Category Archives: Soil

Agronomy, Controlled Traffic Systems, Irrigation, Precision Agriculture, Projects, Soil, Tillage, Water

Intensive cropping: Dealing with reality

We have a group in Hawke’s Bay focused on best management for field cropping.  We want to know how far we can push production without degrading the soil, our base resource.

We have drafted a five year cropping programme, based around process crops, but with other crops in the mix. This is typical in the region where process crops are mixed with onions, squash, some cereals, occasional potatoes and often winter grass.

In our programme we have tried to eliminate animals and pasture, looking instead at maximising vegetable production. Given the different seasons, season lengths and the realities of planting dates that must fit factory schedules, this gets a bit tricky.

Central to our plan are vining peas and green beans, two crops with specialist harvest equipment. Viners are very heavy. The bean harvester weighs in at about 18 tonnes plus 4 tonnes of crop when full. The pea viners are around 22 tonnes, plus a couple more of crop when full.

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These machines have large wheel or track footprints, so impact a wide path. And pea viners typically travel across the lie of the crop, not up and down rows, so can track anywhere. How does that fit our plans to adopt controlled traffic!

Gary Cutts of Tasman Harvester Contractors is at the centre of the action. The company currently has nine harvesting machines with a price tag of around $1million each. From December, the machines earn their keep, harvesting 24 hours a day, seven days a week.

Peas are a very delicate crop and only have a premium harvesting window of 24 hours. Before that they’re too young, and after that they’re too old. It’s an exact science to determine when to pick.

For a successful harvest Gary’s team must respond to demand from the factory and deliver on time. Delays that affect factory processing are costly.  

The new harvesters, especially those on tracks, can get on to the ground even in very poor weather. But what is their impact on the soil? They are very heavy, they have big feet, and the soil may be weakened by wetness.

Gary contacted Marc Dresser at Landcare Research after hearing him at a LandWISE Conference. Marc is a specialist in soils and mechanical engineering whose knowledge is unrivalled. He worked with Gary on tyre selection and tyre pressures to optimise performance.

Together they reduced harvester tyre pressures from around 30psi to 20psi. They reversed the direction of jockey bin tyres too. Gary says the difference is immediately noticeable in the field. Coupled with a change to tracks, the soil load has been greatly reduced.

Gary still wants to know what the impact on the soil is. Are harvesters doing damage? If they are causing compaction, what is best practice remediation? When should it be done? How does it impact following crops?

We want to know too. And we want to know what a farmer can do to best prepare their soils before the harvesters arrive. Before the crop is even planted.

We can control traffic in pretty much all operations with the equipment in use now – except for the viners. We’ve looked at a number of scenarios, which suggest that the 30” row is the factor that sets the standard. Smaller tractors might straddle two rows, bigger machines can straddle four. If equipment is sized accordingly, we can get the trafficked area down to about 17% of the ground. Except for the viners.

Most paddocks only see peas about once in five years, so that leaves 4 years and 11 months of controlled traffic. But in our super-intensive farm, we might see peas almost every year and green beans too. We really do need to know how to manage this aspect of some of our important regional crops.

Controlled Traffic Systems, Precision Agriculture, Soil, Uncategorized

A wide span tractor designed for vegetable production

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Hans Henrik Pedersen is completing a PhD at Aarhus University in Denmark. He was a key speaker at LandWISE 2013: “New Ideas”. Hans told delegates about his work investigating a wide-span tractor as an option for cropping farmers.

Vegetable farmers, who adopt CTF, face serious challenges at harvest because very few harvesters are designed to match CTF systems. The soil structure is severely damaged when heavy harvest machines run over the well structured growing beds. A few farmers have modified harvesters, but to our knowledge only one CTF vegetable farmer has succeeded in matching harvest machines for all his crops.

As CTF farmers are still a minority the limited demand means that machinery manufacturers do not yet perceive a need. Also 3 m track width, as used by most CTF vegetable farmers, is a challenge as mass produced harvest machines need to meet road regulations in different countries.

In a Danish project partly funded by the Danish Business Innovation Fund a 9.6 m prototype wide span tractor has been developed. It will be tested by a commercial farmer (Jens Kjeldahl, Samsø) who will grow onions on 9.6 m wide beds spanned by the tractor. ASA-Lift A/S has designed and built the wide span tractor. Besides cultivation, drilling and plant care operations, the tractor will be used as a bunker harvester for onions and possibly for other crops. At harvest, the machine will unload at the field edges, thereby avoiding tractors and trailers in the field.

