Speciation and Isotopic Composition of Sulfur in Limestone Soil and Yellow Soil in Karst Areas of Southwest China: Implications of Different Responses to Acid Deposition

Abstract

The contents and stable S isotope ratio (δS) values of total S, organic S, SO-S, and total reduced inorganic S (TRS) in typical limestone soil and yellow soil were analyzed in this study to examine the general distributions of S forms and their δS values in soils in karst areas of southwest China. Under a similar level of acid deposition, the vertical profiles of the S forms and their δS values differed in limesto\ne soil and yellow soil, indicating the different geochemical responses of these soils to acid deposition. The deposited SO was retained as organic S in both soils. The depletion in S of TRS relative to SO and the parallel increasing δS values of TRS and SO indicate a bacterial reduction process of sulfate in both soils. The different extents of C-bonded S mineralization and organic sulfate transport explain the different vertical profiles of total S and organic S contents in both soils. Sulfate adsorption in limestone soil was negligible because of high pH values. Sulfate adsorption in yellow soil was another important S retention process in addition to biological S retention to form organic S and TRS because of low pH values. The effect of acid deposition on yellow soil appeared more serious because of the accumulation and leaching of deposited SO, which can result in soil acidification and accelerate the loss of basic cations from yellow soil. However, compared with yellow soil, limestone soil released more S into rivers by organic S mineralization after a large decrease in annual S deposition rate.

Nitrogen loss from karst area in China in recent 50 years: An in‐situ simulated rainfall experiment's assessment

“…Soil formation in karst areas is slow due to its base geology, and soil loss by accelerated soil erosion by water from the steeply sloping terrain is widespread. The geochemical consequences of erosion vary and are based on the characteristics of the (1) epikarst, (2) the surface of the karst, and (3) the geological structure of the drainage basin and the underlying bedrock (Wang et al, ; Zhang et al, ). Anthropogenic factors (e.g., agricultural cultivation, grazing, deforestation, and burning) also significantly influence erosion and drainage in karst systems (Gao et al., ; Wang et al, ).…”

“…Soil formation in karst areas is slow due to its base geology, and soil loss by accelerated soil erosion by water from the steeply sloping terrain is widespread. The geochemical consequences of erosion vary and are based on the characteristics of the (1) epikarst, (2) the surface of the karst, and (3) the geological structure of the drainage basin and the underlying bedrock (Wang et al, 2004;Zhang et al, 2014).…”

“…Overuse of mineral fertilizers in China has been the subject of recent scrutiny because of the negative impacts on human and environmental health, and the increasing disconnect between application rates and yield benefits: from 1996 to 2005, grain yields in China increased by only 3.5%, while use of the chemical fertilizers supplying N, increased by 24% (Zhang et al., ). Environmental pollution related to poor nutrient management has become a serious issue over last 20 years, with N concentrations in surface and ground water regularly exceeding WHO recommendations (Zhu and Chen, ).…”

Alteration of soil chitinolytic bacterial and ammonia oxidizing archaeal community diversity by rainwater redistribution in an epiphyte-laden Quercus virginiana canopy

“…4). To the knowledge of the authors, increased SO 4 2in soils has not been connected to changes in chitinolytic bacteria or AOA amoA communities, though increased SO 4 2is associated with soil acidification and cation loss through SO 4 2leaching (Zhang et al, 2014). Cation losses along with acidification potentially impact several soil conditions affecting bacteria and archaea containing N-functional genes.…”

Use of nutrient medium technique for vegetation restoration in Karst region of Southwest China

“…Therefore, the loss of nutrients in the nutrient medium is dominated by surface runoff, which is only a small part of the total nutrient loss. In addition, Karst water contains some residual nutrients due to the use of fertilisers, such as N (Zhang et al 2014), and mineral elements produced by the dissolution of carbonate rocks, which can be absorbed by the nutrient medium and water absorption bar to increase the fertility of the matrix, and finally moves to root system of plants by diffusion can be absorbed by the roots (F. Somma et al 1998). The economy of the nutrient medium technique is an important indicator to determine whether it can be widely used.…”