Variability in crops implies lost production. While the very best parts in a paddock may still give less than potential yields, anything less is a sure sign of loss.
LandWISE developed a simple “crop loss calculator” called YieldEst. The purpose of YieldEst is to assess how much crop variability is costing a grower.
We have been watching establishment of the onion and pea crops at the MicroFarm. Both have shown high levels of variability, apparent very early in crop establishment. From there it can only increase.
We have visited a number of other sites this spring, looking in particular at crop establishment and seeking reasons for variations seen. We have been a little surprised at the level of acceptance among growers; not happy but somewhat resigned.
Where does variability start? What are the most important causes? What can we do about it?
Variability starts at the start; with variations in genetic potential within seeds in a line. It is surprising how little we really know about this. We do know hybrid lines can be more uniform that open pollinated ones, mainly because they have a narrower genetic spread. But gene differences are hugely complex too. One gene can express differently depending on environmental factors. For example, we don’t know much about the effect that growing conditions of the mother plant may have on the seed we sow.
We have an idea about soil conditions for best establishment, although we wonder if we don’t over-cultivate to get a satisfactory seedbed. We hope we don’t have carry-over herbicides or weeds so growers have started using precision ag section control to get the right dose in the right place. We try not to plant if soil is too wet or too dry. Sometimes it is both in the same paddock.
We do know more about plant density and plant spacing. We know crops have a target population for best returns, and that many are sensitive to variable spacing between neighbours. Precision ag again helps with planter controls. But maybe we are trying to plant too fast when under pressure to get seed into the ground. A lot of research has shown planting speed has a direct impact on yield, largely through spacing uniformity effects.
We know that planting equipment set up and operation has a big effect. Check planting rate is as intended. Get seed to even depth into moisture, cover it properly. Ensure every seed gets sufficient nutrients, but don’t put fertiliser too close.
There is some evidence that weather conditions straight after planting can have a big effect on emergence and establishment. Heavy rain caps weak soils, and if that dries we suffer.
Heavy rain after planting capped this soil and created poor conditions for germination and emergence.
If plants do emerge, they have to survive strong winds, hail, frost, birds and slugs. And our herbicides.
And that is just getting to establishment. There is still most of the crop life to go, but it seems a fail to thrive infant never does as well as a bonny one.
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. More>
Crop covers laid on onions and peas
Squares of Cosio cover cloth placed on peas and onions
Following the lead of Dr Charles Merfield at the BHU Future Farming Centre at Lincoln, we laid some trial crop covers at the MicroFarm. More>
Linear Move Irrigator
The MicroFarm has a linear move irrigator. The Ritchies replaced the original linear at Drumpeel, and after Hugh made some necessary adjustments to the old one, arrived with a truck and trailer carrying a single span linear and a Manitou to put it up with. More>
Queensland University of Technology is investigating robotic technologies as a new generation of tools for site-specific crop and weed management. Tristan Perez described “AgBot”, a platform currently being manufactured to a design by QUT. AgBot is 2m long, 3m (adjustable) wide and 1.4m high.
AgBot – image from Queensland University of Technology
Tristan suggests the use of a swarm of small light robots, that operate at lower speeds and have a suit of sensor-acting devices, could lead to a better application of agrochemicals. He also sees them having a key role addressing herbicide resistance as they could enable use of mechanical or microwave weed destruction techniques.
Now we have your attention:
LandWISE’s Dan Bloomer attended the 17th Precision Agriculture Symposia of Australasia in Adelaide. This event is a collaboration between SPAA and the University of Sydney, bringing together researchers and practitioners with the aim of promoting the development of PA to profit agricultural production.
The Symposium has a broad coverage including new technologies, big data, precision cropping and viticulture and spatially enabled livestock management.
As well as an excellent range of speakers, the symposium is a very good networking opportunity for people active in this space. There is a close alignment with LandWISE interests and the supporting Trade Displays were very relevant and informative
A few notes about some of the other presentations:
Lucas Haag, Professor at Kansas Sate University and Partner and agronomist in his family’s large farming operation, described the evolution of PA in the dryland environment of the US High Plains. While a very different context to New Zealand agriculture, the lessons appear readily transferable.
He noted the critical role of autosteer, rather than yield mapping, in accelerating the adoption of precision agriculture tools among a wide spread of cropping farmers, and the subsequent search by those farmers to gain additional return on that significant investment. This is a pattern very familiar to us.
A take home message from Lucas was the use of PA technologies to make better whole field or whole farm analysis and decisions. While they use PA tools to help evaluate new varieties, seed treatments and other new product options, machinery management decisions have added considerable value to their business.
