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Presentation

2nd Revision

Introduction

 
Arguments - Impact
Arable Land
There are (at least) three land-related factors that could affect China's food security: (1) the expected decline of arable land (especially around urban areas); (2) the ongoing restructuring of cultivated land, primarily the use of cropland for growing high-value agricultural products such as vegetables, fruit, tobacco, or ground nuts; and (3) the degradation and loss of soils, mainly due to water and wind erosion as well as chemical and physical deterioration. These degradation problems are also exacerbated by agricultural overutilization and industrial pollution.
While all these trends could potentially threaten China's food security, it is my opinion that they have been blown out of proportion by various authors. Decreases in cultivated land area due to infrastructure construction certainly occur, but they are very small compared with China's huge area of cultivated land (and much smaller than the currently unused land reserves). Agricultural restructuring, which makes up the bulk of China's land-use change, is a positive trend related to greater market orientation that will increase food security. More serious are concerns that soil erosion, pollution, and overutilization of cultivated land might affect China's agricultural productivity. However, hard data on pollution are scarce (most analyses are based on models) and the pollution is restricted to certain - relatively small - areas. Soil degradation is certainly a serious problem, but not a recent one. Chinese farmers have battled the desert and fought soil erosion for thousands of years. With modern technologies of reforestation and soil management, their chances of winning against erosion have actually increased.
Short Description of the Problem
Here we discuss two factors that can diminish the food production capacity of China's arable land:
WB00860_.gif (262 bytes) The decline of cultivated land, especially around urban areas
WB00860_.gif (262 bytes) The problem of soil degradation
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Discussion
The impact of decreases in cultivated land, especially around urban areas Tables & Charts
Between 1988 and 1995, China lost some 980,000 ha of cropland to construction activities (see Tables 1 and 2). This includes losses to all kinds of rural and urban infrastructure and settlement expansion, mining activities, and industrial use. While this area is much less than 1% of the total cultivated land area (approximately 132 million ha), it is still a serious problem for three reasons. First, the land loss is permanent. Once the arable land is converted to some kind of infrastructure, there is no chance that it can be returned to cultivation. Second, the losses affect core agricultural land in China's highly productive zones. Infrastructure is primarily expanded in the densely populated Eastern and Southern provinces, which produce the bulk of China's crops. Third, there is a high probability that these losses will increase with further population growth and urbanization. With China's economic development, its infrastructure - especially roads, railways, canals, water reservoirs, industrial sites, and settlements - will have to be expanded. China still has a huge deficit in transportation infrastructure, and urban growth is only beginning. We consider the losses of cultivated land due to construction activities to be one of the most serious problems for China's food security, because these losses will most likely increase with further economic development.
Strict measures must be implemented and enforced to minimize construction-related losses of cultivated land. China needs concepts for infrastructure development that minimize land use, especially in the rapidly developing coastal provinces. Currently, much cropland is wasted by land-extensive development projects, such as the Three Gorges Dam project. There are also large areas of "horizontal" growth at the periphery of urban agglomerates. With its extreme shortage of arable land, China cannot afford the type of urban sprawl seen in many parts of the USA.
Land-use change by province, 1988 - 1995
Table 1

Land-use change by province, 1988 - 1995
Table 2

How serious is soil degradation in China's arable land?
It is not only the area of arable land that is important for China's food security, but also the quality of its soils. Many authors have published grim assessments of China's soil degradation (Smil, 1995; Brown, 1998).  IIASA's LUC Project has analyzed data from a global data set (GLASOD) and a regional data set (ASSOD) on soil degradation. Both data sets - from the International Soil Reference and Information Centre (ISRIC) in the Netherlands - include all of China. (For details, see the In-depth Analysis.)
LUC found that various types of soil degradation are causing serious problems in China. There is considerable water erosion in the Loess Plateau and in the river valleys of the South (see Table 1). The ongoing measures to stop or diminish loss of topsoil due to water erosion must therefore be intensified, not only to prevent productivity loss in the agricultural sector, but also to minimize hydrological problems (flooding) in areas downstream. Wind erosion, which can lead to desertification, is a major problem in the arid regions of Northern China, and further reforestation efforts are necessary. However, this degradation problem primarily affects marginal agricultural areas and grasslands in arid regions, which contribute little to China's overall food supply. The core agricultural regions, which produce the bulk of China's crops, are less seriously affected by this problem. Many agricultural areas have a high percentage of "stable land," where no soil degradation was identified. Areas where all the land is affected by soil degradation are relatively small and usually outside agricultural areas (see the red areas in Map 1). Chemical and physical forms of degradation (salinization), on the other hand, are more serious problems in the major crop areas. However, various vegetation conservation methods and adequate land management practices are available. These practices have been able to reduce  the impact of degradation considerably in the past; otherwise it would be difficult to explain how China has managed to multiply crop production during the last few decades.
Soil Degradation in China - the ASSOD assesment
Table 1

ASSOD assessment

ASSOD Soil Degradation Assessment: Stable Land
Map 1

Related Arguments

Arable Land:   Trends     Impact    Data Quality    Prediction Error    Intervention Possibilities    Intervention Costs

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Revision 2.0 (First revision published in 1999)  - Copyright 2011 by Gerhard K. Heilig. All rights reserved. (First revision: Copyright 1999 by IIASA.)