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March, 2010 Journal of Resources and Ecology Article Grain Production Driven by Variations in Farmland Use in China: An Analysis of Security Patterns LONG Hualou1 and ZOU Jian1, 2 1 Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; 2 Graduate University of Chinese Academy of Sciences, Beijing 100049, China Abstract: In China, the pattern of farmland use has been greatly changed due to the rapid development of the economy, since economic reform in 1978. Variations in available farmland, in terms of both quantity and quality, have brought about changes in grain production. This paper analyzes the spatiotemporal pattern of China’s level of farmland use for the period 1978 to 2004, and develops a “farmland-grain elasticity coefficient” (FGEC) to reflect the interrelationship between changes in farmland use and levels of grain production, using agricultural statistical data from local governments. The outcome of this study indicates that since 1978 the effect of farmland loss on grain security has been somewhat abated, due to increased investments and the subsequent improvements on farmland. Since the initiation of economic reform, China’s level of farmland use has been generally improved. These improvements are mainly due to rapid economic development and constitute a move across a gradient from the southeast coast of China to the Chinese inland areas, following the same path as that of economic development. However, continuous improvements in the level of farmland use may not always bring about sustainable and steady growth in grain output. Therefore, considering the law of diminishing marginal utility, in developing countries, the area of available farmland will play a key role in maintaining security in grain production. This will also constitute a practical scientific basis for strict farmland protection objectives and strategies for China. Key words: farmland quality; land use; farmland-grain elasticity coefficient; grain production; security pattern 1 Introduction Since economic reform and an open-door policy was adopted in 1978, China’s traditional communal agricultural production system in the central planning economic system has been gradually replaced by a household responsibility system, which transformed the previous agricultural sector from collective management to private production (Tilt 2008). The household responsibility system contracted land to individual households for a period of 15 years#, with relative autonomy over land-use decisions and crop selection. After fulfilling procurement quota obligations, farmers are entitled to sell their surplus on the market or retain it for their own use. By linking rewards directly to effort, the contracting system enhanced incentives and promoted efficient production. Simultaneously, China experienced rapid transitions since Deng Xiaoping launched economic reforms in 1978 (Long et al. 2007a). The traditional central planning economy was changed into a market-based economy and the primarily agricultural economy is now being transformed into an urban, industrial economy. As a result, China’s farmland use has been greatly changed following rapid socioeconomic development. On the one hand, much farmland has been lost due to rapid industrialization and urbanization (Xie et al. 2005; Liu et al. 2005, 2009; Long et al. 2007b, 2009), and many rural workers have been forced to find a job in the cities. This has left large areas of farmland uncultivated Received: 2009-11-10 Accepted: 2010-01-20 Foundation: the Ministry of Science and Technology of China (Grant NO. 2007BAC03A11-01), the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant NO. KZCX2-YW-QN304), and the National Natural Science Foundation of China (Grant NOS. 40771014 and 40635029). Corresponding author: LONG Hualou. Email: [email protected]. # : Initially, the term of land contracts was 15 years. In 1995, it was extended to 30 years. Although an extension to 70 years has been discussed, the continuation of 15-year term was confirmed in government documents in early 2009 (http://www.bjreview.com.cn/document/txt/2009-01/05/content_ 173368_3.htm). LONG Hualou, et al.: Grain Production Driven by Variations in Farmland Use in China:An Analysis of Security Patterns (Long et al. 2010; Zhang et al. 2001). On the other hand, rapid economic development has guaranteed the improvements in agricultural productivity and an increase in farmland use level. Recently, China’s farmland use and food security has attracted interest in academic circles both at home and abroad, ranging from the intensive and sustainable use of farmland resources, farmland change and protection (Lichtenberg and Ding 2008; Tan et al. 2005), farmland degradation (Bai and Dent 2009), influential factors of grain production (Yang and Li 2000; Heilig et al. 2000; Tao