Examples included evaluating the economics of grain stripper versus conventional header harvesting, grain cart logistics and the value of a dedicated tender truck to support spraying operations – all applications that were not anticipated. Better telematics and machine monitoring technologies and costs of machinery suggest this will continue to be an area of focus.
As manufacturers have increased claims of spreading width, and farmers and contractors have increased bout widths accordingly, arable farmers have noted increased striping and lodging in crops where blended fertilisers are applied. The Massey studies identify the different ballistic properties of blend components, and the increased bout widths, explain these symptoms.
A number of presentations included reference to UAV technologies. Some are very sophisticated and used to carry very high-spec sensors. Some are just used to get up above the crop for a new perspective. Regardless, the potential benefits are clear and the price dropping and capability rapidly rising.
Luke Schelosky of RoboFlight Australia their approach using either piloted or unpiloted aerial vehicles to capture ultra-high resolution imagery create 2 cm resolution maps. As we have seen before, the key to the technology is the processing software rather than the choice of vehicle.
Miles Grafton also reported Massey work using remote sensing for pasture management. They use a number of Remote Piloted Aerial Systems (RPAS) including multi-rotor (e.g. QuadCopter) and fixed wing (e.g. Trimble UX5) as well as a range of multi- and hyper-spectral sensors and imaging systems. While at an early stage, Massey research is showing promise in remotely sensing pasture quantity and quality, including assessing pasture nutrient levels.
Lucas Haag also discussed the role of UAVs, suggesting three unique features create special potential:
Temporal Resolution -The data are fresh, not from the last cloud free satellite pass
Spatial Resolution – the user can control flight height and pattern to gain the redolution needed for the intended use of the data
A separate step – because it requires a separate trip to the field, there is opportunity to add external knowledge before inputs are applied. This allows, for example, adding historical yield monitor knowledge (and perhaps knowledge of herbicide mistakes) to UAV NDVI imagery when creating a Nitrogen application map.
Lucas further addressed spatial and temporal variability measures determined from Yield Maps, contrasting Normalised Yield and Yield Stability. Multi-year Normalised Yield provides the measure of Spatial Variability or spatial yield potential, and the standard deviation (defined perhaps as stable high, stable low and unstable yield) provides a measure of temporal (over time) variability.
Cheryl McCarthy presented crop sensing and weed detection work being undertaken at the National Centre for Engineering in Agriculture at the University of Southern Queensland. Colour and depth image analysis is enabling them to identify weeds in real time, and spot spray them at 10 – 15 km/h. Interesting to note this requires analysis of 30 images per second, as at least three image frames per plant are needed for sufficient confidence.
Two Trade Displays that caught attention were SST Software and PA Source; both aimed at helping farmers and their advisors access the benefits of Precision Agriculture.
Mark Pawsey demonstrated SST Software’s Sirrus programme, a cloud based data access, storage and analysis package. Of additional interest was their decision to open their agX Platformto other developers creating supplementary apps. This reflects the opening also of the John Deere platform and similar moves by other organisations.
Ben Jones of PA Source spoke at LandWISE in 2012 and has facilitated our use of that platform for supply and analysis of spatial data including yield maps, EM maps and satellite data. New offerings include www.watch.farm and www.pastack.com.
Watch.farm delivers Landsat satellite sourced vigour maps to your email every 16 days (cloud cover permitting). Part of the watch.farm package includes change maps, so you can track growth change in individual paddocks. We want to try this service in the current summer season and see it having a significant role to play if the resolution coverage is satisfactory in the “Land of the Long White Cloud”.
PAStack also uses Landsat imagery, “stacking” images from as far back as 1999 to 2013 to see which areas provide more or less biomass and how consistent they are. We will also investigate this product as there appear to be a number of uses of potential benefit to LandWISE farmers and their supporters.
We have been making elevation maps of cropping paddocks. It is the first step in determining the optimum plan to manage drainage and sediment loss.
If it can, water will flow downhill. It flows faster on steeper, smoother land and faster when it is deeper. The faster it flows, the higher the risk of soil erosion and loss. If water can’t find a down-slope, it will sit until it soaks or evaporates away. If that takes too long, plants will suffer.
The rate at which water infiltrates (soaks into) the soil is largely related to soil texture and structural condition. A coarse soil generally lets water in faster than a “tight” clay soil. If the natural porosity has been damaged by over-cultivation, water movement is reduced. Other factors such as hydrophobic organic matter (think oilskin raincoats) also stop or reduce infiltration.
