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Phosphorus Leaching in Sandy Outwash Soils following Potato‐Processing Wastewater Application
Author(s) -
Zvomuya Francis,
Gupta Satish C.,
Rosen Carl J.
Publication year - 2005
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2004.0381
Subject(s) - outwash plain , leaching (pedology) , soil water , environmental science , wastewater , phosphorus , agronomy , environmental engineering , environmental chemistry , chemistry , soil science , geology , biology , paleontology , glacier , organic chemistry
Land application of wastewater presents potential for ground water pollution if not properly managed. In situ breakthrough tests were conducted using potato ( Solanum tuberosum L.)–processing wastewater and a Br tracer to characterize P leaching in seasonally frozen sandy outwash soils. In the first test, P and Br breakthrough were measured in a 7‐m deep well following wastewater [2.94 mg L −1 total P (TP); 280 mg L −1 Br] application at the site that had 13.1 mg water‐extractable P (WEP) kg −1 and 94.4 mg Bray‐1 P kg −1 Bromide was detected in the well after ∼0.4 pore volumes, but there was no P break‐through after 7 pore volumes. In the second breakthrough test, wastewater containing 3.6 mg L −1 TP and 259 mg L −1 Br was applied on 1.5‐m deep lysimeters at low (0.8 mg WEP kg −1 ; 12.1 mg Bray‐1 P kg −1 ) and high soil test P sites (104 mg WEP kg −1 ; 585 mg Bray‐1 P kg −1 ). Leachate TP concentration during the test remained constant (0.04 mg L −1 ) at the low P sites but increased from ∼3.5 to 5.6 mg L −1 at the high P sites. These results indicate no P leaching in low P soils, but leaching in high P soils, thus suggesting that most of the P leached at the high P sites was mainly due to desorption and dissolution of weakly adsorbed P from prior P applications. This was consistent with P transport simulations using the convective–dispersive equation. We conclude that P concentration in land‐applied wastewater should be regulated based on soil test‐P level plus wastewater P loading.