Category Archives: Water

Soil to sprinkler, automating irrigation management

Anthony (Tony) Davoren is a Director of Aqualinc with responsibility for the HydroServices business unit that provides irrigation and environmental management services; soil moisture, and water level and water meter monitoring. 

Tony’s expertise in and knowledge of soils and hydraulic properties, irrigation systems and design, and crop water demand has been applied and enhanced over the last 35 years working in these fields.

We asked Tony to talk about automating irrigation – from the soil to the sprinkler and round again. He’s doing just that at LandWISE 2017: Are we ready for automation?

Tony says several questions need to be asked and honest answers or solutions given:

  • Are we and you ready?
  • What do we need?
  • Is automating irrigation management wise or the right solution?

Are we or you ready?

When considering automating irrigation management, both the provider and the user must be an “innovators”; i.e. they must be in the top 2.5% of the industry.  It may be that some “early adopters”, the next 13.5% of the industry, might be ready for the technology and its application to automate irrigation management.

What do we need?

Because it will be the innovators who adopt and field prove any technologies, these technologies must be robust and proven with a sound scientific backing.  Innovators will identify the financial benefits of the automation, which needs:

  • Well-designed irrigation systems
  • High uniformity irrigation systems
  • Well maintained irrigation systems
  • Precise soil moisture and/or crop monitoring systems
  • Interface “model” to irrigation controller

Are these all in place?

Is automation wise or the right solution?

Tony established HydroServices providing on-farm irrigation management services based on in situ soil moisture measurements in Canterbury, Pukekohe, Waikato, Gisborne, Hawkes Bay, Manawatu, Wairarapa and Central Otago. During this he provided specialist soil moisture monitoring for Foundation for Arable Research, LandWISE, Crown Research Institutes, Regional Councils, Clandeboye Dairy Factory and others.

Tony completed his PhD in Engineering Science at Washington State University, Pullman, USA.

Benchmarking Onion Variability 2016-17

Now in year two of our OnionsNZ SFF project, we have trials at the MicroFarm and monitoring sites at three commercial farms in Hawke’s Bay and three more in Pukekohe.


A summary of Year 1 is on our website. A key aspect was testing a range of sensors and camera systems for assessing crop size and variability. Because onions are like needles poking from the ground, all sensors struggled especially when plants were small. This is when we want to know about the developing crop, as it is the time we make decisions and apply management.

By November our sensing was more satisfactory. At this stage we captured satellite, UAV, smartphone and GreenSeeker data and created a series of maps. 

We used the satellite image  to create canopy maps and identify zones. We sampled within the zones at harvest, and used the raltioship between November canopy and February yield to create yield maps and profit maps.

Yield assessments show considerable variation, limits imposed by population, growth of individual plants, or both

We also developed relationships between photographs of ground cover, laboratory measurements of fresh weight and leaf area and the final crop yield.

In reviewing the season’s worth of MicroFarm plot measurements and noticed there were areas where yield reached its potential, areas where yield was limited by population (establishment), some where yield was limited by canopy growth (development) and some by both population and development.

This observation helped us form a concept of Management Action Zones, based on population and canopy development assessments.

Management Action Zones – If population is low work for better establishment next season. If plants are small see if there is something that can be done this season


Our aims for Year 2 are on the website. We set out to confirm the relationships we found in Year 1.

This required developing population expectations and determining estimates of canopy development as the season progressed, against which field measurement could be compared.

We had to select our “zones” before the crop got established as we did a lot of base line testing of the soil. So our zones were chosen based on paddock history and a fair bit of guess work. Really, we need to be able to identify zones within an establishing or developing crop, then determine what is going on so we can try to fix it as quickly as possible.

In previous seasons we experimented with smartphone cameras and image processing to assess canopy size and relate that to final yields. We are very pleased that photographs of sampling plots processed using the “Canopeo” app compare very well with Leaf Area Index again this season.

Through the season we tracked crop development in the plots and using plant counts and canopy cover assessments to try and separate the effects of population (establishment) and soil or other management factors.

