Uptake and Distribution of Nutrients by Yams (Dioscorea spp.) in Western Nigeria

Abstract

The nutrient composition of leaves and petioles of three yam species were studied at fortnightly intervals, and in the tubers when harvested at maturity. Highest concentrations of plant nutrients were recorded in D. alata, while D. cqyenensis had the lowest. The lamina was more appropriate for determination of N and P contents, while the petiole was more satisfactory for K. Peak nutrient concentration occurred between late June and early July, suggesting that that was the period of maximum demand for nutrients. The dependence of yields on nutrients was demonstrated.

Produtividade do inhame em função de fertilização orgânica e mineral e de épocas de colheita

“…Freqüentemente são empregados materiais orgânicos na sua adubação sendo ainda pouco estudada a relação entre a fertilização orgâ-nica e a produtividade. A matéria orgâ-nica presente no solo, por meio do processo de mineralização, fornece principalmente nitrogênio, fósforo, enxofre e micronutrientes para as plantas e microflora do solo (Kiehl, 1985;Oliveira Filho et al, 1987).…”

“…Estudos desenvolvidos sobre a absorção de nutrientes por inhame mostraram que o nitrogênio e o potássio são os principais nutrientes removidos pela cultura, seguidos do cálcio e do fósforo e que ocorrem mudanças notáveis na composição mineral das folhas durante suas fases de crescimento, com o conteúdo de N e K aumentando continuamente até o quinto mês após o plantio e atingindo o seu pico durante o sexto mês para depois diminuir, correspondendo assim ao tempo de máxima atividade de crescimento e de maior demanda por nutrientes (Obigbesan & Agboola, 1978).…”

Nitrogen Use by Yam as Affected by Mineral Fertilizer Application

“…To reduce the risk of soil nutrient mining by these high‐yielding cultivars, fertilizer recommendations need to be developed and tested. When harvested, yams remove 3 to 5 kg N, 0.3 to 0.5 kg P, and 3 to 6 kg K Mg −1 of tuber fresh matter (Sobulo, 1972a, 1972b; Le Buanec, 1973; Obigbesan and Agboola, 1978; Ferguson et al, 1980; Budelman, 1989; Rodriguez et al, 1989; Degras, 1993; Diby, 2005). The amount of nutrients returned to the soil from senescent organs remains unknown, however.…”

“…The amount of nutrients returned to the soil from senescent organs remains unknown, however. While the concentration of nutrients has been measured in other plant organs, e.g., by Sobulo (1972a, 1972b), Obigbesan and Agboola (1978), Aduayi and Okpon (1980), Irizarry and Rivera (1985), O'Sullivan and Jenner (2006), O'Sullivan et al (2008), and Law‐Ogbomo and Remison (2009), these data have rarely been used to quantify the total nutrient uptake by yams at different stages of crop growth (Sobulo, 1972a), making it difficult to assess what the maximum nutrient need would be and when it would be reached during the growing season. This, in turn, would be important for the timing of fertilizer addition.…”

“…Thus the aim of this research was to determine the fate of 160 kg N ha −1 applied to D. alata together with sufficient P and K. The relatively high N input used in this study was calculated from published data (Le Buanec 1973; Obigbesan and Agboola, 1978; Rodriguez et al, 1989) so as to cover the amount of N to be exported by a tuber yield of 40 Mg fresh matter ha −1 . More specifically, this work aimed at assessing (i) the amount of N taken up by yam that was derived from the soil and from the fertilizer during the entire growth season, (ii) the maximum amount of N needed by the plant, and (iii) the time at which the maximum need was observed.…”