|Huang, Chi Hua|
Submitted to: Ambio
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/10/2014
Publication Date: 2/15/2015
Publication URL: http://handle.nal.usda.gov/10113/61157
Citation: Smith, D.R., Francesconi, W., Livingston, S.J., Huang, C. 2015. Phosphorus losses from monitored fields with conservation practices in the Lake Erie Basin, USA. Ambio. 44(2):S319-S331.
Interpretive Summary: The Conservation Effects Assessment Project was intended to study the impact of Farm Bill conservation programs on environmental quality. In this study, we tested the impact of the following conservation practices: conservation tillage, conservation crop rotation, grassed waterways, and blind inlets. Results from runoff data from four fields where these practices were installed was used for the period 2004 through 20012. In general total phosphorus was reduced by these conservation practices. Conservation tillage and grassed waterways have both been designed to reduce erosion and sediment delivery to surface waters. While these practices also provide the benefit of decreasing total phosphorus loss, they can increase soluble phosphorus loss to receiving waters. Conservation crop rotation and the use of blind inlets effectively reduce both soluble phosphorus and total phosphorus. The results of this research are to provide hard evidence that conservation practices placed on the ground as a result of Farm Bill programs result in improved water quality with respect to phosphorus loss to receiving waters.
Technical Abstract: Conservation practices are placed on farm fields in the USA through Farm Bill programs; however, there has been very little verification that these practices provide environmental benefits. This study was conducted to assess the impact of placing Farm Bill eligible conservation practices on soluble P (SP) and total P (TP) losses from four fields that have been monitored for surface runoff since 2004. No-tillage doubled SP loading compared to rotational tillage, but in these same fields demonstrated that no-tillage decreased TP loading by 69% compared to rotational tillage. Similarly, grassed waterways were shown to increase SP loads, but not TP loads. A corn-soybean-wheat-oat rotation reduced SP loads by 85% and TP loads by 83% compared to the standard corn-soybean rotation in the region. Practices designed to decrease sediment loss (i.e. no-tillage or grassed waterway) seem to decrease TP losses; however, there is sometimes a tradeoff with greater SP losses.