“…The maturity of summer maize is 2 September, 15 May corresponds to the completion of winter wheat, 24 June corresponds to the emergence of summer maize, and the NDVI inversion from the completion of winter wheat to the maturity of summer maize is too large. For regions with frequent vegetation changes, high heterogeneity, and complex surfaces, the images often contain many mixed image elements (Meng et al., 2021; Wei et al., 2020), which in turn leads to a decrease in data fusion accuracy (M. Liu, Liu, et al., 2020), making the predicted results of 2 September poorly correlated with Sentinel‐2A at the corresponding time. From summer maize harvest to winter wheat sowing, before NDVI values were smaller, spectral abruptness of different features was reduced, differences were smaller, and fusion prediction accuracy was better (M. Wu et al., 2016), as shown by the better correlation between STNLFFM NDVI and Sentinel‐2A NDVI.…”