So, What is Soil Moisture

 

I recently heard a gardening segment on a NZ radio station. The gardening commentator was answering questions and providing advice on ‘how to irrigate your garden’. Her advice was: “Deep watering will encourage the roots to grow into the water table below. This is desirable as it allows the plants to be self-sufficient in accessing water.”

We all have our own perception of water and how it is stored in the soil, but the gardening commentator’s description isn’t an accurate description of what actually happens within the soil or what we are aiming to achieve through irrigation.

There are several processes at play when water is “stored” in the soil: 

·        cohesion - the attraction of water molecules (H₂O) to one another it causes water molecules to stick to one another and form water droplets;

·        adhesion – the attraction between water molecules and solid surfaces, in this case soil particles;

·        surface tension – as a result of the cohesive properties of water molecules and their attraction to other water molecules, a water surface behaves like an expandable film; and

·        capillarity – is a combination of cohesion/adhesion and surface tension forces and is the primary force that enables the soil to retain water and to regulate its movement.

In this article we will take a closer look at these terms and and apply the concepts to soil moisture storage.

To demonstrate or understand adhesion and cohesion, pick up a rock or stone, dip it into a pool of water, pull it out again. The water dripping off the rock is free water (lost to gravity, same as free water will be lost to drainage when soil is at saturation point). If you give the rock a shake you will free it of more water - this is the water “stored” by cohesion. The rock is still wet even after the shaking - the water left on the rock is “stored” by adhesion (Figure 1). Water is stored in this way on all soil particle surfaces, whether it be a clay, silt, sand or gravel particle.

Figure 1: Soil moisture is stored on soil particles like a film via adhesion. On this stone adhesion is demonstrated by dipping it into water solution containing blue dye.

Capillarity is the key to storage of water in the soil. It allows water to move upward (and through) soil pores against the force of gravity. The finer-textured the soil (silts and clays) the greater the ability to hold and retain water in the soil in the spaces between particles. The pores between small silt (less than 0.02mm diameter) and tiny clay (less than 0.002mm diameter) particles are known as micropores. Compare these to the larger pore spacing between larger particles, such as sand (0.2-2mm) and stones (larger than 2mm) which are called macropores. Micropores enable greater capillarity rise.

Capillarity can also be simply demonstrated by placing a dry sponge into water – it will progressively wet upwards through the sponge (Figure 2). The finer the sponge material the higher the water will wet the sponge.

Figure 2: Fine sponge placed into a dish with water solution containing blue dye demonstrating capillarity.

When we irrigate, we want the water to have the opportunity for adhesion and capillarity to take place; i.e. “coat” the soil particle surfaces with water and be retained in the micro pores by capillarity this is best achieved through low application rates and by matching the applied depth to soil moisture deficit.

Back to the garden commentator’s recommendation to practice deep watering and aim to push roots into a water table. Very few farmers/growers/irrigators will have a water table shallow enough for roots to reach the water table. When roots explore the soil profile, they form perfect contact with soil particles, via this contact they can extract the moisture stored on particle surfaces. Deep watering is accurate to an extent. We want roots to explore as much soil as possible as this allows them to access more water and nutrients. Roots will only grow in moist soil, so they’ll only explore the soil profile if it’s been wetted. However, it is unusual for the subsoil not to be moist enough for root growth as the plant advances through its growth stages. Irrigation should therefore only be aimed at wetting the soil within the active root zone.

Aquacheck sensors measure soil moisture at several depths. This depth profile is a very useful tool in managing your irrigation. It allows you to see if you are wetting the active root zone and whether the subsoil is wet enough to allow for root growth.

Jane Robb 

Vantage NZ Customer Support Specialist

Maximising the Value of Irrigation

The H2Grow Team are excited to introduce Carolyn Hedley as our guest contributor, it is with great pleasure that we can share with you her valuable expertise. Carolyn is a Soil Scientist with Manaaki Whenua, based in Palmerston North, and lives on a small Kairanga farm with husband, Mike. Carolyn has combined her interests in soil science, proximal soil sensing and precision agriculture with on-farm studies of precision irrigation and soil carbon mapping. She has led several nationally funded projects in irrigation and soil carbon, including current leadership of the MBIE funded programme “Maximising the Value of Irrigation”.

Maximising the Value of Irrigation  -  Carolyn Hedley

Early in the new millennium I found out about EM mapping and in 2004 published a method in the Australian Journal of Soil Research to rapidly EM map soil variability on a basis of soil texture. I realised that EM mapping was a really useful new technology to rapidly survey soil variability. The EM map had picked the difference between a Kairanga silt loam and a Kairanga clay loam, and this had management implications for the farmer because the heavier textured soil would compact sooner when grazed in wet conditions.