We  built a web calculator to do the maths, aiming for a tool any grower or agronomist can use to aid decision making. The web calculator was used to test our theories about yield prediction and management zones.

ASL Software updated the “CoverMap” smartphone application and we obtained consistent results from it. The app calculates canopy ground cover and logs data against GPS position in real time. Because we have confidence that ground cover from image processing is closely related to Leaf Area Index we are working to turn our maps into predictions of final yields.

Maps of canopy cover created from the CoverMap smartphone application show significant variability across the paddock. Canopy increase is seen over time in two maps created a week apart

The current season’s MicroFarm crop is certainly variable. Some is deliberate: we sat the irrigator over some areas after planting to simulate heavy rain events, and we have a poorly irrigated strip. We know some relates to different soil and cover crop histories.

But some differences are unexpected and so far reasons unexplained.

Wide variation within the area new to onions does not follow artificial rain or topographic drainage patterns. This photo is of the area shown far right in the cover maps above.

Together with Plant and Food Research we have been taking additional soil samples to try and uncover the causes of patchiness.

We’ve determined one factor is our artificial rain storm, some crop loss is probably runoff from that and some is historic compaction.  We’ve even identified where a shift in our GPS AB line has left 300mm strips of low production where plants are on last year’s wheel tracks!

But there is a long way to go before this tricky crop gives up its secrets.

This project is in collaboration with Plant and Food Research and is funded by OnionsNZ and the MPI Sustainable Farming Fund.

We also appreciate the support of growers, seed companies and our MicroFarm sponsors Ballance AgriNutrients, BASF Crop Protection and the Centre for Land and Water.


Drainage and Erosion Planning

The Arawhata Catchment Integrated Storm Water Management project is drawing to a close, the majority of work is done but farm follow-ups continue. The aim of the project was to reduce crop loss from ponding and minimise erosion of soil to Lake Horowhenua. 

We completed OptiSurface drainage analyses for 26 Levin properties covering 450ha of intensive vegetable cropping. OptiSurface calculates flood patterns and erosion risk and creates cut & fill maps for GPS levelling. An example is shown in our earlier post “Mapping for Drainage”.

Drainage and Erosion Management Plans were developed for each block. The plans identify drainage problem areas and erosion risks and recommend management strategies to respond.

Individual farms have done significant work to prevent erosion and reduce crop damage. Farmer actions to reduce sediment runoff and ponding include realigning bed direction, levelling, grassed headlands and drains and swales and sediment traps.

Stages in headland redevelopment

Original design used narrow headlands subject to pugging in wet weather with high risk of slumping soil into vegetation-free drains
Headland lowered to ensure adequate drainage from furrows. Vegetation being encouraged to protect drain from sediment inflows
Land-shaping created a much wider headland for a greater vegetation buffer between cultivated land and drains
Completed headland with its well-established vegetated buffer filtering sediment from drainage water

Now farms are required to have consent in this catchment, the Drainage and Erosion Management Plans are a useful component of the overall Farm Nutrient Management Plans required.

Onion Crop Development

The crop at the MicroFarm is showing increasing variability.  The cause of some is understood, essentially excessive water pre-germination.  But in some poor performing areas the causes have yet to be determined.

The effect of our artificially applied rain event pre-emergence is clearly evident in late November.

The lasting effect of a heavy (artificial) rain event pre-emergence (right panel) shows low population and poor growth compared to areas without heavy rain (left panel)
The lasting effect of a heavy (artificial) rain event pre-emergence (right panel) shows low population and poor growth compared to areas without heavy rain (left panel)

However, we also see other areas that have poor crop development that are outside the area irrigated to create the artificial rain event.

Wide variation within the area new to onions does not follow artificial rain or topographic drainage patterns.
Wide variation within the area new to onions does not follow artificial rain or topographic drainage patterns.

Sharp differences in crop growth are evident in the new onion ground. Some parts that were heavily irrigated to simulate heavy rain show reasonable development. Areas that were not irrigated also show good development, but in some patches total crop loss.

