Effects of Organic and Inorganic Materials on Soil Acidity and Phosphorus Availability in a Soil Incubation Study

Figure 1

Increase in Olsen P above the control treatment as affected by tithonia and TSP at Bukura. Note: “combined appl.” refers to the observed increase in Olsen P above the control obtained when tithonia (at 20 kg P ha⁻¹) was applied in combination with TSP (at 40 kg P ha⁻¹), while “individual appl.” refers to the increase in Olsen P above the control obtained when tithonia, applied alone at 20 kg P ha⁻¹, was added to the increase in Olsen P above the control obtained when TSP was applied alone at 40 kg P ha⁻¹.