Category Archives: Irrigation

Soil Moisture Monitoring


HydroServices continues to monitor our crops weekly using neutron probes to assess soil moisture status.

We use their measurements and reports to plan our irrigations.  We also consider predicted weather using MetService, and HortPlus services. But we don’t always get it right.

For example, on 3rd November we irrigated our onion crop, aiming to get the irrigator around to the peas for the following day. At the time we were told of a 10% chance of significant rain. After filling our profile, we got a lot of rain and most was effectively wasted. You can see that in the HydroServices report here>.

Since November we’ve pretty much kept within the target range of full point to stress point with 15-18 mm irrigation events.

We are finding that 15-18 mm is around the most we want to apply for efficient irrigation. If we apply larger amounts we get surface run off to low spots. While we can prepare a budget that says we applied it, we are not able to account for the full amount in soil moisture readings.

Surface ponding onions
Surface ponding in onions crop following 20 mm irrigation application

The low spots in our onion paddock are easily seen in this image. We could help drainage from the wheel tracks by furrow dyking to hold water where it falls, and by ripping a slot to allow drainage through the compacted track. But we also observe increased run off from the beds to the wheel tracks when heavy applications are made.

In field crops such as vining peas and process sweetcorn we also see lower application efficiencies if we attempt deeper irrigation events. So it is not just wheel track compaction that is involved. We think our soil’s infiltration rate slows significantly once it gets wet. It just won’t let the extra soak in fast enough.

Monitoring variability in soil moisture

We are familiar with soil moisture changing over time, and aware that there are differences between different soils and different crops. But what about variation within a crop on the same relatively similar soil?  Is any soil the same?

The MicroFarm is collaborating with Wintec Research & Development to investigate using cost effective sensor technologies to monitor soil moisture at a large number of points in a paddock.

Installing Sensor Array
Gert Hattingh from WINTEC Research & Development installing wireless sensor node at the MicroFarm


In our first trial on a sweetcorn crop, we established an array of sensors connected wirelessly and to the cloud. At each of nine positions, three sensors measure soil moisture at 10cm, 30cm and 50cm depth.

At three positions the sensors are running in parallel with HydroServices neutron probe measurement sites. This provides in-situ calibration and enable us to compare the moisture patterns of the new sensors against the industry “gold standard”.

View the neutron probe data here>

WINTEC has developed ways to present the data on-line and allow it to be queried. We look forward to seeing our soil moisture in near real time, viewable by soil depth at various positions across the crop. We will be focusing on improving our understanding to better manage and operate our Drumpeel Farms linear move irrigator.

2014 Peas – crop summary

Tasman Harvester Contractors dealing with wide pea maturity range - crop harvested early at average TR=91
Tasman Harvester Contractors dealing with wide pea maturity range – crop harvested early at average TR=91

With four of our paddocks in vining peas this spring, we keenly awaited the harvest. It came late, but still early . . .

High levels of damage in the more tender areas reduced yield
High levels of damage in the more tender areas reduced yield. Both lots from same sample and at same scale – peas on left mature, on right immature and damaged during harvest

All four paddocks were planted on 29 August by Patrick Nicolle using a 3m Great Plains drill. Significant damage done by pigeons at all stages from planting through germination and early growth. Tim Geuze implemented a bird management programme.

We plan to use Cosio covers on plots in paddocks in future, in part to assess the degree of bird damage we suffer.

We know from weather records that this spring was cold. FAR‘s Maize Action news shows that Hastings had only half the average Growing Degree Days from 15 September to mid-December. Cold weather means crops mature slowly, and we certainly saw a long period of flowering in the pea crops.

We did receive higher than average radiation – the factor that most drive biomass growth. And we did see good canopy development.

The paddocks received about 75mm of irrigation as four lots from the linear irrigator. HydroServices recommendations were based on neutron probe monitoring in P3 and P4. The data show that the paddocks used the same total amount of water but from different parts of the soil profile.

With drawn out flowering and cold temperatures, there was a wide spread of pod fill across and within the Paddocks. P3 and P4 continued flowering up until harvest. Some base pods were over optimum maturity (TR ~ 130) while others were only just beginning to fill.

An extended flowering period gave wide range in pea maturity - difficult for harvesters
An extended flowering period gave wide range in pea maturity – difficult for harvesters

The average results across all four paddocks were:

  • TR 91
  • Net Weight 11.040 t
  • Deductions (%) 4.6 %
  • Paid Weight 10.532 t
  • Paid Weight 4.713 t/ha

Spring at the MicroFarm

Two thirds of the way through spring our micropaddocks are approaching full canopy. Onions that progressed so slowly over winter are growing rapidly and peas planted in September are well established. A key question now is when to irrigate.

ThinkWater installed flushing sub-mains in our drip irrigation block and that system is all primed. We expect to run the dripline every couple of days, applying 10mm of irrigation.

