中国P站

Abstract

In Ethiopia, sorghum covers 60% of the land and climate variation affects major producing regions. The study assessed rainfall variability and trends in the sorghum growing semiarid rift valley. 40 years of rainfall data analyzed for 11 stations studying variability and trend using Mann-Kendall methods. Analyses also included growing season start and end, length and dry spells. Rainfall patterns in the Ethiopian Rift Valley varied over 40 years, with August, July and September being the rainiest months. Short rainy season: 19.4%-33.2% yearly rainfall; main rainy season: 52.3%-70.8%. Varied short rainy season, most variability in Northern Rift Valley Escarpment (116.6-296.8 mm). During the main season, 91% of areas got <250 mm rain, but it varied from 315.05 to 618.8 mm. Sen's slope estimates for NRVE, ERVE and CRV show an increase ranging from 0.02-0.81, 0.05-0.71, 0.02-0.81 mm/yr in September respectively. Rainfall varies with a 0.31-2.76 mm/year decrease and 0.19-5.12 mm/year increase between short and main seasons. Some places have more rain each year than before (0.042 to 3.88 mm/yr), but in 5 stations it has been less (1.29 to 3.71 mm/yr). Data from 11 stations with different rainfall onset dates and CV ranges (4.9%-16.6%). Rainy seasons range from 24 to 200 days, with changing start and stop dates, affecting crop yield. Longer periods decrease risk; rain needed within 90 days for crop growth. Optimize crop management based on differing LGP at stations with varied rainfall days (67-110) and variability (8.1%-25.1%) over 40 years. Few dry spells over 5-15 days after June, odds decrease in peak season but reach 40% at 245 DOY for 5-10 days’ droughts. Climate complexity affects planting decisions, risking crop yields. Strategies to consider include early crops and rainwater collection.