Case Studies

Type of work

Irrigation Services were engaged by T&G to design and implement an irrigation system over a newly developed 47 hectare apple orchard.  The whole premise of T&G’s Ebbett orchard development is geared towards future automation, including robotic apple harvesting.

Problem that needed solving

Crops need to be grown in new trellis systems that allow robots to see and harvest the fruit.  To be “robot-ready” tree architecture and apple placement needs to be compatible with robotics.  Quite simply the fruit needs to be accessible.  If a person can reach their hand out and pick an apple without having to go around wires or behind branches, then a robot can also perform the same task. 

The irrigation system needed to support this new tree growing structure and not hinder the mechanical picking process.

Size/scale of project

The 47 hectare Ebbett Orchard on the banks of the Tutaekuri River at Moteo in Hawke’s Bay is the single largest development undertaken by T&G.  A total of 113,000 trees were planted at a spacing of 3 metres between rows and 1.4 metre between trees.

To effectively irrigate this size orchard 165,500 metres of pressure compensating drip line was run using a 4WD quad bike.

With 1.4-million metres of wire, and 22,000 posts, the development  kept teams of fencers working for seven months. 

Complexities and challenges

Prior to planting the long narrow block (450 metres at the widest point, 150 metres at the slimmest) a year of preparation work was needed to change the area from a flood plain to become suitable for fixed crop horticulture.  The landowner established a stop-bank to contain the river, and drainage was put in around the entire block to redirect run-off from the steep surrounding hills back into the river.  Twelve months work went into preparing the land before planting in August 2017. 

As well as being developed in a new “robot-ready” structure this block is also off the grid.  The design therefore needed to use products that are not reliant on electricity or use renewable energy sources.

Description of outcome/solution

DaanDanJain pressure-compensating (PC) anti-syphon dripline was selected.  This enables water application accuracy at variable topograpgy, and the installation of long laterals as needed for this shape block.

The Amnon dripline is ideally suited to subsurface drip irrigation, allowing for accurate orchard irrigation.

The labyrinth design of the dripper allows efficient self-cleaning, and ensures continuous flushing of sediments and small dirt particles. 

With a 2.2 litre/hour flow rate and 0.4m spacing the higher flow rate dripline was selected as it allows for a quicker watering and depth of irrigation. 

The 47 hectares are divided into 16 irrigation zones which are run from 8 irrigation stations.  Flow rate across the zones varies from 5.3 litres per second to 39.8 litres per second and can deliver 1.8mm of irrigation depth per hour.

Twin pumps provide capacity for the irrigation zones to be co-valved to 4 stations per pump.  A rotation time of 22 hours pumping per day allows for 5.5hours per station, equating to an approximate application of 10mm applied.

With no power run to the orchard two 4 cylinder Perkins diesel pumps are used to drive the Goulds 125 x 100 irrigation pump, and solar panels are used to power the irrigation controller.  Two pumps also offers contingency should failure occur.

Monitoring and water application at the orchard can be performed remotely via an online application. 

A comprehensive irrigation control and management system was installed at the Ebbett Block, allowing remote control of the whole system.

Details

Location

Hawke's Bay

Client

T&G Ebbett Block

Year

2018