Dry Soil Planting Risks for Maize and Sorghum in Ethiopia.

On-set of rainfall in parts of Ethiopia is highly variable while high productivity requires early establishment of maize and sorghum. Farmers dry soil plant to improve the chances of early crop establishment, but information on best planting depth and the risks of failed establishment was lacking. Field research reviewed that the optimal planting depths were 5 and 7 cm for sorghum and maize, respectively. For both crops, a germinating rainfall followed by a 2-week dry period was more detrimental to stand establishment compared with the seed lying in dry soil for 15 days. Long-term climatic data for eight locations were analyzed to evaluate three types of risk: 1) germinating rainfall was followed by an extended dry period; 2) seed stayed in dry soil for more than 20 days; and 3) rainfall resulted in the Vertisols being too wet to work and in excessively delayed planting. The analysis was for eight locations representing Vertisols throughout Ethiopia. Probability of the first risk occurring ranged from 0 to 80% and declined with time. The probability of the second and third risks ranged from 15-75% and from 0 to 69%, and both increased with time. Therefore, some risk was always present but a less risky time period was identified for each location providing a basis for advising farmers on the timing of dry soil planting.