Abstract

This study investigates the adsorption and dissipation of glyphosate and the formation/dissipation of AMPA in non-tilled (NT) and conventionally tilled (CT) soil at 0–5 and 5–20 cm depth. Glyphosate adsorption was mainly related to the different NT and CT soil properties (clay and amorphous Al oxides), whereas an effect of the soil management could not be identified. Glyphosate dissipation was initially fast, and it slowed down later. The initial glyphosate concentration in NT soil at 0–5 cm was significantly lower than the dose applied due to the interception by the weeds and crop residues. AMPA began to form early after treatment and persisted longer than glyphosate. The DT50 range was 8–18 days for glyphosate and 99–250 days for AMPA. Longer glyphosate and AMPA DT50 were observed in NT soil compared to CT soil but, for glyphosate, the difference was significant only at 5–20 cm. Higher glyphosate and AMPA concentrations were detected in NT than in CT soil at the end of the study at 0–5 cm. The differences in glyphosate and AMPA DT50 and persistence were mainly attributable to the influence of different NT and CT soil characteristics. However, other factors could have contributed to the different glyphosate and AMPA dynamics between the soils, like glyphosate wash-off from crop residues on NT soil with the rainfall, the delayed glyphosate return to the soil by weed root exudation or weeds decomposition, and the NT soil compaction which may have reduced the microbial degradation of glyphosate at low concentrations.

Graphic abstract

中文翻译：

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常规和保护性耕作土壤中草甘膦和氨基甲基膦酸的动态变化

摘要

本研究调查了草甘膦的吸附和消散以及 AMPA 在 0-5 和 5-20 厘米深度的非耕作 (NT) 和常规耕作 (CT) 土壤中的形成/消散。草甘膦吸附主要与不同的 NT 和 CT 土壤特性（粘土和无定形氧化铝）有关，而土壤管理的影响无法确定。草甘膦的消散最初很快，后来减慢了。由于杂草和作物残留物的拦截，NT 土壤中 0-5 cm 处的初始草甘膦浓度显着低于施用的剂量。AMPA 在处理后较早开始形成，并且比草甘膦持续时间更长。草甘膦的 DT50 范围为 8-18 天，AMPA 为 99-250 天。与 CT 土壤相比，在 NT 土壤中观察到更长的草甘膦和 AMPA DT50，但对于草甘膦，差异仅在 5-20 厘米处显着。在研究结束时，在 0-5 cm 处，NT 中检测到的草甘膦和 AMPA 浓度高于 CT 土壤。草甘膦和AMPA DT50和持久性的差异主要归因于不同NT和CT土壤特性的影响。然而，其他因素可能导致土壤之间不同的草甘膦和 AMPA 动态，例如随着降雨从北领地土壤上的作物残留物中冲走草甘膦，通过杂草根系分泌物或杂草分解延迟草甘膦返回土壤，以及NT 土壤压实可能会减少低浓度草甘膦的微生物降解。草甘膦和AMPA DT50和持久性的差异主要归因于不同NT和CT土壤特性的影响。然而，其他因素可能导致土壤之间不同的草甘膦和 AMPA 动态，例如随着降雨从北领地土壤上的作物残留物中冲走草甘膦，通过杂草根系分泌物或杂草分解延迟草甘膦返回土壤，以及NT 土壤压实可能会减少低浓度草甘膦的微生物降解。草甘膦和AMPA DT50和持久性的差异主要归因于不同NT和CT土壤特性的影响。然而，其他因素可能导致土壤之间不同的草甘膦和 AMPA 动态，例如随着降雨从北领地土壤上的作物残留物中冲走草甘膦，通过杂草根系分泌物或杂草分解延迟草甘膦返回土壤，以及NT 土壤压实可能会减少低浓度草甘膦的微生物降解。

图形摘要