Xinjun Huang , Lanting Liu , Yali Wang , Yongqiang Yang , Linlin Zhao , Rainer Horn , Liping Li
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引用次数: 0
Abstract
Soil compaction induced by frequent field traffic often causes surface waterlogging in wheel rut areas during the rainy season. In arsenic (As)-contaminated farmlands, this process creates varying redox conditions that affect As mobility and transformation at different depths. This study examined the effects of compaction on As behavior in a clay loam Alfisol (from A horizon) under periodic waterlogging over 66 days. Four soil columns were packed with two bulk densities of 1.3 g cm⁻³ and 1.65 g cm⁻³ to simulate different compaction treatments across a 0–40 cm profile: no compaction(CK), low compaction(LC), medium compaction (MC), and heavy compaction (HC) with corresponding compacted thickness of 0 cm, 16 cm, 24 cm, and 32 cm. Results showed that compaction significantly decreased soil air permeability (Ka) and redox potential (Eh). During waterlogging, excess water stagnated in compacted layers, creating reducing conditions that promoted the release of the mobile As (III) species into pore water. In the first two waterlogging cycles, As(III) concentrations in pore water peaked at 5.6, 6.2, 7.3, and 8.0 μg L⁻¹ under CK, LC, MC, and HC, respectively, while the average Fe-(hydr)oxide-bound As decreased by 22.9 %, 22.9 %, 23.7 %, and 26.5 %, respectively. During the subsequent waterlogging cycles, with the increase of Ka, Eh, and microbial activity of aerobic species the As was stabilized on soil particles in the fractions of specifically bound As and Fe-(hydr)oxide-bound As with reduced mobility. These findings highlight the potential risks of soil compaction-induced As transformations, particularly the conversion of less mobile As(V) to the more toxic and mobile As(III), posing environmental and health concerns.
期刊介绍:
Soil & Tillage Research examines the physical, chemical and biological changes in the soil caused by tillage and field traffic. Manuscripts will be considered on aspects of soil science, physics, technology, mechanization and applied engineering for a sustainable balance among productivity, environmental quality and profitability. The following are examples of suitable topics within the scope of the journal of Soil and Tillage Research:
The agricultural and biosystems engineering associated with tillage (including no-tillage, reduced-tillage and direct drilling), irrigation and drainage, crops and crop rotations, fertilization, rehabilitation of mine spoils and processes used to modify soils. Soil change effects on establishment and yield of crops, growth of plants and roots, structure and erosion of soil, cycling of carbon and nutrients, greenhouse gas emissions, leaching, runoff and other processes that affect environmental quality. Characterization or modeling of tillage and field traffic responses, soil, climate, or topographic effects, soil deformation processes, tillage tools, traction devices, energy requirements, economics, surface and subsurface water quality effects, tillage effects on weed, pest and disease control, and their interactions.