There is more concern these days about water pollution from dairy farming. This is partly because there are many more dairy farms these days. Sheep farms, beef cattle farms and forests have been converted into dairy farms. The price of wool from sheep is low whereas milk prices are high and the future for dairy farming looks good.
Water pollution is caused by three main things. The first is where cows are allowed to walk in streams. Fences around streams and bridges over streams all cost money. Sometimes it is almost impossible to fence streams if there are so many streams on a farm. Sometimes farmers can plant grasses and native shrubs along the river banks to stop cows standing in the water.
Another problem is nitrates which run into the water from the land. Nitrates come from fertilizers and effluent from the cows. A further problem is caused by phosphorus also from fertilisers.
More than 280,000 hectares of land have been converted to dairy across the nation between 1996 and 2008 – at the same time, sheep and beef farming land has dropped by around 500,000ha.
Listen to December 6th 2011 to hear more about dirty rivers.
Vocabulary
- converted – changed from one thing to another
- nitrate – a form of nitrogen
- fertilizer – chemicals to make the grass grow
- effluent – urine and faeces (manure) from cows
- phosphorus – from phosphate fertiliser