I could see great potential in this new technology and so embarked on a PhD in proximal soil sensing and this is when I started to relate the EM map to soil available water holding capacity and realised how useful this could be for irrigation scheduling. But critics commented that irrigation systems cannot irrigate to such a complex pattern (example shown in Figure 1 below). Enter Stu Bradbury and George Ricketts, who had worked with me on some EM mapping projects when they were students at Massey University. There was an engineering solution to this problem – control the sprinkler system on a pivot to irrigate to any pattern – which led to the development of the Precision VRI system. Precision VRI, the world’s first true variable rate irrigation system, turned the heads of the global irrigation giants and as a result Lindsay Corporation acquired the technology development company founded by Stu and George.

Figure 1: Available Water-holding Capacity map derived from an EM map for a 100-ha area irrigated by a VRI linear move irrigation system

There was still work to be done though and a proposal put to the Ministry for Business Innovation and Employment received six years funding in 2013 to further research methods to improve management of irrigated land. Now in its final year, the “Maximising the Value of Irrigation” programme has been able to refine methods to use proximal sensor data to create prescription maps for precision irrigation. It has developed soil and crop sensing methods that can inform in near real time the prescription map, and a prototype scheduling tool has been tested with participating farmers as a smart phone app. The in-field sensor monitoring methods have been used to support Lindsay further refine the software control features for the Precision VRI system, which is remotely managed through the FieldNET platform.

Ekanayake, J. and Hedley, C. (2018) Advances in Information Provision from Wireless Sensor Networks for Irrigated Crops. Wireless Sensor Network, 10, 71-92. 

Research into different soil management methods has identified correct tillage and soil surface management methods to store more water in the soil and reduce irrigation requirement and water losses. A spatial framework to run the APSIM model has been created to test the effect of different irrigation scenarios on yield, drainage and water use efficiency. Spatial-APSIM simultaneously runs the model for up to 1,400 grid cells for one irrigation system to compare results of different irrigation scenarios at spatial resolution < 50 m, over several decades.

The MBIE Programme “Maximising the Value of Irrigation” is now working closely with its industry advisory group to ensure that its findings are communicated effectively and to find ways to integrate new tools and support improved management of irrigated land in New Zealand.

Celebrating 10 years of Irrigation Innovation

It’s a classic story of Kiwi innovation.

One summer’s evening in 2004, two Massey University engineering graduates, Stu Bradbury and George Ricketts were working a summer job assembling irrigators on the South Wairarapa farm of Brian and Jo Bosch. 

Over a cuppa, Stu, George and Brian discussed the challenges on the Bosch’s farm caused by the limitations of the existing pivot irrigation system.

“Where the pivot went over the races was wet and mucky,” says Brian.  “We were also getting a number of lame cows, who got wet feet and bruising on the muddy race.”

Brian Bosch on his Wairarapa dairy farm

Blanket irrigation was the problem. They needed a way of irrigating specific areas that needed it but keeping vulnerable parts such as the race dry.

Back then nothing on the market could manage the water flow in targeted and controlled quantities, to specific parts of the farm depending on topography and soil type.

“We saw wet areas where crops weren’t growing, and dry areas without much water. So there was an obvious need for a system to specify where you needed water and how much,” says Stu.

Before long George had the solution and in 2006 they began developing the prototype that would become Precision VRI. VRI stands for variable rate irrigation, ensuring precise amounts of water or nutrients are delivered over multiple crops, soil types and terrains.

To make best use of the technology on paddocks with variable soil types and terrain electromagnetic (EM) soil mapping is recommended. EM mapping measures soil conductivity which is an indicator of soil texture (along with other characteristics) and therefore soil water holding capacity. The Precision VRI system can be easily programmed using the FieldNET app to customise irrigation according to the EM map.

The system can be used to ensure that only the areas that need water, get water, and at the right levels.

Over the past decade Precision VRI has enabled New Zealand’s farmers, food producers and agricultural contractors to achieve better results, driving efficiencies and saving money – to the benefit of agribusiness, not only for dairying, but in sheep, beef, horticulture and arable farming.

In 2011 global agribusiness leader Lindsay Corporation acquired the NZ company WMC Technology Ltd under which the Precision VRI technology was developed. Through doing so the not only gained the rights to market the award-winning technology but also provided significant backing for George, Stu and the team to continue developing irrigation solutions.

From the archives: George and Stu at a farm mapping job in 2010 (above). Stu, George and Paul (below) receiving the Supreme Award at the Manawatu Business Awards 2010, WMC Technology Ltd also won the Innovation Award and the Workplace Health and Safety Award.

