Managing the nutrient problem
Dr Ross Monaghan from AgResearch at Invermay in Otago talks about various practices that can be employed to manage nutrient losses from becoming a problem on farmland.
Some of the farm management practices that are most commonly employed to minimise the risk of nitrogen loss are to make sure that you don’t apply too much nitrogen per application or too much in any one year. We make sure that farm dairy effluent we’re collecting back in the milking parlour is well managed, so it’s returned to land at a low rate. Something that can help reduce direct losses of urine near to streams is just to prevent stock from urinating directly into those riparian zones.
Another strategy involves being careful about when urine is deposited back to pastures. Where we can have animals under cover or on a stand-off where we capture the urine and we store it through the risky winter period and return it to land in the following spring, we can reduce nitrate leaching losses quite considerably.
One important strategy for helping to manage the nitrogen problem is the way we look after riparian and wetland areas. Wetlands are really important parts of our landscape that act as filters for some of the run-off, particularly for filtering out nitrogen that’s passing through wetlands. So it’s really important that we protect the wetlands that we have remaining and reinstall some that have been drained and are perhaps overgrazed and to make sure that we don’t allow stock to graze those riparian zones and either cause treading damage or excrete urine or dung directly into the waterways.