Dry Soil Planting of Sorghum for Vertisols of Ethiopia

Abstract

Soil water deficits constrain productivity in Ethiopia. Farmers respond to variable onset of rain in the Central Rift Valley (CRV) of Ethiopia by dry soil planting sorghum [Sorghum bicolor (L.) Moench] to take advantage of early rains and increase the period of crop growth before rains cease in late September or early October. Crop establishment is often unsatisfactory. The effect of dry soil planting depth for sorghum was evaluated with three water deficit scenarios on Vertisols in CRV. Dry soil planting at 5‐cm depth resulted in relatively better seedling emergence, plant survival, individual plant wt., and leaf plant−1 for all water regimes as compared with other dry planting depths. The best plant establishment (80%) occurred with a local variety planted at 5‐cm depth with no water applied for 15 d after dry soil planting followed by 30 mm applied at 5‐d intervals from 15 to 30 d after planting (W3). The worst establishment (12%) was with planting at 7‐cm depth and irrigating after planting with 30 mm of water and then adding 30 mm at 5‐d intervals from 15 to 30 d after planting (W1). Risk of failed crop establishment with dry soil planting on a Vertisol is less with 5 cm compared with other planting depths. The W3 type of water deficit, with seed lying in dry soil for 15 d before water was applied, is less detrimental to sorghum establishment and early growth, compared with rainfall after planting followed by a dry period of 15 d.