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    20 June 2017, Volume 32 Issue 6 Previous Issue    Next Issue
    Special Forum of“Food Security”
    The Balance between Grain Supply and Demand and the Reconstruction of China’s Food Security Strategy in the New Period
    XIE Gao-di, CHENG Sheng-kui, XIAO Yu, LU Chun-xia, LIU Xiao-jie, XU Jie
    2017, 32 (6):  895-903.  doi: 10.11849/zrzyxb.20170110
    Abstract ( )   HTML ( )   PDF (578KB) ( )   Save

    Food security ensures anybody can get enough food for survival and health at any time. During 2015-2050, the potential of domestic agricultural resources is close to the limit, and the overall plan of China’s food security need change. Food security means nutrition security at the individual level and the food availability, including food production and food imports, at the national level. The paper analyzed the balance between grain supply and demand during 2015-2050 in context of personal nutrition security and national food availability in China. The results of analysis showed that, in case of maintaining the existing grain production capacity, the total grain security degree is 110.88%-117.49%, the food grain security degree reaches 158.57%-168.02%, and the feed grain security degree is 79.41%-84.15%. This situation provides a tolerance space to achieve dynamic equilibrium of supply and demand of grain in grain market, also an opportunity for national food policy adjustment. In order to establish food security system in the new period to ensure the general balance of supply and demand of grain in China, the paper suggests: 1) to make regulations of basic farmland to maintain sustainable grain production capacity at the resources side; 2) to gradually develop larger professional grain production entities at the production side; 3) to make full use of modern network technology and electronic business model to develop modern national and regional as well as international market system of grain; and 4) to adjust the structure and size of grain reserves.

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    Analysis on Grain Subsidy Policy of China from 1953 to 2016
    ZHEN Lin, WANG Chao, CHENG Sheng-kui
    2017, 32 (6):  904-914.  doi: 10.11849/zrzyxb.20170326
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    Grain subsidy policy is an important measure to ensure grain production, farmers’ income and national food security. In order to provide a reference for the government to improve the present grain subsidy policies, this paper analyzed the general features of grain subsidy policies over the past 63 years extending from 1953 to 2016, and explored the details of the policy changes by dividing the history of grain subsidy into three phases. Meanwhile, the spatial and temporal changes of subsidy policies in four procedures, i.e. grain production, grain processing, grain storage and market sales were analyzed. It is found that the categories, the objects, the scope and the goal of the grain subsidy policy changed greatly during the initial phase (1953-1978), the adjustment phase (1979-2003) and the reform and development phase (2004-2016). The subsidy funds have been increasing over the past years though there are regional variations. The grain subsidy tended to support the main producing areas and economically developed areas more. Problems in current grain subsidy policies in China are mainly reflected in the following aspects: the gap between the goal and the real effect, the identification and clarification of the objects and scope of the subsidy, the structure and component of the subsidy, the role and influence of the policy, and the farmers’ awareness and perception of the subsidy policy. This study attempts to serve as a reference to improve grain subsidy policy making and increase the effectiveness of the implementation.

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    A Study on the Trade and External Dependence of Agricultural Products in China—Analysis and Evaluation Based on Virtual Land Resources
    LIU Ai-min, XUE Li, CHENG Sheng-kui, QIANG Wen-li, YAGN Xiao, JIA Pan-na
    2017, 32 (6):  915-926.  doi: 10.11849/zrzyxb.20170306
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    China has become a major importer of agricultural products. Arable land resource is implicit in agricultural products. This paper aims to study the pattern of agricultural products trade and external dependence based on the analysis of virtual land resources of agricultural products. The agricultural products discussed in this paper are mainly land resources intensive products, including seven categories (grain, oil, cassava,vegetable oil, cotton, sugar and feed meal), comprising of 24 specific varieties. This study analyzed and evaluated the virtual land resources from the consumer’s perspective based on the trade data from 2000 to 2016. The results showed that Chinese virtual land resources import has increased from 675×104 hm2 in 2000 to 5 928 ×104 hm2 in 2016. The USA and Brazil are the largest exporting country to China, the exported volume increased from 342×104 and 146×104 hm2 to 2 101×104 hm2 and 2 192×104 hm2 respectively, accounting for more than 70% of the total import of virtual arable land. The external dependence of agricultural land in China reached 30.5% in 2016, accordingly the dependence on Brazil and USA being 11.3% and 10.8%. The large quantities of land intensive agricultural products import alleviate the pressure of being short of arable land resource in our country to a certain extent, and ensure food security.

