On Thursday 15th August, we visited Evenden and Red Barn orchards to view the Smart Tools for Orchard Drainage trial blocks.
A few months have now passed since the various drainage treatments were implemented in the trial areas – the soil has settled and the grass is beginning to establish in the interrows.
A group of growers arrived to see the different treatments which we will continue to track to monitor their effectiveness and longevity. One of the main tools we are using is the RutMeter we developed for the project.
The RutMeter automatically measures rut depth and records the location using SBAS GPS for accuracy
After several months, regrassing, pruning and mulching, inter-row 1-2 is looking pretty good. By minimising soil movement during levelling, there is only a small rise/drop between the inter-row and the undertree row ground level.
The inter-row between rows 1 and 2 several months after levelling. been regrassed, then after pruning the branches were mulched. A few weeks for regrowth and the surface should be looking green again
Very good discussion among the growers covered the different treatments, how they affected orchard operations (especially use of hydraladas) and what future remediation they thought would be needed.
Orchard managers are happy with results to date. They think there may need to be work later after wet periods, but the foundation for better surface drainage in in place.
Many thanks to T&G and Bostocks for hosting the trials and the field walks. And project funders, MPIU SFF and NZ Apples and Pears Inc.
We’re not quite sure what to call the job: science manager, extensionist, project manager, consultant? We know it offers diverse activities and needs excellent communication skills and practical knowledge of horticulture and technology.
We are looking for someone to help identify and lead research projects and extension activities across a variety of issues and regions. For the right person, this is a role with considerable potential to grow.
This will be a Page Bloomer Associates appointment. They provide our science, management and support services while having addditional private consultancy activities. Working closely together, we know they share our passion for sustainable land and water management.
Since the dawn of the new millennium we’ve been providing progressive, pragmatic and independent services through projects and consultancy. A key feature of our work is close collaboration with end users, researchers and developers. We talk about “linking thinking from the farm out”.
The role includes engaging with growers, industry and researchers to identify opportunities to review practices and integrate new technologies to create sustainable cropping systems. The appointee will develop and manage projects and support services that support economically and environmentally sustainable primary production.
If you know someone with passion for smarter farming who wants a key role in a small dedicated organisation, Page Bloomer Associates would like to chat with them!
Figure 1. Gene Williams’ levelling blade fitted with Trimble RTK-GPS and FMX with WM-Drain drainage software
Drainage treatments in trial blocks at T&G Global’s Evenden orchard and Bostock’s Red Barn orchard. The narrow window between finishing harvest and the soil becoming too wet to work was longer than anticipated this autumn making the task easier. All earthworks were completed and pasture re-sown. Vehicle access was restricted to allow the pasture to establish and soil to settle.
A range of treatments was included and implemented to compare to the new land shaping approach including Crasborn’s harrow and planter (Figure 2) and Aqualine V-blade, slotting and ripping and rut filling (Figure 3).
Figure 2. Crasborn Orchard Inter-row RutFiller and RegrasserFigure 3. Aqualine fill trailer with splitter to direct brought in fill to rutted wheel tracks
GPS Levelling
Land levelling is a proven technique more commonly used in cropping, where soil is moved around to create fall across a field and allow surface water to drain off. Growers use this approach to reduce water lying on the surface and saturating areas of crop which results in reduce yield. Software is used that is specifically designed to minimise and optimise movement of soil. The height of the blade or scoop used to cut and fill soil is controlled by software through the tractor hydraulics. The same principles are being applied to existing orchard rows to create fall along the inter-rows and drain surface water off the block.
The inter-rows were rotary hoed to create a suitable tilth, to allow small volumes of soil to be moved along the inter-row (Figure 4). The elevation profiles indicated that only light shaping would be required to create fall along the inter-rows, where 100mm would be the maximum change in height (cut/fill) necessary.
Figure 4. Orchard Inter-rows pre and post hoeing, prior to land shaping
Hugh Ritchie’s Trimble RTK-GPS base station was set up in the orchard. Patrick Nicolle’s Trimble FMX unit with WM-Drain software was mounted on the T&G and Bostock tractors. A GPS Control Systems Trimble GPS antenna was mounted above Gene Williams’ 2.5m wide levelling blade, see Figure 1. The tractor hydraulics were used to control the blade height.
WM-Drain was used to record the elevation of each section in the orchard. An accurate RTK-GPS elevation profile was recorded by driving along the inter-row and the WM-Drain software used to generate the optimal profile (Figure 5), within specified parameters, such as minimum slope.