ASALiftGantry First presentation of the ASA-Lift WS-9600 tractor, summer 2012. Photo: Brdr. Kjeldahl

A wide span tractor solves two main challenges facing the traditional tractor:

  • Restrictions in width (e.g. due to road regulations) are solved by changing the direction of travel between field work and road transport. The machine is wide in the field and long when transported on roads but only 2.55 m wide.
  • Weight of the tractor can be reduced as implements can be mounted within the span of the tractor. The forces from the implements are transferred directly to the tractor as opposed to traditional mounting systems, where the tractor needs weight to pull the implement. Also, in conventional implement designs, a strong, heavy and often complex structure is needed to transfer the forces through the tractor hitch, as well as to fold the implement for transport.

Earlier work on wide span tractor designs e.g. as described by Chamen et al. (1994), unfortunately did not lead to commercial production.

A key point in design of any technology is to ensure that the development process is targeted to the priorities of potential customers. As part of my PhD. Studies I have performed a Quality Function Deployment (QFD) to derive user-requirements and design parameters.

Twenty eight farmers and farm managers in Europe and Australia have been interviewed about their priorities for the design of a new growing concept based on wide span machines. The majority of those interviewed were CTF farmers. The farmers were asked to score 28 specific requirements on a scale from 0 to 4.

The 10 requirements with the highest priority were: (average scores are given in parentheses)

  • Automatic accurate steering of the carrier (3.9)
  • Reducing soil compaction (3.8)
  • Durability of the machine (3.4)
  • Overview of the entire machine from the operator’s seat (3.4)
  • Total costs per hour (3.3)
  • Clear view and manoeuvrability to avoid damage (3.3)
  • Semi-automatic control for increased productivity and ease of operation for the driver (3.3)
  • Comfort of the driver (3.3)
  • Automatic accurate steering of mounted implements (3.3)
  • Capability to carry heavy loads in the field (3.2)

A next step involved technical experts suggesting technical solutions (Design Parameters) to accommodate the priorities set by the farmers. The results of this QFD analysis can be used by any manufacturer who wishes to develop wide span machines.

Tractors as we know them today were very successful in replacing horses. Since they were introduced in the 1920s, rubber tyres and four-wheel drive have been established, along with other features, but basically the design has not changed. However, the power output has increased more than 10 fold and the weight of tractors has increased by a similar factor. The load of agricultural machines is challenging the productivity of soils. We believe it is time for a change to the traditional tractor and that the wide span alternative can be designed to suit the needs of modern agriculture while significantly improving production efficiency.

Reference:  Chamen, W. C. T., Dowler, D., Leede, P. R., and Longstaff, D. J. (1994). Design, Operation and Performance of a Gantry System: Experience in Arable Cropping. Journal of Agricultural Engineering Research 59, 45-60.

Look also at the CTF-Europe website for more from Hans Pedersen, Tim Chamen and colleagues

 

 

Agronomy, Controlled Traffic Systems, Precision Agriculture, Soil, Tillage

International Controlled Traffic Farming Conference – Queensland

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Very few farmers globally have converted fully to controlled traffic farming. So why did over 100 people from 13 countries gather in Toowoomba to talk about it?

“It offers huge benefits,” say farmers who are doing it.  “It offers huge benefits,” say researchers assessing its merits.

Who’s doing it? What benefits?

Few New Zealand farmers consider themselves to be CTF farmers. The system David Clark developed for maize in Gisborne is as pure CTF as any seen in Australia or reported in conference sessions. The system Chris Butler developed for salads and one being refined for onions and potatoes by Wilcox staff are also as advanced as any described at the conference.

PermBedsWeb

Permanent beds that leave wheel tracks unworked are a form of CTF for intensive vegetable production. They offer better access in wet conditions.

Many New Zealand arable and vegetable farmers are tramlining on a crop by crop or seasonal basis.

Controlled traffic farming (CTF) is any farming system built on keeping all wheel tracks to closely defined paths. This must take into account the interactions between farmers and their farms, soils, topography, crops, climate, equipment and technology.

Many studies have monitored a wide range of economic, biological and physical factors and seen positive gains. Numerous examples show very significant economic advantages from reduced costs and increased returns.