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    The Balance between Supply and Consumption of the Main Types of Grain in China
    XIAO Yu, CHENG Sheng-kui, XIE Gao-di, LIU Ai-min, LU Chun-xia, WANG Yang-yang
    2017, 32 (6):  927-936.  doi: 10.11849/zrzyxb.20170084
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    Government has paid much attention to grain security, especially to grain production security. The grain subsidy has encouraged the farmers to produce more and more grain. In recent years, the grain occupation has been much more than the grain demand, which leads to great pressure on grain stock. The grain subsidy is unsustainable. It is necessary to calculate the grain consumption in order to determine the relationship between grain occupation and grain consumption and develop grain security system. In this study, we calculated the actually edible grain consumption based on the urban and rural population and the edible grain per capita, estimated the industrial grain consumption based on the outputs of grain industry products and the grain coefficient for each grain industrial product, computed the feed grain consumption based on the production of meat, beef, mutton, egg, milk and aquaculture products and the ratios of feed to meat, calculated the seed grain consumption based on the seeding area and the seed consumption per hectare, and estimated the grain loss as 5% of the grain production. The ideal edible and feed grain consumption in balanced diet was calculated based on “Dietary Guidelines for Chinese Residents (2016)” with urban and rural population and their edible grain per capita. The total ideal grain consumption in balanced diet were obtained by combining the ideally edible and feed grain consumption, the actual industrial and seed grain consumption, and grain loss. The results indicated that: 1) In 2013, most of rice, wheat, maize and potato were supported domestically, while the soybean occupation mainly depended on imports. 2) Most of rice and wheat were consumed as edible grain. The consumptions of maize and soybean were mainly used for feed grain. Potato was mainly used in industrial production and feed. In balanced diet, the edible consumption of potato and soybean increased apparently. 3) The grain occupations were much higher than the consumptions, while the soybean occupation was close to soybean consumption. 4) The consumption of rice and wheat in productions were much more than as edible grain. Only 39% of current rice and wheat production could meet the edible grain consumption in balance diet and 59% of current rice production and 43% of current wheat production could meet the actually edible grain consumption. Considering the grain security index of 1.2, 71% of current rice production and 52% of current wheat production could meet the actually edible grain consumption. In the future, government should pay more attention to the edible grain production of rice and wheat, develop supervisory system and provide financial and technical support for production, transportation, storage and trading of rice and wheat. The rice and wheat in industrial product, feed and seed and other consumption should be regulated by market, supplemented by government guidance and technical support. Thus, it would be helpful for the sustainability of the grain production and consumption.

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    Resource Utilization and Management
    Spatio-temporal Pattern Changes of Cereal Production and Trade in China-ASEAN Free Trade Area
    FENG Zhi-ming, XIAO Chi-wei, LI Peng
    2017, 32 (6):  937-950.  doi: 10.11849/zrzyxb.20160654
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    Southeast Asia is not only the important part of China and the Association of Southeast Asian Nations (ASEAN) Free Trade Area (CAFTA), but also the foremost frontier and transportation junction of the 21st Century Maritime Silk Road. Since the 1990s, especially after the establishment of the CAFTA in 2010, the economic and trade exchanges in the CAFTA have been enhanced extensively and deeply. The investigations on the statuses of cereal production in China, the largest food consuming and importing country, and in the most important rice producing and exporting regions in the world, and the trade between them, are of great significance to implement the national strategies of “Going Out” and “Bringing In”, develop the Maritime Silk Road, and improve the geo-security environment. With the annual cereal production and trade statistics of China and the ASEAN countries during 1961-2013 from the FAOSTAT, the temporal dynamics and spatial patterns of cereal production and trade at country and sub-regional scales were analyzed by means of the concentration index and regression analysis methods. The results showed that: 1) With respect to cereal production, the total cereal production increased 4.06 times in the ASEAN during 1961-2013 at an annual growth rate of 3.10%, about 8.09×108 t in 2013. The cereal trade increased 3.19 times in the ASEAN during 1961-2013 at an average annual growth rate of 2.79%. The import of cereal grew at an average annual rate of 3.05% while the total export of the cereals increased 2.40 times during this period. The import quantities of cereal outnumbered those of the export was mostly caused by the adjustment of import and export in China. However, the cereal’ import and export in other countries of the CAFTA were increasingly balanced. 2) Spatially, China, Indonesia, Thailand and Vietnam were the major grain producing countries, dominated by maize and rice crops. The trade deficit of cereals in China was increasingly enlarged and the trade center gradually moved to Southeast Asia. 3) The relationship between cereal production and trade (import and export) in China and the ASEAN was intensive, and the cereal trade was greatly influenced by cereal grain production. However, there existed much difference at country level. Among them, China’s cereals export is the barometer of cereals trade in the CAFTA.

