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United States Department of Agriculture

Agricultural Research Service

Research Project: POULTRY MANURE MANAGEMENT STRATEGIES TO REDUCE NON-POINT SOURCE PHOSPHORUS POLLUTION Title: Effects of pasture renovation on hydrology, nutrient runoff, and forage yield

Authors
item DE Koff, Jason
item Moore, Philip
item Pote, Daniel
item Formica, Sandi -
item Van Eps, Matt -
item Delaune, Paul -

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 15, 2010
Publication Date: January 31, 2011
Citation: De Koff, J.P., Moore Jr., P.A., Pote, D.H., Formica, S., Van Eps, M., Delaune, P. 2011. Effects of pasture renovation on hydrology, nutrient runoff, and forage yield. Journal of Environmental Quality. 40:320-328.

Interpretive Summary: Proper pasture management is important in promoting optimal forage growth and reducing runoff and nutrient loss. Nutrient losses can lead to reduced forage growth and accelerate eutrophication in natural water systems, leading to algal blooms and reduced aquatic life. Pastures that apply manures to forage areas are most affected by improper pasture management due to the addition of water-soluble nutrients that can be removed by runoff. Renovation of pasture systems creates slits or holes in the upper soil to break up compacted layers and allow improved water infiltration. Recent research has focused on the effect that renovation may have on the management of manure-applied pasture systems. Three study sites were monitored for the effect of renovation on runoff of dissolved reactive phosphorus (DRP), total P (TP), total nitrogen (TN), hydrological characteristics, and forage growth following manure application. The first two study sites included rainfall simulations on grassed plots for three different soil types. The third study site focused on 0.23 ha watersheds with runoff produced by natural rainfall. Renovation of pasture soils in small plots resulted in significant and beneficial hydrological changes. The plots fertilized with poultry litter led to significant reductions in DRP (74-88%), TP (76-84%), and TN (72-78%) loads in two of the three soils studied following the first rainfall simulation. Forage yields were not significantly affected by renovation. Renovation of the watershed applied with poultry litter led to lower P loads in the initial 3 months of the first year of study but greater overall annual runoff volumes and P loads than the non-renovated watershed. Higher forage yields (30%) were observed on the renovated watershed. Results from the watershed study were inconclusive due to the low replication and high variability inherent in these studies. Overall, beneficial impacts of renovation lasted around three months in all studies, the most critical period for nutrient runoff following manure application. Therefore, renovation could be an important best management practice in these areas.

Technical Abstract: Proper pasture management is important in promoting optimal forage growth and reducing runoff and nutrient loss. Pasture renovation was performed prior to manure application (poultry litter or swine slurry) on different pasture soils and rainfall simulations were conducted to identify the effects of pasture renovation on nutrient runoff and forage growth. A larger-scale study was also performed to identify effects of renovation and manure application on phosphorus (P) runoff and forage yield from 0.23 ha watersheds under natural rainfall. Renovation of small plots resulted in significant and beneficial hydrological changes. Renovation of pasture soils fertilized with poultry litter led to significant reductions in dissolved reactive P (DRP) (74 to 88%), total P (TP) (76 to 84%), and total nitrogen (TN) (72 to 78%) loads in two of the three soils studied following the first rainfall simulation. Renovation did not result in any significant differences in forage yields in the rainfall simulation studies. The renovated watershed of the larger-scale runoff study had lower P loads in the initial 3 months of the first year of study but greater overall annual runoff volumes and P loads than the non-renovated watershed. Higher forage yields (30%) were observed on the renovated watershed. Results from the watershed study were inconclusive due to the low replication and high variability inherent in these studies. Overall, beneficial impacts of renovation lasted around three months in all studies, the most critical period for nutrient runoff following manure application. Therefore, renovation could be an important best management practice in these areas.

Last Modified: 11/27/2014