Changes in Cultivated Land Area and Associated Soil and SOC Losses in Northeastern China: The Role of Land Use Policies.

Haiyan Fang

doi:10.3390/ijerph182111314

Abstract

Land use policy is the driving factor influencing land use; however, little research has been conducted to identify the role of agricultural policy in influencing land cultivation and associated soil and soil organic carbon (SOC) losses. The aims of this study were to explore temporal changes in cultivated land, soil erosion, and SOC loss and to identify the role of land use policy. The present study was conducted using the revised universal soil loss equation by integrating remote sensing images from 1980, 1990, 2000, and 2017. The study found that cultivated land areas increased from 275.11 thousand km2 in 1980, to 300.03 thousand km2 in 2000, and to 344.16 thousand km2 in 2010, and then decreased by 326.94 thousand km2. The mean soil loss rates changed from 590.66 t·km−2·yr−1 in 1980 to 634.25 t·km−2·yr−1 in 2010, and then decreased to 495.66 t·km−2·yr−1 in 2017. Soil loss rate increased with increasing slope gradient. The changes in SOC loss rates demonstrated the same pattern as that of soil loss, with the largest loss rate of 728.27 kg·km−2·yr−1. These changes can be explained by changed land use policy and population growth. In future land use management, reasonable implementation of soil conservation measures should be undertaken to reduce soil and SOC losses in the black soil region of northeastern China.

Highlights

With increasing population and economic development in the world, more land has been converted into arable land [1]
It can be seen that the cultivated land spreads northward, and that more land was cultivated with time duration
The cultivated land areas increased from 275.11 thousand km2 in 1980, to 300.03 thousand km2 in 2000, to

Summary

Introduction

With increasing population and economic development in the world, more land has been converted into arable land [1]. Between 1960 and 2015, an average of 2.5 million hectares of land was converted each year into cultivated land [2,3]. Changes to cultivated land and induced soil erosion and associated SOC dynamics need to be carefully studied [10,11,12]. The number of studies on land use policies’ impacts has increased significantly in recent years. In Norway, agricultural subsidy policy in 1950 increased the total cropland area by 80% between 1950 and 1990, resulting in severe soil erosion, whereas subsequent sustainable agricultural production policy alleviated the environmental problems [14]. Similar studies have been conducted in other regions of the world [15,16]

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Discussion

Conclusion