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    Food Security Situation and Major Grain Supply and Demand in Tibetan Region
    GAO Li-wei, XU Zeng-rang, CHENG Sheng-kui, XU Shi-wei, ZHANG Xian-zhou, YU Cheng-qun, SUN Wei, WU Jun-xi, QU Yun-he, MA Jie
    2017, 32 (6):  951-960.  doi: 10.11849/zrzyxb.20160133
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    Food security is related to the lasting stability and the sustainable development of social economy in Tibet. Based on data from household food survey and data from food market, food processing enterprises and government departments, we investigated grain production and consumption (highland barley, wheat and paddy) in Tibet. An analysis of grain supply and demand in the year of 2010 was carried out. The result showed that there was a high grain supply in 2010, which indicated that there was a high grain security in Tibet. The total grain production in 2010 was 85.09 thousand tons, and the total amount of grain consumed by local population was 88.81 thousand tons, so there was roughly a balance between grain production and consumption. But when considering that 60.8% of the grain consumed was from local production, the actual of local grain consumption was 54.0 thousand tons, which indicated that the amount of local grain production was higher than local grain consumption. Although the grain supply has been greater than the demand in Tibet (the total grain supply from major grain crop was 146.3 thousand tons, and the total grain demand was 95.9 thousand tons, and the supply was 1.5 times of demand), there was large regional disparities, especially in north Tibet (for example Nagqu prefecture) where there was an large grain supply gap in Nagqu. It is needed to strengthen the food supply in that region and improve the food security. With the increasing number and variety of foods from other provinces, the Tibetan government should transform the food marketing system of Tibet to take food producers (farmers) into the grain circulation market, and further strengthen and emphasize the role they played in food market, and focus on highland barley industry to raise local farmers’ income.

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    Resource Ecology
    Arable Land Use Transitions and Its Response of Ecosystem Services Value Change in Jiangsu Coastal Areas
    SHI Yang-yang, LÜ Xiao, HUANG Xian-jin, YU Miao
    2017, 32 (6):  961-976.  doi: 10.11849/zrzyxb.20160587
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    The research of the arable land use transitions and its impact on the ecological environment from the dual perspective of arable land occupation and supplement can provide scientific basis for sustainable land use and ecological protection. This paper chose coastal areas in Jiangsu Province as a case where the economy develops rapidly and there are serious problems of land use. Based on the land use data in Jiangsu coastal areas (1990, 2000, and 2010), the models of arable land use transitions and ecosystem service value were synthesized with GIS. The methodology of ecosystem service value calculation from R. Costanza et al. was used to analyze arable land use transitions in two phases, 1990-2000 and 2000-2010, and the Geo-spectrum of arable land use transitions model and ecosystem service value during 1990-2010 was acquired. Then, the article studied spatio-temporal variation characteristics of arable land use transitions and its response of ecosystem service value change in Jiangsu coastal areas. The results showed that: 1) During 1990-2000, the occupation of arable land was mainly caused by construction land, water body and grassland, and the supplementary of arable land was from construction land, water body, forestland, and grassland. The occupation of arable land was more than the supplementary of arable land during 1990-2000. The most obvious changes were “arable land → construction land” and “grassland → arable land”, with low spatial separation degrees. 2) During 2000-2010, unused land became another type of occupation of arable land, and grassland was still the main supplementary of arable land. The most obvious changes was “arable land → construction land” and “arable land → water body”, and the spatial separation degree became larger. The occupation of arable land was still more than the supplementary of arable during 2000-2010. 3) The most obvious arable land use transitions mostly happened in the later period of 1990-2010. 4) The total value of ecosystem service increased from 17.085 billion yuan to 18.223 billion yuan during the past two decades in Jiangsu coastal areas, in which water body is the most important contribution to the ecosystem service value. Arable land use transitions resulted in the decrease of ecosystem service value of arable land, in which “arable land → construction land” was the main impairment of ecosystem service value.

