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).
