Soil salinization of cultivated land in Shandong Province, China-Dynamics during the past 40 years

An objective requirement of the sustainable utilization of soil resources and agricultural production management is the determination of the status of soil salinization and an understanding of its dynamics. This study selected the coastal plain, the Yellow River flood plain, and key inland areas with salinization in Shandong Province. Sampling and analysis of soil salinization in cultivated lands were conducted in 2015-2016, and 3,551 valid samples were obtained. Statistical and spatial analyses were performed and compared with the data from the Second Soil Survey (1979-1985). The degree, area, distribution, and dynamic characteristics of soil salinization in Shandong Province were analyzed. The results showed that the total salt content of the study area was mainly slight to moderate, and the salinization was dominated by chloride salts. At present, the land area of salinized cultivated land was 384.00 thousand ha, accounting for 11.30% of the total cultivated land area. Soil salinization showed a concentrated distribution along the coastal plain that was scattered in the Yellow River flood plain and inland areas, and the salinity decreased from the coast to the inland area. Compared with the Second Soil Survey period, the salinized cultivated land area had decreased by 431.59 thousand ha, a decrease of 52.9%. The degree of salinization, especially in coastal area, was substantial, and the gravity center moved northeastward. In this study, the characteristics and dynamics of the present state of soil salinization in Shandong Province were examined, providing a scientific basis for the utilization and management of cultivated land resources in saline areas.