Ritchie from ThinkWater finishing the flushing valve installation on the buried-drip in paddock 2
Ritchie from ThinkWater finishing the flushing valve installation on the buried-drip in paddock 2

With wheels and a sprinkler package from WaterForce, our Drumpeel linear irrigator is finished, fully commissioned  and tested and has completed its first lap of the MicroFarm.

Drumpeel Linear irrigating our onions
Drumpeel Linear irrigating our onions


Thanks to a radiometer from Steve Green and anemometer from Plant and Food Research we have a full set of climate readings on-site. HortPlus use the radiation and wind speed together with temperature and humidity to produce PET readings so we can track water use as well as rainfall. See details here>

We complement the climate data with soil moisture monitoring. Our weather station has an Aquaflex sensor which is tracking dryland pasture soil water content.

We need to adjust PET to our crops’ individual ET values. This means reducing potential pasture water use to a partial crop cover water use. The crop factor is a combination of crop type, ground cover and soil surface evaporation and prior to canopy closure most growers will be making best estimates. We have been working with a developer on a simple sensor to help assess groundcover. Figure 2 shows sensor images and percentage of ground cover (green) in two areas of peas.

So what is the actual soil moisture in the different paddocks? HydroServices installed neutron probe tubes into our crops and gives weekly status reports. The neutron probe data is collected as a number of depths through the profile, so it also helps determine active root depth. We just got to trigger point in before 18mm of rain fell. A week later we got another 8mm to top things up.

This spring we also tried Cosio® cover cloth on the onions and the peas. We were a bit late getting the covers and so didn’t get all the information or benefits we hoped for. We covered the onions at early two leaf stage and left them on for several weeks. In that time they caused some plant form disturbance and the more horizontal leaves did appear to get some chemical burn. Next time the covers will be on much earlier, possibly from planting, and off at two leaf stage.

We also covered the peas. This was in part due to frustration of pigeons consuming vast quantities of seed then later nipping the shoot tips of the survivors. More shotguns earlier next season! Although there was likely some seed loss before we got the covers on, we did see significantly more growth in the covered areas. When we first took the covers off, our ground cover sensor suggested as much as 50% more under the covers. The plants were notably taller and visibly covered more ground. Weeks later there is still a significant difference.

Vining peas after three weeks covering by Cosio cloth
Vining peas that were covered by Cosio cloth for three weeks showed 15% more ground cover

Once again though, the pea crops have high variability, both population count and plant size. When we harvest a whole crop in a matter of hours, being days apart in maturity is not acceptable.

The MicroFarm discussion group determined to put strong focus on preparation and planting next time. Peas can be a profitable crop, especially in combination with a second crop such as sweetcorn or beans. But if we don’t get even germination, even development and higher yields, it can be a great disappointment. We think growers should pay attention to this crop, aim to do well from it, and avoid temptations to do everything as cheaply as possible.

Linear Move On-site

Thanks to Hugh and Sharon Ritchie the MicroFarm now has a linear move irrigator.

The Ritchies replaced the original linear at Drumpeel, and after Hugh made some necessary adjustments, arrived with a truck and trailer carrying a single span linear and a Manitou to put it up with.

Progress Day 1

We followed progress on Day 1, which saw the basic structure erected and the power plant in place.

The next stage is filling the hydraulics, connecting the electrics, and sorting out the plumbing. Rather than use the full span pipe, we intend to carry an under-slung lateral to supply 11 nozzles. We will only be pumping about 4.7 L/s.

And we need to find some wheels. . . .

Buried-drip flushing manifold installed

Our pre-season maintenance reached a milestone when ThinkWater installed a flushing manifold. We ran without flushing for the first season, relying on the high quality of our bore water. But definitely a better plan to have flushing!

Ritchie from ThinkWater finishing the flushing valve installation on the buried-drip in paddock 2
Ritchie from ThinkWater finishing the flushing valve installation on the buried-drip in paddock 2

Because the block is split in two length-ways, we have paired flushing manifolds, each clearing 24 laterals. The manifold pipes are relatively small bore to ensure correct flows carry any debris. We marked each end with permanent posts, as we did for the header, so anyone can see where the buried manifold pipes are.

We are once again grateful for the support of Anthony Waites at ThinkWater Hawke’s Bay for this aspect of the MicroFarm irrigation. Thanks too Netafim for supplying componentry.

thinkwater260     Netafim200


Autumn Open Day

Website Open Day StripThe LandWISE MicroFarm held its second Open Day in April 2014. The two crops for discussion were sweet corn and green beans.

MicroFarm IrrigationWeb

Green beans are a relatively new crop here, and questions over best management remain. The MicroFarm Discussion Group selected a few options this season.  Some may require following up with more investigations.

