WaterMetrics helps conversion become a “grass factory.”
Rangitata 280ha Dairy Conversion - Leighton Pye.

Light stony soil and limited water resources meant restrictions on water take and effluent application were inevitable when Leighton Pye converted a 220ha (effective) Rangitata property to dairying last year.

ECan compliance included water meters on the farm’s four wells, and restrictions on effluent application.  Working with WaterMetrics NZ (A strategic member of the Hydrocom Alliance) however means those compliance requirements have become a valuable management tool to help the farm reach its full grass growing potential sooner, and more efficiently. The farm has fully integrated irrigation technology providing real time data from its four wells, soil moisture and temperature data all linked by telemetry technology and delivered via the internet to the farm computer. For farm sharemilker Joe Wyborn and his staff despite only being in their first season with the system, the guess work has been removed from their irrigation decisions.

Andrew Neill General Manager of WatermerticsNZ

After a few “twitchy” weeks of wanting to check what the neighbours were doing, Joe admits he now feels confident the remote information he gets delivers a far better idea of when to start and stop irrigating. The farm’s light stony soils mean irrigation decisions are made along a fine line between too little too late in hot nor-wester conditions, and too much that flushes through beyond the plant root zone. Even within the light soils some parts of the farm have an underlying clay pan that creates more moisture retentive environment than the straight stony profile.

To help determine best application for these differing profiles Aquaflex, A strategic member of the Hydrocom Alliance installed two Aquaflex soil moisture meters. Information from them has revealed Joe needs to apply “a little often” on the straight stony profile, averaging 10mm an application. On the clay pan soil he varies it to around 20mm over four days because it can hold the higher rates better. He can now monitor the impact soil temperature and evapo-transpiration rates can have on the application.

“The risk you run is you put on too little, and lose it before it even gets into the soil profile, we can manage that now.” While nor-easterlies predominated this summer, real time data means he can adjust for the significant evapo-transpiration rates that nor-westers bring with them, sucking moisture out as fast as 7mm a day.
Data on water use from each of the farms four wells is also collected, and it is “just a push of a button” to calculate how far through their consented take they are.

“It becomes critical to know that exactly at this time of year (February) – any water we can save now can be used later in the season, and it could be we have a dry autumn and really need it then.”
He says there is no doubt the data removes the tendency to over water, and over spend on electricity – by Joe’s estimate if he can save 40 irrigation days in a season the technology has paid for itself.

Meanwhile effluent application decisions can be made knowing there is no risk of consents being breached, with soil moisture levels easily accessed and up to date before applying.  The ability to check the data off the internet is not only convenient, but appeals to Joe’s younger staff who have grown up with computer technology - he has encouraged them to understand and use it. “It's great to be able to check moisture from anywhere on the internet.”

In the early stages of the conversion the information has meant the young grass has not been stressed at any stage, receiving optimal moisture through establishment. Longer term, Joe and his staff are building up a history of what combination of temperature and moisture the conversion grows the most grass. For coming seasons he can utilise that history to keep grass as the main driver of increased production, with grain supplement stabilised at approximately 500kg/cow/year. Like any project, starting with a blank slate in the conversion has been ideal, but Joe says the skill and knowledge WaterMetrics, Aquaflex and Boraman Consulting , (The Hydrocom team,) bought to the project has been unparalleled.

“Andrew has been a man of his word, and we have a system that will probably pay for itself in a year, that will last for at least 10-20 – it’s a no brainer to have really.”

Where:         Rangitata – Orari Bridge Highway.
Farm Type:   Dairy conversion.
Area:           280ha
Owner:        Leighton Pye.
Issues:        Strict compliance around take and water application. Effluent application restricted to compliant soil moisture levels. WaterMetrics solution: Telemetry data feeds from 4 farm wells, 2 * Aquaflex soil moisture/temperature strips. Outcome: Developing farm history of optimum growth conditions,  clean non compliance record, optimum application rates minimising electricity usage and maximising grass growth.