Thursday, February 28, 2013
Effects of Grazing on Streambank Erosion and Phosphorous Loading
Iowa State University researchers published a study looking at grazing effects on streambank erosion and phosphorous loading. They have found that stocking rates of cattle do affect sediment loading in streams. Although the paper seems to have conflicting conclusions, my interpretation is that while stocking rates can affect phosphorous loading and sediment loading in the stream, there are other variables that play a more significant role. They found that annual rainfall and stream order played a bigger role in sediment and phosphorous loading. They also implied that increased phosphorous loading might be more related to an increased contribution from manure. One way to manage both sediment and manure contributions to phosphorous loading is to use intensive grazing to limit the amount of time the animals spend in any one area.