Phosphorus Supplying Capacity of Lowland Rice Soils1
- S. K. DeDatta,
- J. C. Moomaw,
- V. V. Racho and
- G. V. Simsiman2
In a greenhouse experiment with rice (Oryza sativa L.) on four lowland soils, Milfor 6(2), an indica variety from the Philippines, was used to test the relative utilization of soil and fertilizer P (P32-labelled superphosphate) at various N rates. Added P remaining in solution in six soils was also determined using Ca (H2P32O4)2 at various equilibration times.
From 8 to 27% of the total P in the plant was derived from applied P, the amount presumably depending on the availability of soil P under continuous submergence. In general the amount derived was not affected by different levels of N fertilization. The results indicate that, by using the ‘A’ value concept, the rice plant itself gives an indication of the P supplying capacity of some flooded rice soils. Results also show that within 4 days of equilibration the added P remaining in solution was lowest in acid latosolic soils containing kaolin type minerals, moderately high in soils containing mainly montmorillonite, and essentially unaltered in calcareous soil.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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