Improvement of Sweet potato ( Ipomoea batatas (L.) Lam) Production with Fertilizer and Organic Inputs in Rwanda

Sweet potato (Ipomoea batatas (L.) Lam) is one of the staple food crops for the Rwandese population with yields varying from 7 to 8 Mg/ha. Continuous land cultivation has resulted in nutrient depletion to an extent that further increase in productivity will require external nutrients. New high yielding sweet potato cultivars have been screened and tested for their response to fertilizer and lime and organic inputs in the main agroecological zones of Rwanda. Due to a period of institutional instability, some important results from 1980 to 1982 could not be published as yet. These data showed that each agroecological zone has its most adapted cultivar(s) and that the use of fertilizer/organic inputs improved yields. However, the high rates of fertilizer/organic inputs applied on the selected sweet potato cultivars had not led to the maximum yield. The effect of these inputs was highly influenced by crop husbandry and health, climatic conditions during the growth period, and soil properties of the experimental plots. Agroecological conditions are masking the cultivars’ capacity to fully respond to fertilizer/organic inputs. It is recommended that types and rates of fertilizer/organic inputs be determined according to the types and levels of soil fertility.