et al. 2009), sustainable agricultural development (Zhao et al. 2008), and to the modeling of land-use change and grain production (Yan et al. 2009; Verburg et al. 1999). Food security in China has long been of major concern because of factors such as population growth, farmland loss due to urbanization and industrialization, land-use changes and water scarcity, increasing income levels and nutritional changes, turbulence in global food markets, climate change, and unfavorable land administration. All these factors have influenced grain production and food security by driving the variations in farmland use in regard to both quantity and quality. Correlation analysis between farmland area and grain production indicates that farmland loss directly caused the decrease in grain production (Fu et al. 2001). However, the increase in the farmland multi-cropping index mitigated the negative influence on grain production to some extent (Yao et al. 2007). However, food security cannot be guaranteed simply by protecting the area of available farmland. Appropriate adjustment of the agricultural production structure and means of increasing human investments in farmland, to improve quality, are also effective ways to ensure food security (Chen and Zhou 2004). While there are numerous studies analyzing the impact of farmland loss on China’s grain production and food security (Yang and Li 2000; Yu and Lu 2006; Tao et al. 2009), due to difficulties in quantifying farmland quality, the analysis of grain production variation driven by farmland-use change both in quantity and quality at a national scale has been given much less attention. The aims of this paper are to analyze the changes of China's level of farmland use, and to develop a“farmland-grain elasticity coefficient”(FGEC) in order to reveal the interaction between farmland-use change and grain production security. 2 Materials and Methods 2.1 Data source and processing Due to data deficiency and the complex change of farmland use on a large scale, it is difficult to use traditional methods to classify and assess the quality of the farmland over a large area. Grain productivity is determined not only by the physical conditions, but also by the human investments, such as man-made materials, technology and capital. Currently, the latter is more important than the former. To a large extent, the farmland use level (FUL) may be used to replace the role of farmland quality for measuring grain production. Considering the diversity of the factors affecting farmland use, to assess the FUL completely and systematically needs a scientific assessment indicator system which takes farmland use characteristics into account (Liu 2005; Li et al. 2008). We chose nine indicators reflecting the FUL to establish an assessment system at the provincial level (Table 1). Analytic Hierarchy Process (AHP) was used to establish the FUL indicator system with a target layer, a rule layer and an indicator layer. The target layer is the farmland-use level, and the rule layer involves three factors: (i) investment intensity; (ii) management level; and (iii) production effect. In addition, there are nine indicators in the indicator layer. Then we used the AHP and Delphi to evaluate the weight to the rule layer and the indicator layer. Data are from the China’s statistical yearbooks and all provincial statistical yearbooks. To describe the 31 provinces for the whole country, excluding Taiwan Province, Table 1 Indicator system for farmland use assessment. Rule layer factors Weight Investment intensity (0.329) Managing level (0.293) Production effect (0.378) 61 Indicator layer factors Weight Power Investment (0.361) Labor Investment (0.329) Fertilizer Investment (0.310) Multi-cropping index (0.436) Irrigation index (0.328) Grain-farmland index (0.236) Grain yield (0.357) Farming output value per ha (0.386) Grain output per capita (0.257) Definition Gross power of farming mechanism per ha Gross farming labors per ha Gross fertilizer utilization per ha Dividing the crop area by the area of farmland Dividing the irrigated farmland area by the area of farmland The proportion of grain-crop area in the total crop area Grain yield per ha - - 62 more consistently, the territory is divided into six regions according to geographic locations and similar physical conditions (Fig. 1). To assess the FUL, section data for 1978, 1985, 1995 and 2004 are selected. Data for farming output values are converted as constant prices in 1990. However, some data are lacking, i.e. data for 1985 in Jiangxi and Anhui provinces, data for 1978 in Xinjiang Autonomous Region, data for 1978 and 1985 in Guizhou Province. Considering the integrality of the data and analysis, data for 1985 in Jiangxi, Anhui and Guizhou provinces are substituted by data for 1987 in the same three provinces. Data for 1978 in Guizhou and Xinjiang are treated as deficient. Journal of Resources and Ecology Vol.1 No.1, 2010 0 500 1000 km Fig. 1 Divisions of China’ s provinces for study. 