Category Archives: Agronomy

Satellite Imagery

A large part of Heretaunga Plains horticulture was photographed for us by satellite at the end of November.

World View 2 satellite coverage of the Heretaunga Plains on 23 November 2105
World View 2 satellite coverage of the Heretaunga Plains on 23 November 2105

Part of our OnionsNZ Variability project, the World View 2 coverage targeted our crop and other onion crops east of Hastings.

By capturing four bands of light, Blue, Green, Red and Near Infrared, we are able to get a “normal” colour image like an aerial photo, and a biomass map using the NDVI index.

The satellite image pixel size in 0.5m x 0.5m, so we get at least two pixels across each onion bed.

World View 2 NDVI image captured 23 november 2015 of MicroFarm onion and vining pea crops
World View 2 NDVI image captured 23 November 2015 of MicroFarm onion and vining pea crops

In the NDVI image, the onion crop is lower left paddock, the vining peas upper right. Red areas indicate low or no biomass, yellow light, green moderate and blue heavy cover. Note however that the value of each colour is slightly different for each crop.

Because the pea canopy is full ground cover while the onions are only roughly half ground cover, we had to use different value bands to see variation within each crop. If we used the same range, either the peas would all be blue, or the onions mostly yellow and red.

The striping effect in the onions is the onion beds. Some adjacent beds have quite different canopy densities.  The red edge around the onions is bare soil and light canopy in the outer beds. The blue area in the centre is influenced by charcoal from an old bonfire site. Even taking these things into account, there is a reasonably large amount of variation in this crop.

Red spots in the pea crop are patches with no plants. The red headlands show light canopy areas and the red strip centre right the irrigator access track. There are three different seed lines of Ashton peas making up the pea crop. These are not discernable in the satellite image. The crop was harvested on 14 December, and there was no significant difference seen in hand harvested plots or in the viner.

 

 

Phosphate Starter Fertiliser for Onions?

Some growers have observed that adding phosphate fertiliser at planting time seems to improve the growth of onions, especially at early stages.

To test this, we’ve set up a small trial with our Ballance AgriNutrients partners. In each of 5 small plots, we placed the equivalent of 250 kg/ha of triple superphosphate 50 mm below and beside the onion seed.20150814_170007_P-Trial_640

We’ll track development of the plants in the treated plots and in corresponding neighbouring plots to see if there is a significant difference.

Why five plots?

Having replicated plots means we can better understand if any differences are “real” or “due to chance”.  We know there is always variation in any paddock in any crop, so how can we tell if our treatment (added P) caused any difference we see?

In crude terms: If the difference between our “Plus-P” plots and our “No-P” plots is greater than the difference between the different “Plus-P” plots, we can assume the difference is real.

Generally four replicated plots would be OK for a first look at something like this. It lets us run an ANOVA test to check statistical differences. We put five plots in, partly to cover the chance of one being damaged by field operations including turning our irrigator.

Check out the LandWISE/FAR “On-Farm Trial Guide” series for explanations and templates if you want to do a trial that you can really learn from. It includes a downloadable spreadsheet that will do your ANOVA stats and interpret the result for you.

Thanks Ballance  Ballance web150

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.

Navy Beans at the MicroFarm

Planting Envoy and Cargo Navy Beans marks the first MicroFarm collaboration with Heinz-Watties. We are grateful to them for supplying the seed and to Te Mata Contractors for paddock preparation and planting.

TeMataContractors planting Navy Beans
TeMataContractors planting Navy Beans

In Paddock 3, planting was started before rain on 17 December. A heavy shower put paid to work for the day with sticky soil building up on the planter. It also caused soil crusting over the cultivated area, including the first planting passes.
Planting was restarted on 18 December. The soil was dry enough on the surface for the planter to run, but wet underneath so we ended up with significant compaction. It was notable that a rougher surface was left when planting into the drying soil, but there was no noticeable soil crusting after planting.

