| As a large agricultural country,China is rich in crop straw resources.However,under the influence of traditional consumption concept and life style,there are many unreasonable phenomena in the utilization of crop straw in our country.Farmers usually burn or dump crop straw,and crop straw is not fully utilized,which results in serious pollution.It also wastes valuable renewable resources.Therefore,it is one of the basic work of straw utilization that how to choose a reasonable and regional crop straw utilization mode in the diversified comprehensive utilization of crop straw.The correct choice will benefit the comprehensive benefit of crop straw utilization mode.On the basis of investigation and analysis of crop straw resources and utilization in Changzhou,this paper uses analytic hierarchy process(AHP)and fuzzy comprehensive evaluation method to construct the evaluation model of straw utilization efficiency,calculates the weight of the index,and evaluates the comprehensive benefits of straw utilization in Changzhou.The direction of straw utilization in the state city has been proposed to solve the existing problems in the comprehensive utilization of straw in Changzhou,which provides a reference for the comprehensive benefit evaluation of straw utilization in other areas.The main research results include the following aspects:(1)The yield of straw in former Changzhou City is larger.It is mainly composed of straw of rice,straw of wheat and straw of rapeseed.The comprehensive utilization rate of straw is high,up to 95%.The main ways to use the straw can be attributed to straw returning,forage,biogas,power generation and basic material.The proportion of straw returning to the field is the largest,reaching 52.36%.However,there are still some problems,such as single utilization mode,immature key technology,imperfect collection,storage and transportation system,imperfect policy incentive mechanism and lack of farmers' enthusiasm.(2)Based on the three aspects of economic benefit,social benefit and ecological benefit brought by different straw utilization methods,the evaluation index system of straw utilization benefit is established in this paper,and the target layer is the comprehensive utilization benefit evaluation of straw.The quasi-lateral layer includes three aspects: economic benefit,social benefit and ecological benefit,and the index layer includes 9 items,such as input-output rate,investment return rate,etc.Analytic hierarchy process is used to determine the weight of each index.In the quasilateral layer,the economic benefit weight is 0.4934,the social benefit weight is 0.3108,and the ecological benefit weight is 0.1958.Subcriteria layer,The weight of input-output ratio is 0.1030,the weight of return on investment is 0.3223,the weight of straw conversion utilization ratio is 0.4558,the weight of industrial development ability is 0.1189,the weight of new jobs is 0.2089,the average annual income of farmers is 0.2402,the weight of resource substitute income is 0.5499.The weight of recycling efficiency of resource is 0.3333,and the weight of emission reduction of pollution gas is 0.6667.Based on the theory of fuzzy mathematics,the membership function of each benefit evaluation index of straw utilization is constructed,the quantification of the index is realized,and the specification of specific index value without dimensionality is reached to the 0 ~ 1 interval.On this basis,the evaluation model of straw utilization benefit based on fuzzy comprehensive evaluation is established by using fuzzy weighted synthesis method.(3)The results show that the comprehensive benefit of straw base material was the best,followed by straw big point,straw making and straw returning to the field,and straw making feed was at a disadvantage.Straw base material has the characteristics of low investment,simple operation,short cycle,high economic return rate,and has the value of being popularized in Changzhou on a large scale.The characteristics of large initial one-time investment and long return period of straw power generation lead to relatively weak economic benefits,more suitable for the formation of technology,and more experienced developers in the relatively rich straw resources,concentrated local investment and development.Straw biogas is suitable for popularizing in the low utilization rate of straw.In particular,it is suggested to build a centralized biogas project in rural areas,and take this as a link to vigorously develop ecological agriculture;Straw returning to the field can also be combined with other utilization methods to develop circular ecological agriculture.The utilization rate of straw for livestock and poultry breeding is low and the feeding rate is poor.Therefore it is not recommended to be popularized on a large scale and can be used in moderation. |
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