2.2 Methods 2.2.1 Data normalizing Since the socioeconomic data for the various indicators in Table 1 are in different dimensions, to compare these data, they need to be transformed into common units by normalizing all measures, according to Equation (1): (1) where is the standardized value of the indicator; ij means the No.i indicator in the No.j rule layer; Xij is the value of the indicator ij; Xi.max is the maximum value of indicator ij of all provinces; Xi.min is the minimum value of the indicator ij of all provinces. To compare the FUL among all the provinces, the same type data from different provinces are normalized by the same extremum. This guarantees the final FUL of different provinces are comparable. 2.2.2 Farmland Use Level (FUL) We used the weight and the normalized values to calculate the FUL of each province in each year according to Equations (2) and (3): (2) (3) where Fj is the score of rule layer j; is the standardized value of indicator ij; Wij is the weight for indicator ij; F is the FUL; Wj is the weight for rule layer j. 2.2.3 FUL Changes To reflect the FUL changes, we chose the simple measurement to calculate the direct change between comparative years. It reflects the change of human investment in farmland use, to provide more intuitive information explaining the relationship between FUL changes and Farmland-grain elasticity coefficient (FGEC), according to Equation (4). (4) where is the FUL change of a specific province from year i to year j; F i and F j are the specific province's FUL in year i and year j, respectively. 2.2.4 Farmland-Grain Elasticity Coefficient (FGEC) To analyze the relationship between the farmland quantity change and variation of grain output or the impact of farmland change on grain production, the FGEC index was established according to Equation (5): (5) where j represents a province; Qi and Qi +1 are province's grain output in year i and year i + 1, respectively; Si and Si + 1 are j province's farmland area in year i and year i +1, respectively; Cj is the FGEC, which means the relationship between the farmland change and variation of grain output of j province from year i to year i+1. Before we analyze this index, it is necessary to understand the trend in farmland change, in order to make clear the meaning of the index. When Cj >0, this indicates that grain output shows the same change in the trend as that of available farmland area. Grain production is remarkably influenced by the changes in farmland area. When the area of farmland in- LONG Hualou, et al.: Grain Production Driven by Variations in Farmland Use in China:An Analysis of Security Patterns creases, the higher the value of Cj, the less the influence of farmland change on grain production and the more the influence of farmland quality change or the changes of FUL on grain production. When farmland area decreases, the higher the value of Cj, the more serious is the reduction in grain production, and the more negative is the influence of farmland area decrease on grain production. When Cj <0, this indicates that grain output shows the opposite change in the trend as that of available farmland area. Grain production is remarkably influenced by non-farmland factors. The higher of the absolute value of Cj , the more remarkable the influence of non-farmland area factors on grain production: if farmland increases, it means that the decrease in FUL has more negative influence on grain production than the positive influence from an increase in farmland; if the farmland decreases, it means that the FUL improvements have a more positive influence on grain production than the negative influence of farmland decrease. Thus, when Cj <0 and the higher of the absolute value of Cj, the more remarkable the influence of FUL or farmland quality change on grain production than that of farmland area change. 63 chemical industry. This strategy resulted in a weak capital accumulation in agricultural production. Capital and technical investments in agriculture have been at a standstill for a long time, and this resulted in a lag in agricultural productivity before 1978 (Lin et al. 1999). Poor production conditions led to agricultural production strongly determined by natural conditions, and the FULs of all provinces were generally low. Since better water and heat conditions in southern provinces of China can sustain higher rates of farmland multiple cropping and higher grain yields, i.e. better output values, than those in the northern provinces, the southern provinces had higher FULs than those in the north. With increasing latitude, the FUL index decreases from over 0.3 in the southern provinces to below 0.2 in the northern provinces (Fig. 2). In general, all provinces had similar levels of human investment in farmland use, and the differences in FUL for the different provinces were determined to a great extent by natural conditions. Therefore, the spatial patterns of China's FUL showed a descending trend from south to north. 