“We are working on new iterations of the software,” says Stu.

“Now, everything needs to be mobile-friendly so that is where our efforts are focused.”

Future plans to market the system internationally will give farmers world-wide the advantages experienced by New Zealand farmers using the system.

To find out more about the Growsmart Precision VRI system call 0800 438 627 or visit www.lindsaynz.com.

Irrigation Evaluations (aka Bucket Testing) - Including tips for testing VRI systems

Spring is here but we are seeing all four seasons rolled into one some weeks which is not an anomaly. The soil moisture levels in our region have had a healthy boost in the last few days but if the media reports are true we may be in for a dry summer - please don't shoot the messenger, I'm only relaying what I have heard.

Should this transpire then that is even more reason to ensure that our irrigation systems are applying water as efficiently as possible so that we are maximising the amount of water applied that is available for plants to grow. An irrigation evaluation is a way to assess the efficiency and distribution uniformity of your irrigation system to ensure it is performing as expected.

An irrigation evaluation will help identify causes of any poor performance and (sometimes with the assistance of a qualified professional) show how these can be resolved. Increasing irrigation effectiveness and efficiency will allow you to grow more for less.

An irrigation evaluation (often referred to as a bucket test) is simple enough to carry out yourself, there are several good guides freely available to walk you through this process. For more information check out:

IrrigationNZ - Bucket Testing Resources
DairyNZ - Irrigation Evaluation Guide

The guides recommended above will walk you through how to carry out a standard bucket test however before you begin you need to consider any additional technologies that enhance your irrigation system. For instance if your system has variable rate irrigation (VRI) technology then you will need to take this into account when planning your bucket test. Lindsay NZ, the developers of the Growsmart Precision VRI system, have created a step-by-step guide that explain these additional considerations in more detail.

Growsmart Precision VRI - Bucket Testing Tip Card

If you are not in favour of the DIY irrigation evaluation option then consider contacting an accredited evaluator, this would also be recommended if your own test identifies potential issues that warrant further investigation. If you have additional technology such as a VRI system then ensure that whoever is carrying out the test is aware of this and that they carry out the recommended additional steps. If you need further help then contact your irrigation dealer, many dealers also have accredited evaluators on hand.

Irrigation system checks and maintenance should be undertaken at scheduled times over the irrigation season (the more hours your irrigator runs for the more regularly these checks should be carried out). Recommended irrigation system maintenance will be covered in more detail in the next H2Grow blog post, this will include a checklist that you can download and print off to help you with this task.

Keep an eye out for the next post or subscribe by entering your email in the box to the top right of the screen to ensure that you don't miss it!

Today's blog was written by Sarah Elliot from Lindsay NZ - I hope you have found it useful!

Key Learnings from the IrrigationNZ Study Tour to Nebraska

I was part of a 24-person group who went to Nebraska at the start of September 2018.  The tour was organised by IrrigationNZ and was an amazing opportunity to go and see how another part of the world deals with the same issues that we have here.  Below is an overview of my key learnings from the tour.  

Governance of Water

The governance of water in Nebraska is complex. There is Federal legislation, such as the

Endangered Species Act, which the state has to abide by. Alongside this there are also Federal agencies, such as the Bureau of Reclamation that control most of the surface water through storage and diversion infrastructure. The state then sets its own laws around how it will manage its water.

In Nebraska the surface water is manged at state level by the Department of Natural Resources, but groundwater is managed by Natural Resource District’s (NRD) at a local level. For a number of surface water bodies, there are also interstate pacts that determine how much water must remain in the river to reach downstream states.

The NRD’s have a Board that is democratically elected, and are often dominated by rural people including farmers. Despite this, the farmer representatives have been proactive in driving practical change among their peers.  

The NRD system in Nebraska has been very successful in managing groundwater. All takes are controlled through a well permit system that allows for a given number of hectares to be irrigated per well.

Both of the NRD’s that we visited had invested heavily in science to help them better understand their resource. They also look for solutions as both a farm and catchment level, the latter including raising capital to build environmental infrastructure such as that required for augmentation projects.  

Conjunctive Management

‘Conjunctive management’ is a recent development in Nebraska that has largely come about through the management of ground and surface water takes in ‘conjunction’ to achieve interstate pacts. This has involved the NRD’s (the managers of the groundwater) working closely with irrigation districts and the Department of Natural Resources to ensure downstream flows are achieved.

This has included restriction of individual water takes (wells) – controlling any new ones, limiting the irrigated area from existing ones and in some cases placing a seasonal limit on usage. Alongside the implementation of environmental infrastructure such as Managed Aquifer Recharge and Stream Augmentation projects.