Figure 5. Screenshot of WM-Drain software, the grey area the current ground surface and the green line generated as the optimal profile
Soil was shifted using the blade to cut and fill areas to achieve the optimal profile designed in WM-Drain. Because the tractor hydraulics were not suited to automation without major changes, the blade height was manually controlled using the tractor hydraulics and lowered or raised. Multiple passes (up to six) were required along each row to move soil to create the desired profile. The results of the land levelling are shown in Figures 6 and 7.
Figure 6. Examples of inter-rows after land levelling has been completed
Figure 7. Inter-row profiles after cultivation and before land levelling (grey dotted line) and after land levelling (green line).
After earthworks the alleyways were re-sown in pasture. Vehicle access has been restricted to allow the pasture to establish and soil to settle. Timing is important to ensure orchardists can access blocks to continue their yearly programme in a timely manner, without damaging the newly formed alleyways.
The Crasborn machine cultivates and pulls soil from outside the wheel tracks using a set of angled discs. Harrows are used to break up and smooth the soil. A levelling bar with raised sections above the wheel tracks is used to further even out the soil. A compressed air seeder is used to sow pasture along the inter-row. Finally, a cambered roller creates a crowned inter-row and compacts the soil surface. The all in one implement (Figure 2) completes the final product (Figure 8) in one pass.
Figure 8. Inter-rows after Ricks Crasborn’s implement has been used to cultivate and fill wheel ruts
The Smart Tools for Orchard Drainage project has completed key steps to prepare and implement inter-row land levelling. Terrain analysis has provided a clear indication that a gentle gradient could be developed along the inter-row with minimal soil movement. However, the effects of reducing ponding through slight land shaping would be substantial for management and health and safety in the orchard.
Orchard Contour Mapping
LiDAR data from Hawke’s Bay Regional Council and Gisborne District Council were used to assess the feasibility of inter-row land levelling in the orchard blocks of interest. LiDAR (light detection and ranging) is a type of airborne optical sensing that is used to generate a model of the earth’s surface. It let us create contour maps and look at ground profiles (Figure 1).
Figure 1: Steps for creating interrow profiles: a – LiDAR raw data showing bare earth points (brown) and above ground points (green) from rows of trees (note the difference in the frequency of green points indicating greater tree canopy in the bottom rows in the image); b – contour map created from digital elevation model; c – interrow profiles lines over aerial image; and d – example of an interrow profile
The inter-row profiles were used as a ‘first look’ to estimate the fall across the orchard and provide an indication of the approximate amount of soil to be shifted to remove and prevent areas of ponding.
We also surveyed using ground-based vehicles (quad bike or tractor) with RTK GPS (Figure 2). This system has a vertical accuracy of approximately 20 mm. Corrected elevation data were recorded along the inter-rows using WM-Drain. These data were also used to create accurate interrow profiles.
Figure 2. RTK GPS set up on ground-based vehicles at orchards near Gisborne and NapierFigure 3: Comparison of profiles generated from LiDAR data (grey line) and ground based RKT survey (red line)
The comparison of the different methods of generating profiles has given confidence that LiDAR is useful for an initial block analysis.
Ponding maps
Two of the orchards were visited after a significant rain event (30+ mm over a weekend). Locations of ponding were collected using the ESRI Collector smartphone app and an EOS Arrow SBAS GPS with a horizontal accuracy of 30-40cm. The interrows at one orchard were covered by Extenday, which meant the areas of shallow ponding were difficult to identify (Figure 6).
Figure 6: Recording ponding areas in the orchards’ interrows after a significant rain event
A drainage analysis created in Optisurface was used as a base map to display ponding locations (Figure 7). After this rain event, the majority of areas of ponding appeared to be located within areas identified by the drainage analysis as areas where ponding would occur.
Figure 7: Map of OptiSurface drainage analysis and measured ponding spots – brown represents drier areas and blue/purple areas of ponding. Points locate areas of ponding after a significant rain eventFigure 8: Example of ruts highlighting the issues of ponding and mud splash on the fruit.
The ponding locations were also compared to the interrow profiles. Although no formal analysis was completed, many of the ponding spots appear to match dips in the profiles (Figure 9).
Figure 9: Profiles generated from LiDAR data (grey line) and ground based RKT survey (red line) with ponding areas after a significant rain event identified (blue dots)
Rut depth measurements
The key measurement for monitoring the effectiveness of the different drainage treatments will be the formation of ruts. A sled has been specifically designed to measure and record the depth of ruts and the location within the orchard blocks, see Figure 10.
