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Volume 10, Pages 1498-1508
Research Article

Phosphorus Leaching in an Acid Tropical Soil “Recapitalized” with Phosphate Rock and Triple Superphosphate

1Kenya Agricultural Research Institute, Kabete, Nairobi, Kenya
2Institute of Tropical Agriculture, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
3Department of Land Management, Universiti Putra Malaysia, Serdang, Selangor, Malaysia

Received 17 December 2009; Revised 8 July 2010; Accepted 9 July 2010

Academic Editor: Ahmet R. Mermut

Copyright © 2010 E. Gikonyo et al.


With high rates of phosphorus applied to increase “capital P” as a stock for plant uptake over several years, the question of P leaching is inevitable. We conducted an intact soil column experiment in the field to evaluate P leached from soils treated with triple superphosphate (TSP) and Gafsa phosphate rock (GPR) at 300, 600, and 900 kg P ha-1 with and without integration of cattle manure. The lysimeters, made from PVC tubes of 30-cm length, were inserted into the soil up to the 25-cm depth. The tubes were fitted with a resin bag containing a mixture of cation and anion exchange resin (50:50) at the lower end of the tube inserted into the soil. The tubes, arranged in a completely randomized design, were sampled randomly at 10-week intervals for 12 months. Phosphorus extractable from the top- and subsoil at the end of experiment and leached P were determined. More P was leached out from TSP (threefold) compared to GPR, and the amount of P leached increased with increasing rates of P fertilizer applied. Application of manure intensified the amounts of P leached from TSP, particularly at the 6-month sampling time. There was hardly any substantial P leached from the soil treated with GPR. Thus, for effective and efficient long-term P fertilizer management strategies, choosing the right P fertilizer source and monitoring P losses through leaching has to be done for enhanced fertilizer use efficiency and thus reducing P pollution of ground waters.