Spatio-Temporal Patterns of Cropland Conversion in Response to the “Grain for Green Project” in China’s Loess Hilly Region of Yanchuan County

Jieyong Wang,Zhigao Liu,Yansui Liu

doi:10.3390/rs5115642

Abstract

To prevent environmental degradation, China’s central government launched the “Grain for Green Project” (GGP) in 1999. Since its beginning, the effects and influences of the GGP have been hotly debated among domestic and international scholars and policymakers. This paper is taking the County of Yanchuan in the Loess Plateau as a case study, examines the spatio-temporal patterns of cropland conversion in response to the GGP. This research is methodologically based on remote sensing (RS) and geographic information systems (GIS), and also employs personal interviews with local government officials and farmers. The results show that land use/cover patterns in Yanchuan County have changed dramatically after the implementation of GGP. Cropland has decreased remarkably, while orchard land and sparse forest has increased significantly: 23.84% of cropland was converted to orchard, and 22.25% to sparse forest. Simultaneously, the landscape has become more fragmented but also more diversified, forestland has become more dominant. A total of 61.19% of the total converted cropland was on slopes greater than 15 degrees, 64.85% of which was lower-grade land. The converted cropland is mostly located in more accessible areas for convenient management. Partially affected by farmers’ self-willingness, sloping cropland was preferred to orchard (economic forest), and some gentle slope (less than 15 degrees) or higher-grade cropland were involved in the GGP. To maintain and reinforce the achievements of the GGP and further contribute to the GGP’s sustainability and rural development, the paper recommends that the Chinese government should build a continuous compensation mechanism for the households who lost cropland for the GGP while improving the productivity of flat cropland.

Highlights

It has been widely recognized that China, over the years, has experienced severe environmental degradation
We focused on what kinds of cropland that have been converted to what kinds of afforestation, using Yanchuan County in the Loess Plateau as a case study
The two images were interpreted by the method of supervised classification using Maximum Likelihood Classifier (MLC), visual interpretation involved the use of image characteristics such as texture, pattern, and color to translate image into land use

Summary

Introduction

It has been widely recognized that China, over the years, has experienced severe environmental degradation. The Chinese Government, in recent years, has made efforts to rescue the degraded environment [1,2] Among these efforts, the “Grain for Green Project” (GGP), known as the “Sloping Land Conversion Program” (SLCP), is an extremely ambitious conservation program to prevent soil erosion. Responding to severe and prolonged droughts on the lower reaches of the Yellow River in 1997, and massive flooding on the Yangtze River in 1998, China’s central government initiated the GGP in 1999, with a primary aim to reduce soil erosion from sloping cropland through transforming them into grassland or forest. The GGP planned to convert 14.7 million hectares of cropland on steep slopes in the upper reaches of the Yellow and Yangtze River Basins back to forest and into natural grassland. Twenty-five provinces are involved in the project, encompassing all of China with the exception of the densely populated and developed eastern regions (Figure 1)

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