Monday 23 May 2016

Variable Rate Irrigation and Soil Moisture Management - Introducing The Kowhais

Name: Tom Macfarlane
Farm: The Kowhais
Type: Intensive grazing
Location: Raincliff
Total Area: 800Ha
Total Effective Area: 655Ha
Area under VRI: 86Ha
AquaCheck soil moisture probes: 6
Annual Production: 1000 Lambs, 1500 deer and 1000 bulls
Average Pasture Production: 9500kgDM/Ha

Efficient meat production is the goal for Raincliff farmer Tom Macfarlane. After taking over the property 3 years ago Tom is striving to lift production whilst doing so in a sustainable manner. The Opuha River runs along the boundary of the property and this means that Tom is wary of the impact that his intensive farming operations may have on the environment.

Finishing 700-800 bulls before their 2nd winter on farm requires a high level of feed intake and the bulls need to be growing every day. The techno system is intensive and requires daily management of multiple small mobs of animals. Juggling the stocking rate according to the feed supply and demand requires effective pasture management strategies to maintain quality throughout the spring and summer.

Water use efficiency is also high on the agenda at Macfarlane’s as water for the properties irrigation system is supplied from the often restricted Opuha Water scheme. Roughly 180 Ha is under irrigation on the property and his pivot and lateral, both with Growsmart Precision VRI, water an area of 86 Ha. Irrigation is also applied through K-Line, hard hose gun and Roto-Rainer systems which cover 31.8, 32.5 and 56 Ha respectively.
The Kowhais EM Zone Map to be used with VRI
The Growsmart Precision VRI really proves its worth when water restrictions kick in as Macfarlane is able to use planned moisture deficit management to water different areas of ground cover at reduced rates. When water is short the fodder beet is watered less frequently to free up more water for the higher quality pastures. Macfarlane also is able to reduce applications on heavier soils to spread his water further. All of this is enabled by the combination of EM Soil Surveys, AquaCheck soil moisture sensors and Growsmart Precision VRI.

The installation of AquaCheck soil moisture sensors has added to Tom’s suite of decision support tools. Tom is now aiming to forecast potential pasture production from soil temperature and moisture data received from the AquaCheck probes. This will enable him to better decide how many head of stock he will be able to carry and will aid in planning for the upcoming season.

The combination of AquaCheck moisture probes and a Growsmart Precision VRI system enables Tom to better manage his irrigation scheduling. The ability to see what is happening to soil moisture and applying the correct amount of water at the correct time has benefits in terms of sustainability and pasture growth. Pasture growth is critical in Macfarlane’s techno beef system where pasture utilisation needs to be kept as high as possible. With potential harvest efficiencies of up to 85 to 90% the cost of overwatering is not just limited to run off and nutrient loss. Pasture damage caused by heavy 18 month old bulls has a significant impact on the level of wastage and future pasture production. The AquaCheck probes will allow Tom to see how soil moisture is tracking and can alert him to when soil moisture rises above the pasture damage threshold. 

With one eye always on efficiency at The Kowhais the use of variable rate irrigation, EM soil surveying and AquaCheck soil moisture probes has given Tom Macfarlane the tools to help improve efficiency and productivity. Watch this space to see how things evolve at The Kowhais.