In Paddock 4, planting was completed on 18 December with the same effect as Paddock 3. The paddock was split with Envoy planted next to the centre access track and Cargo along the northern boundary. Target population was 275,000 plants/hectare

TeMataContractors125WATTIES-125

Four Cosio cover cloth plots were laid out after planting, two on each of the varieties.

Cosio cover cloth laid on emerging navy beans
Cosio cover cloth laid on emerging navy beans

Emergence counts

Emergence Counts 24/12/2014
Covered Plot Row #/m Uncovered Plot Row #/m
Envoy 1 1 13 1 1 9
Envoy 1 2 11 1 2 10
Envoy 1 3 12 1 3 9
Envoy 1 4 10 1 4 12
Cargo 2 1 10 2 1 13
Cargo 2 2 12 2 2 6
Cargo 2 3 12 2 3 11
Cargo 2 4 12 2 4 15
Envoy 3 1 10 3 1 10
Envoy 3 2 9 3 2 10
Envoy 3 3 11 3 3 11
Envoy 3 4 9 3 4 9
Cargo 4 1 13 4 1 12
Cargo 4 2 11 4 2 7
Cargo 4 3 11 4 3 10
Cargo 4 4 11 4 4 10

ANOVA shows no significant difference between the varieties or covered versus uncovered plots.

At 11 plants/metre of row at 0.508m centres, the population is 216,535 plants/hectare or 79% emergence.

The emergence was checked again two days later. Notable was that a number of plants had their growing tips nipped out. The data showing emergence minus shoots with no tips are shown below.

Emergence Counts 26/12/2014
Covered Plot Row #/m Uncovered Plot Row #/m
Envoy 1 1 9 1 1 9
Envoy 1 2 7 1 2 9
Envoy 1 3 12 1 3 10
Envoy 1 4 8 1 4 9
Cargo 2 1 14 2 1 9
Cargo 2 2 10 2 2 12
Cargo 2 3 9 2 3 12
Cargo 2 4 14 2 4 14
Envoy 3 1 9 3 1 8
Envoy 3 2 8 3 2 9
Envoy 3 3 10 3 3 8
Envoy 3 4 8 3 4 7
Cargo 4 1 10 4 1 12
Cargo 4 2 13 4 2 9
Cargo 4 3 12 4 3 14
Cargo 4 4 11 4 4 9

ANOVA shows no significant difference between covered versus uncovered plots but a definite difference between varieties. Envoy population was 173,000/ha and Cargo population 225,800/ha. The probability that the difference is due to chance is less than 0.5%.

A final emergence count was made 17 days after planting.
The emergence was checked again two days later. Notable was that a number of plants had their growing tips nipped out. The data showing emergence minus shoots with no tips are shown below.

Emergence Counts 03/01/2015
Covered Plot Row #/m Uncovered Plot Row #/m
Envoy 1 1 13 1 1 10
Envoy 1 2 10 1 2 10
Envoy 1 3 12 1 3 10
Envoy 1 4 11 1 4 12
Cargo 2 1 11 2 1 14
Cargo 2 2 15 2 2 13
Cargo 2 3 13 2 3 13
Cargo 2 4 13 2 4 15
Envoy 3 1 10 3 1 9
Envoy 3 2 10 3 2 10
Envoy 3 3 12 3 3 10
Envoy 3 4 13 3 4 10
Cargo 4 1 14 4 1 11
Cargo 4 2 13 4 2 12
Cargo 4 3 13 4 3 14
Cargo 4 4 13 4 4 10

ANOVA shows that when all data are combined, there is no significant difference between covered and uncovered plots. However, there is a significant difference between covered versus uncovered plots for Envoy, with the probability that the difference is due to chance being less than 5%. There is no significant difference between covered and uncovered plots for the Cargo variety (p=0.65).

There is a definite difference between varieties. Envoy population was 214,570/ha and Cargo population 257,880/ha. The probability that the difference is due to chance is less than 1%.

