Wheat yield and changes in some major soil variables as affected by gypsum application in the Central Ethiopian highland agricultural soils

Abstract

Field experiments were conducted in three locations: Arsi, East Shewa and West Shewa zones during 2014–16 aimed at exploring the influence of gypsum on wheat yield and soil properties. Results showed that gypsum application significantly increased wheat yield and affected soil composition. The applied highest rate of gypsum gave significantly higher wheat grain yield (**p < 0.01); and increased soil SO4-S and Ca2+ compared with the control variant (CK) and the lower gypsum rates. With applied highest rate of gypsum, grain yield advantage ranging from 93.3% at Berfeta Tokofa2, to 166.7% at Keteba2 sites compared with CK were obtained. While with applied nitrogen, percent grain yield advantages ranged from 68.8% at Wonji Gora, to 133.3% at Keteba2 sites compared with CK were obtained. The soil variables: sulfur, calcium, calcium saturation and saturation percent also showed dramatic changes after gypsum application. But, the contents of magnesium, potassium, sodium and phosphorus were reduced with the rate of gypsum applied. But, fertilizers urea and triple super phosphate (TSP) application increased soil phosphorus. Changes in soil pH due to gypsum were inconsistent or trendless. Overall, the significantly increasing wheat yield and enhanced soil composition signifies the role gypsum could play in organic farming in the country. However, as this was the on-farm experiment affected by multitude of factors, for proper recommendation and improvement of significance in the variables considered, it is therefore suggested that further works should be installed using controlled conditions and specialized laboratory techniques.