Significant savings in energy, labour and equipment operating costs were reported by all conference speakers. The relative spread and importance of savings varied. Labour savings are often more important in horticulture than in arable. Fuel saving in broadacre is relatively more beneficial than in intensive horticulture.

Soil quality improvements are well documented. CTF gives improved field access, higher soil strength and stability, deeper root exploration, increased water infiltration rates, increased water holding and nutrient access and elevated biological activity.

The farmers and researchers spoke of CTF as a system of farming, and noted that once traffic is managed, other benefits are found. They include enhanced irrigation, ability to establish crops more quickly and exploit smaller windows of opportunity and the ability to grow new crops.

Better field access allows more timely planting, field operations and harvest. These generally translate to better yields and crop quality and less frequent losses from adverse climatic events. No one reported significant yield depression.

The cost of conversion to CTF depends on the inventory of equipment on-farm. At first glance, the cost of transition can look prohibitive. But it need not be problematic if considered over a longer time period.

JD Axle extension Toowoomba Web

Axle extension for wide track CTF

Customising tractors and harvesters can be very expensive, but working with common standard widths is not. And under controlled traffic systems, a lot of equipment may become redundant.

Once optimum track and bout widths have been determined, a plan can be created. Few farmers will go out and replace all their equipment at once. But they can ensure new equipment purchased will fit the system that has been planned.

As several farmers stated, “Just get started, and think when you buy new gear. One day you’ll wake up and find it all just fits.”

Dan Bloomer was a presenter at the CTF Conference, on behalf of LandWISE members and New Zealand CTF farmers.

Agronomy, Soil, Tillage, Uncategorized

Learning Lessons Again

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This article first appeared in The GROWER magazine in 2012. We were getting more reports of cropping paddocks disappearing in the wind, something I regard as a disaster. With a comprehensive flood protection system in place stopping alluvial deposition, no ice age looming to create more loess and hopefully no more major volcanic eruptions donating ash, our local Heretaunga Plains soils are no longer replenished. Once gone, they are gone.

Learning Lessons Again

Do we really forget strong winds are a regular feature in Spring?

Clouds of soil need not be part of this picture. Why do we not plan, or plan not, to account for these winds? I admit to frustration – wind is normal!

Many New Zealand cropping soils are loess covered gravels. Loess is wind-blown silt, ground out of the ranges during the ice age, and exposed by retreated glaciers. Unless we have another ice age, we are not going to get much re‑nourishment.

Many others are volcanic ash – such as from Taupo. Unless we have another (really, really) major eruption, we’ll not get more of that either. So we need to look after what we have.

The very simple message on light soils is that is if you open them up, they can blow away. And blow away they have.

When first developed, horses were used to till land for pasture and cereals. The late soil scientist, Elwyn Griffiths, said that in some parts of the Ruataniwha Plains “about three feet” of soil was lost within a few decades.

Mechanisation replaced horses, powered implements created fine seed beds and wind erosion continued. In the mid-1990s severe erosion events were reported.

A local field rep said, “We lost over 50mm of soil this Spring. I know we did; we planted peas an inch deep, the wind blew and the pea seed bounced across the highway. We replanted and that lot blew away too. Then it was too late to grow peas so we planted sweetcorn instead. Even that got damage.”

In 1999 LandWISE set out to stop wind erosion.  Valuable knowledge about how to keep soil from drifting across the plains and out to sea was gained and disseminated.

Direct drilling or no-till stops wind erosion completely. So long as there is effective ground cover, the particles are retained.  No-till was good for grass and cereals, but less promising for process crops and squash.

LandWISE developed and proved strip-till techniques that allow for seed bed creation yet keep soil intact. With half to two-thirds of the ground still covered with thatch or residues, the soil avalanche can’t get started: strip-till stops wind erosion too.

The additional benefits are numerous: Better water holding capacity, better drainage, reduced fuel consumption, no sand-blasted young crops, less grit in your eye, a soil resource to pass on through the generations, time and energy savings, reducing costs and carbon footprint into the bargain.

Minimising tillage consistently proved viable and cost effective on light soils. It rapidly showed benefits on heavy soils too. The soils were stronger, better draining and generally in better condition. Machinery cost and fuel use were halved.

“It’s a no-brainer,” we said, and devoted several years to demonstrating the techniques, pitfalls and benefits.

