Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 7-Day Trial for You or Your Team.

Learn More →

Relating Extractable Soil Phosphorus to Phosphorus Losses in Runoff

Relating Extractable Soil Phosphorus to Phosphorus Losses in Runoff Phosphorus in agricultural runoff can cause accelerated lake and stream eutrophication. Where producers have applied P at rates exceeding crop uptake, soil P has sometimes become the main source of P in runoff. We hypothesized that soil test P (STP) correlation to dissolved reactive P (DRP) and bioavailable P (BAP) in runoff varies, depending on the extraction method. To investigate which STP extraction method would be best for predicting DRP and BAP concentration and load in runoff, soil samples were taken from the 0‐ to 2‐cm depth of 54 grass plots (5% slopes) on Captina silt loam (fine‐silty, siliceous, mesic Typic Fragiudult). The STP was extracted by six methods and the ranges of results (mg kg−1) were: 54–490 (Mehlich III), 27–592 (Bray‐Kurtz P1), 25–169 (Olsen), 14–110 (distilled water), 23–170 (Fe oxide paper), and 105–1131 (acidified ammonium oxalate). The soil P saturation ranged from 16 to 80%. Simulated rain was applied at 100 mm h−1 and runoff was collected for 30 min. The concentration of DRP in total runoff ranged from 0.31 to 1.81 mg L−1, and BAP from 0.37 to 2.18 mg L−1. The r2 values for STP by each extraction method correlated with runoff DRP and BAP, respectively, were: 0.72 and 0.72 (Mehlich III), 0.75 and 0.73 (Bray‐Kurtz P1), 0.72 and 0.72 (Olsen), 0.82 and 0.82 (distilled water), 0.82 and 0.82 (iron oxide paper), 0.85 and 0.82 (acidified ammonium oxalate), and 0.77 and 0.76 (P‐saturation). All correlations were significant (P < 0.001), but the high r2 values of those obtained from distilled water, iron oxide paper, and acidified ammonium oxalate extractants indicate better precision for predicting DRP and BAP concentrations in runoff. Correlations of STP with DRP load (range: 43.4 to 472.8 g ha−1) and BAP load (54.2 to 542.0 g ha−1) were not useful (r2 < 0.18), possibly because runoff volumes were highly variable. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Soil Science Society of America Journal Wiley

Relating Extractable Soil Phosphorus to Phosphorus Losses in Runoff

Download PDF
5 pages

Loading next page...
 
/lp/wiley/relating-extractable-soil-phosphorus-to-phosphorus-losses-in-runoff-yKoj6JRq5r

References (0)

References for this paper are not available at this time. We will be adding them shortly, thank you for your patience.

Publisher
Wiley
Copyright
© Soil Science Society of America
ISSN
0361-5995
eISSN
1435-0661
DOI
10.2136/sssaj1996.03615995006000030025x
Publisher site
See Article on Publisher Site

Abstract

Phosphorus in agricultural runoff can cause accelerated lake and stream eutrophication. Where producers have applied P at rates exceeding crop uptake, soil P has sometimes become the main source of P in runoff. We hypothesized that soil test P (STP) correlation to dissolved reactive P (DRP) and bioavailable P (BAP) in runoff varies, depending on the extraction method. To investigate which STP extraction method would be best for predicting DRP and BAP concentration and load in runoff, soil samples were taken from the 0‐ to 2‐cm depth of 54 grass plots (5% slopes) on Captina silt loam (fine‐silty, siliceous, mesic Typic Fragiudult). The STP was extracted by six methods and the ranges of results (mg kg−1) were: 54–490 (Mehlich III), 27–592 (Bray‐Kurtz P1), 25–169 (Olsen), 14–110 (distilled water), 23–170 (Fe oxide paper), and 105–1131 (acidified ammonium oxalate). The soil P saturation ranged from 16 to 80%. Simulated rain was applied at 100 mm h−1 and runoff was collected for 30 min. The concentration of DRP in total runoff ranged from 0.31 to 1.81 mg L−1, and BAP from 0.37 to 2.18 mg L−1. The r2 values for STP by each extraction method correlated with runoff DRP and BAP, respectively, were: 0.72 and 0.72 (Mehlich III), 0.75 and 0.73 (Bray‐Kurtz P1), 0.72 and 0.72 (Olsen), 0.82 and 0.82 (distilled water), 0.82 and 0.82 (iron oxide paper), 0.85 and 0.82 (acidified ammonium oxalate), and 0.77 and 0.76 (P‐saturation). All correlations were significant (P < 0.001), but the high r2 values of those obtained from distilled water, iron oxide paper, and acidified ammonium oxalate extractants indicate better precision for predicting DRP and BAP concentrations in runoff. Correlations of STP with DRP load (range: 43.4 to 472.8 g ha−1) and BAP load (54.2 to 542.0 g ha−1) were not useful (r2 < 0.18), possibly because runoff volumes were highly variable.

Journal

Soil Science Society of America Journal – Wiley

Published: May 1, 1996

There are no references for this article.