Abstract
The influence of soil pH on the dissolution of phosphate rock fertilizers was investigated in laboratory experiments with reactive North Carolina phosphate rock (PR) in a lateritic soil adjusted to several pH values. Increased soil pH resulted in decreased dissolution as estimated by the increase in exchangeable calcium (ΔCa) method. The extent of PR dissolution was related to soil pH by an equation of the form Log ΔCa = a–b pH, and it increased with contact period and rate of PR application. Increased plant available P, as estimated by NaHCO3 soluble-P (ΔBicP) was about one third of the P dissolved from PR. ΔBicP was related to soil pH by an equation of the form Log ΔBic P = c–d pH. Dissolution of PR in soil can be considered as a simple chemical reaction between apatite and hydrogen ions supplied by soil constituents.
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Kanabo, I.A.K., Gilkes, R.J. The role of soil pH in the dissolution of phosphate rock fertilizers. Fertilizer Research 12, 165–173 (1987). https://doi.org/10.1007/BF01048916
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DOI: https://doi.org/10.1007/BF01048916