3.1.2 FUL of 1985 Since the socioeconomic reform policy implemented in 1978, the household responsibility system has been gradu3 Results ally established in rural areas, and the rural workers have become strongly motivated. The downturn in the national 3.1 Spatiotemporal pattern of FUL industrial catch-up strategy has resulted in more technolo3.1.1 FUL of 1978 The industrial catch-up strategy adopted by the Chinese gy and capital being invested in farm production. All of these changes have promoted rapid development in the agcentral government when the PRC was founded, dericultural sector. The FUL at the national level has risen creased capital investments in agriculture in order to guarantee capital accumulation in heavy industry and in the universally (Fig. 2). In the area of South China, Central China and North China, the low topography facilitated extensive mechanization extending, and the coastal advantages obvious in the reform and open-door policy made the economies for these regions develop rapidly. This led to the establishment of a good economic basis for increased capital and technological investments in farm production. It promoted the swift rise of FUL in these areas. FUL of South- and Central China generally exceeded 0.4, and that of North China exceeded 0.3. However, limited by the low farming population and weak economic development, farming in the northwestern area and Heilongjiang province developed slowly, resulting in most of their Fig. 2 Spatiotemporal pattern of China’s FUL between 1978 and 2004. FULs being under 0.2. Constrained 64 Journal of Resources and Ecology Vol.1 No.1, 2010 by an upland topography, it is difficult for the southwestern area of China to increase farm mechanization, and together with extremely weak economic development, the FUL for this area increased less than that in 1978, with the exception of Sichuan province which has a relatively well-developed economy. 3.1.3 FUL of 1995 With the successful implementation of market-economy system, China’s economy has been developing at high speed. Great progress has been made in socioeconomic and technology development, farm mechanization has been extended, and fertilizer-use has increased. All of which have led to large increases in the FUL Fig. 3 The variations in FGEC between 1978 and 2004. (Fig. 2). The eastern coastal provBeijing, Tianjing and Shanghai municipalities is only 0.5, inces have developed at the fastest rate, their FULs exi.e. almost the same level as that for 1995. The FUL of ceeding 0.6. In Central China, Northern China and the southeastern provinces increased only slightly, even with Northeast, increased mechanization, extensive fertilizer inthe obvious increase in fertilizer investments and grain vestments, the establishment of irrigation, and an increasoutput value, and it still at 0.6 to 0.7. The FULs of Zhejiing farming population with no shift to industry, have all ang and Jiangsu provinces have changed very little, bepromoted the effective increase of the FUL. The progrescause improvements in agricultural production have coexsive development of the Southwestern region has guaranisted with rapid shift of farm workers to non-agricultural teed an increase in human investment, and FULs exceedjobs and an increasing loss of farmland. On the other ed 0.4. This has made the region other growth motor for hand, the inland economy has also developed rapidly over FUL. In the Loess Plateau, Qinghai-Tibet Plateau and the last decade. Farming investments and multiple cropnorthwestern China, because of slow economic developping have increased, and the non-agricultural shift of farm ment and inferior physical conditions, the development of workers has been halted, all of which has resulted in imagriculture has been generally impeded and the FUL proved FULs. shows less improvement, most of which in these areas In general, at the national level, FUL has increased due was between only 0.2 and 0.3. to rapid economic development since 1978. However, 3.1.4 FUL of 2004 FUL may not increase persistently with the sustainable deDuring the period 1995 to 2004, there were obvious imvelopment of the Chinese economy. On the one hand, conprovements in each province’s economy. However, the version of farmland and transfer of farm workers together impacts of this economic development on the FUL difwith other agricultural structural adjustments have defered. In some regions with a rapid speed of development, pressed the FULs. On the other hand, the growth potential e.g. Beijing and Tianjin, the Yangtze River Delta and the of farming machinery and