Zablotowicz Robert M, Accinelli Cesare, Krutz L Jason, Reddy Krishna N
US Department of Agriculture, Southern Weed Science Research Unit, Agricultural Research Service, Stoneville, Mississippi 38776, USA.
J Agric Food Chem. 2009 Jun 10;57(11):4867-71. doi: 10.1021/jf900272w.
The use of glyphosate-resistant crops facilitated the widespread adoption of no-tillage (NT) cropping systems. The experimental objectives were to determine glyphosate sorption, mineralization, and persistence at two depths [0-2 cm (A) and 2-10 cm (B)] in a silt loam managed under long-term conventional tillage (CT) or NT soybean. Relative to the other soils, organic carbon (OC) and fluorescein diacetate (FDA) hydrolytic activity were at least 1.4-fold higher in NT-A. Glyphosate K(d) values ranged from 78.2 to 48.1 and were not correlated with OC. Cumulative glyphosate mineralized after 35 days was highest in NT-A soil (70%), intermediate in CT-A and CT-B (63%), and least in NT-B (51%). Mineralization was positively correlated with OC and FDA activity, but negatively correlated with K(d), indicating that sorption decreased bioavailability. Independent of tillage and depth, the half-lives for 0.01 N CaCl(2) and 0.1 N NaOH extractable residues (bioavailable residues and residues bound to iron and aluminum oxides, respectively) were <or=1.2 h and <or=14.2 days, respectively. These data indicate that glyphosate sorption and persistence are similar between the surface of NT and CT soils and that the adoption of NT will likely have minimal impact on the risk for nontarget effects of glyphosate on soil microflora or transport in surface runoff.
抗草甘膦作物的使用促进了免耕（NT）种植系统的广泛采用。实验目的是确定在长期传统耕作（CT）或NT大豆管理下的粉质壤土中，草甘膦在两个深度[0 - 2厘米（A）和2 - 10厘米（B）]处的吸附、矿化和持久性。相对于其他土壤，NT - A中的有机碳（OC）和荧光素二乙酸酯（FDA）水解活性至少高1.4倍。草甘膦的K(d)值范围为78.2至48.1，且与OC不相关。35天后矿化的累积草甘膦在NT - A土壤中最高（70%），在CT - A和CT - B中居中（63%），在NT - B中最低（51%）。矿化与OC和FDA活性呈正相关，但与K(d)呈负相关，表明吸附降低了生物有效性。与耕作和深度无关，0.01 N氯化钙和0.1 N氢氧化钠可提取残留物（分别为生物可利用残留物以及与铁和铝氧化物结合的残留物）的半衰期分别≤1.2小时和≤14.2天。这些数据表明，NT和CT土壤表面的草甘膦吸附和持久性相似，采用NT可能对草甘膦对土壤微生物群的非靶标效应风险或地表径流中的迁移影响最小。
