The element composition of herbage at urine patch sites in a ryegrass pasture

Abstract
SUMMARY: The variation in the sodium, potassium, calcium, magnesium, zinc, iron, manganese, copper, phosphorus and nitrogen concentrations in autumn regrowth herbage across a perennial ryegrass (Lolium perenne) pasture has been measured. The regrowth resulting from urine return by sheep to a pasture takes the form of an ‘island’ of herbage in which nitrogen (27%) and potassium (28%) are significantly higher than, and calcium (20%), magnesium (10%), phosphorus (24%), and manganese (40%) are significantly lower than in the surrounding herbage. Because of the selective grazing behaviour of sheep the possible implications for animal health of this pattern of element composition across a pasture are discussed.