Step two is using a computer to analyse our detailed elevation maps and determine where water will pond and how deep it will be. Knowing how much land is affected lets us gauge the cost of ponding. We can “apply” a rain event and see where the water runs, how deep and how fast. This lets us identify, and make plans to manage, erosion risk areas.
The third step is creating plans to remove water in a controlled way; not too fast and not too slow. For many years this has been done by laser-grading. This creates a flat plane with a set slope so water can drain at a set rate across the land. Unfortunately it often requires a huge amount of soil movement.
High accuracy GPS and smart software has enormous benefits. Our detailed elevation maps are analysed to create optimised cut-and-fill plans that move only enough soil to enable surface drainage. We don’t mind that the surface is not a flat plane, so long as the water can move. We can set the maximum slope (to avoid erosion) and the minimum slope (to avoid ponding) and the direction we want water to flow.
OptiSurface software calculates where to cut high points and fill low points, balancing the soil so one just fits the other. Rather than a flat plane, we get a varied terrain with lower points connected to ensure drainage. While much is automated, there is still a need for farmer and designer input. The theoretical design must be practical.
Once completed, design files are loaded back into the tractor which controls the height of a levelling blade to get the exact cuts and fills we have determined. Advice is to use the same type of GPS for both surveying and levelling. Subtle differences between brands and even models of GPS system can create problems. It is also important to have a base station within 2 km so the vertical error is minimised. Having 40 or 50mm of GPS error when the soil cut is 20mm just doesn’t work.
The series of maps cover a case study 40ha cropping property. We mapped it using the farmer’s Trimble FmX and analysed the data in OptiSurface.
Map 1 shows the existing topography on the farm, each colour change being a 1m change in elevation.
Map 2 shows where water will pond, and how deep it will get.
Next we looked at some solutions.
Map 3 shows the possible topography if part was levelled to a single plane (purple through green strips) and part was OptiSurfaced (green through red strips).
Map 4 shows the cut and fill required to achieve each solution. The amount of movement for a single plane is huge – over 700m3/ha for single plane and under 20m3/ha for OptiSurfaced areas.
Map 5 shows the cut and fill required if the whole area is optimally resurfaced.
A new initiative in Horowhenua will reduce sediment and nutrient input into the Arawhata Stream and Lake Horowhenua. And it will increase farm productivity by managing drainage and reducing crop losses.
LandWISE is working with local farmers, the Tararua Vegetable Growers’ Association and Horizons Regional Council in this Ministry for the Environment supported project.
The team will create integrated drainage and sediment control plans for up to 500ha of cropping farms. The plans will identify ways to manage risks using mix of land shaping and storm water management, supported as necessary by erosion control and sediment capture techniques. Where appropriate, cut and fill plans for reshaping will be prepared, enabling farmers to have automatic control of earthmoving equipment.
The current drainage system, actually the legacy of an historic stock drinking water race scheme, cannot contain run-off from severe storm events. Inadequate drains spill flood waters on to cropping land, creating strong rivers that erode cultivated soil and wash it, along with crops, into the Arawhata and into Lake Horowhenua. Nobody wins.
When drains fail, flood-generated erosion destroys valuable crops and discharges sediments to the stream and lake (John Clarke photo)
Local grower, John Clarke, believes additional drainage he has installed has addressed a large part of the problem. Interceptor drains and increased capacity capture and contain water from higher up the catchment, and guide it safely to the outlets.
More is needed. The whole system must work together from top to bottom. A problem on one farm inevitable flows on to the next.
Horizons staff have completed a survey of the existing drainage system, measuring channel dimensions and culvert sizes. They met with local growers to hear first-hand of the issues the growers understand only too well. They are now designing a new system that will be the core of enhanced drainage in the catchment.
Stock water system culverts do not provide necessary drainage capacity. A redesign is needed
On-farm, precision surveying with GPS tractors has begun. Using their Trimble technology, the growers can map their properties in 3D, with an error of millimetres.
High precision survey creates very accurate maps and allows drainage analysis and planning
The data collected will be processed using OptiSurface software that determines ponding areas, flow paths and depths. It can create optimized cut and fill plans requiring the minimum amount of soil movement that allows effective drainage. Those plans are fed back into the tractor guidance system and control the blade depth on ground shaping equipment.
Expectations are that ponding areas will be identified and removed through strategic levelling. This removes two problems: the bathtubs of ponded, stagnant water that can collect and row ends and destroy crops, and the risk of blow-outs that cause erosion and sediment being lost to the lake.
