Nutrient Fluxes from Soil to Market in African Indigenous Vegetables Production System
Godfrey Nambafu1, Anna Adam1, Enos Onyuka1, Holger Bessler1, Darius O. Andika2, Samuel Mwonga3, Joseph Patrick Gweyi-Onyango4, Christof Engels1
1Humboldt-Universität zu Berlin, Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences (ADTI), Germany
In many smallholder farming systems in sub-Saharan Africa, nutrient supply is either too low leading to soil fertility decline due to soil mining or too high leading to environmental pollution. The aim of our study was the quantification of mineral nutrient transfer from soil to market in African indigenous vegetable (AIV) production systems as guide for development of fertiliser recommendations. In a field experiment under optimal nutrient supply, we measured biomass and mineral nutrient concentrations (nitrogen, phosphorus, sulfur, potassium, magnesium, calcium) of edible (leaves, tender laterals) and non-edible (stems, coarse roots, fine roots) plant organs of six leafy vegetable species (amaranthus Amaranthus cruentus, cowpea Vigna unguiculata, African kale Brassica carinata, African nightshade Solanum scabrum, spider plant Cleome gynandra, common kale Brassica oleracea acephala). In a “batch system”, plants were completely harvested five weeks after transplanting. In a “continuous system”, plants stayed in the field for 15 weeks whereby sprouts were harvested every five weeks. Plants were harvested by pulling out or cutting five cm above soil surface or cutting edible organs only.
Keywords: Fertiliser need, harvesting technique, leafy vegetables
Contact Address: Christof Engels, Humboldt-Universität zu Berlin, Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences (ADTI), Berlin, Germany, e-mail: christof.engelsagrar.hu-berlin.de