Nitrate and phosphorus transport through subsurface drains under free and controlled drainage
| Autor: | Laura C. Bowling, Eileen J. Kladivko, Samaneh Saadat, Jane R. Frankenberger |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Indiana
Environmental Engineering Nitrogen Flow (psychology) chemistry.chemical_element 010501 environmental sciences 01 natural sciences chemistry.chemical_compound Animal science Nutrient Nitrate Water Quality Drainage Waste Management and Disposal 0105 earth and related environmental sciences Water Science and Technology Civil and Structural Engineering Conservation of Water Resources Nitrates Ecological Modeling Phosphorus Agriculture 04 agricultural and veterinary sciences Pollution Volume (thermodynamics) chemistry 040103 agronomy & agriculture 0401 agriculture forestry and fisheries Environmental science Seasons Water quality Environmental Monitoring |
| Zdroj: | Water Research. 142:196-207 |
| ISSN: | 0043-1354 |
| DOI: | 10.1016/j.watres.2018.05.040 |
| Popis: | Controlled drainage (CD) is a structural conservation practice in which the drainage outlet is managed in order to reduce drain flow volume and nutrient loads to water bodies. The goal of this study was to evaluate the potential of CD to improve water quality for two different seasons and levels of outlet control, using ten years of data collected from an agricultural drained field in eastern Indiana with two sets of paired plots. The Rank Sum test was used to quantify the impact of CD on cumulative annual drain flow and nitrate-N and phosphorus loads. CD plots had a statistically significant (at 5% level) lower annual drain flow (eastern pair: 39%; western pair: 25%) and nitrate load (eastern pair: 43%; western pair: 26%) compared to free draining (FD) plots, while annual soluble reactive phosphorus (SRP) and total phosphorus (TP) loads were not significantly different. An ANCOVA model was used to evaluate the impact of CD on daily drain flow, nitrate-N, SRP and TP concentrations and loads during the two different periods of control. The average percent reduction of daily drain flow was 68% in the eastern pair and 58% in the western pair during controlled drainage at the higher outlet level (winter) and 64% and 58% at the lower outlet level (summer) in the eastern and western pairs, respectively. Nitrate load reduction was similar to drain flow reduction, while the effect of CD on SRP and TP loads was not significant except for the increase in SRP in one pair. These results from a decade-long field monitoring and two different statistical methods enhance our knowledge about water quality impacts of CD system and support this management practice as a reliable system for reducing nitrate loss through subsurface drains, mainly caused by flow reduction. |
| Databáze: | OpenAIRE |
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