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    Community Residents’ Willingness to Contribute to Wetland Ecosystem Services in Sanjiang Plain Nature Reserves
    DAI Hu-xuan, LEE Chun-hung, CHENG Kun, ZONG Cheng
    2017, 32 (6):  977-987.  doi: 10.11849/zrzyxb.20160604
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    This paper conducted a questionnaire survey in communities of five nature reserves in Sanjiang Plain, using double bounded dichotomous choice model of the contingent valuation method to explore residents’ willingness to contribute to ecosystem service in nature reserves. We found that: 1) the residents had higher willingness of labor contribution (73.57%) than willingness of financial contribution (55.65%), the mean willingness to pay (WTP) by individual being 387.25±7.08 yuan per year and the mean willingness to work (WTW) being 31.40±0.39 hours per month. 2) Residents with higher income and higher acceptance of paying money expressed higher WTP for ecosystem service. Male residents and those who joined environmental defense association, were better educated or had higher acceptance of paying money expressed higher WTW for ecosystem service. 3) 49.46% of the residents are willing to contribute both money and labor, whose proportion is much higher than other types of contribution, and people in this group averagely showed higher WTP and WTW. To take full play of the location advantage in the practice of nature reserves management, we suggest to encourage community volunteers to participate in the ecosystem conservation.

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    Assessment of Urban Land Ecological Security in Yinchuan City Based on the Grid Method
    LI Jian-chun, YUAN Wen-hua
    2017, 32 (6):  988-1001.  doi: 10.11849/zrzyxb.20160633
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    To explore the spatial effect and scale characteristics of the land ecological system within the scope of the city, this paper constructs a scientific evaluation system of land ecosystem based on PSR model. The basic unit of the evaluation system is 1 km×1 km grid. Entropy method is used to calculate the regional land ecological security index. We assess the land ecological security index in Yinchuan city, and the results show that the regional land ecological index is 0.488 2 in 2015. The land ecological security has dual characteristics which includes structure function differentiation and spatial heterogeneity. From the macro perspective, the gaps among the three central districts are very small, while the difference between the two suburban counties is very large. Only the ecological security value of Helan County (0.557 7) is higher than the overall average in the city. From the micro perspective, there is a certain relationship between land ecological security and the way people use the land. At the micro level, the composite index in the north and center of the city was higher, while it is lower at the fringe of the city. From the view of land use function, the core composite indexes of agricultural areas, urban built-up areas, wetlands and nature reserves are higher, while the index in cross-functional areas is very low. There is coupling relationship between the land ecological security and the land use pattern. The important factors of land ecological security in Yinchuan include per capita arable land area, industrial structure and pollution control efforts, etc. By ESDA spatial analysis, the global Moran’s I of land ecological security in Yinchuan city is 0.780 4, which means inherent spatial correlation of ecological security. The land ecological security in Yinchuan city as a whole has characteristics of spatial continuity and spatial dependence. Therefore, we should make full use of the spatial diffusion and spillover benefits in high-high aggregation area, and improve the restriction factors in low-low aggregation area, so as to reduce the environmental risk and optimize the allocation of space.

