ABSTRACT
Crop production in Sub-Saharan Africa is primarily limited by soil fertility decline. In view of this, the fertilizer value of locally available organic materials (OMs) was assessed for their nutrient release to crop growth. Crop residues and farmyard manure (FYM) were evaluated along with mineral fertilizers to grow a test crop maize variety – Gibe 2. The maize allometric parameters, nutrient ratios (NRs), nutrient recovery (NRy) and mineral fertilizer equivalency (MFE) were used to assess the mineral fertilizer value (MFV) of OMs. MFE of OMs was estimated as the available mineral N and P out of the fraction of total nitrogen and phosphorus applied relative to mineral fertilizers supply. The results revealed that maize allometry, NRy and MFE were significantly influenced by fertilizer sources. OM amendment resulted in poor maize allometry and low NRy. Interestingly, MFE of OM amended ranged from −201% with chickpea (CHP) residue to 63% with FYM. The results demonstrate that CHP has the poorest quality, while FYM is a good-quality OM as a fertilizer source.
ACKNOWLEDGEMENTS
The study was financially supported by the International Foundation for Science (IFS) through small competitive grant scheme. The author also thanks Mr. Samson Henta and Mr. Dereje Haile who provided technical support during the execution of the experiment. The author sincerely acknowledges Dr. Wakene Negassa for his quite detailed and constructive comments and suggestions.
Disclosure statement
No potential conflict of interest was reported by the author.