lowest at the middle section of the shoal, which was consistent with that in soil. In most plants of P. australis wetland, the nutrients content was in the order of N>K>P, which was not inconsistent with that in soil. The absorption coefficient of nutrients in different wetlands was N>P>K, and the utilization coefficient was in the order of P>K>N. N had the greatest cycling coefficient, while P had the least one.

Key words: Pest mites, Damage index, Typhlodromus bambusae, Outbreaks