Evaluating the productivity and economic benefits of cereal-legume intercropping with and without supplementary irrigation in the semi-arid highlands of Tigray, Ethiopia

Farmers in the northern dryland areas of Ethiopia practice a cereal based rainfed crop-livestock mixed farming and are predominantly rainfed. However, low soil fertility and limited water availability are the major hampering factors to crop production thus poverty and food shortage is evident to the ever increasing population. Comprehensive integration of n-fixing leguminous species with cereals supported with supplementary irrigation could greatly improve soil fertility, moisture availability and increase livestock feed-base, resulting in increased production and productivity. In line with this, a study was conducted at Mekelle University main campus, located in the northern highlands of Ethiopia to evaluate the economic and agronomic performance of cereal-legume intercropping under rainfed conditions and with supplementary irrigation, during the 2015/16 rainfall season. Wheat (Triticum aestivum L.) was intercropped with lentil (Lens culinaris Medik) and dekoko (psium aestivum var. abyssinicum) in a solitary ratio and supplemented with irrigation. The experiment was laid in a split-plot design with three replications under traditional management practices. Each of the crops were grown in single-stand for comparison. The results from analysis of variance indicated that intercropping increased significantly the grain yield of wheat up to 30.5% under rainfed conditions in wheat-lentil mixture and a noticeable yield increase was also noted in wheat-dekoko intercropping, nevertheless, supplementary irrigation increased the yields by up to 100%. Yield reduction in legumes was compensated by higher cumulative yield per unit area. This was reflected in the higher LER (1.83 and 2.38) and LEC (0.82 and 1.34) registered for wheat-lentil intercropping under rainfed and supplementary irrigation respectively. Monetary equivalent index (MAI) for wheat-lentil were7,937.2 ETB and 20,642 ETB for rainfed and supplementary irrigation respectively. It was concluded that intercropping provided more advantage to sole cropping, both in terms of total yield per unit area and profitability. However, wheat-lentil combination is recommended for the area since it showed minimum interspecific competition, higher yield as well as economic viability. Wheat-dekoko was overall more profitable both under rainfed and supplementary irrigation.