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    Resource Evaluation
    Research on Coupling Coordination among Cultivated Land Protection, Construction Land Intensive Use and Urbanization
    ZHANG Hao, FENG Shu-yi, QU Fu-tian
    2017, 32 (6):  1002-1015.  doi: 10.11849/zrzyxb.20160622
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    Coordinated development among cultivated land protection, constrcution land intensive use and urbanization can promote synergies among “food”, “construction” and “development”, and is conductive to China’s new urbanization construction and social sustainable development. Based on the interactive coupling mechanisms among cultivated land protection, construction land intensive use and urbanization, taking Shaanxi Province and its ten municipalities as example, this paper analyzed the temporal and spatial differences of coupling coordination among cultivated land protection, construction land intensive use and urbanization. Results indicate that: 1) Temporally, the overall coupling coordination degree among cultivated land protection, construction land intensive use and urbanization in Shaanxi Province during 2005-2014 is on the rise, from moderate coupling coordination to highly coupling coordination (0.549-0.800). Regarding coupling degree, any two as well as the overall coupling degree among cultivated land protection, construction land intensive use and urbanization in Shaanxi Province during 2005-2014 shows an inversed “U” shape, with 2009 as the turning point. The coupling degree between cultivated land protection and construction land intensive use fluctuated in the high value interval (0.9-1.0). As for coordination index, its variation is divided into three stages during 2005-2014, with 2007 and 2009 as the turning points, respectively. The coordination index between cultivated land protection and urbanization (T2), the coordination index between construction land intensive use and urbanization (T3), and the overall coordination index (T) show an overall upward trend, while the decline of the coordination index between cultivated land protection and construction land intensive use (T1) is greater than the rise. 2) Spatially, the coupling coordination degree among cultivated land protection, construction land intensive use and urbanization in Shaanxi Province in 2014 was high in northwest and low in southeast. Ankang, Hanzhong, Shangluo and Weinan municipalities are located in the moderate coupling coordination area (0.40-0.59); Xianyang, Baoji, Tongchuan, Yulin and Yan’an municipalities are situated in the high coupling coordination area (0.60-0.79); while Xi’an municipality, the capital of Shaanxi Province, is in the excellent coupling coordination area (0.80-0.10). As a whole, six municipalities are located in the high and excellent coupling coordination area (0.60-1.0), and only one municipality falls into the low coupling coordination area (0.0-0.39). It indicates that the overall coupling coordination degree among cultivated land protection, construction land intensive use and urbanization in Shaanxi Province is good. To achieve the coupling coordination among cultivated land protection, construction land intensive use and urbanization in Shaanxi Province, the paper puts forward three suggestons: increasing the overall level of cultivated land protection in Shaanxi Province, improving construction land intensive use in Shaanxi Province, and formulating social and economic develeopment policies according to local conditions.

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    The Impact of Conservation Tillage on Reduction in Rice Yield Loss:Evidence from 1 080 Chinese Rice Farmers
    TANG Li-qun, ZHOU Jie-hong, YU Xiao-hua
    2017, 32 (6):  1016-1028.  doi: 10.11849/zrzyxb.20160635
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    Droughts and floods have become two kinds of major natural disasters causing rice yield loss. The challenges on food security caused by increasing natural disasters have drawn much attention of researchers. Recent studies have identified a variety of effective adaptation measures taken by farmers to cope with natural disasters. Conservation tillage, considered as one of the main adaptation measures, could help farmers reduce yield loss. A three-year survey of 1 080 Chinese rice farms was conducted in major rice producing provinces in China, Zhejiang and Jiangsu in the coastal area of eastern China, Sichuan in southwest China, and Hunan in central China. Based on the panel survey, we identified the factors influencing farmers’ taking measures of conservation tillage, and evaluated the effectiveness of conservation tillage as a main adaptation measure against droughts and floods. Particularly, the behavior of taking the measure of conservation tillage could be endogenous, which has not been well examined in the literature. Taking into account the endogeneity of the behavior, we employed an endogenous switching regression model to estimate the effects of whether or not taking the measure of conservation tillage. The results revealed that the coefficients of droughts and floods for taking the measure of conservation tillage are 0.099 and 0.315 respectively, and both are statistically significant. It is consistent to our common sense that rice farmers are more likely to take the measure of conservation tillage when they have suffered from droughts and floods. Besides, whether farmers take the measure of conservation tillage also depends on labor cost, local access to public services for coping with droughts and floods, the tolerant variety of rice, agricultural labor forces, famers experience on rice production and soil quality. The former four factors can encourage farmers to take the measure of conservation tillage, while more experience on rice production and better soil quality discourage farmers to take the measure of conservation tillage. Moreover, we found that taking the measure of conservation tillage increased the yield by 457.95 kg/hm2 (about 7%). In contrast, the farmers who did not take the measure would increase the rice yield by 225 kg/hm2 (about 4%) if they take the measure. These findings suggest conversation tillage does increase the rice production and help reduce the rice yield loss caused by drought and floods. It also indicates that the possible benefit for those who have not taken the measure of conservation tillage is much smaller than the benefit for those who have already taken the measure.