Monitoring Variability in Peas

Peas are one crop that has huge variation. It’s hard to know if the crop will yield four tonnes per hectare or twelve. Even within small sampling plots we measured yields less than 4 t/ha and greater than 13 t/ha.

Our peas were planted into wet soil and had cold weather afterwards. Then they were savaged by pigeons. So right from the start there was variation. There were bald patches, slow germinating plants and plants with growing tips nipped out.

Counting the number of peas in 1m2 to assess paddock population. Repeating measurements shows variability.
Counting the number of peas in 1m2 to assess paddock population. Comparing repeated measurements allows statistical variability to be calculated.

We put some cover cloth over plants and observed different growth. After three weeks we removed the covers and could see difference. We got a sensor that measures ground cover and compared covered and uncovered areas. There was as much as 50% difference with covered plants much bigger. We think some of the difference is pigeon related. But maybe the covers also have other effects.

After crop cover was removed, greater growth and fuller ground cover was obvious
After crop cover was removed, greater growth and fuller ground cover was obvious

We visited a number of pea crops in Central Hawke’s Bay. We saw the same variability in young crops and old. The rate of maturation is critical for vining peas as they have to peak the day (hour?) they are harvested. We’ve identified condensed flowering as a target for pea crops. We want flowering to start and stop in a short period, and pods to fill evenly to be similar maturity for harvest. In variable paddocks (uneven soils, dry areas) flowering can start and finish at different times. A long period means later pods will still be filling while the first are already getting past their prime.

This crop shows areas of delayed and advanced flowering. All is to be harvested at the same time so some will be ready and some not.
This crop shows areas of delayed and advanced flowering. All is to be harvested at the same time so some will be ready and some not.

We had cool conditions at the MicroFarm and think this extended the flowering period. We could see pods filling while new flowers were starting to bloom.

Variation occurs on a single plant when long flowering times see pods filling while new flowers are opening.
Variation occurs on a single plant when long flowering times see pods filling while new flowers are opening.

The variability is a problem at harvest. Setting beater speed is a difficult task when the TR range is wide; hard enough to get tougher pods open yet soft enough to save the tenderest young peas. The problem is very obvious then, but it started long ago.

Peas taken and hand sorted from a single sample from the harvester - those on the left are mature, those on the right too young and damaged.
Peas taken and hand sorted from a single sample from the harvester – those on the left are mature, those on the right too young and damaged.

Monitoring Variability in Onions

Our first MicroFarm onion crop is extremely variable. The view below was taken from on the linear move irrigator, a useful vantage point

Variability is obvious when viewed from the irrigator
Variability is obvious when viewed from the irrigator

We want to measure variability so we can better assess it. If we can measure objectively we can make better decisions. We are interested in spatial variability and temporal variability.

The image above shows spatial variability: some parts of the paddock are better than others. We want to understand why some plants have done quite well, while others have done very poorly. If we can identify patterns, it can help us identify causes.

There are two patterns showing up in the image. There seems to be a large area where growth is poor. Perhaps that is a lower, wetter area? We can also see that every third bed is stronger than those on either side. That pattern is quite strong across the whole paddock and matches planting pattern from our three bed planter.

We wanted to map our crop so we could look for more patterns. We took a GPS connected sensor that measures the amount of ground cover and went up and down the beds.

CropCoverMap
Ground cover map of MicroFarm onion crop from data collected in early December

In the image above, the sensor data is displayed as a colour scheme. Green is highest ground cover (the biggest plants and most continuous planting). Red is lowest ground cover (small plants or larger gaps between plants or both). We used a cheaper GPS without correction so our bed readings have strayed off line. But even still, we can see the same pattern as in the photo above.

Will this pattern reappear in future years? Temporal variability seeks to understand how crop performance changes from year to year. If we can identify “always high”, “always low” and “sometimes high/sometimes low” areas we can develop management strategies to suit. Sensor based mapping is one of the best ways to identify such zones.

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.

Crop covers laid on onions and peas

Following the lead of Dr Charles Merfield at the BHU Future Farming Centre at Lincoln, we’ve laid some trial crop covers at the MicroFarm.

