System Variable Analysis on Development Stages of Urban Agriculture in Large Cities

Min ZHANG，Fengjun LU，Runlian MIAO ，Yan JIN

1.Beijing Institute of Science and Technology Information，Beijing 100044，China；2.College of Economics and Management，China Agricultural University，Beijing 100083，China

The introduction of concept of urban agriculture reflects expectation of urban residents for multifunction of agriculture when industrialization，urbanization and agricultural modernization develop to certain level.The development of urban agriculture is an evolution process of dynamic supply and demand balance accompanied with advance of urban-rural integration and oriented towards adjustment of demand structure with satisfaction of objective demands of urban residents as its purpose.In different period of urban and rural social economic development in large cities of China，such objective demand has different form，supply methods and influence factors.And these differences and changes thereof lead to changes of functional structure and customer structure of urban agriculture，and accordingly evolution of industrial organization and spatial form.

1 Overview of studies on stage characteristics of urban agricultural development in large cities

In 1898，Ebenezer Howard put forward the concept of Garden Cities and urban agriculture started sprouting.However，the practice of urban agriculture began in Germany and Japan.In 1919，German government built＂allotment gardens＂.In 1935，Japanese scholar Shiro Aoshika initially introduced the concept of urban agriculture.Later，the urban agriculture spread in European and American developed countries and regions，especially in recent40 years.The practice of urban agriculture in China started in the end of 1980s and the early of1990s.In large cities，such as Beijing and Shanghai，the urban agriculture has made outstanding achievements.

In foreign countries，theories of urban agriculture focuses on functions，mode，land use，scientific and technological innovation，performance evaluation，and institutional policies，while few researches touch on development stages of the urban agriculture.Among documents published，The Changes of the Concept of Urban Agriculture in Japan and Its Developmentissued by Professor Zhou Weihong from Beijing Center for Japanese Studies in 2009 is representative.This paper discussed the concept，development power，ideological system，development achievements of Japanese urban agriculture，and divided Japanese urban agriculture into formation stage，development stage，consolidation stage，and overall development stage［1］.

Domestic scholars also made some useful studies on development stages of the urban agriculture.Han Shiyuan designed an evaluation indicator system including 8 indicators（per capita GDP，rate of scientific and technological contribution，forest coverage rate，etc），and described integrated development degree and overall level of the urban agriculture［2］.Wen Huaet al.calculated the composite index of Beijing urban agriculture in 2005 from 5 aspects，namely，integrated production level，social service level，ecological security level，regional harmony level，and development ability construction，obtained that the composite index was61.49，and believed that Beijing remains at the early stage of urban agriculture［3］.Huang Yinghuiet al.evaluated development stages of Beijing urban agriculture from 22 indicators reflecting integrated production level，resource utilization level，social service level and security level［4］.Guo Yajinget al.evaluated development level and stages of Beijing urban agriculture based on gray evaluation method according to evaluation indicator system reflecting economic development level，social development level and ecological and environmental sustainable development level［5］. Lu Fengjunet al.divided urban modern agriculture into starting，growth（early，middle and later stages）and maturity stages，established the stage study and evaluation indicator system including 12 indicators in basic background，development essence and de-velopment characteristics，and concluded that Dalian urban modern agriculture stays at the transition stage from early stage of growth to middle stage［6］.

Most of the above researches focus on building an indicator system from integrated production，social service，and ecological security，emphasize production and supply，function and service of urban agriculture.However，few researches touch upon indicators reflecting characteristics of demands and customer structure，and few researches touch upon evolution power of urban agriculture as an open system in large cities.With reference to existing researches，we studied the stage characteristics of urban agriculture in large cities from a completely new perspective，system variable analysis method.

