Effect of hill shaping on phosphate fixation in different west indian soil types
Chevignard, T.; Fardeau J C.; Doulbeau Piasco, S.; Feller, C.; Turenne J F.; Vallerie, M.
Agronomie 6(2): 149-156
ISSN/ISBN: 0249-5627 Accession: 005244071
Levelling of the soil for mechanical agriculture brings to the top soil a layer poor or very poor in organic matter content. Experiments were conducted by isotope methods to analyse the phosphate fertility of some typical West Indian soils. It was concluded that all the soils were not only poor in available soil phosphorus but also had a very high fixing capacity for phosphate ions, and that the fixing capacity of top soil for phosphorus was lower than for the subsoil. This observation explains the increased fixing capacity of the soils modified by hill shaping. A positive effect of organic matter appears from the comparison of different soil types. The more water-soluble P fertilizers, such as diammonium phosphate, were fixed very quickly: 96% in 24 h. For this reason and due to soil acidity, the use of soft rock-phosphates remains the best choice for phosphate fertilization.