The Waimakariri River has been regarded as a taonga by generations of Ngāi Tahu whānau – a treasure to be carefully looked after.
Today, as Ngāi Tahu Farming branch into dairy farming, drawing essentials water from the Waimakariri, the iwi role as kaitiaki in the management of waterways enters a new phase.
Ngāi Tahu whānau see the health and well being of our waterways as important to the health of all New Zealanders and to that end, Ngāi Tahu Farming has invested heavily in research and development that will mitigate any nutrient and water quality issues associated with dairying.
Glen Clayton, Development Manager, Ngāi Tahu Farming says ongoing research and development is critical for the dairy industry as it moves forward.
“We’ve got to keep moving ahead; if we don’t, things in the industry won’t improve. We’ve set up our first Eyrewell dairy farm as a model farm – one that will act as a showpiece and role model for every future farm we develop.
“We want to be ahead of industry trends instead of waiting to see what happens. We need to experiment and test our practices on farm one, so we can be certain we are ticking all the right boxes, to make sure we’ve got a sustainable farming operation. We want to be a model for the dairy farms of the future.”
There is no question that water is an integral part of dairy farming. Not only does each and every cow require 70 litres of drinking water a day to produce high quality milk, water is also required for irrigation, to get maximum benefit in growth and quality of grass. With irrigation, a growth rate of 70kg of dry matter per day is ideal; without irrigation, that can drop to 15-20kg of dry matter a day, which in turn reduces productivity.
To ensure reliability of water for irrigation, Ngāi Tahu Farming are part of the Waimakariri Irrigation Scheme (owned by Waimakariri Irrigation Ltd). To maximize efficient use of their water take, the company is developing a series of large water storage ponds. This is to insure against the impact of water restrictions during the critical production period between February and April.
By analyzing farms in the area without water storage, the team established that, on average, 300-350kg of milk solids per hectare is attributable to water storage.
“To hedge against the risk of that sort of loss, we needed to find a solution during drought and periods of water restrictions,” says Clayton.
The team collected historic records, including flow rates of the Waimakariri River for the last 40 years plus NIWA data from weather stations close to the farms. Based on that, they calculated the required water-holding capacity of the soil and how much water storage would be required to give 85% reliability of water, or 850 cubic metres of storage per effective hectare. That provides 17 days of water for irrigation when summer water restrictions are in place.
“There are only a few months of concern in regard to drought and restriction but those are our critical high production months.”
One storage pond is already operation on farm one and another two huge ponds, covering a total of 45 hectares, are under construction. One of the ponds (550,000 cubic metres) will service farms one and two; the other (about 500,000 cubic metres) will service farms three and four. A cubic metre is equivalent to 1,000 litres. By creating two ponds, there is less of an issue with wind erosion.
One pond will start filling by Christmas and the second should be filled by the end of March. Further storage ponds will be developed progressively – one is already complete on farm 17 – and another, to service farms 14 and 15, will also be complete by March.
In line with their philosophy of being ahead of dairying trends, Ngāi Tahu Farming has also invested in a number of significant practices that reduce over-watering and leaching. These include NIWA weather stations, which provide accurate data on rainfall, weather predictions and soil temperature, which in turn mean farm managers can reduce water use and the risk of leaching by irrigation when soil moisture levels and weather forecasts are acceptable.
Variable pivot irrigators allow farm managers to control how much water is used, and how and where effluent is recycled onto pasture. Every nozzle is fitted with GPS and can be individually shut off to within metres of accuracy. This ensures that when effluent is sprayed, the farms are getting 100% coverage of effective area; and if there is a problem with water ponding in any given area, nozzles covering that area can be shut off. The whole process is computerized and is operated from the Cloud, enabling staff members to log on and control the pivots from anywhere in the world.
Soil moisture indicators on the pivots also determine soil moisture levels and based on that information supplied by the NIWA weather stations, managers can determine the need for irrigation.
Another innovation to reduce the farms’ nutrient footprint is the GPS-tracking of all fertilizer trucks. This ensures there is no overlap of application, which loads the soil with more nutrients than required, leading to leaching.
“This way we know exactly what nutrients have gone into each paddock. All that information is stored in the Cloud and is used to generate management reports; so basically, we understand every input going onto our farm,” says Clayton.
Of vital importance to this detailed farm management programme is a joint research project with Lincoln University and the installation of forty lysimeters on farm one. It is one of the few farms in the country with lysimeters, which measure nutrient leaching.
“According to Clayton, their placement on farm one will give a good overview of the any leaching across the entire farming block. He acknowledges that it requires high capital input but says the development of twenty farms will mitigate that expenditure.
“We also use the farm management modelling tool, Overseer, which provides a good picture of any potential leaching but the lysimeters eliminate any variation or guesswork from the leaching equation.”
“We see the lysimeters and all our investment in technology and research and development, as essential for future-proofing against any likely impairment of water quality in our key sources. We think it’s worth the money.”
“I think investment of this nature will become more and more important in the dairy industry and perhaps in five year’s time, what we are doing now to protect our water sources, will be standard. As far as we are concerned, it’s the responsible thing to do.”