Labour weekend 2012, thirteen years later, and across Hawke’s Bay we see clouds of topsoil leaving fully cultivated paddocks. The wind is taking away the richest part of the soil, removing nutrients and water holding capacity and damaging developing crops.

My frustration is amplified. One of these disappearing paddocks is the very one where all our work started. Others are paddocks where strip-till or no-till has been used very successfully in the past.

Why do we have to learn these lessons again and again?

Dan Bloomer, LandWISE

Agronomy, Soil, Tillage, Uncategorized, Water

Risk Management for Good Practice

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The future hasn’t happened yet. Today we make educated guesses and do something. Later, we’ll discover if our choices were good.

We use “good agricultural practice” even though it is no guarantee. What seems right today turns out not to be. Hindsight is easy. Its value is in building knowledge for foresight the next time around. Foresight is part gamble, but greatly enhanced with local knowledge, historical context and good advice.

Growers need to make a profit. And they are expected to keep people, property and the environment safe. This is central to good agricultural practice. With so much uncertainty about so many factors, and so many things to consider, getting it “right” is a big ask.

Good agricultural practice applies deliberate choices based on good information, acknowledging and accounting for unknowns. It weighs the likelihood and implications of possible events against potential costs and rewards. Much attention has been placed on the financial side, but increasingly the environmental aspects must be taken into account.

Implementing a formal risk management approach enhances good agricultural practice. Risk management involves identifying hazards, assessing associated risks and implementing interventions. Things will go wrong, but the frequency and consequence are reduced.

Hazards are things that can cause or lead to events with undesirable consequences. Heavy rain, frost, pests and market collapse are hazards.

Risk combines the likelihood of the event happening with the severity of consequence. There will be heavy rain events, but how often? They can destroy crops, leach nutrients, wash away soil and damage infrastructure. What are the immediate and on-going severe consequences? How much will they cost? What effect on waterways?

Interventions are actions that avoid, minimise or mitigate the event or consequence. The size of risk and effectiveness of intervention help determine the investment that is justified.

Good practice has always had an element of risk management. Making it explicit helps demonstrate that the potential impacts of adverse events have been considered and appropriate management applied.

Who should decide what good practice is? Should it be prescribed, or should farmers have choice?

We prefer to have choice. Every site on every farm is unique – yes, your soils are different! By assessing our own situation and making our own justified plans, we can get the best fit for site, fit for purpose good practice.

Creating a full risk management plan for every aspect of farming is a daunting task. The same process can be followed to manage any risk. But it will be harder if we are dealing with unfamiliar topics or are not sure of the possible problems and solutions. We want to make it easier.

As part of the “Holding it Together” project, we scoped a risk management process to address soil quality and loss. We saw resources to help farmers work efficiently through a robust process, identifying and quantifying hazards and risks, and sifting through potential interventions would be useful.

A book or website with checklists and supporting information would make things much easier. Imagine clicking on a “hazard” and seeing a list of risks and image sets showing relative severity and ideas on avoiding the impact. Follow the cues relating things to your farm. Click “Print” and your Good Practice Risk Management Plan is complete.

Dan Bloomer and Phillipa Page, LandWISE

Agronomy, Drainage, Irrigation, Soil, Uncategorized, Water

Steps towards Farming Within Limits

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The article was first published in The GROWER magazine.

Farming within limits is the phrase of the year, by-line of numerous conferences, and part of many conversations. Farming within limits is nothing new. Financial constraints, market size, climate and soils, labour . . . you name it.

But farming within off-farm environmental limits puts a new spin on the topic. Both regulators and growers are under pressure to lift performance. Fortunately Horticulture New Zealand took a lead role years ago when it launched New Zealand Good Agricultural Practice.

New Zealand GAP is constantly evolving to meet new opportunities and requirements. And the bar will continually lift as governments, markets and other stakeholders expect ever higher standards from producers. But good agricultural practice is, and will be, the core of farming successfully within limits.

Successful growers already aim for profitable production with environmental stewardship. They have systems that ensure the basics are done well, and for continuous improvement. They measure to manage, they record to report.

These leaders of the pack are prepared for, and often do well from, change. They have a mind-set of adapting management to meet or beat changing situations. They already do a bit extra such as riparian planting and supporting local stream care. They are ready for most, if not all, that “farming within limits” may throw at them.