2 System variable analysis model of urban agricultural development in large cities

2.1 The system variable method and its applicationThe system variable analysis is a scenario analysis method introduced by Lu Fengjun based on system thought.This method divides system variables into characteristic variables and causal variables；the causal variables include key causal variables and induced causal variables；the induced causal variables include environmental condition variables and behavior selection variables［7］；through building system variable analysis model and running the model，it is expected to analyze feature characteristics，formation causes and evolution power in different situations.This method has been widely applied in business management，industrial economy and regional economy field.Yan Huahong applied it to analyze investment decision quality of agricultural listed companies［8］；Su Wenfeng used it to evaluate performance of provincial electric network enterprises［9］；Sun Shimin used it to study behavior selection of pig farms in suburbs of large cities［10］；Zhang Min adopted it to analyze cluster and upgrade of regional instant noodle industry［11］；Zhang Lin applied it to study the development strategy of modern agricultural scientific and technological parks［12］.

2.2 Development background and system variable analysis of the urban agriculture in large cities In the end of 1980s and the early of the1990s，with rapid advance of urbanization，industrialization and agricultural modernization，agricultural development environment has great changes in large cities.The situation of short supply of agricultural product market has been fundamentally changed，living conditions of urban and rural residents are significantly improved，and non-production functional demand of cities for agriculture is increasingly strong.Large cities such as Shanghai，Beijing，Shenzhen and Nanjing have realized the importance of urban agriculture in urban social and economic development and start to develop the urban agriculture one after another.Since entry to the 21st century，more and more large cities have incorporated the urban agriculture into their urban economic and social development plan in the background of deterioration of urban ecological environment，improvement of agricultural product quality，and diversification of consumption demands of urban residents，as well as rapid changes of modern science and technology and operation and management mode.In April，2012，the Ministry of Agriculture convened national urban agriculture site exchange in Shanghai，indicating that China's urban agriculture enters key period of deep understanding and joint promotion from pilot projects in all areas［13］；in future，the urban agriculture will become mainstream of regional agricultural development in large cities of China.

Based on urban agricultural development in large cities，using the system variable analysismethod，we take the urban agriculture in large cities as a controllable open system.This system should have at least two basic functions，i.e.revealing reasons of urban agricultural development in large cities and providing theoretical basis for optimizing related behavior selection.Also，it should have following 6 types of functional variables.

（i）Subject characteristic variable.The subject characteristic variables are used to describe state of the system and reflect formation and change trend of subject characteristics.The subject characteristic variables of urban agricultural development system are functional structure，balanced by the deviation between supply structure of products and services and demand structure of urban residents.These variables directly influence value level，structure，and scale of urban agriculture.

（ii）Key causal variable.Key causal variables are direct causes promoting formation and change of characteristic variables.Cost，efficiency，risk and opportunity are key causal variables determining the development of urban agriculture.Variable state and its change trend directly decide supply structure，functional structure and adjustment direction of the urban agriculture.

（iii）Internal condition variable.Internal condition variables are various support conditions provided by the system for system behavior and also factors restricting development of the system.Internal conditions of urban agricultural development system mainly include element resource，ability（learning，innovation，and financing ability）of production and operation entities，and informationization level of urban agricultural system.

（iv）External environment variable.External environment variables are environmental factors uncontrollable or slightly controllable but the system relying on for existence，and also external support conditions and restrictive factors of the system.External environment variables mainly include technical environment of world urban agriculture，domestic market situation，systems and laws，metropolis circle，and integration of urban agglomeration，as well as integration and development level of agriculture and tourism.

（v）External regulation variable.External regulation variables are policies and laws regulating external environment and internal condition of the system，and also the results of behavior selection of subjects（mainly referring to enterprises and government）.External regulation variables of urban agricultural development system mainly include development strategy and plan，related policies，systems and laws and regulations of the national urban agriculture.

（vi）Behavior selection variable.The behavior selection variables are subject actions leading to formation and change of key causal variables and are decisive factors of system behavior.The behavior selection variables mainly include various policies and regulations formulated by government，innovation activities of production and operation entities，formulation of standards，and cultivation of brands.

2.3 System variable analysis model of urban agricultural development in large cities The above6 types of functional variables interact with each other and jointly influence functional structure，supply structure，demand realization degree and overall industrial value of the urban agriculture in large cities.Specifically，the deviation between characteristic variables and target variables leads to changes of internal condition variables and external regulation variables through changing the behavior selection variables，causes changes of key causal variables，and accordingly promotes characteristic variables to approach to targetvariables，as illustrated in Fig.1.

