Impact Assessments on Agricultural Productivity of Land-Use Change

Abstract

Currently, food safety and its related influencing factors in China are the hot research topics, and cultivated land conversion is one of the significant factors influencing food safety in China. In this chapter, we first investigated land degradation induced by land-use change. Land degradation is a complex process which involves both the natural ecosystem and the socioeconomic system, among which climate and land-use change are the two predominant driving factors. To comprehensively and quantitatively analyze the land degradation process, we employed the normalized difference vegetation index (NDVI) as a proxy to assess land degradation and further applied the binary panel logistic regression model to analyze the impacts of the driving factors on land degradation in the North China Plain. The results revealed that increasing in rainfall and temperature would significantly and positively contribute to the land improvement, and conversion from cultivated land to grassland and forest land showed positive relationship with land improvement, while conversion to built-up area will lead to land degradation. Besides, human agricultural intensification represented by fertilizer utilization will help to improve the land quality. The economic development may exert positive impacts on land quality to alleviate land degradation, although the rural economic development and agricultural production will exert negative impacts on the land and lead to land degradation. Infrastructure construction would modify the land surface and further resulted in land degradation. The findings of the research will provide scientific information for sustainable land management. Second, we predicted land-use conversions in the North China Plain based on the scenario analysis. Scenario analysis and dynamic prediction of land-use structure which involve many driving factors are helpful to investigate the mechanism of land-use change and even to optimize land-use allocation for sustainable development. In this study, land-use structure changes during 1988–2010 in North China Plain were discerned and the effects of various natural and socioeconomic driving factors on land-use structure changes were quantitatively analyzed based on an econometric model. The key drivers of land-use structure changes in the model are county-level net returns of land resource. In this research, we modified the net returns of each land-use type for three scenarios, including business as usual (BAU) scenario, rapid economic growth (REG) scenario, and coordinated environmental sustainability (CES) scenario. The simulation results showed that, under different scenarios, future land-use structures were different due to the competition among various land-use types. The land-use structure changes in North China Plain in the 40-year future will experience a transfer from cultivated land to built-up area, an increase of forestry land, and decrease of grassland. The results will provide some significant references for land-use management and planning in the study area. Third, we simulated shifting patterns of agroecological zones across China. An agroecological zone (AEZ) is a land resource mapping unit, defined in terms of climate, landform, and soils, and has a specific range of potentials and constraints for cropping (FAO 1996). The shifting patterns of AEZs in China driven by future climatic changes were assessed by applying the agroecological zoning methodology proposed by International Institute for Applied Systems Analysis (IIASA) and Food and Agriculture Organization of the United Nations (FAO) in this study. A data processing scheme was proposed to reduce systematic errors in projected climate data using observed data from meteorological stations. AEZs in China of each of the four periods: 2011–2020, 2021–2030, 2031–2040, and 2041–2050 were drawn. It is found that the future climate change will lead to significant local changes of AEZs in China and the overall pattern of AEZs in China is stable. The shifting patterns of AEZs will be characterized by northward expansion of humid AEZs to subhumid AEZs in south China, eastward expansion of arid AEZs to dry and moist semiarid AEZs in north China, and southward expansion of dry semiarid AEZs to arid AEZs in southwest China.