Assessing Phosphorus Availability in a High pH, Biochar Amended Soil under Inorganic and Organic Fertilization

Abstract

Phosphorous remains as one of the most limiting nutrients to plant growth, second only to nitrogen. Research on use of biochar as a soil amendment for available phosphorus in temperate calcareous soils has limited studies compared with to tropical acidic soils. An incubation experiment to assess phosphorous availability in a biochar amended calcareous soil under inorganic (Fused superphosphate, FSP) and organic fertilizer (bone meal, BM) and respectively, at the dose of 40, 80 and 120 mg P kg-1 was carried out. Soil was incubated at 25oC for 70 days. Results show that the rate of increase in available P was proportional to the fertilizer application rate with or without biochar amendment. Biochar did not have a significant effect on soils amended with either fertilizer on the values of available P. However, time had a significant effect (p<0.001) on the amount of available P during the incubation period. Inorganic fertilizer treatments had recorded high amount of available P with time compared to organic fertilizer treatments. Organic fertilizer treatment sample were significantly not different from control and for most of the incubation time biochar acted as a soil conditioner. Further research is required to understand the holistic and long-term effect of biochar.