Evaluation Of Sustainable Development Of Minqin Oasis Farmland Ecosystem Based On Emergy Analysis

Minqin oasis has a very important strategic position on ecological security of Chinawhich blocks the Badain Jaran Desert and Tengger Desert to merge together and is aneffective ecological security barrier for Wuwei oasis and the Hexi corridor. Agriculture is thefoundation of the Minqin oasis economy, sustainable development of agriculture is directlyrelated to the security of oasis ecological environment. Farmland ecosystem is the basis ofagricultural eco-economic system, the efficient and intensive utilization of resources; thereasonable planting structure with high yield determines the stability of agriculturaleco-economic system, thus the quantitative evaluation of Minqin oasis farmland ecosystemhas very vital significance.In this paper, Minqin oasis farmland ecosystem is analyzed and evaluated with thetheory of Emergy Analysis based on its input and output data during1997and2011, from thethree aspects that include the input and output structure, efficiency of resource utilization andsustainable development of the ecosystem, the conclusions follow:(1) During1997-2011, the total emergy input of Minqin oasis farmland ecosystemdecreases after increasing first, on the whole increases by10.15%for15years, the change ofthe total emergy input is relatively stable. Rate of environmental contribution generallyshows a decreasing trend, accounting for an average of1.89%of the total input emergy.Unrenewable industrial emergy is mainly the total emergy input, accounting for an average of79.51%. In unrenewable industrial emergy, the average proportion of fertilizer of emergyinput is the largest at87.92%. Renewable organic gradually reduces an average of18.17%.Emergy investment ratio increases from36.80in1997to41.18in2011. Researches showthat level of mechanization is improved continually in the oasis field producing, degree ofmodernization gradually is strengthened step by step, but the capacity of environmentalsustainable development reduces. From the perspective of space, there is significantdifference of economic development degree in Minqin oasis farmland ecosystem, developedtownships have obvious advantages, and towns surrounding urban area are relatively higherthan relatively remote areas on the farmers’ living standard and the strength and level of theeconomic development of farmland ecosystem. (2) During1997-2011, the total emergy output in Minqin oasis farmland ecosystemshows a increasing trend, increases by2.15times. Cotton, oil crops, wheat and corn are themain crops of emergy output, during these years the emergy output of the cotton increases by7.14times, the emergy output of oil crops increases by4.38times, the emergy output of cornslightly increases by38.34%, the emergy output of wheat present a decreasing trend by45.09%, the emergy output of fruit, vegetables and melons account for little, but shows asharply increasing trend, increase by3.28times,5.04times,3.01times respectively. Minqinoasis during these years reduces the number of food crops, improving the number ofeconomic crops with high returns. Balance degree of planting structure of Minqin oasisfarmland ecosystem present downtrend on the whole, drops from1.93in1997to1.25in2011.From two aspects of space and time with the comparative study of emergy output density andbalance degree of planting structure,it shows negative correlation relationship that thebalance degree of planting structure is small when emergy output density is large,and thebalance degree of planting structure is large when emergy output density is small. Withcomparative study of emergy output density and scale efficiency advantage index of differentareas farmland ecosystem, it shows that forming advantage of scale about cotton and oilcrops in Minqin oasis will have great significance to improve Minqin oasis farmlandecosystem productivity.(3) Resources use efficiency of Minqin oasis farmland ecosystem is low, net emergyoutput rate increases from0.35in1997to1.00in2011, if oasis agricultural products want tohave competitiveness in the market, net emergy output rate need to be improved. With respectto the spatial scale, net emergy output rate has greatly been improved from1997to2011.Resources use efficiency of Caiqi township and Chongxing township is low,while it is high inJiahe township, Hongshaliang township and Xiqu town, in other areas it is relatively low andunstable.To do regression analysis about the total emergy output and emergy input elementsof Minqin oasis farmland ecosystem, results show that the input elements of fertilizer, organicfertilizer, labor, agricultural machinery and plastic film have great influence on outputs, theregression coefficient are0.1989,0.1935,0.1377,0.1993,0.1168respectively. With poorsoils Minqin oasis need to add nutrients from the external system, improvement of themechanization degree in oasis farmland producing has remarkable effect on output. Using plastic film also have a promoting effect, in the arid Minqin oasis the use of plastic film canbe further expended.(4) The emergy sustainability index of Minqin oasis farmland ecosystem increasesfrom0.11in1997to0.25in2011, is far less than1, with low emergy yield ratio, highenvironmental load ratio, high level of modernization in field producing and largeenvironment pressure, the ecosystem belongs to a consumer ecological economic system andis not sustainable. With respect to the spatial scale, spatial differentiation characteristics of theemergy sustainability index is significant, except for the Hongshagang town, Hongshaliangtownship and Jiahe township, the index of minqin oasis other areas farmland ecosystem isgenerally low. During these years the comprehensive level of sustainable development inMinqin oasis farmland ecosystem increases. There is clear regional difference in Minqin oasisfarmland ecosystems which present the geographical distribution of northeast abovesouthwest and oasis edge band above center zone. farmland area of not and highly notharmonious development regions account for73.68%of the total farmland area in Minqinoasis; farmland area of strong, relatively strong, weak harmonious development regionsaccount for26.32%.Therefore, at present unsustainable status that the farmland ecosystem inMinqin oasis faces should cause the attention of the relevant departments.