Managing Water Quality

Nitrates in groundwater are of significant concern in the heavily irrigated districts of central Nebraska. In some areas over 50% of the land is now under irrigated crop-farming. Historic poor nutrient management (type and timing) and poor irrigation practice resulted in nitrate concentrations being frequently observed over 30ppm – well over the US drinking water standard of 10ppm.

However, in recent years there has been a significant declining trend, with relatively few areas now exceeding 20ppm. This has largely been brought about by a non-regulatory approach.

State law requires the production of water quality and quantity management plans that identify the issues and then require the development of an implementation plan to address them. All the NRD’s have a rule framework, but most of the rules are currently focused on managing water takes and farming practice reporting. Incentives, knowledge and enabling peer to peer learning in combination with environmental infrastructure is currently seen as the way forward for water quality.

The widespread move from surface flood to centre pivot irrigation has been instrumental in reducing nitrate losses to groundwater. This has enabled soils to be irrigated on an ‘as and when’ basis to minimise nitrate leaching. There is now also a push towards the more widespread adoption of fertigation, as it allows ‘as and when’ nutrient applications – significantly reducing the risk of leaching from rainfall events.

Public perception

Despite the widespread use of intensive farming methods, and the water quality and quantity challenges facing Nebraska, the one issue currently not facing farmers at the state level is pressure from the anti-farming lobby or environmental groups.

Of the almost 2 million people living in Nebraska, the majority understand the role of crop farming and ranching in providing for their social-economic well-being. The Nebraskan economy is based on the irrigation of almost 4 million hectares of corn and soy beans and this is widely understood. 

The University of Nebraska research and extension service runs an outreach programme to attract the next generation to agriculture. This currently interacts with one in every three school age children in the state, providing an agriculture ‘101’ and highlighting the exciting career opportunities that exist within it.

Keri Johnston, Irricon

Natural Resources Engineer

It's starting to get dry...

Other than this slightly cooler snap we've had over the last couple of days you'd have to say spring is well and truly here! And with these nor-west winds (in Canterbury anyway) and warmer days things are starting to dry out and there's not much rain on the horizon. The seasonal weather outlook from NIWA suggests that we're in for a dryer than average season in most places (https://www.niwa.co.nz/climate/seasonal-climate-outlook/seasonal-climate-outlook-september-november-2018) and at this point I'd have to say they're about on the money. 

The joys of being a farmer or in the ag industry is that everything you do hinges on the weather, so we get really good (for the most-part) at managing timings and inputs and reading the signs to optimise what we do on farm. Now is no different. Whether you're an irrigated farmer or a dryland one now is the time to be installing your soil moisture probes if you haven't done so already so that you can accurately measure and manage your soil moisture and timings of related inputs on farm. 

Soil moisture probes allow you to know whats going on under your feet and make accurate and timely decisions to set yourself, your farm, your crops and your livestock up to perform to the best of their ability for the coming season. Soil moisture is one of the key drivers for plant growth so it's important that we know where we're currently sitting in terms of soil moisture levels so we can react to it accordingly. Decisions around fertiliser (and other input) timings, timing and amount of irrigation, stock carrying-capacity decisions etc can all be driven by more accurate information regarding soil moisture levels. 

If you want to find out more about some of the leading soil moisture probes in the NZ market have a look here: https://bit.ly/2OyeVj1 

And if you're wanting to get some installed for the coming season please pick up the phone and give the Agri Optics team a call now before you run out of time and you're left carrying a spade in the back of your ute or ruining the tip of your good pocket knife for the upcoming summer. 

All the best for an upcoming and prosperous season ahead! 

Cheers, 

Jemma

Rain gauges – why they're a powerful tool for your operation

Do you know how much rain has fallen on your farm?  Or on your block of land down the road?  Do you sometimes forget to tip out the rain gauge?  Accurate rainfall figures for farm records are becoming more and more important in this age of transparency.  Knowing how much rain fell on any given day on your own farm or on a particular crop will give you the ability to make more accurate decisions.  Telemetered rain gauges save you the hassle of manually reading the rain gauge and provide up to date data straight to your phone or computer. 

Rain gauges can be installed along with your soil moisture probe and positioned under the irrigator or installed in a dryland area.  Positioning the rain gauge under the irrigator enables you to monitor exactly what application depth the irrigator is applying.  Application depths can change as a result of adding extra irrigators to the system, blocked or broken nozzles and changes to system pressures to name a few.  Excessive application depths are expected to account for on average 10% of water losses on an average irrigation system, that’s wasted power, water and most importantly money.  Not applying enough water may result in yield losses and shallow rooted plants.    

