Raturi S, Islam K R, Caroll M J, Hill R L
Department of Natural Resource Sciences and Landscape Architecture, University of Maryland, College Park, Maryland, USA.
J Environ Sci Health B. 2005;40(5):697-710. doi: 10.1080/03601230500189345.
Thatch development in intensively managed turf sites may cause environmental concerns for greater sorption or leaching of applied chemicals in terrestrial ecosystems. To determine the adsorption potential of Carbaryl (1-Napthyl N-methylcarbamate), 2,4-D (2,4-dichloro-phenoxyacetic acid), and Triclopyr (3,5,6-trichloro-2-pyridinyloxyacetic acid) in turf ecosystems, composite thatch and underlying soil samples from three-and six-year-old stands of cool-season Southshore creeping bentgrass (Agrostis palustris Huds.) and warm-season Meyer zoysiagrass (Zoysia japonica Steud.) were collected. The samples were processed and analyzed for total organic carbon (COrg); extractable (CExt), humic (CHA) and fulvic acid (CFA); anthrone reactive nonhumic carbon (ARC) fractions; and CHA and CFA associated iron (Fe) contents. Pesticide adsorption capacity (Kf) and intensity (1/n), organic carbon partition coefficient (KOC) and Gibbs free energy change (deltaG) were calculated for thatch materials and the underlying soils using a modified batch/flow technique. Both bentgrass (BT) and zoysiagrass thatch (ZT) contained a greater concentration of CExt, CFA, CHA, and ARC than the respective soils (BS and ZS). The CExt, CFA, CHA, and ARC concentration was higher in BT compared with ZT. The BT contained a greater concentration of bound Fe in both CFA and CHA fractions than in BS, whereas ZT had more bound Fe in CHA fraction than in ZS. On average, the BT had a greater concentration of bound Fe in CExt, CFA, and CHA fractions than in the ZT. Among the pesticides, Carbaryl had higher Kf and 1/n values than 2,4-D and Triclopyr for both thatch and soil. Although the KOC and deltaG values of Carbaryl were higher in both BT and ZT than in the underlying soils, the KOC and deltaG values of 2,4-D were significantly higher in BS and ZS than in the overlying thatch materials. The 2,4-D and Triclopyr had higher leaching indices (LI) than Carbaryl for both BT and ZT materials than the respective soils. The Carbaryl, however, had a higher LI for soils than for thatch materials. Averaged across thatch materials and soils, COrg accounted for 96, 85, and 84% variations in Carbaryl, 2,4-D, and Triclopyr adsorption, respectively. Among the COrg fractions, lignin followed by CFA and CHA accounted for greater adsorption of pesticides, especially Carbaryl. The concentration of CHA and CFA bound Fe did not correlate with Kf and 1/n values of pesticides.
在集约管理的草坪场地中，枯草层的形成可能会引发环境问题，因为在陆地生态系统中，施用的化学物质会更多地被吸附或淋溶。为了确定西维因（1-萘基N-甲基氨基甲酸酯）、2,4-滴（2,4-二氯苯氧乙酸）和绿草定（3,5,6-三氯-2-吡啶氧基乙酸）在草坪生态系统中的吸附潜力，采集了来自3年生和6年生冷季型南岸匍匐翦股颖（匍匐翦股颖）和暖季型 Meyer 结缕草（日本结缕草）草皮的复合枯草层及下层土壤样本。对样本进行处理并分析其总有机碳（COrg）；可提取碳（CExt）、腐殖酸（CHA）和富里酸（CFA）；蒽酮反应性非腐殖碳（ARC）组分；以及与 CHA 和 CFA 相关的铁（Fe）含量。使用改良的批量/流动技术计算了枯草层材料和下层土壤的农药吸附容量（Kf）和强度（1/n）、有机碳分配系数（KOC）和吉布斯自由能变化（deltaG）。匍匐翦股颖枯草层（BT）和结缕草枯草层（ZT）中的 CExt、CFA、CHA 和 ARC 浓度均高于各自对应的土壤（BS 和 ZS）。与 ZT 相比，BT 中的 CExt、CFA、CHA 和 ARC 浓度更高。BT 的 CFA 和 CHA 组分中结合铁的浓度高于 BS，而 ZT 的 CHA 组分中结合铁的含量高于 ZS。平均而言，BT 的 CExt、CFA 和 CHA 组分中结合铁的浓度高于 ZT。在这些农药中，西维因在枯草层和土壤中的 Kf 和 1/n 值均高于 2,4-滴和绿草定。尽管西维因在 BT 和 ZT 中的 KOC 和 deltaG 值均高于下层土壤，但 2,4-滴在 BS 和 ZS 中的 KOC 和 deltaG 值显著高于上层的枯草层材料。对于 BT 和 ZT 材料，2,4-滴和绿草定的淋溶指数（LI）均高于西维因，且高于各自对应的土壤。然而，西维因在土壤中的 LI 高于枯草层材料。综合枯草层材料和土壤来看平均而言，COrg 分别解释了西维因、2,4-滴和绿草定吸附变化的 96%、85%和 84%。在 COrg 组分中，木质素之后是 CFA 和 CHA 对农药的吸附作用更大，尤其是对西维因。CHA 和 CFA 结合铁的浓度与农药的 Kf 和 1/n 值无关。
