Hill-country land has its own challenges when it comes to nutrient management, resource management consultant Keri Johnston writes.
A lot of land use and water quality articles relate to more intensive land uses such as irrigation and winter grazing of cattle on fodder crops, or being break fed. These types of activities are deemed “high risk” from an environmental point of view and so have been a particular focus for regulators to date. With this, there is also an emphasis on managing nitrogen, which leaches into groundwater and surface water through excess drainage.
As the rule frameworks around the country are developing, one area that is starting to come to the fore is land-use on hill and high-country land. About 70% of New Zealand’s lambs and beef calves are born and weaned on hill country, and it occupies 5.6 million hectares of our 7.9m ha of improved grassland and freshwater catchments. It also presents very different challenges environmentally, especially around erosion and sediment loss. In this case, the emphasis is not so much on nitrogen, but on phosphorous and faecal contaminants. Regions such as Gisborne and its Freshwater Plan have certainly recognised this in their regional planning processes. There are also still mumblings about stock exclusion in these areas and whether this should or shouldn’t be required.
Unlike nitrogen, phosphorous and faecal contaminants are actually easier to deal with. Nitrogen is the unseen contaminant – it leaches below the root zone and disappears from sight. Given this, less is known about what happens to it at that point – where it actually goes, and how it gets there. But phosphorous and faecal contaminants enter waterways through runoff or overland flow – you can see it, so you can do something about it. The answer to these things isn’t rocket science. Environmental performance in these areas can simply be improved through riparian management, erosion control and grazing management, and there are plenty of people and resources around to provide support in these areas.
The best way to work out what you might need to do is to follow the Farm Environment Plan process: Identify the risks, plan to address the risks and carry out the plan. There is still no expectation that everything gets dealt with overnight, but you tackle the low-hanging fruit and the high-risk areas first, then work your way down the list.
One of the key risk identification tasks you will address is that of the ‘Critical Source Areas’. These are gullies, swales or depressions where runoff accumulates in high concentrations and delivers it to waterways or field tiles. These areas are a particular problem when cultivation or intensive grazing is carried out in close proximity, or the area is significantly de-vegetated by stock or cultivation. They tend to also be more prominent during seasonal wet periods (spring and winter), or when heavy rain occurs. Planting, or the creation of grass buffer zones to these areas, will reduce the loss of topsoil and nutrient and sediment loss to waterways. Thinking about where you plant crops (avoiding steep areas) and how you graze these areas will make a big (positive) impact.
Hill and high-country farmers are no longer avoiding the spotlight, but the good news is that – stock exclusion aside – most of what you have to deal with from an environmental point of view is totally achievable. So, get on with it.
