Impacts of Cultivated Land Conversion on Environmental Sustainability and Grain Self-sufficiency in China

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  • 75China & World Economy / 75 92, Vol. 16, No. 3, 2008

    2008 The AuthorJournal compilation 2008 Institute of World Economics and Politics, Chinese Academy of Social Sciences

    Impacts of Cultivated Land Conversion onEnvironmental Sustainability and Grain

    Self-sufficiency in China

    Shuhao Tan *

    Abstract

    Using provincial data, the present paper examines the impact of cultivated land conversion onagriculture and the environment. It is found that the grain production center is graduallymoving towards more fragile and water scarce areas, putting more pressure on the environment.Land conversion caused large losses in ecosystem service values in the 1990s, but large scaleecological restoration programs have been implemented since 2000 to compensate for suchlosses. The ecological restoration programs are concentrated in regions with relatively lowland productivity, whereas cultivated land conversion usually takes place in areas with relativelyhigh land productivity. Newly-cultivated land, especially that in areas marginally suit foragricultural production, is likely to have much lower productivity levels than the originalcultivated land. Because the stock of potentially cultivable land is almost exhausted, Chinasgrain self-sufficiency policy can only be maintained by preserving the available stock of arableland and increasing its productivity in a sustainable way.

    Key words: China, cultivated land conversion, environmental quality, grain self-sufficiency,land policy

    JEL codes: Q01, Q15, Q28

    I. Introduction

    Grain self-sufficiency is an important agricultural policy goal in China.1 The Chinese

    * Shuhao Tan, Associate Professor, School of Agricultural Economics and Rural Development, RenminUniversity of China, Beijing, China. Email: Shuhtan68@gmail.com. The author is grateful for thefinancial support provided by the program of Natural Science Foundation of China (30571094), theprogram of National Social Science Foundation of China (07&ZD048) and the 973 Program of Ministryof Sciences and Technology of China (2004CB720401).1In this paper China refers to Chinese mainland.

  • 76 Shuhao Tan / 75 92, Vol. 16, No. 3, 2008

    2008 The AuthorJournal compilation 2008 Institute of World Economics and Politics, Chinese Academy of Social Sciences

    Government has set a target of at least 95 percent grain self-sufficiency under normalconditions. Very limited land resources are available to feed its large population, whichreached 1.3 billion. Of the total land area, 960 million ha, only 13.5 percent can be used asarable land. As a result, only 0.10 ha per capita is available for agricultural production (NBS,2006).

    Chinas population is expected to stabilize at a level of 1.6 billion by 2030 (Zhong et al.,1999). In the coming years, the growing population will place a greater burden on thecountrys agricultural sector. Sustaining the agricultural production base and improvingagricultural productivity have been widely considered by researchers and the ChineseGovernment as the most effective ways of guaranteeing an adequate level of food productionin the long run. Strengthening the agricultural production capacity and developing a modernagricultural sector while sticking to the policy of food self-reliance have become nationalpolicy priorities since 2000 (State Council, 2007). Proposed measures include intensifyingthe conservation of arable land and improving the ecological environment, accelerating theconstruction of irrigation and water conservation facilities, stimulating the use ofenvironmentally-friendly fertilizers and pesticides, and investing in agricultural scienceand technology.

    In the long run, the agricultural production capacity in China might be greatlyrestricted by further reductions in the available arable land, resulting in overuse of thecurrent arable land, which, in turn, could lead to the depletion of the natural resourcebase through, for example, soil degradation, water scarcity and water pollution, andfurther reduce the efficiency of fertilizer application. This raises the question of whetherChina can maintain its grain self-sufficiency policy in the long run. In addition, what willbe the impact of this policy on environmental quality? An important issue causing concernis the conversion of cultivated land into, for example construction land. Shao and Xie(2007) show that 9.3 percent of the arable land was taken out of cultivation during theperiod 19962004, whereas 2.9 percent was added to the stock of cultivated land over thesame period.