Plant arrangement and population

Tasman Harvesters Director, Gary Cutts returned from a trip to Europe where he saw most green beans are planted on 15” or 381mm rows. Gary was very keen to try the narrower row spacing. He has noticed smaller canopy crops that do not fully fill the allocated row space are difficult to harvest well.

This season we have planted one MicroFarm paddock at 15” or 381mm spacing, increasing the in-row spacing to keep the population near the norm.  At half the usual spacing for crops such as process sweetcorn or maize, fitting tyres into the mix is a challenge.

McCain Foods Field Officer, Ben Watson was interested to know what plant population might be optimal. He set up four rates from 300,000 to 370,000 plants per hectare.


Ballance AgriNutrients’ Mark Redshaw has used double rate phosphorous in one half and no phosphorous in the other. Other nutrients are the same, at rates determined following soil testing at Hill Laboratories.

Herbicide strategy

Scott Marillier and Vaughan Redshaw at Fruitfed Supplies selected a standard herbicide programme for most of the area. Haydn of Greville Groundspraying applied 600mL/ha BASF Frontier and 500mL/ha Magister as a pre-emergent spray. This was followed by 3L/ha BASF Basagran (Bentazone) at two trifoliates.

In two half paddocks, they left out the pre-emergent, and applied 1.5 L/ha Basagran (bentazone) at cotyledon stage, then 3 L/ha at 2 trifoliates.


By the end of February the buried drip installed by ThinkWater had applied four 10mm irrigations. That was enough to keep just above stress point. In early March the crop justified 10mm applications every two days. We are seeing some bypass as the deeper soil shows increasing moisture. The outside rows planted are outside the area irrigated with drip. The differences are very evident.

HydroServices’ soil moisture monitoring showed the un-irrigated paddocks were stressed from early on. Funding constraints have prevented us getting the dream irrigation system so we started using our mini-gun, applying 35mm at the end of February.  While adequate on pasture, it is not ideal for crops.

Irrigation has continued with a second round in early March applying another 35mm. Windy conditions at the start of the month affected application patterns, and some days we did not bother irrigating at all. View the edges of the paddocks to see the difference!

The Netafim dripline extends under the first part of the sweetcorn in paddock 3. Again, the difference between irrigated and unirrigated is extremely obvious.

More information on the main LandWISE website

Many thanks to:

Centre for Land and Water, ThinkWater, Netafim, HydroServices, McCain Foods,
Ballance AgriNutrients, BASF Crop Protection, FruitFed Supplies, Agronica NZ,
Nicolle Contracting, Te Mata Contractors, Drumpeel Farms, Greville Ground Spraying,
True Earth Organics, Tasman Harvesting, Plant & Food Research and Peracto Research for support with this work.

Foundation MicroFarm Sponsors

Ballance web150  BASF web  CLAW-light-150

Green Beans Planted

MicroFarm Paddocks 1, 2, 5 and 6 have been planted in Green Beans, destined for McCain Foods in Hastings.


These paddocks were previously in vining peas, and issues with compaction and paddock humps were noted. See the post, Removing Compaction for more details.

A number of different options are being observed, including:

  • row spacing
  • plant population
  • varieties
  • fertiliser programme
  • herbicide strategy
  • drip irrigation dryland
  • and hopefully spray irrigation

Row spacing

At the instigation of Gary Cutts of Tasman Harvesting, responsible for harvesting the beans in Hawke’s Bay, Paddock 1 has been planted with a 15″  (381mm) row spacing. This compares to the standard 20″ (508mm) spacing in the other three paddocks. (Originally beans here were planted on 30″ (762mm)rows.)

Gary has noted that in lighter canopies planted on wider spaced rows, some beans get lost at the edges of the harvest swath. He believes we should try the closer spacing which is common in Europe.

Others in the MicroFarm discussion group has raised the potential increase in disease risk with a more closed canopy, so this will be monitored with interest.

Getting the beans planted at the narrow spacing was a challenge as the Monosem NG plus 4 planter being used would not close up enough. The units are capable, but the current toolbar arrangement with wheels in the way is not.

Instead, Patrick and the Nicolle Contracting staff used their John Deere 8-row MaxEmerge XP planter set on 30″ spacing, and simply moved the whole machine across 15″ to do intermendiate rows. This resulted in some planted rows being driven over – the group decided that was an acceptable limitation for a first look.

Preparing the JD MaxEmerge for 15″ row planting

Rain after planting may have aided emergence even in these rows although it may be delayed and less successful.

Tough bean seedlings emerging through wheel track

Plant Population

Ben Watson of McCain Foods is leading a plant population comparison in Paddock 6. Here four different plant desities are being tried, all on the standard 30″ (762mm) row spacing planted with the Monosem planter.

