Alexa E, Bragea M, Sumalan R, Negrea M, Lazureanu A
Banat' s University of Agricultural Science, Department of Horticulture, Calea Aradului 119, Timisoara, Romania.
Commun Agric Appl Biol Sci. 2009;74(1):197-204.
Glyphosate (N-phosphonomethyl-glycine), the active ingredient in several herbicide formulations, is a non-selective, post-emergent herbicide used in a variety of crop and non-crop situations. Glyphosate is a non-volatile herbicide that is relatively immobile in soil. Its degradation is due to microbiological processes and most laboratory studies have been conducted with 14C-glyphosate with the rate of 14CO2 evolution being used as an indication of herbicide breakdown. In this paper we have studied the glyphosate degradation in compost amendment soils using Scientilator Liquid TRIATHLER and Glyphosate-phosphonomethyl-14C-labeled with specific activity 2,2mCi/mmol. Four types of soils have been taken under study: Black Chernozem, Vertisol, Gleysol and Phaeozem with different characteristics. For the each type of soil have been realized four experimental variants (glyphosate blind sample with 1,5 ppm, concentration, autoclaved soil, soil with glyphosate and addition of compost in field concentration of 40 t/ha, respectively 60 t/ha. The mineralization curves of 14CO2 accumulated were compared during of 40 days. All the mineralization curves for the soils exhibited same patterns, with only two phases, the initial rapid phase of degradation, for about 20 days, attributed to microbial action on the free glyphosate and the second slow phase, when the curves attained plateaus. Compost applied with different concentrations to Vertisol and Black Chernozem did not appear to stimulate the microbial degradation of glyphosate. In Gleysol and Phaeozem with lower humus content, the mineralization curve of 14C indicate the increase degradation capacity, expressed as accumulated 14CO2 as % total 14C, with the increase of compost concentration.
草甘膦（N-膦酰基甲基甘氨酸）是几种除草剂配方中的活性成分，是一种非选择性的苗后除草剂，用于多种作物和非作物种植环境。草甘膦是一种非挥发性除草剂，在土壤中相对不易移动。其降解归因于微生物过程，大多数实验室研究使用14C-草甘膦进行，以14CO2释放速率作为除草剂分解的指标。在本文中，我们使用Scientilator Liquid TRIATHLER和比活度为2.2mCi/mmol的膦酰基甲基-14C-标记草甘膦，研究了堆肥改良土壤中草甘膦的降解情况。研究选取了四种具有不同特性的土壤：黑钙土、变性土、潜育土和灰化土。对于每种土壤，分别设置了四个实验变体（1.5 ppm草甘膦空白样品、浓度、高压灭菌土壤、添加田间浓度分别为40吨/公顷和60吨/公顷堆肥的草甘膦土壤）。在40天内比较了累积的14CO2矿化曲线。所有土壤的矿化曲线呈现相同模式，只有两个阶段，初始快速降解阶段约20天，归因于微生物对游离草甘膦的作用，第二阶段为缓慢阶段，此时曲线达到平稳期。向变性土和黑钙土施加不同浓度的堆肥似乎并未刺激草甘膦的微生物降解。在腐殖质含量较低的潜育土和灰化土中，14C的矿化曲线表明，随着堆肥浓度的增加，以累积14CO2占总14C的百分比表示的降解能力增强。
