Effect of Mulching and Tied Ridge on Crop Production and Soil Improvement in Dry Land Areas

Abstract

Rain fed crop production in dryland areas is unreliable due to high evapo-transpiration, high run-off rates, delay onset, and early cessation of rains. So soil moisture deficiency is one of the primary factors that limit crop production in the area. Soil conservation is another important issue in dryland areas because high run-off rates leads to severe soil erosion. Due to shortage of soil moisture there have been attempts to optimize crop yield by planting drought-tolerant crops, particularly maize, sorghum and millet. This is not enough because crop failure due to water stress is still observed in dry lands. Therefore the proper use of soil moisture conservation structures like tied ridge helps to reduce the runoff rate, nutrient losses from soil and improve the soil moisture for plant growth which in turn, boost the productivity of land and plants. In addition to tied ridge mulching is a good practice used to reduce soil erosion and enhance water conservation. Tied ridge is one of the structures used to reduce water runoff and increase infiltration of rain water to the soil. It is a form of micro-basin tillage which consists of ridging the soil typically to heights of 0.20 to 0.30 m and is blocked with earth ties spaced considering slope of the land. Tied-ridging increased soil water by more than 25% compared to the traditional tillage practice in northern Ethiopia. It has been reported that tied ridging is beneficial for increasing crop yield. Tied-ridging increased sorghum grain yield by more than 40% compared to the traditional tillage practice in northern Ethiopia. It has beneficial effects of reducing runoff loss and soil loss. Mulching is also on the positive side of the balance in dry land. When adequate residues are available and conservation tillage is used, soil erosion is greatly reduced and water conservation is enhanced. Management of crop residues on the farm lands increased the grain yields of maize, sorghum and wheat crops both by improving soil fertility and conserving water at Haramaya area. Mulch conserved more water and led to higher dry matter and grain yields of maize compared to minimum tillage.