Optimization Of Agricultural Water And Land Resources In County Level Of Henan Province Based On Carbon Emission Constraints

One of the main reasons for agricultural carbon emissions is the mismatch of agricultural water and land resources and their irrational use.The exploitation of agricultural water and land resources is inseparable from energy consumption and carbon emissions,and material and energy inputs for agricultural production activities are mainly concentrated in the exploitation of water and land resources.At the same time,due to differences in natural conditions,planting structure,irrigation methods,etc,and the amount of land input,energy and water used in agricultural production process in different regions is different,so it leads to obvious regional differences in the efficiency of water and land resources exploitation.Therefore,carrying out the research on optimization of water and land resources based on carbon emissions constraints not only helps to scientifically evaluate the carbon reduction potential of land and water resources management,but also has important practical significance for resource conservation,improving the efficiency of water and land resources exploitation,and ensuring food security.Based on survey data of agricultural production in65 villages in Henan Province and relevant statistical data in Henan Province,this study measured carbon emissions from agricultural water and land resources exploitation in villages and counties.Based on agricultural input-output principle,using Super-SBM model,measured the agricultural production efficiency of county-level units under carbon emissions constraints.Refer to the city and county constraints in the implementation plan of the 13th Five-Year Plan for controlling greenhouse gas emissions in the country and in Henan Province,analyzed the spatial differences in agricultural production efficiency and carbon emissions in the exploitation of agricultural water and land resources in county units in Henan Province,and figured out the agricultural carbon emission threshold of each county unit.At last,based on the goals of minimizing carbon emissions and maximizing grain production,obtained the optimized exploitation model for agricultural water and land resources in county units.The main conclusions are as follows:(1)The spatial differences of carbon emission intensity of water and land resources exploitation in surveyed villages and county-level is significant,which shows"South-North High,Middle Low"spatial distribution characteristics on the whole.On the other words,the intensity of carbon emissions in surveyed villages in southern and northern Henan is higher than that in central Henan,and the agricultural carbon emission intensity of villages at the same latitude is comparable.The agricultural carbon emission intensity of surveyed villages is mainly distributed in medium-intensity and high-intensity areas,which accounts for 63.08%of the total number of surveyed villages.The high value distribution of agricultural carbon emissions intensity in surveyed villeges is relatively discrete,but there are also relatively high-value area,the northern area of Henan.Same as the agricultural water and land resources development carbon emission intensity of surveyed villages,the spatial difference in carbon emission intensity of agricultural water and land resources exploitation of county-level units is also large,whose carbon emission intensity of land resource exploitation is far greater than the carbon emission intensity of water resources development.Among them,the carbon emission intensity of the exploitation of agricultural water and land resources in Xun County is the largest,which is 1664.67 kg/hm~2,and the carbon emission intensity of the exploitation of agricultural water and land resources in Xin County is the lowest,which is 350.31 kg/hm~2.The average carbon emission intensity of county-level spatial water and land resources exploitation is 918.10 kg/hm~2.The carbon emissions intensity from land inputs is significantly higher than that of other input methods,and the carbon emission intensity of the water and land resources exploitation in county-level unit has obvious spatial distribution characteristics of high in the north and south and low in the middle.(2)The results indicated that the differences in agricultural production efficiency between county-level units in Henan Province are very different,the high value of which is mainly concentrated in areas such as southern Henan,northern Henan,and Kaifeng in central Henan,but the agricultural production efficiency in the western Henan region still needs to be further improved.And the value of agricultural production efficiency of county-level unit is mainly concentrated between the III and IV categories,accounting for 77.2%of the province's total.Among them,the agricultural production efficiency of Huaibin County is the largest,which is 1.7209,and the agricultural production efficiency of Linzhou City is the smallest,which is 0.1987.The average agricultural production efficiency of the county-level unit in Henan Province is 0.8419.There are 58 counties below the average,and 67 counties above the average.(3)The result shows that the irrigation level of cultivated land,the intensity of land input,the resource endowment of cultivated land,and the development level of rural economy have a significant impact on agricultural production efficiency,and all have passed the significance test at the 1%level.The impact of farmland irrigation level on agricultural production efficiency is relatively significant,and the level of agricultural economic development has a relatively small impact on agricultural production efficiency.The irrigated area of cultivated land and the level of agricultural economic development have a positive impact on agricultural production efficiency.But the intensity of land input and the endowment of cultivated land resources have a negative impact on agricultural production efficiency.(4)According to the carbon reduction target of the Henan Provincial Government,the carbon emission threshold of the county-level unit was defined.After decomposing the carbon reduction targets of the 13th Five-Year Plan in Henan Province,the total carbon emission intensity of land resources in each county is 93052.67 kg/hm~2,overall reduction of which is 1.76%.The total carbon emission intensity of water resources was 157.43 kg/m~3,and the threshold of total carbon emission intensity of water resources in each county was154.81 kg/m~3,which was reduced by 1.67%as a whole.The setting of carbon emission thresholds for county-level unit is in line with national and Henan carbon emission reduction targets.(5)The results show that the optimization scheme in this paper not only improves the utilization efficiency of water and land resources,reduces the direct and indirect energy and material consumption of agriculture and the intensity of carbon emissions,but also improves the food production.After the optimization of the land and water resources of county-level unit in Henan Province,the total grain output increased,from the original 62.348 million tons to 67.387 million tons,a total increase of 50.31 million tons,which has reached the target of65 million tons in Henan Province's"13th Five-Year Plan"for agricultural and rural economic development planning.Agricultural carbon emissions have also been significantly reduced,the threshold carbon emission calculated according to the"13th Five-Year Plan"constraint is 9.2448 million tons.After optimization,the agricultural carbon emissions were8.309 million tons,which was reduced by 915,100 tons.At the same time,the use of land resources such as fertilizers,pesticides,and agricultural films has also been greatly reduced,which meets the needs of the country and agricultural exploitation.The chemical fertilizer was reduced from the original 8.866 million tons to 6.029 million tons,and the agricultural film was reduced from the original 156250.94t to 145011.40t.(6)Based on the above results,the following suggestions are made for the low-carbon agricultural development in Henan Province:(1)Improve agricultural policies and regulations,and change farmers'production concepts;(2)Optimize the combination mode of water and land resources,and promote the efficiency of agricultural production;(3)Strengthen the construction of agricultural infrastructure,and popularize scaled production;(4)Carry out precise governance of agriculture based on the potential division of agricultural water and soil resources.