Aharonson N, Katan J
Department of Chemistry of Pesticides and Natural Products, Agricultural Research Organization, Volcani Center, Bet Dagan, Israel.
Arch Insect Biochem Physiol. 1993;22(3-4):451-66. doi: 10.1002/arch.940220312.
Recent studies have demonstrated that interaction between various agrochemicals and soil microorganisms may either slow down or enhance processes of degradation. Soil disinfestation is employed for the control of soil-borne pathogens and weeds. Soil application of such broad-spectrum biocides, as well as some more selective chemicals, has a strong effect on microbial activity, which may result in drastic reduction in the rate of degradation of pesticides applied to such treated soils. Application of pesticides to previously disinfested soils may extend their biological activity, which in the case of herbicides could cause phytotoxic damage to the next crop. In contrast, repeated application of the same or structurally related pesticides may result in a selective buildup of microbial populations capable of degrading the pesticide at much faster rates. Cases of accelerated degradation were reported for pesticides belonging to various chemical groups. Studies were conducted to evaluate the mechanisms of accelerated degradation. For several pesticides it has been shown that soil fungi are involved in their normal degradation, but not in their accelerated degradation. The shift in the rate of degradation of pesticides such as diphenamid, benomyl, and S-ethyl dipropylthiocarbamate, in soils that have acquired accelerated degradation, seems to be associated with the buildup of populations of bacterial degraders. Moreover, it has been shown that for the herbicide diphenamide, accelerated degradation is apparently linked to the induction of an oxidative demethylation process in soil bacteria, which might be analogous to the development of resistance in pests. Contrary to studies demonstrating accelerated degradation of the systemic insecticide aldicarb and accumulation of aldicarb sulfoxide in non-history soils, our work has shown that repeated application of this carbamate at several locations in Israel over a 10-year period did not induce accelerated degradation. It should be pointed out that in the Israeli soils there was only minimal formation of aldicarb sulfoxide. These studies were performed in soils with a pH ranging from 7.8 to 8.3, which is higher than the pH reported for soils where accelerated degradation was detected.
最近的研究表明，各种农用化学品与土壤微生物之间的相互作用可能会减缓或加速降解过程。土壤消毒用于控制土传病原体和杂草。在土壤中施用此类广谱杀菌剂以及一些更具选择性的化学品，会对微生物活性产生强烈影响，这可能导致施用于此类处理过的土壤中的农药降解速率大幅降低。将农药施用于先前已消毒的土壤可能会延长其生物活性，就除草剂而言，这可能会对下一季作物造成植物毒性损害。相反，重复施用相同或结构相关的农药可能会导致能够以更快速度降解该农药的微生物种群选择性积累。已报道多种化学类别的农药存在加速降解的情况。开展了研究以评估加速降解的机制。对于几种农药，已表明土壤真菌参与其正常降解，但不参与加速降解。在已获得加速降解的土壤中，诸如二苯胺灵、苯菌灵和S - 乙基二丙基硫代氨基甲酸酯等农药降解速率的变化似乎与细菌降解菌种群的积累有关。此外，已表明对于除草剂二苯胺，加速降解显然与土壤细菌中氧化脱甲基过程的诱导有关，这可能类似于害虫抗药性的发展。与证明内吸性杀虫剂涕灭威在非历史土壤中加速降解和涕灭威亚砜积累的研究相反，我们的工作表明，在以色列的几个地点，在10年期间重复施用这种氨基甲酸酯并未诱导加速降解。应该指出的是，在以色列的土壤中，涕灭威亚砜的形成极少。这些研究是在pH值为7.8至8.3的土壤中进行的，该pH值高于检测到加速降解的土壤所报道的pH值。
