The monitoring period (January to April) covers the spring green-up and jointing stages of winter wheat in Huanghuaihai. Due to the delayed sowing last year, the harvest time will be delayed by about 1 week. Agro-climate indicators showed that precipitation (-6%) and radiation (-2%) in this area were below the 15YA, but temperature (+0.5°C) was above. The combination of these weather parameters led to a decrease of potential biomass by 11%. The CALF exceeded the 5YA by 8% but still lower than 2021 JFMA, and the maximum VCI value was 0.94.

Based on the NDVI-based crop growth profile, the crops grew a bit more slowly in February and early March due to cooler than average temperatures, but reached the 5-year maximum level at the peak growing period by the end of April. As the NDVI clusters and profiles showed, only 12.2% of the cropland in Northeastern Anhui was higher than the 5YA before mid-March. Crops in the areas of Southern Hebei, Northeastern Shandong, Eastern Henan, and Northern Jiangsu (blue, red, and dark green colors in the NDVI departure clustering map) presented below-average conditions until mid-March, but recovered quickly thereafter.  The map of maximum VCI presented a similar trend as the spatial NDVI pattern. Generally, the crop conditions in this important winter wheat production region are normal.

(a) Crop condition development graph based on NDVI

(b) Spatial NDVI patterns compared to 5YA(c) NDVI profiles

(d)Time series rainfall profile

(e)Time series temperature profile

(f) Maximum VCI

(g) Biomass departure