Population/ha                           In-row spacing

  1. 377,358 (standard)            5.3 cm
  2. 363,636                               5.5 cm
  3. 333,333                               6.0 cm
  4. 307,692                               6.5 cm
Bean planting P6 Airey 4 web
Planting the population trial with Nicolle Contracting Monosem

Fertiliser Programme

Ballance AgriNutrients’ Mark Redshaw developed a fertiliser programme based on soil test results and crop requirements. Paddocks 1, 2 and 6 each received 250 kg/ha Mila complex at planting.

As an alternative, Paddock 5 received no nitrogen at planting. The southern half received a double rate of phosphorous, and the northern half received no phosphorous.

Herbicide Programmes

The northern half of Paddock 2 and southern half of Paddock 5 (both nearest the centre access track) are receiving an alternative herbicide programme. The rest is being treated with a relatively standard approach.

Standard Programme                             Alternative Programme

Pre Emerge                                              
600 mL/ha Frontier                                  No product applied
500 mL/ha Magister

Cotyledon Stage
No product applied                                 1.5 L/ha Bentazone

2 Trifoliates
3 L/ha Bentazone                                    3 L/ha Bentazone

BASF supplied Bentazone and Frontier. FruitFed Supplies sourced Magister for us.

All herbicides are being applied by Haydn Greville Groundspraying

Soil Moisture Monitoring

HydroServices installed neutron probe access tubes in Paddock 2 (dripline) and Paddock 5 on 14 February.

20140214_neutronprobeinstal 20140214_neutronprobe

Results from soil moisture monitoring are posted on the Irrigation Monitoring page.

Sweetcorn Planted

MicroFarm paddocks 3 and 4 were planted in sweetcorn on 18 December 2014. This is destined for McCain Foods in Hastings.

Following harvest of vining peas, the paddock was sprayed off with glyphosate by Hayden Greville Groundspraying. Key weeds were Indian Doab (Cynodon dactylon) but others including Bindweed (Convolvulus arvensis?) and the usual Heretaunga Plains crop weeds were noted.

The paddocks were strip-tilled by Drumpeel Farms on 13 December using the 12 row Orthman strip-tiller.


A video of Hugh Ritchie with the machine was made by James Powrie of Eco-Eye with funding from and the Queensland Department of Agriculture, Fisheries and Forestry.

The sweetcorn was planted on 18 December by Nicolle Contracting using their John Deere 8-row MaxEmerge XP planter.

WP_20140131_016 web

On 9 January 2014, evidence of Cutworm and Argentine Stem borer justified Haydn Greville Groundspraying applying Agronica Alpha Scud (Alpha Cypermethrin) at 200mL/ha in 300-600L of water.

Fertiliser application plans were  Mark Redshaw. At planting Paddock 3 received 150 kg/ha DAP/PhasedN supplied by Ballance AgriNutrients. It was sidedressed between rain showers with 200 kg/ha of Sustain on 1 February 2014.

The Paddock 4 sweetcorn received 250 kg/ha Cropzeal 20N at planting. This was supplemented on 1 February 2014 with a side dressing between rain showers of 200kg/ha urea supplied by Ballance AgriNutrients.

Soil moisture monitoring by HydroServices has shown the crop reaching deficit levels. With no irrigation option for these blocks, we were to some extent saved by regular rainfall but are actively seeking a suitable irrigation option. Monitoring data are posted in Irrigation Monitoring.

Spot spraying with Agronica Leopard  to control remaining spots of Indian Doab was started on 4 February

Estimated harvest date is early April, before the frost.

Pea Sampling

20140114 DripIrrigatedPeaCrop

Pre-harvest samples were taken from the four pea paddocks on 16 January. They show a wide range in crop maturity and yield expectations.

Four 1 m2 samples were taken in each half hectare paddock. We counted plants, weighed the fresh vine and took it to the McCain Foods mini viner and tenderometer for processing. Each sample was processed, peas weighed and TR tested.

Indicative tonnages averaged for each paddock range from 4.2 to 5.6 t/ha and tenderometer readings from 86 to 105. Within this, there is an even greater range reflecting the variability noted across the region. The lowest sample tonnage was 3 t/ha and the highest 6.8 t/ha. Notably, these were from the same paddock. The lowest TR readings were 78 and the highest 113.

Paddock 2 has buried drip irrigation. It has a much bigger canopy – 39 t/ha fresh weigh compared to the 26 t/ha average of the other paddocks. This paddock is slower maturing, still flowering where others stopped some time ago. While it has the lowest mean TR reading, it has about the average yield at present. If left to get to equivalent maturity, the yield could be close to the higher end of our four paddocks.

Summary of Pre-harvest Pea Sampling
Paddock Plants/m2 Fresh Vine t/ha Peas t/ha TR Irrigated Treated
1 69 29.6 5.57 105 No -
2 53 39.4 4.91 86 Drip Nodulator
5 79 24.9 5.06 94 No -
6 62 23.1 4.19 93 No Nodulator