9 Suggestions for Future Best Practice
The research undertaken for this strategy involved some discussion of possible best practice in dairying. Some of these discussions indicated where the industry could take further initiatives to improve the environmental outcomes from dairying. Some of these initiatives have already been undertaken in the four best practice catchments, and they show where the industry could take further initiatives to minimise the effects of dairying on the environment.
These practices are documented particularly by Mongahan et al (2003) and Mongahan et al (2004). In no particular order, these include the following practices:
- The possible use of low pressure irrigation systems, such as K-Line irrigation, for the disposal of dairy effluent to land. This has the major advantage over current systems, such as the use of travelling irrigators, that the effluent is spread over a much more limited area, and that the chances of mechanical failure are far lower. This means, for instance, that there is much less chance of ponding, or of effluent inadvertently running off to surface water. It is a particular advantage in country with mole and tile drains present; research in progress shows that it can reduce direct transfer of phosphate and microbial contaminants in mole drains in the Bog Burn catchment by up to 90-95 percent.
- The use of nitrification inhibitors, such as Eco-N, [Eco-N is a Ravensdown product. It is a nitrification inhibitor which reduces the activity of nitrosomonas bacteria in the soil and this reduces the rate of conversion of ammonium to nitrate. Ammonium is not as prone to leaching as nitrate and therefore there is less risk of nitrogen 'leaking out' of the plant root zone.] to reduce nitrate run-off to streams and to shallow groundwater, with adverse effects on the quality of that water for domestic supply. Work undertaken at Lincoln University shows these can have very strong benefits, including reducing leaching losses and improving soil nitrate nutrient retention. This results in less need for nitrogen fertiliser to be used, with significant economic gains for farmers.
- Reducing levels of plant available phosphate in soils would have significant benefits for stream water quality and habitat quality.
- Wintering stock on feed pads to reduce nitrogen excretion to pasture.
- Reducing irrigation by-wash from border-dyke irrigation systems, as this run-off typically contains elevated levels of nutrients and microbial contaminants.
- Applying phosphate fertiliser at times when irrigation is not taking place.
Recommendation 15:
Fonterra consider how the best management practices listed in section 9 of this report be included in any future revision of the Dairying and Clean Streams Accord.
