Phosphorus fertilization effect on dry matter production and biomass partitioning in sweet potato (Ipomoea batatas) grown on an acidic loamy-sand Alfisol

Author: Ezekiel Akinkunmi Akinrinde

Received 4 July 2006, accepted 17 October 2006.

Abstract

Augmentation of soil available phosphorus (P) is often essential to reverse the acid infertility conditions of most tropical soils, especially when arable crop growers prefer tubers or grains to excessive vine and leaf production. As part of the ultimate goal to recommend fertilizer use for crop production on a medium acid (pH 5.8) luvisol/alfisol (Typic Paleustalf), this study sought to evaluate the effect of P fertilization on the dry matter (DM) production and biomass partitioning at successive growth periods of sweet potato (Ipomoea batatas) grown on the benchmark soil type. The plants were treated to three levels (0, 30 and 60 kg/ha) of P using single super phosphate, SSP (9% P). The treatments were replicated three times to give a total of nine experimental field plots in randomised complete block design. The changes in DM contribution of the plant parts (vine, root, petiole, lamina and tuber) after 3, 5, 7, 9, 11 and 13 weeks of growth were evaluated. Lamina, tuber and vine contributed most of the crop’s dry biomass at each of the P application levels and sampling periods while the seed stock contributed the least. The highest P contents in the lamina were recorded at the 5th, 9th and 7th weeks after planting (WAP) for the P 0, 30 and 60 kg/ha treatments, respectively while DM production was at its respective peaks during the last sampling period (13 WAP). Maximum production of tuber and lamina was at P 30 and 60 kg/ha, respectively. The short- and long-term responses to SSP (compared with some other fertilizer materials) by selected cultivars of the crop need to be ascertained in future studies.