    The present paper uses provincial and regional data to examine the impact of cultivatedland conversion on agricultural productivity and ecosystem services.2 Various studieshave addressed the cultivated land conversion issue in China. Many of these studiesexamine the link between cultivated land conversion and food self-sufficiency (e.g. Yang

    2 Ecosystem services refer to the goods (such as food or raw materials) and services (such as wasteassimilation or soil conservation) that are derived directly or indirectly by human beings from ecosystems.

  • 77Impacts of Cultivated Land Conversion

    2008 The AuthorJournal compilation 2008 Institute of World Economics and Politics, Chinese Academy of Social Sciences

    and Li, 2000; Deng et al., 2006; Zhu, 2006).3 Other studies examine the environmentaleffects of cultivated land conversion (Tan et al., 2005), while Ash and Edmonds (1998)examine the relationship between land resources and both agricultural production and theenvironment. In the present analysis we take into account the uncultivated land that maybe cultivated in the future. The size of this stock could have a major impact on the arableland size and its quality in the near future. In addition, we use more recent data (up to 2004)that have been estimated with greater precision than the data used in most of the earlierstudies. Use of recent data is quite relevant because land use structure has changedgreatly during the last decade as a result of rapid urbanization and industrialization andincreasing welfare levels. The present study uses a method developed by Costanza et al.(1997) to estimate the value of the change in ecosystem services caused by cultivated landconversion.

    The present paper is organized as follows. Section II outlines the current situation andrecent trends in cultivated land and grain production in China; Section III examines the impactof cultivated land conversion on environmental sustainability using the change in ecosystemservice value as a measure of sustainability; Section IV examines the impact of cultivated landconversion on agricultural production by taking into account differences in productivitybetween land taken into agricultural production and land taken out of agricultural production.Section V concludes the paper and provides some policy implications.

    II. Cultivated Land and Grain Production in China

    Although China has vast land resources, only a small portion can be used for cropping.Table 1 shows that 130 million ha (13.5 percent) of the total available land is cultivated land.Irrigated land accounts for 55 million ha, 42.2 percent of the cultivated land. The land thatis not cultivated, to a large extent, consists of forest land (18.2 percent of the total land area)and useable grassland (32.6 percent of total land area).

    From Table 1 it is evident that the total sown area is larger than the cultivated area,because more than one crop is planted per year in some regions. As a result, the multiplecropping index (calculated as the sown area divided by the cultivated land area) equals1.20. Approximately two-thirds of the sown area is planted with grain (cereals, soybeansand tubers). The three major grain crops, rice, maize and wheat, constitute just over half

    3 The term food security is commonly used in China to refer to food self-sufficiency. As the use of thisterm deviates from the commonly accepted definition of food security (access of all people at all timesto enough food for an active, healthy life), we will use the term food self-sufficiency (or self-reliance) inour study.

  • 78 Shuhao Tan / 75 92, Vol. 16, No. 3, 2008

    2008 The AuthorJournal compilation 2008 Institute of World Economics and Politics, Chinese Academy of Social Sciences

    (50.2 percent) of the sown area. Other major crops are vegetables, oil-bearing crops (e.g.rapeseed and peanuts), fruit and cotton (NBS, 2006).

    Most paddy fields are located in areas with relatively high levels of rainfall (see Table 2).Approximately three-quarters of the paddy fields (75.7 percent) are located in areas withprecipitation levels of more than 1000 mm per year. In contrast, 79.2 percent of the dry landis located in areas with precipitation levels of less than l000 mm. Most cultivated land is flat(slope less than 5). However, 0.8 percent of the paddy land and 1.6 percent of the dry landis located on land with slopes of more than 25 (see Table 2).

    Comparing with the other regions of the world, agriculture in China is characterized by highexternal input and high labor intensity. As shown in Table 3, the chemical fertilizer use equals327 kg /ha. This level is more than twice the average level of the whole of Asia and is more thanthree times the global average. Use of tractors and harvest machines in China is very low. Thesize of the cultivated land per person working in agriculture is by far the lowest in China,confirming the great scarcity of land in China. These figures clearly show that China hasachieved its agricultural growth by adopting a biological pattern of agricultural intensification.

    Figure 1 shows the trend in the cultivated land area in China between 1988 and 2005.4

    4 Note that the figures for cultivated land area for 2005 listed in Table 1 come from a different source(NBS

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