Study On The Adjustment Of Parameters In Cultivated Land Classificatio

The classification of cultivated land is an important,basic and daily work,which can comprehensively grasp and scientifically quantify the quality and value of cultivated land in all aspects,and provide a basis for the reform of cultivated land system,the balance of cultivated land occupation and compensation,the accounting of land productivity,and the transfer of cultivated land.At present,the operation and process of farmland grading are very mature.The production potential used in the grading process is the production potential of the meteorological station.However,due to the great difference between the altitude of some counties and cities and the altitude of the meteorological station,the natural conditions of crops are significantly different from those of the local meteorological station.At this time,the same production potential used in the same county and city will lead to inaccurate farmland grading results.The production potential of crops generally includes the light and temperature production potential of crops and the climate production potential.These two parameters are the basic parameters necessary for the national cultivated land classification,and their accuracy has a great impact on the classification results.Therefore,it is necessary to correct the elevation of the production potential of crops.The yield ratio coefficient is also an important parameter in cultivated land classification,and its accuracy will also affect the results of cultivated land classification.Therefore,it is necessary to study the yield ratio coefficient.Firstly,the relationship between crop productivity potential and altitude is analyzed by using the data of meteorological stations in Central Yunnan,and the altitude correction model of crop productivity potential is obtained.Secondly,the light and temperature production potential of crops at different altitude units in Luquan County was calculated by using the domestic light and temperature production potential step-by-step calculation model and the vertical decline rate of temperature,and then the modified model of light and temperature production potential of crops and altitude was established.Then,the modified models obtained from the two experiments are compared and analyzed,and the altitude modified model of light temperature climate production potential suitable for this paper is established.Nutrient equivalent method and crop production potential ratio method were used to modify the yield ratio coefficient.After comparison,the nutrient equivalent method was used to modify the yield ratio coefficient.At last,the natural quality of cultivated land in the study area is divided by using the altitude correction model to correct the production potential and the nutrient equivalent method to correct the yield ratio.The changes of natural quality of cultivated land in Luquan County before and after the correction of parameters were compared and analyzed,and the following main results were obtained:(1)The production potential of the three crops in Luquan County basically decreased with the increase of altitude.Five altitude correction models of production potential of three crops in Luquan County are obtained: altitude correction model of light and temperature production potential of summer maize,altitude correction model of light and temperature production potential of winter wheat,altitude correction model of light and temperature production potential of one season rice,altitude correction model of climate production potential of summer maize in Luquan County and altitude correction model of climate production potential of winter wheat.(2)After correcting the yield ratio coefficient of crops,the yield ratio coefficients of rice,wheat and corn in Luquan County are 1.0,0.81 and 0.71 respectively.(3)After correcting the production potential and yield ratio coefficient of the three crops,the natural quality of cultivated land in Luquan County has six grades,which is two grades higher than the four grades without modifying the parameters: 9,10,11 and12,which are 8 and 13 respectively.The cultivated land area of two grades decreased by 17794.38hm2,accounting for 20.89% of the total cultivated land area;The cultivated land area of one grade decreased by 59183.82hm2,accounting for 69.47% of the total cultivated land area;The cultivated land area with the same grade is 7907.90hm2,accounting for 9.28% of the total cultivated land area;The cultivated land area of one grade increased by 303.48hm2,accounting for 0.36% of the total cultivated land area.