杀虫剂对土壤温室气体排放的影响

在室内培养条件下，研究了在施用尿素的土壤（有效氮质量分数为200 mg·kg^-1）中分别添加不同剂量（在5、10和50 mg·kg^-1）的吡虫啉和毒死蜱2种杀虫剂时，杀虫剂对土壤温室气体CO2、N2O和CH4排放过程的影响。结果表明：和空白相比，施用尿素明显地增加了土壤中温室气体N2O和CO2的排放量，但对CH4的排放无明显影响。当施用5 mg·kg^-1吡虫啉时，土壤中N2O和CO2排放总量和尿素处理相比无明显差异，但吡虫啉用量上升至10和50 mg·kg^-1时则显著降低了温室气体N2O和CO2的排放量（P〈0.05），N2O排放量分别降低了26.89%和53.10%，CO2排放量分别降低15.14%和13.79%。毒死蜱在5、10和50 mg·kg^-1三种用量时土壤的N2O排放量与尿素处理相比均无明显差异。毒死蜱在5和10 mg·kg^-1用量时则明显抑制了土壤CO2的排放（p〈0.05），分别比尿素处理降低了19.88%和19.02%；用量上升到50 mg·kg^-1用量时，土壤的CO2排放量与尿素处理相比无差异。吡虫啉和毒死蜱对CH4排放量均没有明显影响。可见，杀虫剂施用明显影响到土壤温室气体的排放，但不同杀虫剂品种及其用量的效应也存在明显差异。

Effects of insecticides on greenhouse gas emission in soil

In order to assess the effects of the insecticides imidacloprid and chlorpyrifos on greenhouse gases emission in soil, an incubation experiment was conducted under laboratory condition with 8 treatments control, urea, urea＋imidacloprid （5, 10 and 50 mg active ingredient·kg^-1 dry soil, respectively） and urea＋chlorpyrifos （5, 10 and 50 active ingredient·kg^-1 dry soil, respectively）, 200 mgN·kg^-1 dry soil was applied in each soil sample of urea and pesticides treatments respectively. The results showed that urea ferti-lizer applied greatly increased greenhouse gases N2O and CO2 emission from the soil, but had no significant effects on CH4 emission. The imidacloprid had no effect on soil CO2 and N2O emission under 5 mg·kg^-1 treatment,but showed significant negative effect at10 and 50 mg·kg^-1, compare with urea treatment it reduced the N2O emission 26.89%and 53.10%respectively （P〈0.05）, and decreased the CO2 emission 15.14%and 13.79%respectively （p〈0.05）. The N2O emission under the three concentration levels of chlorpyrifos showed no significant differences compared with the urea treatment, however under 5 and 10 mg·kg^-1 dry soil concentration the chlorpyrifos had significant decreased the CO2 emission 19.88% and 19.02% respectively （P〈0.05）. Both the imidacloprid and chlorpyrifos showed no significant differences compared with urea treatment on CH4 emission under the three concentration levels. The results indicated that insecticides had great influences on greenhouse gases emission but the influences were different with types and concentrations.