A telemetered rain gauge installed under the irrigator will also enable you to see the application rate applied.  If it is above the rates described for your situation in the table below you may be wasting water.  

Agri Optics can add a rain gauge to your soil moisture system to help your decision making.  Ring us today to talk about the options for your farm. 

Agri Optics office: (03) 302 9227

Cindy Lowe 021 796 834 or cindy@agrioptics.co.nz

Email: info@agrioptics.co.nz

EM Surveying - The Uses

In the previous EM survey blog, I ran through the process of conducting the survey, this time I will go through some of the uses.

The data from an EM survey is very useful for irrigation in many ways. The topography data can be used for planning the pivot design itself with your irrigation provider for example working out tower spacing and pivot positioning. The angle of slope can be used to see if the pivot stays within design parameters for insurance purposes as well as design planning.

Figure 1: Contour map on top of elevation map

After the initial pivot or irrigation design plans, we can then look at the EM data itself to determine the amount of variability within the surveyed area. Within the PCT Gateway software we can look at the value and amount of the crop being grown on the area and the cost of installing variable rate irrigation (VRI). The software needs to know the average yield and value of the crop. That way using algorithms it calculates that by not over watering the heavier soli types or under watering the lighter areas you bring the crop yield on those areas up to the average. It looks at the reduction in variability by using VRI as opposed to a blanket application. In the example below the variability from using VRI drops from 30.4% to 4.68%. So, by using the average yield and the price we can see the payback vs the cost of putting VRI on your pivot.

Figure 2: Illustrating the payback from VRI, using an EM map. 

This model just looks at the costs vs savings of VRI from a production prospective. It doesn’t take into consideration savings from reduced water use, power savings, reduced track repairs etc, which will be in addition to this.

The next stage is to make VRI maps up for the pivot, using the different soil zones, predominately we use the shallow EM results. If the area has a lot of variation in topography we can also combine the elevation layers with the EM map to make an application map for the pivot. We can also use other elevation layers to achieve the best solution used for each specific survey, as required.

The map below, shows a three zone EM map, where  red is the lightest soil, green the medium textured soil and blue the heaviest soil. This has been combined with the slope map, where the darker tone indicates a slope of 0-5% and the brighter tone of colour areas where the slope is above 5%.

Figure 3: An EM map and slope map combined to make a VRI application map. Brighter red, green and blue indicate slope for the different soil zones. 

The EM zone maps can also be used for irrigation pod placement, as well as moisture probe placement. If you only have one probe under an irrigation management zone, you want to make sure its under the right area. I will discuss this in more detail in the next blog. In the meantime, if you have any questions about EM surveying please get in touch.

Chris Smith

Operations Manager Agri Optics NZ Ltd.

EM Surveying - it's that time of year again!

With all the early season rainfall we've had the EM Surveying season has started a lot earlier than most years. It's great in a couple of respects: 1) we can get across the ground before it all gets really wet (if that happens) and the potential to make a mess increases and 2) it gives you more time to analyse and incorporate the data into your decision making over the winter months. 

As we're already into it this year, we thought it was time to give you a reminder about EM Surveying and how it all works. Today you'll get the first of a two part blog looking at the process, what you get from an EM Survey and what it can all be used for. 

EM Survey – Part 1 - the process.

When we conduct an EM survey we are measuring the electrically conductivity within the soil profile, the values have close links to the soil texture properties, where clay gives a higher reading than silt that in turn gives a higher reading than sand. So, by driving over a block of land you pick up the differences in the soil texture at two different depths 0-50cm and 0-125cm. Other factors have varying degrees of influence on the readings such as soil bulk density and moisture within the profile at the time of the survey. High salinity readings can have a huge influence on readings, but this is only in specific areas of New Zealand. The EM data is logged using 2cm accurate RTK GPS, so not only do we map the relative changes in soil texture, we are also collecting valuable topography data at the same time.

Agri Optics' EM Survey setup with soil profile shown. The measurements penetrate 1.25m into the ground. 

We drive most commonly at 12m swaths across the area, but closer resolution can be used for more intensive situations such as viticulture. Once the survey has been conducted we write a report about the findings from the two different EM layers, we then zone the EM data up into different management areas and run topography generated maps. Once you have had time to read through the report we arrange a meeting to then run through the report with you in person if you so desire. We also supply the client with software to view the data on their own computers and look at the different layers plus make your own management zones if required. From this point we can then focus on the areas of interest for your requirements.

