Dairy farm roadway surface materials as a P-source within the nutrient transfer continuum framework

Internal farm roadways are connectors within agricultural landscapes, which act as sub-components of the nutrient transfer continuum (NTC). On dairy farms, roadway surface runoff dissolved and particulate phosphorus (P) sources stem from a combination cow excreta deposited at locations that impede animal flow, soil hooves or machinery tyres, run-on up-gradient fields, public farmyards incidental spill organic/inorganic fertilizers. The present study investigates storage potential release P underlying material (i.e. composite stone aggregates) this source component is not considered in NTC framework documented literature. Herein, materials were sampled (to 1 cm depth) 17 avoiding fresh excreta. Multiple location types selected e.g. straight sections, junctions, before adjacent standoff areas associated with cattle underpasses, all varying distance farmyard. Roadway samples analysed for metals (Al, B, Ca, Co, Cu, Fe, K, Mg, Mn) content. Results showed significant legacy themselves P-storage merits inclusion framework. All locations, when compared aggregates surrounding had highly elevated plant available Morgans > 8 mg L -1 (Index 4, ranging 10 – 110 ). Sampling points 100 m farmyard together junctions underpasses beyond highest concentrations. Critical areas, where source, mobilisation transport to waters coincided, formed three locations. Possible mitigation measures a) divert into fields using low-cost water breaks, b) disconnect underpass tanks receiving c) change infrastructure improve flow minimise build-up. Future research should examine loads sections across typologies types.