Abstract: To solve the problem of wilted turf, taking the wilted turf in Beijing Yongfeng green belt area as an example, the study analyzed the proportion of soil nematode trophic group structure, validated the effect of regulatory factors on structural adjustment in the field, and screened out environmentally safe and friendly effective regulation agents. The results showed that with the percentage of 88.6% of all the nematodes, the harmful phytophage nematodes were dominant groups in wilted turf soil in Beijing Yongfeng virescence region, meanwhile the percentage of the total number of beneficial nematodes was only 11.4%. Soil amendment (SA) and Rhabiditis (Oscheius) sp. Tumian strain could reform the nematode trophic group structure significantly, reduce the plant parasitic nematode quantity to 48.9% and 50.5% respectively, and increase about 4.5 times of non-plant nematode quantity. They also increased the Wasilewska Index to 1 so as to make the healthy level increase ten times. The 1.8% abamectin in 3 000 and 2 000 times of dilutions only could reduce the plant parasitic nematode quantity by 3.5%, because they reduced both harmful and beneficial nematode population down to 1/2. These results demonstrated that the plant parasitic nematodes were the main group which led the lawn to be wilted. Soil amendment (SA) and Rhabiditis (Oscheius) sp. Tumian strain were the effective agents on improving the soil nematode trophic group structure, as they could reduce phytophage nematode quantity and increase the number of beneficial nematode group, making turf soil restore to a certain level of health ultimately．

Key words: abamectin, soil amendment, Rhabiditis (Oscheius) sp. Tumian, turf soil health, trophic groups