The sled uses a linear transducer to measure the difference in height between the bottom of the wheel ruts and the ground surface between the wheel tracks. The location is recorded using the SBAS positioning system with an EOS Arrow 100 GPS with a horizontal accuracy of approximately 0.3-0.4m. The data was recorded on a smartphone using an app, Rut-O-Meter. Points are recorded approximately every 0.2m depending on travel speed as the sled was towed by a quadbike along orchard rows.
Figure 10: Sled design to measure rut depth, measuring the difference in height between the bottom of the wheel tracks and the centre of the inter-row.
The average rut depth (of the left and right wheel tracks) throughout the trial block was measured prior to the soil being cultivated. An example of the rut depth along an orchard row and the corresponding elevation profile are presented in Figure 11.
Figure 11: Example of matching rut depth measurements (a) and elevation profile (b).om the rut measuring sled is presented in Figure 18. The measured rut depths appear to correspond to the drainage analysis (Figure 19) completed in OptiSurface.
A map from the rut measurements is shown in Figure 12. Deeper ruts are darker blue. Pale yellow is no rutting or the inter-row is lower than the wheel tracks. This compares well with the OptiSurface generated ponding map of the block (Figure 13).
Figure 11: Map created from the rut depth measurements from the trial block
Figure 13: OptiSurface drainage and ponding analysis from RTK survey of the trial block
Conclusions
Analysis of LiDAR data and ground based RTK elevation data has shown that land levelling should be possible with minimal soil movement.
The ground based RTK survey, with the GPS antenna on a 2m pole has proven that the connection is not interrupted through dense tree canopies.
The use of the SBAS system, a cell phone and EOS Arrow GPS receiver allows information to be recorded against individual trees, with an accuracy of 30-40cm, even in dense tree canopy.
The ponding areas identified in the orchard after a significant rain event appear to show a relationship to the OptiSurface drainage analysis.
The Rut-O-Meter mapping shows good agreement with the other surveys
Project work by Page Bloomer Associates for NZ Apples and Pears Inc and MPI Sustainable Farming Fund
Do we really know why we farm as we do? Or are we constrained in ways we just don’t see?
Often our current practices have evolved over a very long time – thousands of years of human history, decades of technology developments. Remember the space shuttle and the horse’s rear? We’ve long forgotten some of the reasons behind what we do, so maybe it is time for a reset!
Orchard drainage isn’t just about shedding excess surface water quickly – although that is the main aim. Effective orchard drainage mitigates wheel rutting in the interrow which contribute to slips, trips and falls of orchard staff, and restrict orchard access by machinery at critical times of the year (such as harvest).
At LandWISE 2019 we will be taking a closer look at orchard drainage – and the tools and technology that are making it possible in existing orchards.
First up on the programme for Session 3 will be a progress update from Year 1 of Smart Tools for Orchard Drainage. From surveying growers, to analysing LiDAR data, and mapping puddles, there has been considerable progress made preparing for the land levelling work. We look forward to sharing this with conference delegates at LandWISE 19.
Contour Map Example
Mapping ponding using a handheld GPS unit
Ponding and Puddling: Comparing survey and computer generated ponding maps and the locations of puddles (white dots) after a rain event.
Following on from the project update, will be an in-depth presentation about the technical side of mapping land contours.
Technologies that have made the orchard drainage project possible include:
LiDAR (Light Detection And Ranging) a remote sensing method using a pulsed laser light to determine the distance to the earth from an aircraft that enabled us to create contour maps of existing orchards
ESRI ARC GIS, OptiSurface and other software packages for analysis and planning
RTK-GPS and drainage surveying and implementation software
SBAS (Satellite Based Augementation System) which allows us to get very accurate location on our smartphones when scouting
These technologies have a range of applications for horticulture, and have huge potential to improve the precision of our operations – whether in crops, orchards, or vineyards.
RTK-GPS mounted on qud bike and quad tractor (the funnest survey tool ever).
We’ll have our newly developed RutMeasurer available for viewing at the Field Session. We are using it toaccurately measure ruts in orchard inter-rows, and will be able to repeat measurements over time to assess the effectiveness of the different rut fixing approaches taken.
RutMeter – designed for the project to measure the depth and length or inter-row ruts
The MPI Sustainable Farming Fund “Smart Tools to Improve Orchard Drainage” project was initiated in response to extreme weather conditions experienced by pipfruit growers in the late season (March – June) harvest of 2017. It is co-funded by New Zealand Apples and Pears Inc.
