Work

Spatial Distribution of Soil Organic Carbon and Nitrogen Across Salinity Gradients in the Yellow River Delta, China

Year: 2026

Type: article

Abstract: Severe soil salinization and low fertility significantly constrain sustainable agricultural development in the Yellow River Delta, one of the three major estuarine deltas in China. Despite their ecological importance, the regional-scale spatial interactions between soil salinity and nutrients, particularly regarding their vertical variability, remain poorly understood. This study analyzed 228 soil samples from 76 sites distributed across a distinct salinity gradient, which was determined by constructing a spatial salinity distribution map after sampling. Samples were collected at three depths (0–15, 15–30, and 30–45 cm) to investigate the spatial distribution of soil organic carbon (SOC), total nitrogen (TN), and the C/N ratio, along with their underlying driving factors. SOC and TN exhibited similar spatial patterns, with higher values distributed along both banks of the Yellow River. Horizontally, SOC and TN in the 0–15 cm layer decreased gradually from west to east, whereas the 15–30 cm and 30–45 cm layers showed an opposite trend, increasing eastward. Vertically, SOC and TN contents declined significantly with soil depth (p < 0.05), although the magnitude of this decline varied regionally: the 0–15 cm layer in the western area contained markedly higher nutrient levels than deeper layers, while vertical variation was less pronounced in the eastern and estuarine regions. Both variables were positively associated with total phosphorus (TP), available potassium (AK), soil moisture content (MC), clay content, and pH, but negatively correlated with electrical conductivity (EC), particularly in the 0–15 cm layer. Our results highlight that soil texture, moisture, and salinity affect the spatial heterogeneity and vertical decline of SOC and TN in the Yellow River Delta. Future research should focus on the long-term temporal distribution of the coupling of multiple elements under changing hydrological and salinity regimes.

Source: Agriculture

DOI: 10.3390/agriculture16171844

Authors: Yang Liu, Lidong Ren, Shixiang Zhao, Yuhao Dong, Lin Lin

Institutions: Inner Mongolia Agricultural University, Chinese Academy of Sciences, Institute of Geographic Sciences and Natural Resources Research, University of Liège, Ghent University

Language: English

Topic: Soil Carbon and Nitrogen Dynamics

Subfield: Soil Science

Field: Agricultural and Biological Sciences

Domain: Life Sciences

SDGs: Zero hunger, Life on land

Open Access status: gold

Estimated APC paid: $3,137