Irrigation Design

The new fixed grid at Willow Park was designed and installed by Aviemore Irrigation.

Irrigation Scheduling

A handheld probe is used to measure soil moisture before irrigation is started, or restarted after rain to ensure soil moisture deficit can accommodate the irrigation application from each irrigation type as determined by bucket testing.

Timaru and Mayfield are the dominant soils on Willow Park.
Willow Park Soil Map.

Timaru soil has 55mm Profile Available Water to 30cm. For a pasture rooting depth of 300mm the Readily Available Water is 27mm.
Mayfield soil has 60mm Profile Available Water to 30cm. For a pasture rooting depth of 300mm the Readily Available Water is 30mm.

These soils therefore have capacity to hold water in the root zone from the irrigation types used. The main risk is the Rotorainer on the flats. These are managed carefully with the highest speeds selected to minimise chances of run off by applying the lowest possible application depth.
Irrigation applications are managed only by trained staff and are recorded.

Irrigation Water Optimisation

On farm training is recorded for each staff member on a new farm training template.

K-Lines are shifted twice a day. These are shifted across the slope and lines are proactively turned off where there is risk of run off or ponding.

There is an operations manual for K-Line as well as the installation video are used for training.

Operating Procedures

1. Check forecast.

2. Measure soil moisture for irrigation trigger.

3. Check soil temperature when considering irrigation in August and in May.

4. If above conditions allow then start irrigator.

5. Record irrigation online.

6. Check for leaks or other failures.
   
   
   

7. Incident Report Procedure

8. Irrigation is monitored between 5am and 5pm daily. CSA's are monitored for run off in passing.

9. When a leak, run off or ponding is discovered shut water off to leaking line.

10. Notify management and source resources needed such as parts, digger etc.

11. Repair, pressure test and continue to monitor before backfilling.

12. Record maintenance.

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14. Maintenance

15. Preseason checks are carried out and checked again after first start-up for blockages and leaks.

16. Light maintenance is carried out by staff and recorded on a group chat.

17. Heavier maintenance is undertaken by engineer Johnny Grumball.

18. Bucket Tests are carried out to assess performance of each irrigator.

19. End of season checks include draining lines, detaching K-Lines from hydrants and moving to fence lines, and parking rotorainers in wind-safe spots. 

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21. Soils and Nutrients

22. Willow Park is managed to minimise the amount of nutrient that escapes the farm and becomes a pollutant, and to maximise the nutrients that stays within the root zone of the plants as a resource. Infiltration rate is optimised to minimise runoff.

Nitrogen

• N decisions guided by advice from Hamish Campbell at Ravensdown.

  • Nutrient Summary

  • Soil Tests

  • Agronomy Advice: Nitrogen

• Application at Willow Park is by Hyslop Groundspread.

  • Proof of Placement

Phosphorous

• P decisions are guided by advice from Hamish Campbell at Ravensdown.

  • Agronomy Advice: Lime

  • Agronomy Advice: Phosphate

• Critical Source Areas are managed by only grazing when dry, using a 5m buffer if wet, and monitoring for run off.

• The aim is to maintain good soil structure by using the relevant cultivation practices for the given situation, and minimise the period of soil exposure to wind and rain erosion. This also minimises greenhouse gas emissions from exposed soil.

• P applications don't exceed 100kg P/ha and not spread in Jun or July. Waterways are avoided and run off points are monitored.

• Minimum tillage cultivation is used where soil conditions allow, and if full cultivation is necessary slopes are worked across. Steep areas are avoided where possible and weather forecasts are considered when deciding on cultivation timing. Care is taken not to work soil into fine aggregate sizes and a 5m buffer is maintained to waterways. There is minimal delay between cultivation and sowing to minimise the time that soil is exposed.

• Waterways are protected by fencing, vegetative strips.

• Laneways are maintained each year.

• Pugging prevention is achieved by giving larger breaks in wet conditions and cows are allowed to leave longer residuals. Young grass is grazed only briefly and in dry conditions only to minimise damage to the softer soil.

• A winter grazing plan mitigates risk while on crop.

Winter Grazing

See Winter Grazing Plan.

Waterway and CSA Management