It is a year since the National Policy Statement (NPS) for Freshwater Management 2011 came into effect requiring councils to set limits on fresh water quality and the amount of water that can be abstracted from our rivers, lakes and aquifers.

Councils have four years left to establish programmes that will give effect to the NPS by 2030. They will need to amend regional policy statements, proposed regional policy statements, plans, proposed plans, and variations. It is a lot of work, and councils are under pressure to have the necessary changes in place sooner rather than later.

Government stated, “We are committed to monitoring improvements in fresh water management from the NPS and reviewing its effectiveness within five years as the complete package of reforms is rolled out.” There is a strong sense of urgency.

Growers can take action now. Both on and off-farm activities are needed, and many things can happen in parallel. There is a need to be involved, and no need to wait to do things better.

The freshwater quality driver points to many things; irrigation and nutrient management, soil conservation, stream enhancement, eel fishery management, and a range of environmental offsets. It is the effect of the combination of all management and mitigation that will determine the outcome.

Of the off-farm activities, Horticulture New Zealand Natural Resources and Environment Manager, Chris Keenan, says, “The key task in front of growers right now is participating in a limit setting process, because that will determine how much effect limit setting will have on the business.” Chris Keenan further notes that if they are going to do this effectively, they will need to be organised. Catchment management groups will be necessary in many cases, if not all cases.

On-farm, growers can adapt their management.

Two critical on-farm factors under direct grower control are water and nutrient management. We can’t control the rain, but we can definitely control irrigation and artificial drainage. And we are in control of our fertiliser application and can do quite a lot to keep nutrients in the root zone.

Our evaluation of irrigation systems and irrigation management records shows a wide range of performance. Some growers are highly focused, manage intensely and have high water use efficiencies.  Unfortunately, some don’t.

Without carefully monitoring soil moisture levels, weather forecasts and irrigator performance testing, effective efficient irrigation is impossible. You must know how much is needed, and how much is going on. If the basics are not right, no amount of fancy technology will help.

The same is true for nutrient management where a wide range of performance is evident. Some growers apply excellent soil fertility testing, nutrient budgeting and planning, and fertiliser spreader calibration; essential steps to maximise nutrients use.

Water and nutrient management are closely linked. Too much water will cause unnecessary nutrient loss to freshwater, just as will too much fertiliser.  Too little water reduces crop growth which leaves unused nutrients in the soil, often also increasing losses that end up in freshwater.

Fortunately, efforts to manage water and nutrients better can improve farm profitability as well as environmental performance. So it can be a win-win. Focus on getting the basic things right. Look for big, easy gains first. Then look at fine-tuning.

Catchment management groups, farmers getting together to manage the overall effect of all activities on the quality of water in each catchment, are a powerful way to make progress. Such groups provide a forum for ideas, a place of co-operative learning, agreement on actions and priorities, and opportunities for benchmarking performance.

If everyone performed at the level of the top quarter, overall performance would rise significantly. Then the community would be able to see the fresh water quality improvements sought.

Agronomy, Soil, Uncategorized

Assessing Yield Variability

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This article first appeared in The GROWER magazine.

Variability in crops shows that some parts are not performing as well as others. So what?

Variability is a major problem in the vegetable sectors. It is responsible for unknown but very significant financial losses all the way through the value chain. Variability comes in varied forms, from a variety of causes, with variable results and various appropriate management responses.

It may be a timing thing, a size thing, a quality thing or a quantity thing. It could be caused by weather events, soil differences, seed differences, pest or disease effects or some management factor. It may mean missed yield, lower yield, lower price or higher costs.

Process pea crops are a classic example of relatively minor timing variability causing major losses. If plants flower earlier or later, timing the harvest is problematic and both quantity and quality will be affected.  Some plants will not be ready when the harvesters come through. Others will be over mature and downgrade overall quality. Processing, in particular, needs uniform product and reliable supply.

Have you got crop variability? Assume you do, even if it is not at first noticeable. The key is to know if it is significant, what effect is has on your profitability, and whether it is worth fixing. Sometimes the benefits of dealing with it are not worth the cost. But often a cheap fix can avoid an expensive problem.

LandWISE partnered with Horticulture New Zealand to help growers estimate the value of crop yield variation. A spreadsheet calculates the cost of yield variation, based on measurements made in the field.

The three pieces of information needed are the product value, the area affected, and the yields achieved. A small booklet gives guidelines on determining areas and yields and the spreadsheet does the rest. You can download the calculator and guidelines from http://www.landwise.org.nz/projects/crop-variability/.

