Assessment of agricultural drought vulnerability based on crop growth stages: A case study of Huaibei Plain, China
This study focused on evaluating the drought loss vulnerability of soybean on the Huaibei Plain. The specific objectives were: (1) to develop a composite index of soybean drought vulnerability based on precipitation, soil water, and physiological parameters during different growth stages; (2) to construct a soybean vulnerability evaluation model based on a disaster vulnerability framework, crop growth simulation, and spatial interpolation methods; and (3) to fully reveal the spatiotemporal characteristics of soybean drought vulnerability in the region.
The results of the study show that:
- Different physiological parameters of soybean can reflect drought sensitivity during different growth stages. Parameters related to leaves (SLA and LAI) were more sensitive to drought during vegetative growth stages (S and B stages). But during reproductive growth stages (F and P), TW and GW (correlated to yield developing) were more sensitive to drought.
- The relationship between the GDVI and corresponding drought sensitivity parameters can be fitted by a logistic function (S-shaped curves). Drought loss during the seedling (S) stage developed fastest but with lowest limits, whereas the drought loss developed slowest but with the highest upper limit during the pod-filling (P) stage. The pod-filling stage was the key period to ensure stable yield, and attention should be paid to drought monitoring during this period.
- 2001 and 2002 were typical drought years in 1997−2006. In the 2001 season, the highly drought-vulnerable area was concentrated in the southwestern regions including Fuyang and Huainan. In the 2002 season, the highly drought-vulnerable area was concentrated in the northern regions including Huaibei and Suzhou. Furthermore, severe yield reduction was more likely to occur in the regions with a high GDVI during the pod-filling stage. It is recommended to optimize the irrigation scheme and increase the drought resistance investment during crucial periods and in corresponding regions.