Investigations of soil physical properties in these different areas are underway.

Technology to Reduce N Leaching

N-Leach_WorkshopThe Precision Agriculture Association NZ is presenting workshops focused on technologies available to help reduce nitrogen leaching. There are two North Island workshops being offered at:

Massey University on Thursday 1st September 2016 [PDF here]


Ellwood Centre, Hastings on Friday 2nd September 2016 [PDF here]


The ‘Technology to Reduce N Leaching’ workshops are similar to the well received program conducted in Ashburton in March 2016 and will address where we are and what we can do about nitrate leaching limits in a North Island context utilising a range of technologies and farm systems options.

The particular areas for focus for the program are:

  • Variable rate technologies and systems
  • Precision irrigation
  • Precision spreading systems and services
  • Soil mapping
  • Soil moisture monitoring, sensors, metering
  • Nutrient budgeting and environmental monitoring

A Q & A time slot is devoted in the afternoon session for attendees to interact with members and presenters on the day to share learnings and understandings about the issues. This will also be possible over the lunch break on both days with one and half hours devoted for this.


Offer to PAANZ Members

As part of the Hastings program only on 2nd September, PAANZ members are offered the opportunity to participate as trade/sector participants for technologies and products as may be appropriate to support the program.

PAANZ is not able to offer trade/sector stand space at the Palmerston North venue due to space restrictions unfortunately so only the Hastings venue will be able to accommodate this option for members.

If you would like to participate please advise Jim Grennell, E-mail:

Mobile: 021 330 626, places are limited to ten organisations for the Hastings workshop to be involved as a trade/sector participant so it will be on a first come basis.

The cost of participation will be $100.00 plus GST per stand with attendance fee of $100.00 per person additional.

As these are indoors Workshops, with a technology focus and space at the Hastings venue is limited no large equipment or hardware can be accommodated.

Confirmation of members wishing to take up this opportunity is required by Monday 22nd August 2016 after which time the opportunity to participate will be made available to non-members.

Profit Mapping Variability in Onions

Profit Bands Across A Paddock

 Justin Pishief

Justin Pishief and Dan Bloomer
Centre for Land and Water


As part of the Onions NZ project “Benchmarking Variability in Onion Crops” a process was developed to generate yield and profit maps. This presentation explains the process using the example of a 7.3 ha paddock in Hawke’s Bay.

Data from a satellite image captured in late November were used to identify high, medium and low biomass zones.  Paddock yield samples were taken from these zones at harvest and used to generate a paddock yield map. The average yield of the paddock was estimated at 95 t/ha, with a predicted total field harvest of 669 tonnes. This compares to the grower recorded harvest of 614 tonnes.

The relative yield data were combined with grower supplied costs and returns to determine gross margins across the paddock. Data were mapped in ArcGIS and a Gross Margin map with five “profit bands” produced. The highest band had a mean Gross Margin of $11,884/ha compared to the lowest at $3,225/ha.

The breakeven gross margin yield is estimated to be 62.5 t/ha at current costs and prices. The estimated cost to business of low performing areas is $27,945, assuming the whole paddock could achieve the top band mean yield.

The poorest performing areas were identified by the grower as impacted by a failed council drain and areas of slowed drainage in the main paddock areas. An OptiSurface® assessment using historic HBRC LiDAR elevation data analysed of the impact of ponding on the site and also suggested ponding was a significant issue.

An OptiSurface® landform assessment was conducted using both single plain and optimised surface designs and the soil movement required to allow effective surface drainage was determined.

The assessment showed ponding could be avoided by land shaping with 224 m3/ha soil movement and few areas requiring more than 100 mm cut or fill. The cost is estimated at $2,000/ha or approximately $14,000 total.

Rootzone reality – measuring nutrient losses

Drainage fluxmeters in commercial fields across the regions

P Johnstone, M Norris, S Green, G Clemens, C van den Dijssel, P Wright, G Clark & S Thomas
Plant & Food Research

Minimising nutrient losses from cropping systems makes good financial sense. It also minimises any adverse impacts on our waterways, which is increasingly important in many regions as new national water policy requirements are implemented.

