Nitrate leaching losses from lysimeters simulating winter grazing of fodder beet by dairy cows

Nitrate-N (NO3--N) leaching losses from dairy cow urine and non-urine areas of simulated winter grazing of fodder beet (Beta vulgaris L.) were quantified using large intact soil monolith lysimeters (50cm diameter x 70cm depth), containing Balmoral/Lismore stony silt loam soil. Fresh cow urine was applied to half of the lysimeters in mid- to late-June at 300kgNha(-1) in 2012 and 250kgNha(-1) in 2013, following simulated fodder beet grazing. The remaining half did not receive urine to represent non-urine areas of a grazed paddock. Most of the N leached was from the urine-treated lysimeters and 92%-98% was in the form of NO3--N. Total NO3--N leached from the urine-treated lysimeters represented an equivalent of 21% (64kgNO(3)(-)-Nha(-1)) and 32% (84kgNO(3)(-)-Nha(-1)) of the total urine-N applied in 2012 and 2013, respectively. Nitrate-N leaching losses from lysimeters receiving no urine were between 10 and 11kgNO(3)(-)-Nha(-1).