Effect of Rock Phosphate, Lime and Green Manure on Growth and Yield of Maize in a Non Productive Niche of a Rhodic Ferralsol in Farmer’s Fields

Ferralsol and Acrisol soil types important for maize production in Western Kenya have low pH, phosphorus (P) and organic matter plus high levels of Al and Fe oxides that fix P. Minjingu rock phosphate (MRP), lime and green manure (Tithonia) that are cheap and locally available are recommended for use. The low solubility of MRP when directly applied and unavailability of adequate organic materials limits their use. An experiment was carried out in farmers' field to determine the interactive effect of combining MRP and Tithonia or lime in a degraded patch of Ferralsol soil in Western Kenya. The treatments; +/- MRP, +/- lime, +/- Tithonia, +Triple superphosphate (TSP) and their combinations were applied to maize in (4 x 5) m(2) plots. The field layout was in a completely randomized block design replicated four times. Plant height (eight weeks after emergence) and leaf number showed a significant interactive effect between: TSP x Tithonia (P <= 0.0001), TSP x Lime (P <= 0.001), MRP x Tithonia (P <= 0.05), Tithonia x TSP x Lime (P <= 0.005). Leaf area index (m(2) leaf m(-2)) was similarly was significantly affected by TSP (P <= 0.0001), lime (P <= 0.05), lime x TSP (P <= 0.0002) and TSP x Tithonia (P <= 0.0001) and lime x Tithonia x TSP (P <= 0.05). The significant treatments also affected were similarly observed in grain yield (t/ha) as TSP (2.5 t/ha), MRP (1.0 t/ha), lime x TSP (2.5 t/ha), TSP x Tithonia (2.9 t ha(-1)), Tithonia x TSP x lime (2.4). Hence combining TSP or MRP with Tithonia may be used to alleviate multiple problems in the degraded patches of Ferralsols.