According to the regional NDVI development graph, crop condition was generally fair in the Loess region. The main crops in the region are currently winter wheat, spring wheat, and spring Maize. Winter wheat was sowed during late September to middle October and will be harvested in June. Spring wheat and Maize were just sowed during late March to April. During the monitoring period, rainfall (RAIN) exceeded average by 35%, while temperature (TEMP) was 0.3°C above. Radiation (RADPAR) was 2% below average, which may adversely affect the process of photosynthesis. In most of the area, the analyses based on spatial NDVI clusters and profiles are consistent with VCIx. NDVI clusters and profiles show that crop condition was close to average in some parts of the region, such as  northwestern Shanxi, south central Ningxia, and central and eastern Gansu, while the crop condition was below average and underwent some fluctuation during late January to late February in south central Gansu, southern Ningxia, and southwestern Shanxi, etc.  The fraction of cropped arable land (CALF) for the region decreased 20 percentage points when compared with the five-year average, which indicates about one fifth of the land is uncropped. The potential biomass indicator (BIOMASS) was 18% above average, with above average values in every province within the Loess region. According to the VCIx map, current crop condition of the region is quite unfavorable, especially in most parts of Shanxi, and central Shaanxi.

Figure 4.10. Crop condition China Loess region, January-April 2019

(a) Crop condition development graph based on NDVI

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

(d) Maximum VCI                                               (e) Biomass departure