Strategies of African Indigenous Vegetables to Cope with Phosphorus Deficient Soils
Loading...
Date
2016
Authors
Nyaga, Elizabeth Kabura
Nambafu, Godfrey N.
Anyuka, Enos W.
Bessler, Holger
Hoeppner, Nicolai
Andika, Darius O.
Gweyi-Onyango, Joseph P.
Mwonga, Samuel
Engels, Christof
Journal Title
Journal ISSN
Volume Title
Publisher
Tropentag
Abstract
Food production in smallholder farming systems of sub-Saharan Africa is often constrained by low
soil contents of plant-available phosphorus (P). An option to increase food production is cultivation
of species with high P efficiency. Plant strategies to improve growth and P acquisition on low P soils
include root foraging strategies to improve spatial soil exploitation, P mining strategies to enhance
desorption, solubilisation or mineralisation, and improving internal P utilisation efficiency.
The aim of this study was to measure plant responses to low P availability in soil and to determine
if there is variation among African indigenous vegetables (AIV) in their ability to use organic
phosphate and sparingly soluble P forms.
Six AIV species (Spider plant Cleome gynandra, African nightshade Solanum scabrum, Amaranthus
Amaranthus cruentus, Cowpea Vigna unguiculata, African kale Brassica carinata, Common
kale Brassica oleracea) were cultivated under controlled conditions in pots on a low P substrate.
The substrate was amended with P using four different forms (highly soluble K2HPO4, sparingly
soluble FePO4 or phosphate rock, phytate). Measurements included biomass and P concentration
in shoots and roots, morphological root traits (root length and diameter, root hair density) and
substrate characteristics (pH, content of soluble P) after harvest.
The AIV species significantly differed in morphological root traits and rhizosphere pH, and in
the responses of morphological root traits to different P treatments. For example in average of all
P levels rhizosphere pH varied from 3.9 in Amaranthus to 6.0 in African kale. All species were
able to use P from phytate as effectively for biomass formation as P from K2HPO4. The efficiency
for utilisation of sparingly soluble P forms (either FePO4 or rock phosphate) was low in African
nightshade and Spider plant, and high in Amaranthus and African kale. Cowpea was efficient in
utilisation of P from rock phosphate but not from FePO4.
The data indicate large variation among AIV species in root traits relevant for P acquisition and
their ability to use soil P from different sparingly soluble P forms. This information may be used
for site-specific recommendation of species best adapted to low P soils.
Description
A conference Paper
Keywords
P acquisition, Phosphate rock, Phytate, Rhizosphere pH, Root morphology