HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Sanchez, P. A. Articles by Briones, A. M. Search for Related Content PubMed Articles by Sanchez, P. A. Articles by Briones, A. M. Agricola Articles by Sanchez, P. A. Articles by Briones, A. M.

Phosphorus Availability of Some Philippine Rice Soils as Affected by Soil and Water Management Practices¹

It is well established that flooding increases the availability of soil P to rice (Oryza sativa L.). Very little is known, however, on the influence of native soil P status or the type of water management used on the growth and P uptake of this crop. Also, the interaction between these two factors is unknown. In order to clarify these relationships, two greenhouse experiments were conducted on six representative Philippine lowland rice soils. The results indicate that the beneficial effects of flooding to rice vary with the level of available soil P, as measured by P uptake. In soils of high P availability, no differences were observed when rice was grown under constant flooding, on a partially oxidized profile or when flooding was delayed from 15 to 35 days after seeding. The latter two treatments produced lower yields and P uptake in comparison to constant flooding in soils of moderate to low P availability. When severe water stress occurred, rice growth, yield, and P uptake drastically decreased in all soils regardless of P availability. Puddling flooded soils has no effect on rice yields or P uptake at harvest regardless of soil P availability. Puddling unflooded soils severely decreased growth and responses to applied P when severe soil shrinkage took place. The benefits of flooding on P uptake by rice depend both on the available P level and the type of water management used.

Key Words: P uptake • Flooding • Water stress • Oxidation reduction potentials

² Former Graduate Assistant, Agronomy Department, Cornell University (now Assistant Professor, Soil Science Department, North Carolina State University, Raleigh, N. C. 27607).

³ Former Graduate Assistant (now Assistant Professor, Department of Soils, University of the Philippines, Los Baños, Philippines).

Received for publication May 8, 1972.