fertilizer investments has kept southeast coastal provinces, i.e. regions where rapid the FUL at a high and stable level. non-agricultural conversion of farmland and transfer of farm labor, together with a decreasing grain output, agri3.2 The variations in FGEC cultural structural adjustments mitigated the positive influ3.2.1 Variations in FGEC between 1978 and 1985 ence of FUL improvements by the persistent increase of machinery and fertilizer investments. In these areas, the Although large areas of farmland have decreased, driven by economic developments during 1978 – 1985, this did FUL increase was no longer possible (Fig. 2). The FUL of LONG Hualou, et al.: Grain Production Driven by Variations in Farmland Use in China:An Analysis of Security Patterns not cause a general decline in grain production. On the contrary, most provinces increased their grain production, with the exception of Liaoning, Heilongjiang provinces and Shanghai Municipality. As can be seen from Figure 3, the value of most FGECs was negative and their absolute values were almost below 5. The provinces with a high FGEC absolute value are concentrated in the North- and Central China, where there is a rapid increase in grain production. The establishment of the household responsibility system motivated farm workers, which in turn guaranteed the base for effective farmland use. Farmland decrease versus FUL increase indicates the growth of grain production at the national level (Figs. 3 and 4). In the three provinces with decreasing grain production, Liaoning Province's farming level was seriously affected by the flood in 1985, which reduced grain reduction by 4.5 million tonnes. However, this was only a 1.41 million tonnes loss compared to that of 1978, and provides robust proof of how the increase in FUL strengthened grain productivity. There was only a 0.02% decrease from the level of 0.144 in Heilongjiang Province’s FUL from 1978 to 1985, but a weak agricultural foundation caused a grain reduction of 0.73 million tonnes. The FUL of Shanghai decreased by 6% and caused a grain reduction of 0.47 million tonnes. Therefore, due to the initial weak agricultural base, it can be assumed that the rise of FUL largely promoted the grain production and guaranteed grain production security Fig. 4 The variations in FUL between 1978 and 2004. 65 under the conditions of general farmland loss. 3.2.2 Variations in FGEC between 1985 and 1995 There is a sharp contrast between farmland protection and arable land reclamation in the western provinces of China and the rapid farmland loss in the eastern provinces during 1985–1995. However, the general growth of grain production in the whole country showed that the FGEC varied over the different regions. FGECs of the western provinces were almost positive while those of the eastern and central provinces were almost negative. Compared to the previous period, the absolute value of FGECs of the western provinces and the northeast increased, and their grain production increased greatly. However, that of the central and eastern provinces changed only slightly and showed a stable growth level for grain production. The upgraded FUL in the northeast and western provinces and the increase in farmland in the western provinces led to large increases in grain production. However, rapid farmland loss occurred in some developed provinces in the eastern and central regions, but their increasing FUL driven by rapid economic development still guaranteed stable grain production (Figs. 3 and 4). However, especially in the eastern and coastal areas, the decreasing marginal effects of increasing machinery and fertilizer investments led to a situation where the rapidly increasing FUL did not result in massive growth in grain production, and even led to the reduction of grain production in some provinces. Zhejiang Province is an example. Its farmland decreased by 8.9% , and the FGEC was 1.313 during this period. In 1985, the FUL for Zhejiang was 0.54, while it increased by 0.13, to 0.67 in 1995. This was due to a comparatively high FUL, but massive farmland loss cut down the grain production by 11.7% with low marginal effect of FUL increase. 3.2.3 Variations in FGEC between 1995 and 2004 During 1995 – 2004, it appears that the regions with increased farmland areas have had grain production growth while the ones with decreases in farmland area have had grain production reductions, which resulted in generally positive FGECs (Figs. 3 and 4). Rapid industrialization and urbanization caused serious farmland loss (Liu 66 et al. 2008) with the implementation of“grain for green” policy, and large areas of farmland were shifted to other land-use types (Feng et al. 2005; Long et al. 2006). The FUL growth in eastern coastal China will threaten grain production security when FUL was relatively high, and in the central provinces a similar situation of stable grain production or even reduction existed when the FUL was increased. The farming structure adjustment also depressed grain production growth. In this decade, grain production growth mainly occurred in those regions with increasing farmland. Therefore, under conditions of high FUL, it is more important to protect farmland areas for grain production security than to increase the FUL. This would also provide a practical scientific basis that would constitute a strict farmland protection objective and strategy in China. 