The salinization process and its response to the combined processes of climate change–human activity in the Yellow River Delta between 1984 and 2022

Abstract

Within the context of global change, the evolution of salinization in the Yellow River Delta has undergone dramatic changes. However, it is not clear how it responds to the combined processes of climate change and human activity（reclamation projects, changes in land-use types, and increases in fertilizer use）Based on the optimal soil salinization monitoring index model, this study retrieved the annual time series data set for salinization from 1984 to 2022 and then analyzed the spatial and temporal evolution patterns of salinization in the modern Yellow River Delta. The mechanism of the response of salinization evolution to climate change and human activities was investigated using Geodetector. The main conclusions were as follows: (1) From 1984 to 2022, the salinization intensity in the northeastern coastal zone of the Yellow River Delta showed an increasing trend, while that in the southwestern inland area showed an improving trend. (2) The high-frequency salinization zones were mainly concentrated near the mainstream and tributaries of the Yellow River, while zones with desalinization, re-salinization, and new salinization zones were mainly distributed in the main stream of the Yellow River. (3) There were obvious differences in the dominant factors in the evolution of salinization in different historical periods. In 1984, soil component factors and vegetation coverage were the dominant factors in the evolution of salinization. In 2022, vegetation coverage and land-use types had the strongest explanatory power for the salinization process. (4) The influence of natural and human activity factors on the salinization process was not independent, but a mutually reinforcing process. The interaction between NDVI and other factors has dominated the evolution of salinization in the Yellow River Delta. From 1984 to 2022, human activities were the dominant factors that promoted the improvement or intensification of salinization in the region.