Study On Multiple Croppong Index Of Cultivated Land Based On MODIS Time Series

Cropping system has always been the focus of agricultural research,cropping system is an important way of agricultural planting patterns.As the main grain producing area in China,the change of the grain productivity caused by the change of planting mode will affect the grain yield of the whole country.Therefore,it is of great significance to study the change of multi cropping index in the area of Huang Huai Hai in the past fifteen years.In this paper,two provinces in Huanghuaihai area as the study area,the time resolution of 16d,the spatial resolution of MODIS NDVI 1km images as the data source,the image every three years to deal with the use of TIMESAT3.0 software,to obtain NDVI time series curve for a year,due to external factors of interference,NDVI time series curve will be affected by the noise.In order to accurately extract the number of peaks,the Savitzky-Golay filter method is used to fit the NDVI time series curve,which can better reflect the crop system in a year.The extraction of the peak number two times difference method,the extraction algorithm is based on a single pixel,the number of peaks of all pixels within the ranks of the deposit according to a text file,for each text file for image processing by computer R language programming,get the distribution map of Huanghuaihai region provinces multiple cropping space respectively..Through the study of nearly fifteen years of cropping index of arable land in Huanghuaihai region can be seen in Huanghuaihai region(two provinces city)a mature regional overall change is not obvious,but in some areas there will be changes,two crops area increased significantly,with Henan as the center to the periphery expansion.There was a positive correlation between the statistical data and the results of the study,the correlation coefficient was 0.8093,which has a certain reference value for the national agricultural decision-making.