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|Wetlands in farming|
The following is adapted from an article published in the farmers' weekly paper "Straight Furrow", October 2007.
Farmers throughout the country are busy planting their stream-sides to comply with the requirements of their Regional Council and Fonterra. Water quality issues are now among the top priorities for both environmental agencies and export companies wanting to project the "clean, green" image.
The consumer's picture of New Zealand as 100% pure is an essential part of the export marketer's drive to sell our primary produce overseas. Any picture of New Zealand portrays the green image, but we have to show we are clean as well.
What are the benefits to farmers and what are the costs?
Healthier stock from cleaner water is the obvious answer, but there are many other advantages even if some of them are downstream a bit.
Fonterra has set high goals to be met by the dairying industry in the Clean Streams Accord. Farmers have only a few months left to comply with the initial goals set in 2003, and all goals must be met by 2012. The critical goals involve fencing streams to exclude stock, and planting sustainable native vegetation along the stream banks.
The costs may be high, but the cost of doing nothing is considerably higher. Once a water body is polluted it is difficult and expensive to get it back to a healthy state.
Every dairy farmer knows effluent is a major issue and it has to be treated and disposed of without creating problems for neighbours.
Erosion sediments and nutrient runoff are the two worst pollutants of our lakes and coastal waters. Farm management can significantly improve water quality by strategically buffering wetlands and streams with native plants.
Geoff Davidson, a grower of native plants for more than 30 years and owner of the Oratia Native Plant Nursery, says natives provide an ideal filter for the runoff before the water enters a stream. If a catchment can be directed through a natural swamp or man-made wetland, the benefits to water quality are immense. Combined with gully and stream-side plantings the dual water treatment process can eliminate much of the farm-produced pollution.
Different plants provide different solutions to water management. Stream banks intensively planted with native trees, shrubs, and grasses significantly reduce the negative impacts of runoff from adjacent pastures.
Wetlands planted with dense native rushes and sedges soak up runoff, capturing sediment carried by the streams. Wetlands also minimise flood damage by releasing stormwater gently over an extended period.
Farmers gain considerably by planting and fencing. Among the benefits suggested by Environment Waikato are:
Geoff says spring is a perfect time for planting as establishment and growth is rapid. However, he says ground preparation is important. Sites must be sprayed prior to planting to allow the new species to get established without weed competition.
Geoff is adamant that follow-up maintenance is essential and should be scheduled regularly in the early stages to avoid weeds getting established and overgrowing the native species. A well-cared-for planting will soon be able to look after itself with minimal attention to ensure no serious weeds are establishing. Planting of hardy species such as flax and cabbage trees can be continued until late spring/early summer.
Geoff and the team at Oratia Native Plant Nursery have a wealth of experience in revegetation and riparian planting, and can provide advice and guidance for farmers needing a water management solution.