Evaluation of different local lime sources on soil properties and yield of Irish potatoes (Solanum tuberosum L.) in Burera District, Rwanda

Abstract

Background and objective: Agriculture is the most important sector of the Rwandan economy. Irish potato (Solanum tuberosum.L) underpins Rwanda's food security but its production is threatened by widespread acidity in many parts of Rwanda. The problems of acid soils (pH less than 5) is widespread in the country occupying approximately 45% of the total arable land or covering about 60% of the highland areas (Beenart, 1999), which are the major growing areas of Irish potatoes. Potato requires a considerable amount of Nitrogen, and the continuous widespread use of Ammonium or urea based N fertilizers in a high rainfall environment contributes to acceleration of soil acidification (Brett et al., 2005). Acidity limits the fertility of soils through nutrient deficiencies (P, Ca and Mg) and the presence of phytotoxic nutrients such as soluble Al and Mn (Awad et al., 1976). Application of lime has been shown toreduce Al toxicity, improve pH, Ca, Mg and increase both P uptake in high P fixing soil and plant rooting system (Black, 1993).