A survey conducted over 3 weeks in November and December of 2018 covered 2,238 hectares of pipfruit growing orchards. Conducting the survey with growers via face-to-face interviews produced a greater number and depth of answers, however certain details were still difficult to obtain. Many growers were hesitant to provide or lacked confidence in estimations of the extent and area of wheel rut damage as a result of poor drainage.
To help with consistent assessments, we created a four panel photo scale of drainage issues found in orchards (see below). Growers interviewed considered the scale realistic and relevant. They felt able to correctly match problems areas in their blocks to the photos, but differed in their assessments of how much of a problem it might be.
The key impacts on operations identified by
the survey were predominantly categorised into three areas; tree health,
access, and labour. Almost all orchardists surveyed believed that poor drainage
was contributing to poor tree health (either visibly or evident through low
yield) or causing tree deaths (up to 10% in one extreme example). Many
orchardists remarked on wheel ruts resulting in staff injuries (due to ladder slips
in mud, tripping, or the impact of driving over uneven surfaces). Labour
availability was also affected in severe cases where orchard ponding and ruts
were the reason some contracting groups did not want to work at those sites. In
all cases where extreme damage was present, access for sprayers, and tractors
hauling harvest bins was impeded, and occasionally impossible. This meant that
costs were incurred as a result of delaying harvest windows, slowing the pace
of operations, and risking greater levels of disease at an already busy time of
year.
Situational factors common among the
orchards studied included:
Frequent passes by heavy orchard
machinery for many months of the year (7 – 11)
Low spots in the in the
inter-row were the worst affected
Shaded canopies associated with
3D training and mature plantings
The area affected was 44% of the area surveyed (1,479 ha).
Tree Health
Tree trunk width comparison on a poorly drained block left: high elevation spot, right: low elevation spot
Tree health suffers as a result of poor drainage and water-logging of the soil. This was evident in the Motueka and Richmond site visits, where trunk diameter was clearly smaller to the untrained eye in low spots where ponding and wheel ruts were severe. The same observations were made during site visits in Nelson and Hawke’s Bay.
Other important comments included a
noticeably lower yield from trees where drainage problems were evident, and some
bins where mud had covered fruit during harvest resulted in a greater number of
fruit rots in post-harvest storage. One grower also mentioned that the fruit on
Fuji varieties developed russet in the worst affected areas.
Access to the orchard is critical at certain times to complete operational tasks. Where an orchard has particularly severe drainage problems the wheel ruts may be so extreme that tractor or sprayer axles drag through the mud, meaning that they are stuck or unable to enter the block. This has led to some orchardists hiring helicopters to apply fungicides when application during a specific time window is crucial. This is an expensive exercise, and is unable to be utilised for insecticide sprays, as the application method is not effective at reaching the internal area of the canopy. The mud and ruts from poor drainage make harvesting difficult and time consuming as tractors require towing (by another or multiple tractors) out of the mud when they become stuck.
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.
We’ve made a good start on the orchard drainage project, visiting sites in Gisborne, Hawke’s Bay and Nelson.
Many thanks to Illawarra Orchard, T&G Global, MrApple, Bostocks NZ, KONO Horticulture and Waimea West for your active involvement.
The sites confirm the need to address drainage and the consequent track rutting and associated problems in each of the regions. We have begun our survey of sites and regions, aiming to get some objective assessment of the amount and severity of problems, where they most occur and what solutions may be applied. We already see there will not be a one-fix-for-all!
The Gisborne site that initiated the project looks better than it did after harvest 2017. But the issues remain, and we’ll be surveying and planning how to reshape inter-rows to allow surface drainage.
Gisborne orchard after harvest 2017
In Motueka, our preliminary site visit saw the same problems and similar severity. The solution will not be the same, as the land contour is very different and the are no clear exit points for water once it does leave the tree blocks.
Severe rutting in Motueka Orchard
The orchard team has been applying a range of drainage remedies with varying success.
A drainage sump installed in Moteuka. Sumps widely used in low spots, but prone to blocking after a short time.
We visited a number of Hawke’s Bay sites on different soil types. One block in Twyford is being replanted, and pre-plant levelling was carried out. We are looking to trial inter-row levelling in established blocks, with surface water moved to tiles installed at the end of rows.
Installing novaflow in Twyford orchard – pea metal fill to ground level to facilitate entry of surface drainage for inter-rows
