Using Wood Ash to Ameliorate Acidity and Improve Phosphorus Availability in Soils Amended with Partially Decomposed Cattle or Chicken Manure

The application of partially decomposed animal manure can acidify the soil by nitrification and may cause problems with phosphorus (P) availability. This study investigated the influence of applying wood ash to two soils amended with partially decomposed cattle or chicken manure on pH and P. The treatments consisted of two soils, a clay loam and sandy loam, each amended with partially decomposed chicken or cattle manure applied at 0, 5, or 15 t ha−1, and wood ash was applied to each manure treatment at rates of 0 or 2 t ha−1. The addition of wood ash significantly increased pH, thereby making more P available in soil and maize (Zea mays L.) tissues for both soils after being amended by manure. Both chicken and cattle manure significantly increased all the measured variables compared to the unamended soils. These results suggest that wood ash is an important amendment that could be used to amend partially decomposed manure, thereby not jeopardizing P availability to crops.