A common theme in many regions is the requirement that growers should, as a minimum, be managing nutrients according to agreed good management practices. However, there is relatively little long-term measurement of how good management practices throughout New Zealand impact losses of nitrogen (N) and phosphorus (P) from cropping paddocks.

To help fill this gap a network of permanent drainage fluxmeters has been established in commercial fields in the Canterbury, Manawatu, Hawke’s Bay, Waikato and Auckland regions over the last 18 months. There are a total of 12 sites in the network, covering a broad range of cropping systems, soil types, climatic conditions and management practices.

At each site fluxmeters have been installed at a depth of 1 m.  Any water from rainfall or irrigation events that drains to 1 m is captured by the fluxmeters. It is then pumped to the surface and analysed for nutrient concentrations. Net losses can be estimated by combining these measured concentrations and measured drainage volumes.

Preliminary results from the network have highlighted a wide range in N and P losses in drainage water. Many of the losses have been comparatively low to date, evidence that economic and environmental risks can be successfully balanced through the integration of good management practices.

Where high losses have been observed this has resulted from large drainage losses and high nutrient concentrations in the drainage water.

Importantly, this is a long-term initiative and the value of the information from the network will increase over time as growers and regional authorities consider long-term trends.

Investigating variability in potato crops

Sarah SintonLandWISE 2016 Conference presenter Sarah Sinton is a well experienced member of a Plant and Food Research group studying potatoes.

In the 2012-13 growing season the Plant and Food researchers surveyed commercial potato crops in Canterbury and confirmed grower concerns that a “yield plateau” of approximately 60 t/ha was common.  At this level, potato growing is becoming uneconomic.

Plant and Food Research computer-based modelling shows that yields of 90 t/ha (paid yield) are theoretically possible in the surveyed paddocks in most years. This shows a “yield gap” of about 30 t/ha.

The most important factors found to be reducing yield were soil compaction, the soil-borne diseases Rhizoctonia stem canker and Spongospora root galls.

Tuber health, disease management, soil compaction and irrigation all have ability to reduce yields

Using CORE funding, Sarah and colleagues have been running a number of related trials, comparing field performance with modeled potential growth rates. They’ve used DNA to assess soil pathogens, applied a range of treatments and measured disease incidence and yields. They have also looked at the role of seed quality in potato emergence, variability and yield.

But it is not all about diseases. Soil compaction, structure and related issues such as aeration, drainage and water-holding show up as crop limiting factors.  Also implicated are irrigation management and weeds.

Potatoes NZ reports that the use of guidance technology and variable rate application based on soil testing is being undertaken but there is limited crop based management of inputs.  There may be opportunity to manipulate some inputs.

In paddock variability can be relatively easily identified using remote sensing equipment (both NDVI and Infrared) but there are three major problems with potatoes which are:

  • Remote sensing can identify differences in a paddock but these need to be ground truthed to determine what the reason for the difference is – e.g. canopy disease etc.
  • Often by the time a difference is apparent on a crop sensor map, even when it is ground truthed, growers cannot implement a management decision that will change the crop performance.
  • Yield maps are generally used as the baseline reference for Precision Agriculture and this is difficult and expensive to implement for potatoes.

Sarah is presenting some of her group’s work at LandWISE 2016. Look for “Investigating variability in potatoes”.

Excellent LandWISE 2016 Conference Speakers

We published the list and short biographies of our invited speakers today. We are again privileged to have an extremely knowledgeable group representing farmers, technologists and researchers from both sides of the Tasman Sea.

Conference keynotes and new LandWISE Australians include Ian Layden and Julie O’Halloran, precision horticulture researchers and extension specialists from the Queensland Department of Agriculture and Fisheries (DAF).

Ian and Julie are leading a group of two dozen top growers and agronomists for a week of related events built around the LandWISE Conference. Queensland farmer Ben Moore and Tasmanian farmer Robbie Tole will present their own experiences investigating precision horticulture opportunities.