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    Assessment of Spring and Summer Meteorological Droughts Based on SPEI and SPI in Eastern Agricultural Region of Qinghai Province
    TANG Min, ZHANG Bo, ZHANG Yao-zong, WANG Guo-qiang, MA Bin, JIA Yan-qing
    2017, 32 (6):  1029-1042.  doi: 10.11849/zrzyxb.20160584
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    Eastern agricultural region of Qinghai Province is an important grain production base. Spring and summer droughts directly influence the orderly development of agriculture in this region. The average monthly precipitation and temperature data during 1961-2014 at 13 meteorological stations in eastern agricultural region of Qinghai Province were acquired. The trends of spring and summer meteorological droughts were evaluated with methods of SPEI index, SPI index and R/S analysis. The results showed that: 1) In past 54 years, the inter-annual variation of droughts showed by SPEI was the same as that showed by SPI before 2000, however, the trends showed by SPEI and SPI were opposite after 2000. The SPEI index showed that the spring and summer droughts gradually increased after 2000, while the SPI index indicated that the spring droughts were relieved after 2000. The temperature is the main reason for the differences between the two indices. 2) The trends of drought coverage area indicated by the two indices were consistent with the inter-annual variations of droughts that there was great difference before and after the mid 1990s. After the mid 1990s, the drought coverage area disclosed by SPEI was broader than that disclosed by SPI. 3) The trends of frequencies of spring and summer droughts indicated by SPEI and SPI were also opposite after 2000. The SPEI index discloses a high frequency period of droughts in 2000s, while the SPI index disclosed a low frequency period. However, both indices displayed that the high frequency area of spring droughts moved from west to east, and the high frequency area of summer droughts moved from northwest to southeast. 4) According to drought cycles and R/S analysis, spring drought will increase in the future 4-6 years and the high frequency area will be in the north; summer drought also will increase in the future 18-22 years and the high frequency area will be in the east and west. 5) The comparative analysis found that SPEI index is more suitable in this area.

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    Ecological Stoichiometric Characteristics of Main Forest Stands in Ziwuling Forest Region on the Loess Plateau, China
    ZHANG Hai-xin, ZENG Quan-chao, AN Shao-shan, BAI Xue-juan, WANG Bao-rong
    2017, 32 (6):  1043-1052.  doi: 10.11849/zrzyxb.20160585
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    To analyze carbon (C), nitrogen (N), phosphorus (P) and ecological stoichiometric characteristics in green leaf, litter, dead branch and fruit, four forest stands of different species (Platycladus orientalis, Pinus tabuliformis, Quercus wutaishanica and Robinia pseudoacacia L) in Ziwuling forest area on Loess Plateau were collected. The C, N, P contents and C∶N, C∶P, N∶P ratios were measured, and the variations of them were explored in the four forest stands. The results showed that N, P contents of plant were transferred before plant leaf withering and falling, and the resorption efficiencies of various nutrient elements were different. In this study, the highest resorption efficiency of N nutrient was 44.73% (Pinus tabuliformis), the highest resorption efficiency of P nutrient was 41.10% (Robinia pseudoacacia L), respectively. In addition, in Ziwuling forest area, the C content of green leaf under Robinia pseudoacacia L forest was 413.94 g·kg-1, which was a little lower than that of other forest stands. However, the N contents of green leaf, litter, dead branch and fruit under Robinia pseudoacacia L forest were 29.74, 17.10, 8.59, and 24.79 g·kg-1, which were slightly higher than the corresponding components of other forest stands; the P contents of green leaf and fruit under Robinia pseudoacacia L forest were 2.43 and 2.53 g·kg-1, which were higher than the corresponding components of other forest stands. The carbon accumulation capacities of these four forest stands were large. The resorption efficiencies of Pinus tabuliformis and Robinia pseudoacacia L were greater than that of Quercus wutaishanica and Platycladus orientalis. The C∶N, C∶P and N∶P ratios indicated that C accumulation was strong and that N, P nutrient were restricted by its ecosystem condition. The C∶N, C∶P ratios in dead branch were higher than the ratios in other components of the four species of plants. The N∶P ratios in green leaf of the four forest stands were all smaller than 14, showing that carbon accumulation capacity of dead branch was strong and the growth of the four forest stands were limited by N. This study found that Pinus tabuliformis and Robinia pseudoacacia L were more suitable for forest vegetation restoration on the Loess Plateau, China.

