| Composting Busumbu Phosphate Rock (BPR), a residual igneous phosphate rock, with organic materials of Lantana camara, Calliandra calothyrsus, Tithonia diversifolia and bagasse sugarcane waste was investigated through laboratory incubations and/or field trials in Eastern Uganda. In laboratory experiments, composting BPR with organic materials did not result in significant increases in bicarbonate extractable total phosphorus, implying no enhanced dissolution of the BPR when composted with organic materials. Bean ( Phaseolus vulgaris L.) responses grown with Lantana, Tithonia or BPR applications indicated trends of yield increases, however differences were not significant. In the field study only triple super phosphate (TSP) produced statistically significant higher yields, higher P uptake of the bean crop and higher available P in the soil. The phosphorus content of beans resulted in trends towards elevated levels in response to BPR+( Lantana or Tithonia) compost as compared to organic materials alone. However these increases were not significant, Both Tithonia and Lantana composts resulted in increasing trends in bean yield even at low nutrient application rates (<10kg P ha-1). |