Returning LandWISE Australians are Tristan Perez from Queensland University of Technology and John McPhee from the University of Tasmania. Tristan will update us on progress with weeding robot AgBot II and Harvey the capsicum picker. John will tell us about precision horticulture research underway in Tasmania.

Parallel work is being done in New Zealand. Look for reports from  Plant and Food researchers Sarah Sinton, Paul Johnstone and long serving LandWISE Board member Bruce Searle. Chris Smith from AgriOptics, Jane Adams of OnionsNZ and LandWISE’s Dan Bloomer and Justin Pishief will overlay a series of precision cropping and related topics.  Charles Merfield from the Future Farming Centre will give a review of biostimulants and related technologies – a different aspect of the agritech revolution.

Rounding out Day 1 are agritech accelerator Sprout Entrepreneur in Residence Stu Bradbury and two accelerating companies represented by Tom Rivett and Julian McCurdy.

Day 2 has a focus on value from data and robotics. We hear a lot about “big data” and “value chains”: what are they? Alistair Mowat, James Beech and Megan Cushnahan will tell us how they and others are getting real value, and where there’s still value to be tapped. Roger Williams will outline how Plant and Food is investing in digital horticulture research.

Lincoln Agritech’s Armin Werner has been a regular attendee at LandWISE. This year he takes the stage with a global review of field robotics and weeding technologies in particular. Kit Wong will tell us about Callaghan Innovation development of systems for machine vision to manage onion crops.

David Herries of Interpine will take us to a different sector and explain how UAVs are giving value in forest research and management.  And rounding it all up, Simon Morris of ALtus UAS will make sure we understand the regulations governing our use of this still new but very powerful technology.

So come to LandWISE 2016: the value of smart farming. Have you mind expanded, your knowledge updated and your excitement kindled. Mix and mingle with leaders in farming, agronomy and agtech!

Conference programme here>

Speaker biographies here>

Conference registration here>


New food production paradigms: why farm systems are changing



A public lecture offered by the Hawke’s Bay Branch of the Royal Society of New Zealand

Dr Charles Merfield, Director
Future Farming Centre, Biological Husbandry Unit Lincoln

7:00pm – 8:30 pm, Wednesday 26th August 2015
Hawke’s Bay Holt Planetarium, Chambers St,  Napier

13032009338 smModern farming systems are 70 years old. They have been very successful at meeting their key aim; maximising food production. However, society is asking farmers to take on new aims including providing ecosystem services to protect and enhance the environment.

Four key technologies created modern farming: fossil fuels, synthetic nitrogen fertilisers, soluble lithospheric fertilisers and agrichemical pesticides. There are increasing issues with each of these both from the input (e.g. cost, resistance) and outcome (e.g. pollution) sides.

Sustainable agriculture is smart agriculture that uses all available tools to find long lasting alternatives. A key to developing and analysing farm systems is overlapping the sciences of physics, chemistry, biology and ecology. Sustainable farming can be viewed as a martial art, probing and testing the opponent’s strengths and weaknesses then using smarts, not brute force, to win the contest.

Viewing farming through the eye of Darwin’s Law of Evolution will allow more sustainable and durable solutions to be developed.

Charles MerfieldDr Charles Merfield is the founding head of the BHU Future Farming Centre which focuses on ‘old school’ agri/horticultural science and extension.

Charles studied commercial horticulture in the UK and then spent seven years managing organic vegetable farms in the UK and NZ.

In the mid 1990s he moved into research, focusing on sustainable agriculture including soil management, pest, disease and weed management general crop and pasture production.

He has been fortunate to work and experience agriculture in diverse range of countries including NZ, UK, Ireland, USA and Uruguay. He therefore has a broad knowledge of real-world farming as well as science as well a deep understanding of the history of agriculture and science, which enables him to paint the big-picture of where modern farming has come from and where it is going.

Thanks to the Foundation for Arable Research, Charles Merfield will also be offering one day workshops for farmers and industry.  For details see the FAR website>