| Agricultural production is the lifeblood of national development and the foundation of economic development.Solving agricultural development is crucial to the country's future direction.With the impact of high-intensity human activities and the changing environment,the requirements for food production and quality continue to increase,and the area of reclamation area continues to expand.The application of chemical fertilizers and pesticides and the amount of groundwater extraction have also increased,leading to a series of derivative problems such as soil acidification,thickening of the plow bed,and deterioration of groundwater quality.The sustainable development capacity of agricultural areas needs to be improved.Aiming at the problem of insufficient criteria for sustainable development of regional agricultural systems and increasing system uncertainty,the idea of harmony is introduced.Regarding the regional agricu ltural water and soil resource system as a composite system,the agricultural water and soil resource composite system harmony theory is proposed.Taking the Heilongjiang Beidahuang Agricultural Reclamation Group Jiansanjiang Branch as the research base,the measuring method and application of the regional agricultural water and soil resources composite system harmony are carried out in the form of multidisciplinary cross and multiple methods.The research can extend the research field of harmony theory,en rich the research content of agricultural system,and provide a new path for the harmonious development of agricultural regions.It has practical and long-term significance for realizing the sustainable development of regional ecology and society.The specific research content is as follows:(1)Aiming at the uncertainty of the optimal parameter selection of Random Forest(RF),the Dragonfly Algorithm(DA)is used for parameter calibration,and an improved random forest model(DA-RF)is constructed,which provides a more accurate method for multi-objective evaluation and apply it to the water environment assessment of Jiansanjiang Branch.The results show that the water environment of Jiansanjiang Branch generally presents the characteristics of"the water qu ality of Northwest Farm is poor,and the quality of groundwater is better than that of surface water";Surface water TN,TP,groundwater NH3-N,Fe,Mn are the main pollutants;Surface water TP and TN,and groundwater NH3-N exceed the standard due to the application of chemical fertilizers,especially nitrogen fertilizer,and groundwater Fe and Mn are primary harmful substances;According to the characteristics of the water environment,targeted improvement strategies such as reducing the application of nitrogen fertilizers are proposed.(2)Based on the systematic literature review method,the connotation and judgment basis of the agricultural water and soil resources composite system harmony are defined.On this basis,Jiansanjiang branch's evaluation index system is constructed.The results show that the so-called the agricultural water and soil resources composite system harmony means that the three subsystems(social economy,agriculture and resource)are in a healthy operating state,and the external subsystems are mutually tuned and balanced,so that the entire large system presents a stable form of coordination,consistency and balance.According to the"three deletions,one sorting and one adding",the indicator selection database(347 indicators)is re duced to the indicator primary selection database(79 indicators),and then using the Coefficient of Variation-R Clustering-Grey Correlation Advantage method(CV-RC-GCA),eventually 23 indicators were obtained,among which humanities,agriculture,and resource system indicators were 7,11,and 8 respectively;Through comparative analysis with the screening results of the RC-GCA model and the human-water harmony index system,the rationality and reliability of the index system built by the CV-RC-GCA model are verified.(3)The harmony equation of the connotation-based harmony equation and the DA-RF-based harmony measurement model are used to measure and analyze the agricultural water and soil resources composite system harmony of Jiansanjiang Branch.The results show that the two methods have their own advantages and disadvantages.The harmony equation based on connotation is more in line with the requirements of connotation,and the harmony measurement model based on DA-RF is more in line with objective laws and has universal applicability;This article follows objective laws,so the DA-RF-based measurement model is used to evaluate the results.The agricultural water and soil resources complex system harmony of Jiansanjiang Branch has shown an"N"-shaped trend over the years.The 1997-2005 period has not yet entered the peak period of resource and agricultural development,and the water and soil resource composite system harmony has been steadily improved during this period;During the 2005-2008 period,due to predatory management,the agricultural water and soil resource composite system harmony was reduced and the speed was faster;From2008 to 2016,due to the local government strictly controlled the development of water and soil resources,vigorously developed agricultural modernization,the agricultural water and soil resources composite system harmony gradually recovered;In terms of space,due to the advantages of water resources and topography in the farm near the river,the agricultural water and so il resource compound system harmony is higher than that of inland areas;Aiming at the slow growth of the agricultural water and soil resource complex system harmony,based on key driving factors,adaptive control strategies such as the promotion of water-saving irrigation technology et.al,have been proposed.(4)Quantitative and qualitative forecasting methods are used to analyze the future development trend of the agricultural water and soil resources complex system harmony of Jiansanjiang Branch under different scenarios.The results show that,If the key driving factors develop in accordance with multi-year trends and no outside interference,the agricultural water and soil resources composite system harmony of Jiansanjiang Branch will show a"U-type"change from200 to 2030,hovering between the more harmonious and the less harmonious range;When the per capita food production reaches the planned optimal value,and at the same time,according to the harmonious control strategy,the original detuned indic ator is raised to the relevant policy planned value,the local harmony can be effectively and quickly improved,which is the most ideal harmonious development situation;When only the per capita food production is adjusted and other indicators remain unchanged,the local harmony will also be improved,but the growth rate will be slower;When the per capita food production is only the lowest value of the plan,other indicators suffer from"poor"logical development,which means that the local harmony is decli ning year by year,at the same time,in order to reduce the loss of harmony when the worst scenario occurs,suggestions for speeding up water conservancy projects and remedial measures for sealing and filling pumped wells are put forward.(5)Taking the agricultural water and soil resource complex system harmony as a constraint in the optimal allocation of water and soil resources study,and combining the regional economic benefits and resource consumption functions,and use the Plat EMO platform to solve the model,and explore the influence of different harmony constraint scenarios on the optimal allocation of water and land resources.The results show that the higher the harmony of the scenario,the smaller the proportion of rice planting,the higher the proportion of soybean planting,the higher the surface water utilization and development rate,and the more diverse and reasonable the utilization of water and soil resources;Different harmony scenarios have different effects on the optimal allocation of water and soil resources,Less Harmony(LH)will increase the rice planting area by 28%?60%,and the utilization rate of groundwater will decrease by 87%?93%.,More Harmony(MH)will increase the rice area by 20%?30%,and the utilization rate of groundwater drops by 60?92%,Very Harmony(VH)result will increase the area of rice by 6%?14%,and the utilization rate of groundwater will decrease by 20%?30%;Analyzing the benefits of the optimal allocation of water and soil resources under different scenarios,it is found that the higher the harmony of the scenario,the lower the water consumption,but the lower the economic benefit;Compared with the existing research results of water and land resource allocation in Jiansanjiang Branch,the allocation plan in this article has an obvious purpose of"harmonious development". |
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