除草剂对土壤温室气体排放的影响

试验设对照、尿素、尿素+草甘膦和尿素+丁草胺4个处理,尿素氮用量为200mg·kg-1干土,除草剂用量为10mg有效成分·kg-1干土。在实验室恒温培养条件下,研究除草剂对菜田土壤温室气体排放的影响。结果表明,菜田土壤中施用氮肥显著增加了温室气体N2O、CO2和CH4的排放。尿素氮肥中添加草甘膦显著抑制N2O、CO2的排放,分别比尿素处理降低48.4%和20.2%;添加丁草胺显著抑制N2O排放,比尿素处理降低23.2%,对CO2排放略有减少但不显著;草甘膦和丁草胺对CH4排放都无明显影响。这说明除草剂对土壤温室气体的排放具有显著影响,但不同除草剂品种的效应也存在明显差异。因此,在农田温室气体排放估算时应考虑除草剂的施用对温室气体减排所产生的效果。

Effects of Herbicides on Greenhouse Gases Emission from Vegetable Plantation Soil

To assess the effects of herbicides on greenhouse gases emission from vegetable plantation soil, an incubation experiment was conducted under laboratory condition with 4 treatments including control, urea, urea+glyphosate and urea+butachlor, and 200 mgN·kg-1 dry soil and 10 mg active ingredient·kg-1 dry soil were applied in urea and herbicides treatments respectively. The experimental results showed that nitrogen fertilizer greatly increased greenhouse gases N2O、CO2 and CH4 emission from the soil, but glyphosate reduced N2O and CO2 emission by 48.4% and 20.2% contrast to urea treatment respectively; butachlor reduced N2O emission 23.2%, not significantly reduced CO2 emission; however, glyphosate and butachlor had no effect on CH4 emission. These indicated the effective influences and the differences of different herbicides on greenhouse gases emission. Therefore, effects of herbicides on greenhouse gases emission should be taken into account in estimation of total greenhouse gases emission amount from agricultural soils in the future.