4 Discussion and conclusions The serious farmland loss since 1978 has led to great pressure on grain production security, but increasing investments in farmland quality and human incentives have mitigated this pressure to some extent. Farmland protection, in terms of both quantity and quality, is one of the most important measures if national food security is to be guaranteed (Yang and Li 2000). FULs at the national level have increased due to the rapid economic development since 1978. The path of this rapid improvement shows a gradient declining from southeast coastal China to inland China with further economic development. However, the FUL may not increase persistently with the sustainable development of economy, because of the conversion of farmland and transfer of farm workers to non-agricultural activities. Agricultural structural adjustments and the unceasing improvements of FUL may not always bring about sustainable and steady growth in grain outputs. In general, farmland areas and human investments interact with each other to influence grain production. At the beginning of Chinese economic reform, due to the weak agricultural base, improvements in the artificial “quality”of farmlands had great positive effects on maintaining food security. Along with economic development and improvements in the agricultural base, human investments will play only a weak role in increasing grain production and in maintaining food security, without technological breakthroughs in all aspects of agricultural production. Accordingly, the role of farmland areas will become more and more important in maintaining food security. Therefore, considering the law of diminishing marginal utility, in developing countries, the available area of farmland will play a key role in maintaining the security pat- Journal of Resources and Ecology Vol.1 No.1, 2010 tern of grain production. This will also provide a practical scientific basis for constituting strict farmland protection objectives and strategies for China. The central government was advised to maintain the total cultivated land area at no less than 1.8 billion mu (1 ha = 15 mu) until 2020, however, in 2006 there were only 1.82 billion mu. (China determined to retain 1.8-billion-mu of farmland. http://www.china.org.cn/government/NPC_CPPCC_sessions2008/2008-03/17/content_12877551.htm) There is a dilemma in relation to farmland protection in China. Recently, some highly productive farmlands were abandoned for two major reasons. On the one hand, the user of the abandoned farmlands left to seek work in the city, found a job, and made a living. Few people are willing to manage farmland with a low economic incentive and/or low profit margin from grain production (Li and Wang 2003). On the other hand, many rural workers have left for urban areas, while those who stay on in the rural area are old people, women, sick and disabled men, and children (Long et al. 2010). The latter workforce is unable to manage large farmland areas. Thus, to some extent, preventing further farmland decreases may not ensure food security. We suggest that the central government invest in the construction of a grain production base, improve infrastructure, and develop modern agriculture and scale management, in order to increase the profitability and productivity of farming. In addition, more attention needs to be paid to providing job opportunities for the surplus rural labors. Therefore, both protecting farmland from a transformation to other land-use types, and ensuring its effective management constitute key solutions for maintaining grain production security in China. References Bai Z G, D Dent. 2009. Recent land degradation and improvement in China. Ambio, 38(3): 150–156. Chen B M, Zhou X P. 2004. Changes of agriculture resources and grain comprehensive productive capacity of China in recent years. Resources Science, 26(5): 38–45. (in Chinese) Feng Z M, Yang Y Z, Zhang Y Q, Zhang P T, Li Y Q. 2005. Grain-for-green policy and its impacts on grain supply in West China. Land Use Policy, 22: 301–312. Fu Z Q, Cai Y L, Yang Y X, Dai E F. 2001. Research on the relationship of cultivated land change and food security in china. Journal of Natural Resources, 16: 313–319. (in Chinese) Heilig G K, G Fischer, H van Velthuizen. 