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

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (13) Citing Articles via Google Scholar Google Scholar Articles by Wang, X. Articles by Linquist, B.A. Search for Related Content PubMed Articles by Wang, X. Articles by Linquist, B.A. GeoRef GeoRef Citation Agricola Articles by Wang, X. Articles by Linquist, B.A.

DIVISION S-4-SOIL FERTILITY & PLANT NUTRITION

Soil Aggregate Size Affects Phosphorus Desorption from Highly Weathered Soils and Plant Growth

^a Dep. of Tropical Plant and Soil Sciences, Univ. of Hawaii, Honolulu, HI, 96822
^b International Rice Research Institute, P.O. Box 933, Manila 1099, Philippines

Corresponding author (rsyost{at}hawaii.edu)

Because plant absorption of P depends on the desorption of P from soil, understanding P desorption from soils may improve the precision of P diagnosis and fertilization recommendations. Many soils with high P retention due to high levels of Fe and Al are also highly aggregated. Extractable P is sometimes higher on larger size aggregates, which will probably result in increased P release from aggregates. The effects of aggregate size on P availability of three highly weathered soils were quantified with a column-leaching study and a pot experiment. Phosphorus desorption by leaching from small aggregates was greater than that from large aggregates when P had been added to the bulk soil (Kapaa and Leilehua soils) and a mixture of different-sized aggregates (Leilehua soil). When aggregates were separated and then P added, however, P desorption was greater from large aggregates (4–6 mm) than from small aggregates (<0.5 mm). Conformity of the P desorption data to the parabolic diffusion and expanded Elovich equations suggests that P desorption is probably controlled by diffusion processes. A pot experiment showed that total P in lettuce (Lactuca sativa L.) and soybean [Glycine max (L.) Merr.] shoots, and the root dry weights of plants grown in the large aggregates (2–6 mm) were higher than for plants grown in the small aggregates (<0.5 mm) after equal amounts of P were added to the separated aggregate fractions. Increased P uptake with increased aggregate size was attributed to increased P release from aggregates because of reduced P fixation. The results suggest that soil management that favors soil aggregation may, in some cases, increase availability of applied P. Perhaps the distribution of soil aggregates should be considered in making P management decisions.

Abbreviations: Delta P, difference in extractable P between before planting and after planting • GMD, geometric mean diameter • SE, standard error

This article has been cited by other articles:

				M. K. Zhang, Z. L. He, D. V. Calvert, P. J. Stoffella, X. E. Yang, and Y. C. Li Phosphorus and Heavy Metal Attachment and Release in Sandy Soil Aggregate Fractions Soil Sci. Soc. Am. J., July 1, 2003; 67(4): 1158 - 1167. [Abstract] [Full Text] [PDF]

				A. Dobermann, T. George, and N. Thevs Phosphorus Fertilizer Effects on Soil Phosphorus Pools in Acid Upland Soils Soil Sci. Soc. Am. J., March 1, 2002; 66(2): 652 - 660. [Abstract] [Full Text] [PDF]