Why a calculator? While many farmers do observe variability in crops, few spend time quantifying the value (cost). The calculator and guidelines set out a straightforward process that doesn’t take much time, and does the calculations for you. It presents the results as tonnes and dollars in a table, and as graphs showing relative performance.

The Calculator encourages growers to identify the cause of loss in identified parts of the paddock. It then summarises the relative impact each has on yield.

One of the key pieces of information is quantifying the “Yield Gap”. The Yield Gap refers to the difference between the Potential Yield and the Main Area yield. It reflects an overall penalty and often costs more than the obvious losses. But because it affects the whole paddock it is not easily noticed.

If the season has been normal, and there are no obvious seed, equipment or management problems, look to soil condition or irrigation management as possible causes.

The Yield Variability Calculator estimates the value of crop loss. Thinking about how often these losses are suffered, how to avoid them in future what the cost of remediation may be, will help growers determine what, if any, action to take.

Dan Bloomer, LandWISE

Precision Agriculture, Soil, Tillage

My Soil is Different

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This article first appeared in The Grower in March 2012

 

“It won’t work here; our soils are different.” A common response to a new idea.

Two excellent events in Australia had me thinking, “Wow, their soils really are different!” But as to “It won’t work here,” that’s like saying you can’t cook carrot cake in a casserole dish. You can, if you are a bit adaptable. It is principles and processes we need to focus on.

The SPAA Precision Agriculture Expo was held in Port Lincoln in South Australia. The PrecisionAgriculture.com.au conference was in Maroochydore, Queensland. Both were characterised by excellent speakers, strong farmer representation, varied topics, and good industry support.

Speakers discussed nutrient tests we don’t use, plants we seldom grow, pests, diseases and weeds that remain thankfully foreign, and yields most New Zealand farmers would consider disastrous. They talked of soil electromagnetic sensors, pH sensors, biomass sensors, protein sensors, animal trackers and robots.  Of precision farming in Canada, Scotland, England, New Zealand, Queensland, New South Wales, Victoria and South Australia.

At both events, the farm was the focus, the technologies merely tools to help manage better. Much, much better.

Some of their Australian soils must be among the most inhospitable places on earth for a plant: three inches of sand on a deep, highly saline and toxic sub-soil; heavy compacting clay on compacted clay with horrid pH levels. In our young landscape the soils are quite different indeed.

But for all that, the messages were strikingly familiar. In essence; know and look after your soil, monitor your crop, and apply inputs where they give the best returns.

After decades working their land, farmers know their soils very well.  From cultivating and observing patterns in crops they learn about areas that perform differently. Most can draw a pretty good “mud map” if asked. They know where their soil changes physically and use nutrient and pH tests to monitor fertility.

There are new tools to help understand variation, such as the EM38 soil electromagnetic sensor and Thorium sensors. Light sensors can pick up organic matter variation. With GPS the variability can be mapped accurately and we can make more detailed maps. But be cautious.

Sensors almost always measure something other than the thing you are interested in. They have been shown to “correlate well” – under certain conditions. But remember, your soils ARE different! The numbers a sensor provides are not necessarily true for you; the sensor needs to be calibrated to your site. And that goes for practically every sensor I know.

Sensors can be very good at identifying differences, and directing our attention to areas worthy of further investigation. EM maps certainly provide evidence of electrical difference. The numbers the sensor generates vary enormously depending on soil moisture, clay content, density and salinity. So the same number in two different parts of a field may be due to different combinations of any of these.

The maps tell us where to investigate further. The most important tool of all is a spade. Decide on a small number of management zones, sample them separately to understand the causes of variability.

Dan Bloomer, LandWISE

Drainage, Soil, Tillage, Water

Coping with Extreme Weather Events

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This article first appeared in The GROWER in February 2012

 

Growers suffered significant losses during recent heavy rain. We cannot handle the most extreme events without suffering losses. But we can do a lot to reduce impact and avoid damage from minor events.

Building resilience will help with adverse events and returning to normal operation once the event is over. Focus on soil and its ability to absorb, drain and hold together when large rain events occur. Soil must be protected and enhanced and suitable drainage designed and installed. Managing traffic, reducing cultivation and managing water movement are critical.

