ABSTRACT

Herbicide application in farm soil invariably impacts non-target biota including the microbes. Herbicides inhibit microbial exoenzyme activities, crucial for the decomposition of organics and release of nutrients. It was hypothesised that increasing the antioxidant level in soil through organic amendments could reduce the toxicity of the herbicide pretilachlor on soil microbial activity. This study reports the effects of organic amendments with farmyard manure (FYM-T1), poultry manure (PM-T2) and vermimanure (VM-T3) at recommended doses on the activities of the exoenzymes, invertase, amylase and cellulase in farm soils pre-treated with the herbicide pretilachlor. Significant spikes in percent organic carbon (OC), total antioxidant capacity (TAC) and activities of the exoenzymes were observed in amended soils relative to control. The percent soil OC was maximum in T1 (2.63 ) followed by T3 (2.28 ) at 120 h. T3 indicated the maximum amylase (0.27 mg glucose/gsoil/h), cellulase (0.26 mg glucose/gsoil/h), invertase (0.39 mg glucose/gsoil/h) activities and soil TAC (1.03 Mm Trolox/cm³/g soil) at 168 h. A significant positive correlation between % OC, TAC and exoenzyme activities was observed. TAC and invertase proved to be the most responsive markers. It was concluded that selective organic amendments of soil could significantly enhance soil antioxidant level, and reduce herbicide induced stress on soil microbiota with an increase in exoenzyme secretion.

摘要

在农场土壤中使用除草剂总是会影响包括微生物在内的非目标生物群。除草剂抑制微生物外酶活性，这对于有机物的分解和养分的释放至关重要。假设通过有机改良剂增加土壤中的抗氧化剂水平可以降低除草剂丙草胺对土壤微生物活性的毒性。这项研究报告了建议剂量的农家肥（FYM-T1），家禽粪便（PM-T2）和ver菜（VM-T3）有机修饰对农田土壤中外酶，转化酶，淀粉酶和纤维素酶活性的影响用除草剂丙草胺处理。相对于对照，在改良土壤中观察到有机碳百分比（OC），总抗氧化剂能力（TAC）和外切酶活性的显着增加。在120 h时，土壤OC的百分数在T1（2.33）之后最高，随后是T3（2.28）。T3表示最大淀粉酶（0.27 mg葡萄糖/ gsoil / h），纤维素酶（0.26 mg葡萄糖/ gsoil / h），转化酶（0.39 mg葡萄糖/ gsoil / h）活性和土壤TAC（1.03 Mm Trolox / cm³ / g土壤）在168小时。观察到％OC，TAC和外切酶活性之间显着正相关。TAC和转化酶被证明是最敏感的标记。结论是，选择性有机土壤改良剂可以显着提高土壤抗氧化剂水平，并减少除草剂诱导的土壤微生物群上的胁迫，并增加外切酶的分泌。