The survey data has many uses, depending on the farming type and location and includes but is not limited to the following;  being the basis of variable rate irrigation application maps, moisture probe placement, used in zonal soil sampling, in dryland farming areas knowing where to put your effluent, to varying your nitrogen use depending on the underling soil types and used for flood modelling. It can also be used in conjunction with other layers of data such as yield maps, biomass maps and as happens frequency used with the topography data. Over the next few blogs I can drill into more detail on these different uses.

The EM season runs form the end of irrigation in the autumn through to Spring, but from now onwards is the ideal timing. For more information on EM surveying or to book one in for this season, please contact one of the Agri Optics team. Cheers, Chris. 

The Importance of Timeframes – Resource Consent Timeframes That Is…

Christmas seems to be a magic deadline for people – apparently the 25^th of December is the date at which the professional world as we know it will cease to exist and heaven help us if we miss it.

While Christmas is more of a perceived deadline for things, there are some real resource consent timeframes or deadlines that you should be aware of.   As over-allocation of our resources has become an issue, so has the methods by which councils can use to reduce over-allocation.  This is where timeframes around consenting are beginning to bite and councils are actually using their powers. 

Lapse Date and the Cancellation of a Consent

The first is the lapse date on a resource consent.  This is not the expiry date, but rather the “use it or lose it” date.  From the date of grant of a consent, you have up to five years to use the consent, or you lose it.  This is particularly important in over allocated water catchments for example as lapsing a consent is one of the mechanisms that a council will use to claw back over allocation.  You may apply to the council to extend your lapse date, but you have to be able to demonstrate to the council that you have taken considerable action towards actually using the consent.  The maximum extension that would normally be given is a further two years.

Even if a consent has been used before the lapse date, it can still re-lapse if it is not used for a five-year period after that, so this is something that you also need to be aware of.   This is referred to as cancellation of a consent. 

Renewal of Existing Consents

There are also important deadlines around renewing resource consents.  An application to renew a consent that is received by the council at least six months prior to the expiry of the consent is guaranteed to be given ‘continuation’.  What this means is that you can continue to operate under your existing consent until such time that a decision is made on the replacement.  Getting continuation is critical if processing the renewal is likely to take considerable time like we have seen here in Canterbury where renewal applications have spent years in process waiting on plans to be developed. 

A renewal application received after six months but before three months of the expiry date may get given continuation, but it is at the council’s discretion. 

Securing continuation also means that you have priority to a resource over someone else competing for the same resource.  So again, if we think water permits where a resource is nearing its full allocation, you want to be able to re-secure your access to that water ahead of a new user.   

If you find yourself within the three-month window, then continuation cannot be given, and you must cease your activity at the expiry date.  If you are in an over-allocation situation again, this may cause issues with your renewal, and there is a risk of the council not granting the renewal consent (another way to claw back over-allocation). 

Expiry Date

Once a consent expires, and if no application has been received by the council to renew the consent within the required timeframes, then you no longer hold a consent to undertake that activity or have any right at all to renew it.  If you find yourself in this situation, and you do want to carry on undertaking your consented activity, then you have to apply as if you are a brand-new consent.  In over-allocated areas, you may not even be able to apply for consent as many councils have now made it a prohibited activity to apply for consent in over-allocated areas.  Prohibited means that you cannot even apply to the council – the door is shut tight. 

These dates are all things that any consent holder needs to know.  A resource consent is not an unlimited right for unfettered access to a resource, or to undertake an activity.  It can be revoked by not using it, or by failing to meet the timeframes around the renewal process.  

Also, a small request from this consultant.  An application for resource consent can take a fair amount of time to prepare – even if it is for a renewal, the amount of information required to be supplied is just the same as it is for a new application.  Therefore, please give your consultant plenty of time to get the application in – it is no good fronting up a week before the application must be submitted and expecting that it can and will be done in that timeframe, and the same goes for that magic Christmas deadline…

By Keri Johnston, Irricon Resource Solutions

Phone 0272 202 425 or email keri@irricon.co.nz

www.irricon.co.nz

Stock Exclusion - What's the go?

Out and about recently, Lilian Sherman, our North Island Rural Environmental Specialist, has heard a lot of discussion about the stock exclusion rules coming into play.  Unfortunately, a lot of what she has heard has had a serious dose of the ‘chinese whispers’ and the end result is that there are a lot of myths out there with regards to stock exclusion.  Below, Lilian dispels some of those myths and provides you with some confidence around the rules.

