Christine Christensen

Doctor of Philosophy, (Soil science)
Study Completed: 2013
College of Sciences


Thesis Title
Duration-controlled grazing of dairy cows: Impacts on pasture production and on nitrogen, phosphorus and faecal microbe losses to water

Read article at Massey Research Online: MRO icon

As a global exporter of quality milk products, the New Zealand dairy industry requires proven mitigation strategies to reduce nutrient and faecal microbe loss to waterways.  Urine and dung patches from cows, deposited in the paddock at grazing, are the primary cause of these losses, through drainage and surface runoff.  During this study, Christine Christensen implemented Duration-controlled grazing (grazing for 4 hours at a time), and returned collected effluent to the paddock uniformly.  Leaching losses of N were reduced by an average of 52%, with more modest reductions for P and faecal microbes in surface runoff.  Pasture production and cow intakes were able to be maintained with the correct timing of effluent return.  Duration-controlled grazing is now a practicable and recognised management strategy for New Zealand farmers to use if the intention is to achieve reductions in N leaching losses.

Professor Michael Hedley
Professor David Horne
Dr James Hanly