The Study On The Optimized Structure Of Ecological Agricultural System With Commodity Based On CDM In Xiannangou Watershed

As the Sloping Land Conversion Program (SLCP) project developed in Xiannangouwatershed, ecological agriculture with commodity (EAC) improved and agro-resourcesand agro-practices has been restored and advanced steadily. However, the inadequate useof agro-resources and the inconsistency between agro-resources and agro-practices is stillemerging, which definitely constrains the further development of EAC in this area.Meanwhile, the SLCP also brings a great potential of carbon sink. Therefore, optimizingthe chain network structure of ecological agricultural system with commodity (EASC)plays an important role in accelerating agriculture eco-economic coordinate development.Since the system of agro-practices grow inconsistently with agro-resources, the chainnetwork structure of EASC is incomplete. To solve these problems, it’s essential to makeclear the key point of optimized EASC on the basis of resource and industrial structure&carbon sink potential of agro-system analysis after SLCP implemented. EASC isoptimized by setting different phases and scenarios according to the probabledevelopment paths of it. Moreover, the relationship between optimized EASC wasanalyzed by using coupling process model and further clarified the difference of eachphase. Thus, some strategies were proposed. The main results are as follows:(1) The SLCP has changed land use and industrial structure of Xiannangou watershed,and hence EAC also developed. However, the inconsistency between agro-practices andagro-resources is still existed. The SLCP make land use structure from1:0.65:3.71to1:6.31:7.66. A large amount of slope cropland turns to woodland or grassland or terrace.Soil erosion has been controlled for the significant improvement of grass and forestcoverage. The development of fruit and efficient facility agriculture has enhanced thestandard of living. The three dominant industry of Xiannangou watershed are industryfruit, planting and avocation, which account for96percent of net income. Although EASC developed, it remains to be further optimized on account of the inadequate use ofagro-resources and inadequate development of graziery.(2) The change of Land use and location has altered the carbon sink. Total amountof carbon sequestration is increasing and has a great potential of carbon sink. The netcarbon sinks in2012have increased4451.41t compared with that of1999. Different landuse structures bring different net carbon sink, with in descending order: woodland,cultivated land, grassland, orchard, and construction land. The primary land for carbonsink is the woodland of SLCP, whose carbon sink percent increased from56.81%in1999to87.11%in2012. To further enhance the ability of carbon sink in Xiannangouwatershed, it will aim to improve the quality of SLCP land growth. Cultivated land issecond to woodland in carbon sink. But its products such as seed and straw are consumedin different ways of eating, selling, burning and grazing. Then it participates in the nextstep of atmospheric circulation. Location and the degree of SLCP make the difference ofland use structure, and then they make the diversity of location carbon sinks. The abilityof carbon sink in descending order is zhaiziwan, zhuanyaogou, panposhan, yayao,fangjiahe, heta. And the location watershed outlet and gully head have stronger ability ofcarbon sink.(3) According to the possible development path of EAC, it demonstrate that EACfollow the path of “the development trend of the status quo�'the modified chainnetwork construction of EASC�'the optimization of agricultural economic system andagricultural ecosystem coupling” by setting3phases and5scenarios of EAC. And thestructure of agricultural economic system and agro-ecological system optimized couplingphase will have a great change. Xiannangou watershed is controlled by government now,so resources of woodland and grassland are wasted, the chain network structure of EASCis incomplete, and income of farmer is low. When the government slow down thelimitation gradually of woodland and grassland resources, guiding peasants to make fulluse of grassland resources and crop straw, graziery make the chain network structure ofEASC completed, making the chain “planting industry, resources of woodland andgrassland�'graziery�'farmyard manure�'industry fruit, greenhouse” run moresmoothly. In these two phases, the land use structure is1:6.31:7.66. It has a little change,which is the internal adjustment of planting structure about grain land and grassland.When the woodland grows to mature woodland after SLCP, farmer can earn profits byoffering carbon sinks to market under clean development mechanism (CDM). At thesame time, land use structure has a big change to1:12.6:4.4. (4) Mountain apple is the dominant industry along all phases of EAC. At the sametime, phaseⅠshould enhance the construction of efficient facility agriculture, phaseⅡconstruct graziery and phase Ⅲ develop forest estate. Along all phases the developmentof EASC, the dominant industry is apple in Xiannangou watershed. The key point ofphaseⅠis enhance the dominant status of apple and construct efficient facility agriculture.It is important to protect woodland and grassland resources for graziery. The constructionemphasis of phaseⅡis graziery. There have2053sheep for barn feeding in the scenarioB-1and2053sheep for barn feeding and grazing in the scenario B-2. The key point ofphase Ⅲ is carry on forest estate. So farmer can get profit from selling carbon sinks ofwoodland.(5) Optimization scheme improved the coupling effect of EASC, and with theimprovement of the system structure the coupling effect is better. When agro-ecologicalsystem reaches the self-adjusting tipping point, the agricultural economic systemevolution speed of the phase of EASC in the chain network construction&the optimizedcoupling phase of agricultural economic system and agricultural ecosystem respectivelyare0.0913×El(t)&0.0999×El(t). The evolution rate contribution degree thatagricultural ecosystem for agricultural economic system in these two scenarios is biggerthan the development trend of the status quo. This results show that through the contrastof the chain network of EASC and the optimized coupling of agricultural economicsystem and agricultural ecosystem, the degree that the development of agriculturalindustry relies on the agricultural resources is increasing. And the coupling effect ofEASC is increasing too.(6) The EASC in Xiannangou watershed should be with the agricultural industry andagricultural resource coupling as the core in the next development. In order to realize thesustainable development strategies for EASC, some strategies were put forward:adjusting the industrial structure according to the characteristics of different location,completing industrial chain network of EASC through improving the efficiency ofresource use, breaking phases and defining the key point of construction according to thedevelopment of EASC.