While there is no formal definition, stock exclusion generally means to exclude stock by some means from entering a waterbody.  In most cases, the stock exclusion definition does not include sheep or goats, as sheep and goats do not tend to linger in water!  In most cases the means of achieving stock exclusion is not specified, therefore the best method or technology for each situation can be used.  This may be a permanent fence, a hot wire, or as is currently being developed, virtual fencing.
Why is stock exclusion necessary? Stock entering waterways can cause significant damage by contributing nutrients (primarily nitrogen and phosphorus), sediment and faecal coliforms to our waterways. They do this though the direct deposition of dung and urine into rivers, treading damage and reduction in beneficial vegetation that results from grazing stream banks.

As part of the Clean Water package recently released by the Ministry for the Environment, there are proposed National Rules for Stock Exclusion.  Consultation on the proposed stock exclusion regulations and other aspects of the Clean Water package closed on 28 April 2017. This feedback is being considered and will inform the final decision on the National Rules.  The proposed stock exclusion rules are practical and there are different requirements for different classes of stock and for topography (plains, rolling and steep).  More details are available on the Ministry for the Environment Website (https://www.mfe.govt.nz/sites/default/files/media/Fresh%20water/next-steps-for-freshwater.pdf).

The proposed National Rules for Stock Exclusion recognise that for some landowners, there may be significant practical constraints that mean they are unable to meet the new requirements. In those cases, landowners can apply for permission to instead develop a stock exclusion plan with their regional council. The plan may include alternatives to fencing or mitigations to reduce the impact of stock access to waterways.  An example of this would be providing alternative areas of shade and reticulated stock drinking water, which may also provide other economic and animal health benefits.

It is important to note that the National Rules for Stock Exclusion will form the minimum requirements, and councils may choose to regulate over and above these in their regional plans.

There are some challenges excluding stock from waterways, including the effects of flooding, the proliferation of weeds and pests and access through vegetation to waterbodies.  These are valid issues and I have confidence that farmers will find practical solutions for these as the rules come into play.

In the meantime, if you are putting in new fence line or carrying out fencing maintenance, consider whether there is an opportunity to make a change to a fence line to exclude stock or make it easier to exclude stock in the future, but its also an important consideration for any development on farm such as irrigation (whether new or upgrading) and the location of waterways should be a key consideration in any design being undertaken. 

Keep an eye out for the final versions of the National Stock Exclusion Rules.

Lilian Sherman, Irricon Resource Solutions Limited.
Phone: (021) 378 308
E-mail: lilian@irricon.co.nz

Lilian is a Rural Environmental Specialist and Director at Irricon Resource Solutions, who works with farmers and horticulturists to prepare farm environment plans, resource consent applications and to assist with nutrient management and Overseer modelling. 

Lilian grew up on and lives on a sheep and beef farm, she has a practical knowledge of farming, including sheep, beef, deer, dairy, cropping and horticulture and combines her passion for farming with a wealth of nutrient management and environmental expertise in this role.

Farm Environment Plans

There are a lot of buzz words floating around at the moment – nutrient management, nitrogen baseline, change in land use, Overseer, nutrient budget, and the topic of this article – farm environmental plans.

So what is a Farm Environmental Plan, or FEP as we like to call it?  It is a tool that guides farmers through an assessment of a farms environmental risks or issues, and is a written plan outlining how those risks or issues will be managed.  Because no two farms are alike, no two FEP’s will be alike either.  Each farm is unique in terms of its landscape, natural resources, farming practises and goals.

FEP’s are being used as a means for farmers to meet water quality objectives and outcomes, or limits set in regional plans.  In Canterbury for example, nearly every farm will be required to have and implement a FEP by 2017.  

The process in preparing a FEP is the same for all farms, and is really simple.  There are five easy steps.

1. Assessment

What and where are the environmental risks or issues on farm?  The farm specific environmental issues or risks include poorly drained soil, streams, waterways, wetlands, springs, steep or rolling topography, but this also refers to practices being carried out on farm.  Do you store fertiliser on farm?  How is it stored?  How is fertiliser spread and when?  Is the farm irrigated, and if so, how do you determine when to irrigate?  Cultivation practices, location of silage pits…

The second part of this is to consider what has already been accomplished.  Have you already fenced off waterways, carried out riparian planting, swapped to a GPS certified fertiliser spreader, installed soil moisture monitoring probes to determine when to irrigate, only make or purchase balage rather than pit silage?

The third part is the Overseer component. What are the losses that are occurring from your farm now?  How do they compare with any proposed catchment limits being talked about?  If your losses are high, then what changes can you make to reduce these?

2. Response

Now that you have identified the environmental issues or risks, and worked out what you have already accomplished, it’s time to fill the gaps. What else can be done?

