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 HighWire Citing Articles via Google Scholar Google Scholar Articles by Alberts, E. E. Articles by Moldenhauer, W. C. Search for Related Content PubMed Articles by Alberts, E. E. Articles by Moldenhauer, W. C. Agricola Articles by Alberts, E. E. Articles by Moldenhauer, W. C.

Nitrogen and Phosphorus Transported by Eroded Soil Aggregates¹

ABSTRACT

Most mathematical models that are being developed to predict sediment discharges from farm fields, watersheds, and basins consider the detachment, transport, and deposition of soil aggregates. This study was conducted to determine the effect of three tillage treatments and two cornstalk residue levels on the size distribution and N and P concentrations of eroded soil aggregates. Measurements were made by applying simulated rainfall to 3.7 by 10.7 m plots located on a silt loam soil in north central Indiana.

Over 60% of the sediment from moldboard-plowed and disked-only plots was composed of aggregates > 0.05 mm, whereas about 30% of the sediment from chisel-plowed plots was composed of aggregates > 0.05 mm. The addition of cornstalk residue to give 20% surface cover on the moldboard-plowed and disked-only plots decreased the percentage of >0.05-mm aggregates by about 12%.

Nitrogen and P concentrations of the 2- to 1-, 1- to 0.5-, and 0.5- to 0.21-mm aggregates were generally 10% lower than the N and P concentrations of the aggregates <0.05 mm. The highest N and P concentrations were associated with the 0.21- to 0.05-mm aggregates. However, this size fraction represented a small percentage of the eroded particles.

Nitrogen and P concentrations of aggregates eroded from the chisel-plowed plots were about 40% higher than the N and P concentrations of the aggregates eroded from the moldboard-plowed plots. Differences in N and P concentrations reflected differences in the transport capacity of the runoff. As increased residue cover reduced runoff velocity, only those aggregates of lower densities and sand contents were transported. As a result, aggregates eroded from chisel-plowed plots contained a greater proportion of silt and clay which was reflected in their higher N and P concentrations than did aggregates eroded from moldboard-plowed plots.

Nitrogen and P concentrations of uneroded aggregates separated by wet sieving were determined and compared with the N and P concentrations of the eroded aggregates. Enrichment ratios were > 1.0, which indicated that nutrient enrichment occurred for all size fractions of eroded aggregates.

¹ Contribution from the USDA-SEA-AR, Soil, Water & Air Sciences, North Central Region, in cooperation with the Purdue Agric. Exp. Stn. Purdue Journal Paper no. 8001.

² Soil Scientist, USDA, Columbia, MO 65201 (formerly West Lafayette, IN); and Soil Scientist, USDA, and Professor of Agronomy, Purdue Univ., West Lafayette, Ind.

Received for publication August 11, 1980. Accepted for publication November 5, 1980.

This article has been cited by other articles:

				J. D. Grande, K. G. Karthikeyan, P. S. Miller, and J. M. Powell Corn Residue Level and Manure Application Timing Effects on Phosphorus Losses in Runoff J. Environ. Qual., August 9, 2005; 34(5): 1620 - 1631. [Abstract] [Full Text] [PDF]

				J. D. Grande, K. G. Karthikeyan, P. S. Miller, and J. M. Powell Residue Level and Manure Application Timing Effects on Runoff and Sediment Losses J. Environ. Qual., July 5, 2005; 34(4): 1337 - 1346. [Abstract] [Full Text] [PDF]