Using APLE-Lots (Annual Phosphorus Lots Estimator) to estimate annual phosphorus and sediment loss from Wisconsin cattle lots

This training session will review how to use APLE-lots – a modeling tool developed in Wisconsin - to estimate average annual phosphorus and sediment loss from Wisconsin cattle lots. A step by step approach will be provided along with some reference materials. Phosphorus loss from feedlots, barnyards, exercise lots, or over-wintering lots, via surface runoff, is a significant non-point pollution source for two reasons: First, the high concentration of cattle leads to high rates of manure deposition and P accumulation relative to pastures and cropland. Second, cattle holding areas/lots can be partially or completely devoid of vegetation and have compacted soil or an impermeable (e.g., concrete) surface, which can lead to high rates of polluted runoff. The combination of a concentrated P source and transport pathways creates the potential for high rates of P loss from cattle lots and causing pollution of surface waters.

APLE-Lots is intended to be user-friendly and does not require extensive input data to operate. Lot information is entered into a GIS-system where lot boundaries and contributing areas can be drawn over aerial photos and soil maps. APLE-lots only estimates pollutant loads to the edge of the lot; it does not estimate the fraction of pollutants delivered/transported from the lot boundary to surface waters.