Fig.1 System variable analysis model of urban agricultural development in large cities

3 Characteristics and causes of stage development of the urban development in large cities

With systematic thinking and practical exploration for stages of urban agricultural development in large cities in recent years，we found that urban agricultural development takes on different starting，process coordinating，and final integration characteristics in large cities，and the development can be generally divided into three stages：starting and exploration stage，rising and development stage，and integration and innovation stage.The urban agriculture in each stage has different characteristics in functional structure，customer structure，industrial organization，innovation activity，spatial form，and industrial value，as listed in Table 1.With the aid of system variable analysis model，we analyzed stage development of the urban agriculture in large cities and causes of different characteristics.

Table1 Three stages and stage characteristics of the urban agricultural development in large cities

3.1 Starting and exploration stageThe urban agriculture just starts in large cities of China.It gradually grows in the transition from planned economy to market economy.Objectively，it needs change of the fixed mode of ensuring supply of vegetable baskets of cities through the suburban agriculture.On the basis of passing on agricultural production functions，the urban agriculture starts extending living functions such as sightseeing，mainly for satisfying demands of product customers and service customers；most production and operation entities take introduction and imitation innovation of technology and operation modes as major parts，presenting community development from bottom to top；the overall industrial value is slightly low and the level is also slightly low.

Considering development system of the urban agriculture in large cities，the above characteristics are results of relevant entity behavior selection and internal condition change brought about by the behavior selection，as well as external environment conditions such as market demand and regional competition.Satisfying demands of urban residents for agricultural products and recreation services is an objective of the urban agricultural development at this stage and also the source of industrial value.Production and operation entities such as enter prises and large households increase agricultural production efficiency mainly through introducing new varieties and extending new technologies.Besides，some entities start entering the sightseeing field with the aid of advantages of traffic and location and local characteristic resources.However，due to slight difference in quality between products produced by suburbs and those purchased outside and low access limit of sightseeing field，the production and operation entities are faced with price competition of superior production regions，and mutual imitation and competition of internal sightseeing entities.As a result，the urban agriculture in large cities at this stage remains the state of low cost，low efficiency and low risk，slightly low ability of connection opportunity and integration resources，few value sources，high difficulty in formation，and shortage of retention.

3.2 Rising and development stageThe evolution of urban agriculture in large cities lies on rapid advance of urban-rural integration and broad market demand of urban residents for new，novel and special agricultural products and sightseeing experience and tourism.At this stage，living service becomes major function of the urban agriculture in large cities.Diversified customer structure not only satisfies demands of urban and rural residents for feature activities，products and space combining agriculture and tourism，but also provides innovative technologies and commercial mode demonstration for outside relevant enterprises，institutions and government.Various distinctive urban agricultural clusters are formed in the process of government guidance and growth and division of micro entities；the industrial value rapidly increases and the level significantly increases.

From internal environment of large cities，the urban agriculture at this stage has fierce competition with other industries in land，fund，and human resources.The opportunity cost of element use is higher and higher.Profit-seeking nature leads to urban agricultural production and operation developing to high intensification and high added value of products and services.Accordingly，it raises the industrial access limit and promotes upgrade of communities.In the aspect of subject behavior selection，all regions start making arrangement for distribution of the urban agriculture within the framework of large cities，to support development of urban agriculture through plan and policy guidance.Besides，with increasingly frequent technological innovation activities based on cooperation of production，teaching and research，the whole industrial chain quality standard system for green and ecological agricultural products is gradually established and standards for recreation services get clear.Some operating entities with higher innovation ability and competition power start to cultivate brand，development mode and relation customers to get rid of restriction of land resource brought about by the urbanization.On the whole，both the production and operation efficiency and connection opportunities of the urban agriculture have greatly increase.Accordingly，however，it also brings about increase of opportunity cost and operating risk，diversification of value channels，and easier transformation，and greater proportion of retention.