The third level of sediment management is retaining even small amounts of sediment through use of sediment control structures and filter plantings along farm drains. Small but continuous losses add up over time and can constitute a significant loss of nutrients from the farm, as well as more sediment load into the lake.
The project will see individual farm plans for each property that can be integrated in New Zealand GAP and used to demonstrate good practice to stakeholders.
The project is one of eight that together form the Fresh Start for Fresh Water Lake Horowhenua Freshwater Clean-up Fund programme. Horizons’ Fresh Water and Science Manager, Jon Roygard notes efforts to restore the lake have been ongoing for several decades, including in 1987 stopping the discharge of raw sewage into the lake. Recently, and almost complete, a full native planting buffer strip has been established around the lake.
Other efforts include harvesting lake-weed to remove nutrients, a sediment trap where the Arawhata enters the lake, storm water treatment upgrades, a boat wash facility, a fish pass, some further riparian fencing and planting of the tributaries and work with Dairy farmers to complete farm plans.
I visited a farm in Queensland’s Fassifern Valley, Queensland. There, Michael has been using AGPSInc’s Dirt Pro for a levelling programme on his cropping farm.
AGPSInc unit installed in tractor surveys topography and guides equipment for land levelling, ditch digging and pipe laying
AGPS-Dirt Pro is GPS based software option that assists land forming. It is comparable with Trimble’s Land Level II and TerraCutta (Precision Cropping Technologies/John Deere) and effectively replaces laser technology. Dirt Pro is one element of a suite of farm drainage tools from AGPSInc, along with Ditch Pro and Pipe Pro and others.
A few aspects set it apart. For a start, it is a complete package – coming with a Windows(R) based tablet type computer that fits cleanly into any mainstream tractor and connects to a wide range of RTK-GPS units. So anyone without high end GPS could look at this as an option.
Secondly, it is a cost effective option, the full package being about the cost of another brand’s unlock code. So it could be an option if the farm does have high end GPS.
Thirdly it has an in-built version of OptiSurface so can do some optimisation to minimise soil movement. For complex analysis the full OptiSurface product is required, but this integrates easily.
So, we haven’t used it, but Michael has and says it is easy to use and effective.
But regardless, the software/hardware package is only part of the solution. There needs to be an overall farm plan, an understanding of why drain, how to drain and what is needed to achieve farm goals.
Wide swale drains have high capacity yet can be driven through and be used as turning headlands
The broad, shallow, grassed drains at the ends of Michael’s paddocks are his headlands. This approach has application in New Zealand and is another thing to follow up.
Why do we have impassable deep, narrow sprayed out ditches that erode and require headlands on either side, when a grassed swale can be driven over, used as a combined headland, and generate less sediment and maintenance?
After a month with LandWISE researching the implications should Tukituki Plan Change 6 rules be applied to the Heretaunga Plains, our two Interns have returned home.
Makenzie and Rachel at the Flaxmere Community Gardens
While in Hawke’s Bay, they met a number of farmers, policy makers and community stakeholders in order to understand different perspectives. Their report is available here.
We were also able to involve them in an afternoon of soil surface shear strength assessment at Eskdale. Appropriate health and safety equipment supplied by Centre for Land and Water staff.
Equipment used to assess soil surface shear strength on forested rolling hills at Eskdale
At the MicroFarm, we just harvested our second lot of peas. We tracked their water use since planting to build on learning from our first crop (see the December 2013 issue of “Grower” reproduced here>).
Once again, HydroServices’ Melanie Smith established three neutron probe access tubes in each of two crops. These were read weekly and analysed to tell us paddock soil moisture content down to 80 cm.
Both pea crops were planted on the same day with the same drill. Paddock 1 is dryland and Paddock 2 has drip irrigation installed 200mm deep.
Figures Paddock 1 and Paddock 2 show soil water content for each crop.
Paddock 1_PeasPaddock 2_Peas
We see the crops tracked about the same at the start. In mid-December, Paddock 2 received two 9mm irrigations from our buried dripline.
Melanie estimated that the irrigation was 80% efficient, so only added about 7.5mm to the budget each time. Paddock 1 is not irrigated, and continued to drop towards stress point.
Paddock 1 reached Refill Point on Boxing Day two days before rain fortunately lifted it back out of stress. Paddock 1 again hit stress point on about 6th January. With no more significant rain, it stayed stressed. With irrigation applied as required, Paddock 2 remained stress-free throughout.
