Wang D, Browne G, Gao S, Hanson B, Gerik J, Qin R, Tharayil N
USDA-ARS, Water Management Research Unit, San Joaquin Valley Agricultural Sciences Center, Parlier, California 93648, USA.
Environ Sci Technol. 2009 Aug 1;43(15):5783-9. doi: 10.1021/es9015662.
Reducing emissions of volatile organic compounds (VOCs) from fumigant pesticides is mandatory in California, especially in "nonattainment areas" like the San Joaquin Valley that do not meet federal air quality standards. A two-year field study was conducted to examine the feasibility of site-specific fumigant application only at future tree sites with dramatically reduced amounts of fumigant chemicals on an orchard basis. Soil gas distribution and atmospheric emission of 1,3-dichloropropene and chloropicrin were measured after applying InLine using subsurface drip irrigation. It was predicted that except in the surface 20 cm of soil, satisfactory pest control could be achieved within a 15 cm radius from the injection point. Also, at radial distances of 15-51 cm from the point of fumigant injection, effective nematode control may be achieved. Cumulative atmospheric emission of the fumigants was estimated to be 18-23% of the applied active ingredients in plots that had been cover cropped with Sudan grass and 2-6% in plots that had remained bare for several months before treatment. Considering the significantly small amount of fumigant used on an orchard basis, the spot drip fumigation may achieve a 10-fold reduction in atmospheric VOCs load from fumigant pesticides.
在加利福尼亚州，减少熏蒸剂农药中挥发性有机化合物（VOCs）的排放是强制性要求，尤其是在像圣华金谷这样不符合联邦空气质量标准的“未达标地区”。开展了一项为期两年的田间研究，以检验仅在未来树木种植地点进行特定地点熏蒸剂施用的可行性，在果园层面大幅减少熏蒸剂化学品的用量。在使用地下滴灌施用InLine后，测量了土壤气体分布以及1,3 - 二氯丙烯和氯化苦的大气排放情况。据预测，除了土壤表层20厘米外，在距注射点15厘米半径范围内可实现令人满意的害虫防治效果。此外，在距熏蒸剂注射点15 - 51厘米的径向距离处，可有效防治线虫。在种植了苏丹草作为覆盖作物的地块中，熏蒸剂的累积大气排放量估计为施用活性成分的18 - 23%，而在处理前几个月一直裸露的地块中，这一比例为2 - 6%。考虑到在果园层面使用的熏蒸剂数量显著减少，点滴式熏蒸可能使熏蒸剂农药产生的大气VOCs负荷降低10倍。
