| With the booming development of biogas project in large-scale farms,more and more biogas slurry is produced in large-scale farms.The timely absorption,treatment and utilization of biogas slurry have become an important factor restricting the sustainable development of large-scale farms and biogas project.At present,as biogas slurry is the most effective way to use biogas slurry resource utilization,so it is very important to provide farms with enough area to absorb biogas slurry in time.In previous studies,there is a lack of relevant research on the calculation method of supporting area of biogas slurry consumed in large-scale farms,and no corresponding calculation system of farmland area has been formed,at the same time,most of the methods provided by the corresponding EIA reports are calculated under specific conditions.Therefore,in the range of carrying capacity of biogas slurry in farmland,the matching area of biogas slurry in farmland was systematically studied,and the corresponding matching area estimation model was established to provide a new calculation idea for EIA report and reference for solving the problem of matching area of biogas slurry in farmland at present.In this study,the matched area for digesting a certain amount of biogas slurry in farms was taken as the research objective,the reference of upland and paddy field water balance equation theory,theory of Soil Testing and Formula Fertilization and irrigation system,using hierarchical method,system analysis,expert consultation method and leading factor method,combing impact factor and the research goal and the logical relationship between the shadow,in the multifarious factors screening and to determine the dominant impact factors,using the method of mathematical model,further establish the research goal and the impact factor,the number of linear relationship between given to build farmland biogas slurry matched area estimation model.The main studies are as follows:1)Different analytical angles to filter and establish a different impact factor classification system,and then set up a different and specific linear as well as area estimation model,eventually to construct a set of matched area estimation model for biogas slurry.The influence factor grading system of irrigation matched area estimation model is mainly based on crop irrigation,considering factors affecting crop irrigation,screened and established three-level impact factor grading system,that is,3 first-order influencing factors,9 second-order influencing factors and 14 third-order influencing factors,and according to the theory of farmland water balance equation,the actual leading factor method and agricultural production situation,finally one main influencing factors of irrigation matched area estimation model were selected from quantifiable secondary influencing factors.According to the theory of farmland water balance equation and mathematical model method,an estimation model of irrigation matched area was established based on the linear quantitative relationship between the research objective and the eight influencing factors.The influence factor grading system of irrigation and fertilization matched area estimation model is mainly based on the amount of fertilizer applied to crops,considering factors that affect crop fertility,screened and established three-level impact factor grading system,that is,4 first-order influencing factors,6 second-order influencing factors and 15 third-order influencing factors,and according to theory of Soil Testing and Formula Fertilization,the actual leading factor method and agricultural production situation,finally one main influencing factors of irrigation matched area estimation model were selected from quantifiable secondary influencing factors.According to theory of Soil Testing and Formula Fertilization and mathematical model,a model for estimating the matched area of irrigation and fertilization was established.Thus,the matched farmland area estimation model of biogas slurry is composed of the matched area estimation model from the perspective of crop irrigation and the matched area estimation model from the perspective of crop fertilizer application amount.2)According to the actual situation of farms and the growth of farmland crops,the specific matched area estimation model is selected to obtain the corresponding farmland area.In the case of matched farmland area,the calculated value is larger,it can meet the two estimation models of crop safety growth.However,in agricultural production,additional water and fertilizer should be applied according to the growth status and demand of crops.3)The matched farmland area estimated in the environmental assessment report is calculated under the specific crop yield conditions.The model of matched area estimated by this study is to combine the actual agricultural experience of crop cultivation with the crop growth theory,to recover different water and fertilizer quantity of crops according to the specific growth conditions of different growth periods of the crop and the local climatic meteorological conditions,establishment of a set of matching area estimation model based on relevant mathematical theory equation and mathematical model method.This study is different from the calculation method under the specific conditions of environmental assessment report.Compared with environmental assessment report,the matched area estimation model of this study has more extensive applicability.4)Through the application analysis of the case,it can be known that in the actual agricultural management,combining two estimation models to solve the problem of farmland receiving biogas from large-scale farms,farmers and raisers can use biogas slurry for irrigation in the period of crop water demand irrigation according to the cultivation scale of large-scale farms and the crop growth status of matched farmland area.In the bearing area of farmland,biogas slurry can be used as fertilizer during the fertilizer application period,so as to get the maximum absorption and utilization. |
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