Water needs to be absorbed into the soil and allowed to drain through it. The amount absorbed depends on the soil’s infiltration rate and the time that water stays in one place. Well-structured soil has good porosity, which maximises infiltration and drainage.

Compaction means soil damage: soil is deformed forming solid layers with little or no porosity. Water cannot get through these layers fast enough, so builds up in the soil above, drowning plants and weakening soil aggregates.

The common solution is cultivation; ripping soil to break up wheel track compaction. This is expensive and self-defeating as cultivation further weakens the soil and makes future traffic even more damaging.

About 80% of all compaction happens with the first pass, so keep traffic off paddocks in the first place or keep it to defined “roads” as much as possible. Then there is little if any need to cultivate.

While we need to drive on paddocks to plant and harvest crops, we can control essential traffic and keep the rest away. LandWISE farmers have shown clearly that controlled traffic and permanent bed systems reduce equipment needs, save fuel and labour, reduce time to next crop and enhance soil quality. Win, win, win, win and win.

Water runs downhill. Even seemingly flat paddocks have high and low points. If the infiltration rate is too low, water runs to low spots where it ponds. Slowing water down with surface residues or by ground shaping keeps it in place long enough to soak in and avoid ponding and erosion.  Lots of micro-dams hold rain where it falls, and slow any rivulets that may form.

HortNZ’s SFF Holding it Together project showed the benefits of furrow dyking that slows water in wheel tracks, giving it time to soak in rather than pond in low areas. This reduces soil erosion and protects crops against flooding and drowning. To sport nuts: “stop, trap, control the ball”!

Once controlled, pass it in a timely fashion. Consider artificial drainage if the soil cannot drain fast enough. Mole and tile drains provide extra flow capacity through the soil. Open drains provide a controlled way to take water to a safe disposal point.

A number of innovative drainage options are available. Old ideas linked to new GPS and computer mapping have revolutionised tile laying, surface drainage planning and ground contouring. Each has its place.

Precision tile-laying maps paddocks with GPS. It automatically surveys elevations while the tractor drives along the next tile line, calculates the depths and grades required, and precisely controls tile laying depth. It is fast and cheap compared to old practices.

Surface drainage planning controls water movement across the surface. It aims to remove excess water safely before it waterlogs the soil, by ensuring a path without ponding areas. New technology allows very detailed surveys and planning, and results in minimal soil movement for optimum drainage.

In extreme cases, surface levelling changes the whole paddock contour, directing water to safe boundaries. Because it typically moves a large volume of soil it is expensive and can have a significant soil impact. But it has other advantages such as avoiding high, dry spots and ensuring even depth to water table.

We often think of water management as irrigation, especially in summer. But we must have our soils and drainage in good order at all times of the year.

Dan Bloomer – LandWISE

Drainage, Irrigation, Precision Agriculture, Soil, Tillage, Water

LandWISE NEWS June 2012

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Conference 2012

The 10th Annual Conference was our biggest gathering with over 160 attendees. We extend our thanks to the speakers, sponsors, trade supporters and delegates that made the event such a success. There were some important issues up for discussion by excellent speakers and we have received very positive feedback.

2012 saw our first Focus on Viticulture, an extra day dedicated to wine growing technologies. Keynote Rob Bramley started the conference and was well supported by the remaining speakers. Rob and Tim Neale both made a number of presentations over the three days, and we are very grateful for their high quality inputs.

The second day investigated implications of the National Policy Statement for Fresh Water Management. Thanks to Land and Water Forum Chair Alistair Bisley, HBRC CE Andrew Newman, LandWISE Chair Hugh Ritchie and the others who presented clear outlines of the concepts, process and possible future.

The field event at Hugh Ritchie’s farm was also extremely well received and we thank Hugh and the other presenters for their work setting everything up – a significant undertaking. The Anderson Road block was transformed into a precision farmer’s perfect sandpit for the day.

Live demonstrations of Trimble surface levelling and Keith Nicole’s GPS tile laying were of much interest. These drainage options were supported by Precision Irrigation’s variable rate irrigation fitted to the towable pivot on-site. and Hydro-Services showing soil moisture monitoring options including neutron probes and electronic sensors and telemetry from WaterForce.

New Board Members

Long term Board members, David Clark and Chris Butler, retired this year.

We have two new Board members, both from Pukekohe. Paul Munro from Peracto and Brent Wilcox from AS Wilcox were elected at the AGM.