Optimum limestone rates for improved soil fertility and Potato (Solanum tuberosum L.) Yield in two agroecologies zones of Cameroon

Potato (Solanum tuberosum L.) is a high demanding crop in terms of nutrient requirements. In Cameroon soil fertility is poorly managed and lead to very low yield. This study estimates the limestone rate required for sustainable soil management and improved potato production in two main potatoes producing agroecological zones (AEZ). Two field experiments carried out in two villages namely Wassande (Guinean high savannah zone (AEZII)) and Bangou (Western Highlands zone (AEZ III)) consisted to plant potato genotypes Dosa and Jacob2005 on a split plot design including unfertilized, NPK-fertilized and NPK+manure-fertilized soils in which limestone was applied 4 weeks before, at 1, 2, 3, 4 and 5 t.ha-1(ton per hectare) rates. Data were collected on soil physico-chemical properties and potato yield. Limestone rate increased soil pH (hydrogen potential), organic matter (MO) content, cation exchangeable capacity (CEC) as well as sum of exchangeable bases (SEB), and decreased the Al (aluminum) content. P(phosphorus) and Ca (calcium) content Should be increased with limestone rate but decreased at 5 t.ha-1. Potato yield increased with limestone rate on unfertilized soil in both sites. On fertilized soils, the optimum limestone rate was 3 t.ha-1 in Wassande and 4 t.ha-1in Bangou. There was no significant difference between NPK and NPK+manure fertilized soils at higher limestone rates (3-5 t.ha-1) in Wassande, whereas in Bangou, the highest yield was obtained with NPK+manure. Genotype Dosa performed better than Jacob2005 in Wassande but less in Bangou than Jacob2005. The best performance was obtained with 3 t.ha-1 of limestone in Wassande and 4 t.ha-1 in Bangou.