Abstract:In order to screen the effective and environment-friendly nematicides against watermelon root-knot nematodes in arch sheds, the control effects of ammonium bicarbonate, lime nitrogen, dazomet, abamectin b2 and thiazophosphine, and soil environmental effects were compared. The results showed that the control effect of dazomet was 86.40%, which was significantly higher than all the other nematicides. Ammonium bicarbonate, lime nitrogen and abamectin b2 had the second highest level to control root knot nematodes, with control rate of 76.32%, 73.43% and 71.66%, respectively. Thiazophosphine had the lowest control effect on root-knot nematodes, being 61.51%. The final yield of watermelon increased by 53.08% under treatment of dazomet. Compared with the control, ammonium bicarbonate and lime nitrogen significantly increased the ammonium nitrogen in the soil by 170.73% and 142.10%, respectively,thiazophosphine increased the available phosphorus in the soil by 48.07%.The number of bacterias, fungi, actinomycetes, and the activities of catalase, urease,dehydrogenase in the soil showed a decreasing trend first and then increasing trend after it was treated with ammonium bicarbonate, lime nitrogen and dazomet. While the number of soil fungi showed increasing trend first and then decreasing trend after it was treated with thiazophosphine, but the number of actinomycetes showed a constantly increasing trend. At the maturation stage,the number of soil bacteria decreased by 46.08% compared with the control after it was treated with dazomet; the number of actinomycetes increased by 28.32% compared with the control after it was treated with thiazophosphine.In conclusion, dazomet has the best control effect against nematicides and can ensure production yield,ammonium bicarbonate and lime nitrogen can increase the content of available nitrogen in soil, and abamectin b2 is more friendly to the environment. According to the use of nitrogen fertilizer and the incidence of field disease, dazomet, lime nitrogen and abamectin b2 can be chosen as the nematicide to control watermelon root-knot nematode. |