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    Harmony Evaluation of Water Resources Allocation System in Yuyang Area Based on IAHP
    ZHANG Cheng-feng, SU Xiao-ling, CAI Huan-jie
    2017, 32 (6):  1053-1063.  doi: 10.11849/zrzyxb.20160639
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    After optimally allocating the urban water resources, it is of great importance to evaluate the post-allocation harmony of the water resources system in order to determine the adaptability of the allocation model and the allocation schema. Meanwhile, it is one of the effective ways to promote the harmonic relationship between human and water. There are many factors influencing the harmony of water resources system which therefore lead to a variety of evaluation methods. Current methods all suffer from the vagueness of the evaluation process and the vagueness of the index weight. This paper evaluated the post-allocation harmony of water resources system in Yuyang District of Yulin city by analytic hierarchy process coupling with interval number which represents the characterization value of indices and experts’ options. This method employed the characteristic root of the interval number to obtain the interval weights for each layer of factors. Then, the consistency checking was conducted. The results showed that after the optimal water resources allocation, the overall harmony of water resources system in Yuyang District upgraded, as well as the subsystems within the system. Comparing with other common used evaluation methods, the method of analytic hierarchy process coupling with interval number could reflect the vagueness in the process of evaluation and the vagueness of the index weight, which made the evaluation results more flexible, reasonable and reliable.

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    Study on the Road Layout Optimization in Land Consolidation Based on Temporal Accessibility
    YE Ying-cong, KUANG Li-hua, ZHAO Xiao-min, XIE Wen, GUO Xi
    2017, 32 (6):  1064-1073.  doi: 10.11849/zrzyxb.20160651
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    Scientific and reasonable road layout in the process of land consolidation could improve the travel convenience of the farmlands and raise farmers’ satisfaction with the land consolidation project. In this paper, road layout optimization during a land consolidation project was studied. The study area was in Geshan Town, Zhangshu city, Jiangxi Province. Data of the farmers’ traveling preferences were collected through investigation. The local land resource bureau provided the digital maps of topography and land uses. Twenty-seven soil samples were collected and the contents of the soil samples were tested in the lab. The ArcGIS 10.2 software was used to process the data and produce the temporal accessibility layout of the research area. Eight factors were selected from four aspects: the land use condition, the topography condition, the existing roads and the farmland quality. The FAHP method was used to judge the factors’ weights. The suitability evaluation system of the road layout in the land consolidation project was established and the suitability map of road layout was generated. Finally the road layout optimization scheme in the land consolation project was formed. The results showed that the temporal accessibility based on the investigation on farmer’s traveling preferences was vital to the optimization scheme of the road layout. The GIS technology improved the spatial accuracy for the road layout optimization. The optimization scheme could not only provide convenience to the travels of framers, but also protect the quality of the farmland.

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    Resource Research Method
    Soil Organic Matter Prediction Based on Remote Sensing Data and Random Forest Model in Shaanxi Province
    QI Yan-bing, WANG Yin-yin, CHEN Yang, LIU Jiao-jiao, ZHANG Liang-liang
    2017, 32 (6):  1074-1086.  doi: 10.11849/zrzyxb.20160623
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    There exists deviation of predication of soil organic matter (SOM) with observed data in special local topography units. The accuracy of SOM predication can be improved by combining observed data and remote sensing (RS) data, especially for SOM predication in large scale. In this study, AWIFS (Advanced Wide Field Sensor) and MODIS (Moderate Resolution Imaging Spectroradiometer) data, whose spatial resolution are 56 and 250 meters respectively, were combined with observed sample data to predict the spatial distribution of SOM in Shaanxi Province with RF (Random Forest) model. The spatial distribution of SOM in six types of topographical units were summarized, and the prediction accuracies of SOM based on RF model and OK (Ordinary Kriging) model were compared. The results indicated that the spatial differentiation of SOM is obvious in north-south direction in Shaanxi Province. It is the highest in Qinling and Daba mountain areas with SOM content higher than 25 g·kg-1, and it is medium high in the south of Loess Plateau area with the SOM content 22-30 g·kg-1. The content of SOM is lower in Guanzhong Plain and Hanzhong basin areas with SOM content among 13-25 g·kg-1, while it is the lowest in north Loess Plateau and the blown-sand areas with SOM content less than 10 g·kg-1. The prediction results based on AWIFS data (with higher spatial resolution) were better than those based on MODIS (with lower spatial resolution) data. The acquired data of images has little influence on SOM prediction. It is shown that the predicted value of SOM is a bit lower in autumn than in spring. With different percentages of sampling, the SOM prediction based on RF model is always better than that based on Ordinary Kriging model. The prediction accuracy in this study is reliable, because the mean error in independent validation set is no more than 3 g·kg-1,and the correlation coefficient of the predicted values and the observed values are higher than 0.7. Elevation is the most importance factor influencing SOM prediction in Shaanxi Province. When the spatial resolution of RS data decreases, the importance of geographic location of sampling points increase and the importance of vegetation decrease.

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