2000. Can China feed itself? An analysis of China’s food prospects with special reference to water resources. International Journal of Sustainable Development and World Ecology, 7: 153–172. Li X B, Wang X H. 2003. Changes in agricultural land use in China: 1981 – 2000. Asian Geographer, 22: 27–42. Li X B, Zhu H Y, Tan M H, Xin L J. 2008. Measurement of land use intensity. Progress in Geography, 27(6): 12–17. (in Chinese) Lichtenberg E, Ding C R. 2008. Assessing farmland protection policy in Chi- LONG Hualou, et al.: Grain Production Driven by Variations in Farmland Use in China:An Analysis of Security Patterns na. Land Use Policy, 25: 59–68. Lin J Y F, Cai F, Li Z. 1999. The Chinese miracle: development strategy and economic reform. Shanghai: Shanghai People’s Press. (in Chinese) Liu J Y, Zhan J Y, Deng X Z. 2005. Spatio-temporal patterns and driving forces of urban land expansion in China during the economic reform era. Ambio, 34: 450–455. Liu X W. 2005. Study on the cultivated land intensive use and its assessment. Land and Resources Information, 8: 5–10. (in Chinese) Liu Y S, Wang J Y, Long H L. 2010. Analysis of arable land loss and its impact on rural sustainability in Southern Jiangsu Province of China. Journal of Environmental Management, 91: 646–653. Liu Y S, Wang L J, Long H L. 2008. Spatio-temporal analysis of land-use conversion in the eastern coastal China during 1996–2005. Journal of Geographical Sciences, 18: 274–282. Long H L, G K Heilig, Li X B, Zhang M. 2007a. Socio-economic development and land-use change: analysis of rural housing land transition in the Transect of the Yangtse River, China. Land Use Policy, 24(1): 141–153. Long H L, G K Heilig, Wang J, Li X B, Luo M, Wu X Q, Zhang M. 2006. Land use and soil erosion in the upper reaches of the Yangtze River: some socio-economic considerations on China’s Grain-for-green Programme. Land Degradation & Development, 17(6): 589–603. Long H L, Liu Y S, Li X B, Chen Y F. 2010. Building new countryside in China: a geographical perspective. Land Use Policy, 27(2): 457–470. Long H L, Liu Y S, Wu X Q, Dong G H. 2009. Spatio-temporal dynamic patterns of farmland and rural settlements in Su-Xi-Chang region: implications for building a new countryside in coastal China. Land Use Policy, 26 (2): 322–333. Long H L, Tang G P, Li X B, G K Heilig. 2007b. Socio-economic driving forces of land-use change in Kunshan, the Yangtze River Delta Economic Area of China. Journal of Environmental Management, 83(3): 351–364. Tan M H, Li X B, Xie H, Lu C H. 2005. Urban land expansion and arable 67 land loss in China - a case study of Beijing–Tianjin–Hebei region. Land Use Policy, 22: 187–196. Tao F, Yokozawa M, Liu J Y, Zhang Z. 2009. Climate change, land use change, and China’s food security in the twenty-first century: an integrated perspective. Climatic Change, 93: 433–445. Tilt B. 2008. Smallholders and the“household responsibility system” : adapting to institutional change in Chinese agriculture. Human Ecology, 36: 189 –199. Verburg P H, Chen Y Q, T A Veldkamp. 1999. Spatial explorations of land use change and grain production in China. Agriculture Ecosystems & Environment, 82: 333–354. Xie Y C, Yu M, Tian G J, Xing X R. 2005. Socio-economic driving forces of arable land conversion: a case study of Wuxian City, China. Global Environmental Change, 15: 238–252. Yan H M, Liu J Y, Huang H Q, Tao B, Cao M K. 2009. Assessing the consequence of land use change on agricultural productivity in China. Global and Planetary Change, 67: 13–19. Yang H, Li X B. 2000. Cultivated land and food supply in China. Land Use Policy, 17: 73–88. Yao H M, Zhang F R, Zhang X J, Zhu Z L, Sui X Y. 2007. Cultivated land quantity change and its impacts on food security in Tsinan. Chinese Agricultural Science Bulletin, 23: 448–452. (in Chinese) Yu B H, Lu C H. 2006. Change of Cultivated Land and Its Implications on Food Security in China. Chinese Geographical Science, 16: 299–305. Zhang L X, S Rozelle, Huang J K. 2001. Off-farm jobs and on-farm work in periods of boom and bust in rural China. Journal of Comparative Economics, 29: 505–526. Zhao J Z, Luo Q S, Deng H B, Yan Y. 2008. Opportunities and challenges of sustainable agricultural development in China. Philosophical Transactions of the Royal Society B-Biological Sciences, 363: 893–904. 中国耕地利用变化驱动下的粮食生产:安全格局分析 龙花楼 1, 邹 健 1,2 1 中国科学院地理科学与资源研究所, 北京 100101; 2 中国科学院研究生院, 北京 100049 摘要:自从 1978 年改革开放以来,随着经济的迅速发展,中国的耕地利用格局发生了很大的变化。耕地数量和质量的变化直接 导致粮食生产的变动。本文利用来自政府部门的农业统计数据,分析了 1978-2004 年间中国耕地利用水平的时空动态格局,并通过 构建“粮耕弹性系数”来反映耕地利用变化与粮食生产的互动关系。研究结果表明:耕地投入的增加和质量的提升在一定程度上缓解 了 1978 年以来我国耕地资源严重流失给粮食生产安全带来的压力;自改革开放以来,中国耕地利用水平呈现由经济快速发展带来的 普遍性提升局面,并随着经济发展程度由东南沿海向内陆递减,耕地利用水平的提升速率也呈现由东南沿海向内陆梯级递减态势。 然而,耕地集约利用程度的不断提升,并不一定会带来粮食产量的持续稳定增长。耕地集约利用增长的边际效用递减特性,使得中国 粮食生产安全的保障已逐步由耕地集约利用水平的提升转向了耕地面积的保护,由此导致耕地资源的数量成为了左右粮食生产安全 的关键, 这也为当今中国制定严格的耕地保护目标和战略提供了现实的科学依据。 关键词:耕地质量; 土地利用; 粮耕弹性系数; 粮食生产;安全格局