AgTech, Drainage, Orchard, Precision Agriculture, Projects, Research, Soil

Modelling Drainage in Orchards

As part of the MPI Sustainable Farming Fund “Smart Tools to Improve Orchard Drainage” project co-funded by New Zealand Apples and Pears Inc., we have been modelling drainage on case study orchards in Hawke’s Bay and Nelson.

Aerial images can show orchard canopy differences and indicate where tree growth is slowed or trees have died. This can be the result of poor drainage.

Aerial image of Illawarra orchard in Gisborne showing visible areas of missing and sparse canopy

We obtained LiDAR elevation data from the Hawke’s Bay Regional Council and Gisborne District Council which allowed us to create very detailed contour plans in ArcGIS – provided to us by ESRI and Eagle Technologies. An example is shown here, using LiDAR from Gisborne.

Detailed contour map of apple block at Illawarra in Gisborne,
created from LiDAR data provided by Gisborne District Council

We can see that the block should drain from the high left (brown) corner to the low right (blue) corner. But when we examine the ground profile along the rows, we see the grade is not even.

Uneven grade along the inter-rows stops surface drainage, keeping soil wet for longer and creating conditions for pugging and wheel-track rutting.

A similar story is seen in the Hawke’s Bay case study orchard. Using HBRC LiDAR data, another contour map was made.


Detailed contour map of apple block at Evenden in Twyford,
created from LiDAR data provided by HBRC

Again, inspecting the ground profile shows areas where surface drainage is held up, keeping soils wetter for longer.

Profile of inter-row showing areas where surface drainage is held by rising contour.

Our next step is to survey blocks with high accuracy RTK-GPS, measuring the profiles on the ground. We can use these profiles to design new inter-row profiles, and determine what cut and fill will be needed to ensure the rows can drain effectively. We will mount the GPS antenna as high as we can to avoid trees blocking the satellite signals.

A GPS antenna mounted on a 2 m mast to avoid signal obstruction. We have a 3 m mast option for larger, older orchards. The aerial connects the rover GPS on the quad, to a base station that determines and corrects for signal shift to give best possible accuracy

Many thanks to all the people at Illawarra Orchard, T&G Orchards, Bostock Orchards and to GPS Control Systems for your continuing support with this project.