The influence of phosphorus fertilization on growth and tuberization of sweet potato (ipomea batatas lamb)

Abstract

A study was conducted to investigate the effect of 4 P fertilizer levels on growth, tuberization and accumulation of nitrogen, phosphorus, potassium, calcium and magnesium in vines and tuberous roots of 2 sweet potato varieties during the short and long rains seasons (1981 - 1982). The variety Musinya produced significantly higher yields of vines than Gikanda but the latter produced significantly higher yield and more tuberous roots than the former in both seasons. Musinya accumulated more dry matter in vines than Gikanda whereas Gikanda accumulated significantly higher dry matter in tuberous roots than Musinya in both seasons. Gikanda accumulated significantly higher N, P, K and Ca in tuberous roots than Musinya in the short rains season and K and Mg.in the long rains. Musinya accumulated significantly higher Ca in vines than Gikanda whereas the latter accumulated higher N in vines than the former in the short rains season. Nitrogen P, K, Ca and Mg concentrations in vines were higher than in tuberous roots in both the short and long rains seasons. However, the accumulation of similar nutrients in vines and (xvii) tuberous roots were higher in samples collected in the short rains season than in the long rains. Phosphorus fertilizer application levels did not show any significant effect on growth and yield of vines and tuberous roots, dry matter and nutrient accumulation in vines and tuberous roots of both varieties in both seasons. Relationships between nutrient concentrations in vines and dry matter accumulation in vines and tuberous roots showed that higher N concentration in vines of both varieties tended to inhance dry rna tt.ere.ac cumu La.tLon in vines than in tuberous roots. Higher Ca concentration in vines tended to inhance dry matter accumulation in tuberous roots. Phosporus K and Mg concentrations in vines of both varieties showed differences in relationship with dry matter accumulation in vines and tuberous roots with both varieties and seasons."