Overall, the two crops used similar amounts of water through until early January. After that the 0 – 30 cm soil reached stress point, and water use from the unirrigated Paddock 1 began to taper off. The steeper lines in the bottom part of the graphs show it began to get more water from deeper in the profile.
By harvest, Paddock 1 was using only about half as much water as the drip irrigated Paddock 2 and drawing it from much deeper in the profile.
The difference in what a crop did use and what it could have used if the water was available is described by Potential Soil Moisture Deficit. We estimate that by harvest, Paddock 1 suffered about 100mm of PSMD. I am not sure what the pea response is to stress. I am told it is a “very elastic” crop. For many crops this would indicate a growth reduction of about 20%.
So did irrigation pay?
We sampled each crop pre-harvest and found Paddock 2 had about 30% more fresh weight canopy than Paddock 1. The difference was easily seen, being significantly taller and generally more “lush”. The peas in Paddock 1 reached harvest maturity at least three or four days before the irrigated peas in Paddock 2.
We get paid for peas not canopy. We also sampled yields and quality as measured by TR (pea tenderness) and found differences.
There was a lower tonnage in Paddock 2, but the quality (and pay-out value) was much higher.
At harvest the Paddock 1 tonnages were reasonable at 6.85 t/ha paid yield. But TR was 137; a bit high and the lowest pay-out grade.
We delayed harvesting Paddock 2 for two days. The paid yield was similar at 6.55 t/ha but the TR was 102, a 30% higher pay-out grade.
Paddock 1 returned $2,059/ha and Paddock 2 returned $2,625/ha gross, so a benefit of $566/ha from irrigation.
We applied 81 mm so our return from irrigation was $6.99/ha/mm applied. Many people quote an irrigation cost of about $2/ha/mm so let’s claim a benefit of $5/ha/mm applied.
Looking at it another way. If we had a 20ha paddock, irrigation would have made us about $8,000 better off. If we also sold pea hay, the benefit would be even greater.
Answer: Irrigation pays!
Thanks to: Centre for Land and Water, ThinkWater, Netafim, HydroServices, McCain Foods, Ballance AgriNutrients, BASF Crop Protection, FruitFed Supplies, Agronica NZ, Nicolle Contracting, Drumpeel Farms, Greville Ground Spraying, True Earth Organics, Tasman Harvesting, Plant & Food Research, Peracto NZ
LandWISE is hosting two students from the University of Tennessee, Knoxville.
Rachel Eatherly and Makenzie Read are interns through a Massey University programme and are at LandWISE for the month of June. They are both studying Natural Resources and Environmental Economics, which influenced their decision to study abroad in New Zealand through Massey University’s Agricultural College.
Makenzie is concerned with methods of maintaining economic growth while minimizing the impact on water sources. Rachel is interested in sustainable farming practices to minimize the impact on the environment while also increasing profits and production. So the interests of both align very well with LandWISE.
While at LandWISE, Rachel and Makenzie are considering the implications of applying the Tukituki Plan Change 6 to cropping on the Heretaunga Plains. In particular, they are examining the levels of awareness, the scale of potential impact, and what changes may be required if Plan Change 6 were to be implemented. They appreciate the support they have received from farmers, council, industry and other stakeholders. We will post their report once complete.
Their visit to New Zealand began with a two week tour starting in Christchurch. Travelling with five other colleagues and Massey representatives through Otago to the West Coast and Marlborough they saw our fascinating South Island landscapes and visited farms as well as natural areas. They then travelled around the North Island including stops at National Park, LIC in Hamilton, Auckland, Rotorua and Taupo before arriving in Hawke’s Bay.
Rachel and Makenzie at Mt Nicholas Station on Lake Wakatipu
Awapuni Function Centre, Palmerston North. 21-22 May 2014
Just two days to go to LandWISE 2014! The final programme and some tasters of individual presentations are on the website.
In a change to previous years, our “outdoor session” on Day 2 includes a bus tour of a small catchment with intensive land use – vegetable cropping and dairy farming – and a regionally significant lake. This will be in the middle of the day, with buses returning to the conference venue for the final afternoon presentations and panel discussion.
We have a focus on farm plans to avoid or minimise off-farm impacts, especially from sediments and nutrients. This is a critical issue now, and farmers need to understand how new expectations may affect their day to day activities.
Many thanks to our Conference Sponsors and the many speakers and others who bring you this opportunity. We especially thank our Platinum Sponsors, BASF Crop Protection, AGMARDT and John Deere.
Please pass this message on to your friends and colleagues you believe would gain benefit from attending.
