Abstract
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.
Original language | English (US) |
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Pages (from-to) | 2301-2309 |
Number of pages | 9 |
Journal | Journal of Environmental Quality |
Volume | 34 |
Issue number | 6 |
DOIs | |
State | Published - Nov 2005 |
All Science Journal Classification (ASJC) codes
- Environmental Engineering
- Water Science and Technology
- Waste Management and Disposal
- Pollution
- Management, Monitoring, Policy and Law