Funso Kutu, Phatudi Timothy Mahlokoane and Irvine Kwaramba Mariga, Plant Production, Soil Science and Agricultural Engineering, University of Limpopo (Turfloop Campus), Sovenga, South Africa
Compost production and utitilization is considered an essential waste management strategy with significant social and agricultural benefits if well prepared prior to utilization. However, the low phosphorus (P) content and mineralization from composts often leads to expensive inorganic P supplementation to satisfy crop demand. Co-composting technology process was utilized to improve the P content of cattle and goat manure-based composts as well as improve the P mineralization from South Africa’s non-reactive ground phosphate rock. The resulting phospho-composts of variable mix ratios (0:10, 2:8, 3:7, 1:9 and 5:5) were evaluated along with inorganic fertilizer and unamended control under greenhouse condition using maize as test crop. The use of phospho-composts resulted in better maize performance than the pure compost while the 2:8 phospho-compost mix ratio gave significantly (P<0.05) and consistently higher dry maize biomass than other treatments. Results of mineralization study revealed that higher P was released from the 3:7 mix ratio in the two forms of phospho-composts during the first 14 days of incubation. Ongoing investigations are expected to validate the current findings and reveal the possible commercialization of phospho-composting technology as a strategy for ameliorating the widespread P deficiency problem mostly noticeable on small-holding farmlands in South Africa. Such findings will also constitute value addition for the production of P-rich organic wastes utilization in crop production through improved nutrient recycling strategy.
Keywords: Ground phosphate rock, Maize yield, Phospho-composting technology, P mineralization, P uptake