Crop covers laid over onions and peas at the MicroFarm
Crop covers laid over onions and peas at the MicroFarm

Merf first used the covers in an attempt to control the Tomato Potato Psyllid on biologically grown potatoes. His first season trial showed unexpected benefits including greatly reduced potato blight. You can view Merf discussing the trials on Rural Delivery here>

Scott Lawson has been using the covers at True Earth Organics in Hawke’s Bay. His observations are of significant benefit on a number of crops. He bought cloth to cover potatoes, a crop he struggled to produce one TPP arrived. After potatoes, the cloth was going back in the shed but instead he put it on to other crops and has seen benefits in those as well.

We have placed 6 x 8m covers on our onions in Paddocks 1 & 2. We also put covers on to our peas crops, largely to gauge the effect of pigeon attacks at germination.

Plant growth regulators and pea productivity

Paul Johnstone, Sarah Pethybridge, Bruce Searle and Christina Waldon, Plant & Food Research

Commercial pea crops can flower for an extended period. When plants keep on flowering, they can put resources into pods and peas that are often underdeveloped by harvest. Conversely, if flowering can be stopped at the right times, more energy goes into the pods that make up harvestable yield.

This 2013-14 summer we conducted two preliminary comparisons at the MicroFarm to see whether plant growth regulators (PGRs) could affect flowering period and increase harvestable yield. PGRs are plant hormones that influence growth and development. There are many different types and each influences plants in different ways.

We applied a selection of commercially available PGRs to plots within early (sown in September) and late (sown in November) pea crops. The products applied included a mix of PGR types (gibberellins, anti-gibberellins, cytokinins and anti-ethylene), rates and timings. We used two application rates: the recommended dosage and double that rate of each product. The application timings were early vegetative growth, pre-flowering and flowering. The demonstration plots were not replicated.

At harvest we measured pea yields and quality in PGR-treated plots and compared these with values from plots that received no PGR application (our control). The results are presented in Table 1.

Total pea yields averaged 9.7 t/ha in the early planted crops and 6.2 t/ha in the late planted crops. We did see some effects of the PGR products on crop yields but these yields were also influenced by highly variable plant populations and crop maturity.

Anti-gibberellin

In the early trial, the standard rate of Regalis® applied during early vegetative growth resulted in between 2.1 and2.6 t/ha higher total yields than those in other treatments. The differences were primarily related to more peas per pod and heavier peas.

In the late trial, the double rate of Regalis applied during early vegetative growth achieved the highest total yields (8.1 t/ha), but statistically these were not significantly different from those in the untreated plants (7.6 t/ha).

Gibberellin

20131029_webProGibb® caused rapid stem elongation and yellowing for a period, but not a yield benefit

We saw no effect of the ProGibb® treatment on yield in the early planting.

In the late planted crop, ProGibb appeared to reduce pea yields greatly, producing only between 3.4 and 3.6 t/ha. Fewer and lighter individual peas were produced on plants treated with this product.

Cytokinin

Two cytokinin products were tried: Exilis® on the early planting and Sitofex® on the late planting. We saw no effect of either product on pea yields.

Anti-ethylene

We applied Retain® to plots in the early planting but saw no effect. It was not used on the late planting.

Summary

These initial observations suggest that some PGRs may provide a potential yield benefit, although our results were confounded by variation in plant population, which has a strong effect on yield. Unravelling this interaction is necessary before firm recommendations can be made.

Acknowledgements

The trial was sown by Patrick Nicolle (Nicolle Contracting) using seed supplied by McCain Foods. PGR products were supplied by BASF Crop Protection and Agronica. Tim Robinson (Peracto Ltd) applied the various PGR treatments in both demonstrations. Additional assistance was provided by Issy Sorensen, Nathan Arnold, Matthew Norris, Tony White and Colleen Reid (Plant & Food Research) during the harvests.

PGRSponsors nicolle_contracting_100 McCain120