The ability of poplars and willows to coppice gives promise that both riparian plantings and dedicated block plantings will be able to uptake nitrogen from irrigated dairy effluent that can then be fed back to livestock.
NZ Poplar & Willow Research Trust: http://www.poplarandwillow.org.nz/library/reuse-of-farm-dairy-effluent
NZ Poplar & Willow Research Trust: http://www.poplarandwillow.org.nz/library/factsheet-6-benefits-from-using-poplars-and-willows-on-nz-dairy-farms