Estimation Of Crop Straw Burning Area And Burning Amount Based On Multi-source Remote Sensing Data In Songnen Plain

With the development of social economy and the change of rural energy structure,more and more families begin to burn coal for heating.Therefore,straw gradually loses the function of family heating and cooking.The situation of straw burning in the open field is becoming more and more serious,which has a great impact on people’s life and property safety.In the past,most of the statistical methods of straw open-air combustion were traditional manual investigation.This method has high cost,large error and long time consuming,so it can not meet the current demand.However,satellite remote sensing has the advantages of wide coverage,easy access to data and short repetition period.In this study,we mainly focus on the three aspects:(1)Based on 30 m resolution satellite images,the burning area of farmland straw in Songnen Plain was extracted by combustion index method.The combustion and distribution of straw in spring ploughing and autumn harvest in Songnen Plain in 2017 were analyzed.The farmland burning area in spring ploughing season is much higher than that in autumn harvest season.The total crop residue open field burnt area of Songnen Plain in spring ploughing season is 6.057 million hectares,while that in autumn harvest season is 3.794 million hectares.In spring,the burnt area of Heilongjiang Province is about 3.434 million hectares,and that of Jilin Province is about 2.622 million hectares,of which Suihua City is the largest and Heihe City is the smallest.In the autumn harvest season,the crop residue open field burnt area in Heilongjiang Province is about 1.495 million hectares,and that in Jilin Province is 2.296 million hectares,of which the largest area is Baicheng and the smallest is Heihe City.(2)The net primary productivity distribution of vegetation in Songnen Plain is analyzed by using the CASA-Ames-Stanford approach model to simulate the net primary productivity in crop growth period.For spatial distribution,the higher NPP distributed in the eastern of Songnen Plain,and lower NPP distributed in the western of Songnen Plain.The spatial distribution of NPP showed the same pattern with the vegetation species.For temporal distribution,with the recovery of plain weather in March and April,the NPP of vegetation increased gradually,and the peak value reached 84.53 C/m2,in July.After the mature harvest of crops and the decline of plants,the NPP gradually decreased.(3)Building crop straw yield models based on net primary productivity of vegetation.Straw yield was obtained by the relationship between NPP and dry matter content of crops and the ratio of grass to grain.Combined with farmland burnt area,the burning amount and spatial distribution of crop straw in spring and autumn harvest season of Songnen Plain in 2017 were obtained.A total of 23.0726 million tons of straw were burned in the spring and autumn of Songnen Plain in 2017,Among them,in spring ploughing season a total of 15.1987 million tons of crop residue straw were burnt in the field in Songnen Plain,while,about7.8835 million tons of straw were burned in the autumn harvest season.The city with the largest amount of straw burning in spring ploughing is Suihua City,3.4647 million tons,significantly more than other cities.In the autumn harvest,Songyuan is the most burning crop,a total of 1.3512 million tons.Of the three crop types,corn straw burn the most,about 15.833 million tons,of which 10.2965 million tons and 5.5254 million tons were burned in spring and autumn respectively.The rice straw burned 4.8233 million tons,with 3.1754 million tons and 1.6479 million tons were burned in spring and autumn.While for soybean straw 2.4274 million tons were burned,with 1.7267 million tons and 700700 tons burnt in spring and autumn respectively.