Papiernik Sharon K, Dungan Robert S, Zheng Wei, Guo Mingxin, Lesch Scott M, Yates Scott R
USDA-ARS, George E Brown Jr Salinity Laboratory, Riverside, California 92507, USA.
Environ Sci Technol. 2004 Nov 1;38(21):5489-96. doi: 10.1021/es049064q.
Soil fumigation is useful for controlling soil-borne pests and diseases in high-cash-value crops. Fumigants are highly volatile, and approaches to reduce atmospheric emissions are required to protect human and environmental health. Application of fumigants through drip irrigation has been proposed as a means to decrease fumigant emissions, improve fumigant distribution in soil, and minimize worker exposure. These experiments were conducted to investigate the effect of the configuration of the drip system on the volatilization and distribution of the fumigants 1,3-dichloropropene (1,3-D), propargyl bromide (PrBr), and methyl isothiocyanate (MITC) in bedded systems. Results indicated that changing the drip emitter spacing and using multiple drip lines in each bed had little effect on the emissions and distribution of any fumigant. Increasing the depth of application from 15 to 30 cm reduced volatilization of MITC by approximately 20 to >90%; emissions were reduced due to a decrease in the flux from the bed top, and deeper injection did not change the amount of fumigant volatilized from the bed side slope and furrow. Increasing the application depth resulted in a slight decrease in the rate of fumigant dissipation in soil, indicating the potential for some improvement in pest-control efficacy with deeper application.
土壤熏蒸对于控制高经济价值作物中的土传病虫害很有用。熏蒸剂具有高度挥发性，因此需要采取减少大气排放的方法来保护人类和环境健康。通过滴灌施用熏蒸剂已被提议作为一种减少熏蒸剂排放、改善熏蒸剂在土壤中的分布并尽量减少工人接触的手段。进行这些实验是为了研究滴灌系统配置对苗床系统中熏蒸剂1,3 - 二氯丙烯（1,3 - D）、炔丙基溴（PrBr）和异硫氰酸甲酯（MITC）挥发和分布的影响。结果表明，改变滴头间距以及在每个苗床中使用多条滴灌带对任何熏蒸剂的排放和分布影响很小。将施药深度从15厘米增加到30厘米可使MITC的挥发减少约20%至>90%；由于苗床顶部通量降低，排放量减少，而更深的注入并没有改变从苗床边坡和沟渠挥发的熏蒸剂数量。增加施药深度导致熏蒸剂在土壤中的消散速率略有下降，这表明更深施药在害虫防治效果方面有一定的改善潜力。
