Skip-row planting and tie-ridging for sorghum production in semiarid areas of Ethiopia

Soil water deficits during grain fill have been estimated to reduce sorghum [Sorghum bicolor (L.) Moench] grain production in Ethiopia by 300,000 Mg yr^-1. The potential for skip-row planting and its integration with tie-ridging was evaluated for increasing sorghum grain yield in Ethiopia. Skip-row planting is a means of saving soil water for the grain-fill period while tie-ridging is intended to improve soil water availability by reducing runoff. The skip-row treatments were: no skipped rows (S0:0); one planted alternated with one skipped row (S1:1); two planted alternated with two skipped rows (S2:2); and two planted alternated with one skipped row (S2:1). The tillage treatments were flat tillage and tie-ridging. Eight trials were conducted. Grain yield in northern Ethiopia was 50% more with S2:1 compared with S0:0. There was no grain yield advantage to S1:1 compared with planting all rows and a yield loss with S2:2. In northern Ethiopia, there was also a grain yield increase with tie-ridging compared with flat tillage and a positive interaction between tie-ridging and skip-row planting. Striga [Striga hermonthica (Delile.) Benth. and Striga asiatica (L.) Kuntze] infestation in northern Ethiopia was reduced by 70% through a combination of tie-ridging, skip-row planting, and variety choice. Tie-ridging and skip-row planting did not result in increased grain yield in central Ethiopia. The results of this research support the use of tie-ridging and S2:1 planting where serious striga infestation and severe late-season stress caused by soil water deficits are common such as in northern Ethiopia.