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In recent years, the technology of crop production has been greatly expanded using satellite data. Today, Landsat 8 and OLI sensor data, with a spatial resolution of 30 meters, allow the discovery of factors that control phenology on a local scale. In this study, the remote sensing indices - NDVI, EVI, Greenness, and Brightness - obtained from the OLI sensor and the GCC index obtained from digital camera images were used to estimate the phenological stages of the rapeseed plant. The Savitzky-Goli filter was used to remove outlier data and to produce smooth curves of time series of plant indices. The results showed that the curves obtained from the indices of NDVI, EVI, GCC show all four stages of remote sensing phenology – green-up, dormancy, maturity, and senescence - well, but the Greenness index did not show the dormancy stage well. The Brightness index curve shows the inverse behavior to other curves. According to Pearsonchr('39')s correlation test, GCC index data are correlated with NDVI and Brightness index data .we used the ratio threshold, rate of change and first derivative methods, to estimate "start of season" and "end of season" and the results showed that the first derivative and ratio threshold methods with an average difference of 18 and 19 days in the "start of the season"  and the rate of change method, with an average difference of 8 days, has the best performance in estimating the “end of the season”. Also, the Brightness index with an average difference of 16 days and the EVI index with an average difference of 7 days have the best performance in estimating "start of season" and "end of season", respectively.

Each plant needs a certain amount of heat at the time of planting and during its growth and development. The purpose of this research is to determine the thermal requirements of grain corn in the stages of growth phenology in the climatic conditions of Moghan and to determine the suitable cultivation areas in terms of heat requirements in northwest Iran. For this purpose, the technology of corn variety Single Cross 704 recorded consecutively from 2011 to 2014 at the Moghan Meteorological Research Farm and agricultural data from 51 synoptic stations in the northwest of the country (1996-2016) selected from the General Meteorological Organization of the Country have been used. To carry out this research, thermal requirements in each of the 5 main phases of phenology have been determined at the Moghan station, then using the regression equation between the 15-day average of temperature and altitude, a temperature-temperature history map for seed cultivation in all stations from the first half of the year was drawn using Geographic Information System software. Also, the length of scientific periods and the degree of growth day were calculated and the relevant maps were drawn using the Kriging method. Then, it was combined with the layers of altitude, slope of the region and land use, and finally, a zoning map of lands suitable for grain corn cultivation in the northwest of the country was drawn. Based on the results obtained, 27.6 percent of the study area is capable of cultivating this plant.