3.3 Integration and innovation stageIn the tide of world urbanization，deterioration of ecological environment in modern metropolis，growth of environmental protection awareness of urban residents，and high quality and diversification of consumption demands guide the urban agriculture to evolve from rising stage to integration and innovation stage.At this stage，the urban agriculture takes harmony of human and nature and cities as the objective and takes ecological function as leading part.Value innovation activities are carried out on the basis of government guidance and entity operation，and integrating product customers，service customers，mode customers and relation customers.It forms interactive breeding of clusters and communities in space；the industrial value realizes a new round of rapid growth constant improvement of level.

From the aspect of external environment，to realize coordinated regional social and economic development with urban circle and city cluster as the core，the urban agriculture should become a balancer of low-carbon ecological environment and leader of regional agricultural development.Rapid development of modern science and technology，information network，and commercial operation mode provides favorable condition for realization of the above objectives.From the aspect of internal environment，it has become a common understanding of government at all levels and leading enterprises related to agriculture to develop land and energy conservation，knowledge and fund intensive，high，fine and special urban agriculture based on the Principle of Intergenerational Equity.Those enterprises with high innovation ability，large market network and powerful economic strength carry out value innovation，standard formulation and brand operation activities through implementing the Blue Ocean Strategy.In addition，with the aid of experiment and demonstration of innovation achievements，it promotes extension of innovation achievements，realizes interactive breeding of city circle and urban agricultural communi-ties，functional complementation and combined development of urban and surrounding regions.This not only satisfies demands of large cities for ecological，recreation and safety products and services，but also brings high added value output to urban agriculture and great radiation effect to regional economy，accordingly increases operating efficiency and connection opportunity，reduces opportunity cost and operating risks，realizes multiple value sources，easy transformation，high multiplication factor，and great retention proportion，so as to bring the urban agriculture to step to new sustainable development stage.

4 Use of stage development rules of the urban agriculture in large cities

According to development stages and characteristics of the urban agriculture in large cities，combining practice in all regions，we can reach the conclusion that China's urban agriculture in large cities basically completes the starting and exploration stage and has realized exploration development，Early and Pilot Implementation policy，and the stage mission of guaranteeing supply of vegetable basket of cities.In some large cities with higher economic and social development level，such as Shenzhen，Nanjing，Guangzhou，Chengdu，and Dalian，the urban agriculture has entered the rising and development stage and has made outstanding achievements in ensuring safety and emergency supply of urban agricultural products，satisfying recreational，cultural and living demands of urban residents，and improving urban ecological environment.The urban agriculture in Shanghai and Beijing has entered the end of rising and development stage and starts evolving to integration and innovation stage oriented towards ecological function under the guidance of advanced concepts such as people first，ecological capitalization and intellectual capitalization.

Using stage development rules and characteristics of the urban agriculture in large cities，it is able to accurately judge development stage of urban agriculture in a specific city.In combination with causal analysis of stage development characteristics，it is feasible to weaken barrier factors，eliminate restrictive factors，enhance incentive factors，and create conditional factors，which are favorable for effectively promoting the urban agriculture to enter into a benign cycle of stage evolution.In line with existing problems in China's urban agricultural development in large cities，we came up with following recommendations.Firstly，it is recommended to deepen the understanding of people-first awareness，bring into full play functions of ensuring supply，serving living，improving ecology，innovate demonstration，increase employment and income，and carry on culture，and weaken the confinement of fixed thought to the development of urban agriculture.Secondly，it is recommended to encourage and stimulate the innovative operation of enterprises related to agriculture，set food on city circle and urban cluster，and integrate opportunity connection and resources，to form higher level open system and service system for the urban agriculture.Thirdly，it is recommended to innovate upon the system of urban agricultural development，alleviate the restriction of little land resources in suburbs and accelerated movement of labor and funds to urban areas and secondary and tertiary industries.Fourthly，it is recommended to formulate systematic industrial support policy and increase in put of urban agriculture scientific research，information exchange，and social funds，to promote sustainable and healthy development of China's urban agriculture in large cities.

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