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Freeze–Thaw Effects on Phosphorus Loss in Runoff from Manured and Catch‐Cropped Soils
Author(s) -
Bechmann Marianne E.,
Kleinman Peter J. A.,
Sharpley Andrew N.,
Saporito Lou S.
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/jeq2004.0415
Subject(s) - soil water , surface runoff , environmental science , leaching (pedology) , manure , agronomy , lolium multiflorum , nutrient , phosphorus , hydrology (agriculture) , chemistry , soil science , ecology , biology , geology , organic chemistry , geotechnical engineering
Concern over nonpoint source P losses from agricultural lands to surface waters in frigid climates has focused attention on the role of freezing and thawing on P loss from catch crops (cover crops). This study evaluated the effect of freezing and thawing on the fate of P in bare soils, soils mixed with dairy manure, and soils with an established catch crop of annual ryegrass ( Lolium multiflorum L.). Experiments were conducted to evaluate changes in P runoff from packed soil boxes (100 by 20 by 5 cm) and P leaching from intact soil columns (30 cm deep). Before freezing and thawing, total P (TP) in runoff from catch‐cropped soils was lower than from manured and bare soils due to lower erosion. Repeated freezing and thawing significantly increased water‐extractable P (WEP) from catch crop biomass and resulted in significantly elevated concentrations of dissolved P in runoff (9.7 mg L −1 ) compared with manured (0.18 mg L −1 ) and bare soils (0.14 mg L −1 ). Catch crop WEP was strongly correlated with the number of freeze–thaw cycles. Freezing and thawing did not change the WEP of soils mixed with manures, nor were differences observed in subsurface losses of P between catch‐cropped and bare soils before or after manure application. This study illustrates the trade‐offs of establishing catch crops in frigid climates, which can enhance P uptake by biomass and reduce erosion potential but increase dissolved P runoff.