Landscape Ecological Security Evaluation And Sustainability Assessment Of Land Consolidation In Typical State-owned Farms In Sanjiang Plain

Food security is an important thing that matters social harmony,political stability and sustainable development of economy.Nowadays,food security in our country is still faced with big challenges.Improving the the productivity of the cultivated land is the key to solve food security problems.Located in Heilongjiang province and one of the three world's last existing black soil belt,Sanjiang Plain is the important component of China's largest distribution group of state-owned farm,and now has become the important marketable grain base,which is of great significance to maintain foot security.Moreover,Sanjiang Plain is also the largest zone with fresh water marsh and mud flat distributed,which has important ecological function.State-owned farms are the basic units of Sanjiang Plain.This paper selects the three representative state-owned farms: Youyi farm,Honghe farm and 859 farm as the study area,studies the similarities and differences of land consolidation in different historic periods,dicusses the influence of long-term and continuous land consolidation to landscape ecological security,summarizes the past experiences,so as to optimize the rational allocation of land resources in Sanjiang Plain,improve the cultivated land quantity,quality and ecologic protection,and guarantee the sustainable utilization of land resource.This paper firstly verified the evolution of land consolidation in Sanjiang Plain,which laid a solid foundation to the future theoretical and empical studies.On this basis,the comparative contrast of the land consolidation design was conducted among the three state-owned farms from five perspectives: theory,objectives,procedures,content and method,aiming to get the overall knowledge of people's way of using land resource in different historic stages and traditional cultural background.Secondly,based on Landsat images from 1985,1995,2004 and 2014,this paper built landscape ecological security model using landscape security indexes and ecological quality indexes,analyzed the land use and cover change and spatial-temporal differentiation of landscape ecological security,which aimed to explore the continuous implemention of land consolidation to ecological structure,function,stability and restorability andso on.Finally,we built an International Framework for evaluationg sustainable land management(FESLM)and DPSIR causal model to analyze the evolution trend of land consolidation sustainability over 30 years.Results showed that the theoretic development of land consolidate was influenced by natural resource constrains,economic and social development and cultural succession.Between 1985 and 2014,the natural wetland degraded obviously.Landscape security showed a trend of declining first and rebound afterwards,and experienced landscape fragementation,impaired function of ecosystem,and response and repair of land consolidation.At the same time,the sustainability of land consolidation in the three farms also showed a trend of declining-rebound.The change trend of its subsystem had typical causality.As the increase of dricing force,the environmental stress of the system improved,which had an effect to the system and caused the change of influence factor.Finally,the self-regulation function of the system was motivated and responded to this degradation trend in order to repair it.This paper made the conclusion that land consolidation aimed at increasing food quantity in the past days was the main element which influenced the landscape ecological security and land consolidation sustainability.The rational implement of land consolidation could promote the ecological security and sustainable use of land resource.Thus,the land consolidation in Sanjiang Plain should take ecology as the priority,carry on the regional major function given by national stratedy,improve the land consolidation systems,comply with development requirement and environemental restraints,seize the orientation of land consolidation,play the role of the ecological recovery effect while assuring the red line of cultivated land,in order to achieve the harmonious development between human and nature.