Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
Dalian Institute of Administration, Dalian 116013, China.
J Hazard Mater. 2022 Jun 5;431:128467. doi: 10.1016/j.jhazmat.2022.128467. Epub 2022 Feb 11.
Because of the rigid crystalline structure and recalcitrant components, maize straw returned is slowly decomposed in soils. Straw residues are substantially accumulated in soils and pose detrimental impacts to crop plantation. Here we report the pretreatments of urea and NaOH (USH) to enhance maize straw decomposition in the field. The USH reagents interacted synergistically to destruct straw, mainly through breaking the rigid hydrogen bonding network and chemically hydrolyzing recalcitrant lignin. The synergy was evident for the USH reagents containing 6-8% urea and 0.1-1% NaOH under various temperature conditions (-20 °C to 25 °C). The USH (7%/0.1%) pretreatment resulted in notable enhancement (37%) of straw decomposition in the field within 6 months, superior to current biological-based treatments (6-28%). Moreover, this pretreatment posed no influence on the adsorption of straw residues collected at the early stage of decomposition (27 days) toward five commonly used herbicides. Those straw residues collected on 67 days and later exhibited high adsorption capacity, indicated by 0.5- to 4-folded increases in K values. Additionally, the impacts to soil pH and bacterial/fungal community were negligible. The USH pretreatments thus have practical interests in mitigating accumulation of straw residues in straw-returned soils.
由于玉米秸秆具有刚性的晶体结构和顽固的成分，在土壤中缓慢分解。秸秆残体在土壤中大量积累，对作物种植造成不利影响。在这里，我们报告了尿素和 NaOH（USH）预处理以增强玉米秸秆在田间的分解。USH 试剂协同作用破坏秸秆，主要通过打破刚性氢键网络和化学水解顽固木质素。在各种温度条件（-20°C 至 25°C）下，含 6-8%尿素和 0.1-1%NaOH 的 USH 试剂表现出明显的协同作用。USH（7%/0.1%）预处理可在 6 个月内显著提高田间秸秆分解率（37%），优于当前基于生物的处理方法（6-28%）。此外，该预处理对在分解早期（27 天）收集的秸秆残体对五种常用除草剂的吸附没有影响。在 67 天和之后收集的那些秸秆残体表现出高吸附能力，K 值增加了 0.5-4 倍。此外，对土壤 pH 和细菌/真菌群落的影响可以忽略不计。因此，USH 预处理在减轻秸秆还田土壤中秸秆残体积累方面具有实际意义。
