Multi-Year Measurements of Field-Scale Metolachlor Volatilization
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- 作者：John H. Prueger ; Joseph Alfieri ; Timothy J. Gish…
- 关键词：Volatilization ; Metolachlor ; Surface soil moisture ; Micrometeorology
- 刊名：Water, Air, & Soil Pollution
- 出版年：2017
- 出版时间：February 2017
- 年：2017
- 卷：228
- 期：2
- 全文大小：
- 刊物类别：Earth and Environmental Science
- 刊物主题：Environment, general; Water Quality/Water Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Soil Science & Conservation; Hydrogeology; Climate Change/Climate Change Impacts;
- 出版者：Springer International Publishing
- ISSN：1573-2932
- 卷排序：228
文摘
Volatilization is a critical pathway for herbicide loss from agricultural fields, and subsequently deposited downwind from the edge of the field. To better understand the volatilization process, field-scale turbulent volatilization fluxes of metolachlor (2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide) were quantified for 13 consecutive years using a combination of herbicide concentration profiles and eddy diffusivities derived from turbulent fluxes of heat and water vapor. Site location, type of herbicides, and agricultural management practices remained unchanged during this study in order to evaluate the effect of soil moisture on metolachlor volatilization. Twenty gravimetric surface soil moisture samples (0–5 cm) were collected immediately after herbicide application and then at 0430 hours each morning to determine the impact of surface moisture on herbicide volatilization. Five days after application, cumulative herbicide volatilization ranged from 5 to 63% of that applied for metolachlor. Metolachlor volatilization remained an important loss process more than 5 days after application when the soil surface was moist. Conversely, if the soil surface was dry, negligible volatilization occurred beyond 5 days. Furthermore, the total amount of metolachlor volatilized into the atmosphere increased exponentially with surface soil water content during application (r2 = 0.78). Metolachlor volatility was found to be governed largely by surface soil moisture.