Impacts of land use and salinization on soil inorganic and organic carbon in the middle-lower Yellow River Delta

作者：Yang Guo, Xiujun Wang, Xianglan Li, Minggang Xu, Yuan Li, Haonan Zheng, Yongming Luo, Pete Smith · 发表于：Pedosphere · 年份：2021 · DOI：10.1016/s1002-0160(21)60018-8 · 被引用次数：41 · 研究领域：Soil Carbon and Nitrogen Dynamics、Soil and Water Nutrient Dynamics、Soil Geostatistics and Mapping

Soil inorganic carbon (SIC) is an important reservoir of carbon (C) in arid, semi-arid, and semi-humid regions. However, knowledge is incomplete on the dynamics of SIC and its relationship with soil organic C (SOC) under different land use types in the semi-humid region, particularly in coastal zones impacted by soil salinization. We collected 170 soil samples from 34 profiles across various land use types (maize-wheat, cotton, paddy, and reed) in the middle-lower Yellow River Delta (YRD), China. We measured soil pH, electrical conductivity (EC), water-soluble salts, and SOC and SIC contents. Our results showed significant differences in both SOC and SIC among land use types. The dry cropland (maize-wheat and cotton) soils had significantly higher SOC and SIC densities (4.71 and 15.46 kg C m –2 , respectively) than the paddy soils (3.28 and 14.09 kg C m –2 , respectively) in the 0–100 cm layer. Compared with paddy soils, reed soils contained significantly higher SOC (4.68 kg C m –2 ) and similar SIC (15.02 kg C m –2 ) densities. There was a significant positive correlation between SOC and SIC densities over a 0–100 cm soil depth in dry cropland soils, but a negative relationship in the paddy soils. On average, SOC and SIC densities under maize-wheat cropping were 15% and 4% lower, respectively, in the salt-affected soils in the middle-lower YRD than the upper YRD. This study indicated that land use types had great influences on both SOC and SIC and their relationship, and sal...