Jiangxi Academy of Water Science and Engineering, Nanchang, 330029, China.
Key Laboratory of Poyang Lake Watershed Agricultural Resources and Ecology of Jiangxi Province, Jiangxi Agricultural University College of Land Resources and Environment, Jiangxi Agricultural University, Nanchang, 330045, China.
Environ Pollut. 2021 Dec 15;291:118069. doi: 10.1016/j.envpol.2021.118069. Epub 2021 Aug 30.
The on-going and extensive use of neonicotinoids occur in orchards. However, it is still unknown whether and how orchard management affects soil properties, especially the contents and structure of soil organic matter during orchard development, and their further influences on neonicotinoid persistence. Here, surface soil samples were collected from the citrus orchards with different cultivation ages (1, 10, 14, and 20 years), and their physicochemical properties were determined. Changes in the chemical structure of soil organic matter (SOM) were furtherly examined using solid-state CP/TOSS C NMR. Then, the sorption isotherms of imidacloprid in these soils were investigated. The sorption coefficient (K) of imidacloprid at C of 0.05 mg/L in the orchard soils increased by 19.4-23.3%, along a 20-year chronosequence of cultivation, which should be mainly ascribed to the increase of SOM. However, the organic carbon-normalized sorption coefficient (K, sorption per unit mass of OM) of imidacloprid declined with increasing cultivation ages. Moreover, the polar and aliphatic domains of SOM had a significantly positive relation to the K of imidacloprid, suggesting its key role in governing imidacloprid sorption. The results highlighted that reasonable management measures could be adopted to control the occurrence and fate of neonicotinoids in soils, mainly by affecting the content and quality of SOM.
新烟碱类杀虫剂的持续广泛使用发生在果园中。然而，目前尚不清楚果园管理是否以及如何影响土壤特性，特别是在果园发展过程中的土壤有机质含量和结构，以及它们对新烟碱类杀虫剂持久性的进一步影响。本研究中，从不同栽培年限（1、10、14 和 20 年）的柑橘园中采集表层土壤样品，并测定其理化性质。进一步使用固态 CP/TOSS C NMR 研究土壤有机质（SOM）化学结构的变化。然后，研究了这些土壤中吡虫啉的吸附等温线。在果园土壤中，C 为 0.05 mg/L 时吡虫啉的吸附系数（K）在 20 年的栽培时间序列中增加了 19.4-23.3%，这主要归因于 SOM 的增加。然而，吡虫啉的有机碳归一化吸附系数（K，单位质量有机碳的吸附量）随着栽培年限的增加而降低。此外，SOM 的极性和脂肪族域与吡虫啉的 K 呈显著正相关，表明其在控制吡虫啉吸附方面起着关键作用。结果强调，可以采取合理的管理措施来控制土壤中新烟碱类杀虫剂的发生和命运，主要是通过影响 SOM 的含量和质量。