3. Plan

What, how, where, when and how much?  Fencing off waterways for example – your assessment may have shown that there is 10km of fencing that needs to be completed.  There may be financial constraints that mean that all 10km cannot be fenced off in one go, but plan to do 2.5km per year for the next four years, and identify the areas that will be done each year – there may be a section that really needs to be done sooner rather than later as the environmental risk is higher (for example, a section where stock access several times a year as opposed to once a year), and this gets done in year one.

Any plan has to be reasonable and achievable – no point in making a plan that will never be able to be carried out – that defeats the whole purpose!

4. Implement

Carry out your plan.  Monitor what you do and record progress.  This is really important as FEP’s are subject to annual audits by independent people, therefore, you want to be able to show any auditor exactly what you have done, and whether it has achieved the environmental outcome you expected it too.

5. Review

Review your progress annually.  This can be part of the annual audit.  Reviewing your progress is important.  Have you noticed that some of your responses have worked really well, but others seem to be of very little environmental benefit at all?  A FEP is a living document, and as you learn what works and what doesn’t, then your FEP needs to be updated accordingly.

The most important thing to remember is that a FEP is for you and your farm, and it should be written this way.   It should not be an onerous task, nor viewed as a way to “trip you up”.    Use the opportunity to have a good look at the way you do things on farm, and why you do what you do. There are many other benefits too – not just environmental.  There are also financial gains to be made as things like water efficiency increase (less pumping costs), nutrient and fertiliser management practices change (less applied = less purchased).

There are many resources available to assist with preparing a FEP including toolkits and templates. But sometimes, you just need someone to point you in the right direction, and this is where we (Irricon) can help.    We are farmers too, and are going through the same process.  We are also learning as we go – I cannot stress enough that a FEP is not stuck in time – once it’s prepared, that’s it, end of story, but it is a living document, and as we learn, we are passing that knowledge on, as are many others. Therefore, don’t hesitate to seek advice and support from those in the know.

By Keri Johnston - Irricon Resource Solutions Limited.

Keri’s expertise is in the field of natural resources engineering and resource management, primarily in water resources, irrigation and nutrient management. As well as doing this, she farms with her husband and two girls at Geraldine.

Phone: (027) 2202425
E-mail: keri@irricon.co.nz

Reduce the Cost of Nutrient Loss with Precision Ag (Part 1 of 3)

Precision Ag can help you in many ways with your Farm Environment Plan (FEP). Precision nutrient management, EM maps, topography data,variable rate irrigation (VRI) and moisture probes are all tools available to help you manage your FEP and mitigate any potential issues you may face - Reducing costs to your farming operation and the environment.

I will be looking at how each of these can help you over the next few blog posts (to make sure you don't miss out pop your email address in the "Follow By Email" box, to the right). In this first blog of three I am looking into precision nutrient management.

Improving Nutrient Management with Precision Ag

The objective here is to maximise nutrient use efficiency while minimising nutrient losses into water. This can be accomplished by looking at the nutrient levels in the soils themselves as well as monitoring the moisture in the soil profile to ensure you don’t leach nutrients out with over watering. Precision Ag can help you in several ways to achieve this, this week I will look at the nutrient levels themselves.

This is done through either grid or zonal soil sampling. Instead of taking one soil sample per field or block, you sample in a grid at a resolution of one site per hectare or take samples within each known soil zone from your EM survey. Whichever way the samples are collected the sites are geo-referenced that means you can go back to the same point every time you sample so you can see how you are managing your nutrient levels over a number of years. At each site 12-15 cores are taken and placed in a bag, labelled and sent off to the laboratory for that sampling point.

Picture 1: Geo referenced sampling points in a field.

When you receive the laboratory results, they look similar to those you normally get however the critical difference is they are all geo-referenced and are at a higher resolution i.e. one per hectare. The data received can then be processed to create a nutrient zone map; with nutrient levels grouped in ranges for the given area and given nutrient.  From that layer of data application maps are made to match the soil and crop requirements.  The main nutrients commonly applied using this variable rate method are potash, phosphate and magnesium as well as lime for pH.

Picture 2: A map showing the varying Olsen P values across a field.

By only applying what is needed where it is needed means you minimise any over-application of product with financial and environmental implications, and you also maximise the crops potential on a nutrient level. By using this method you can mine nutrient-rich zones reducing nutrient levels in those areas and apply only what is required elsewhere.

Chris Smith

Agri Optics NZ Ltd

Managing Pivot Wheel Track Problems

While centre pivot track management is fairly routine for most growers, those working in more challenging paddocks often need to take extra measures to avoid creating deep tracks or getting stuck.

“During the design phase of a centre pivot is the most cost-effective time to manage tracking issues,” said Steve Melvin, Irrigation Applications Specialist with Lindsay Corporation. “However, there are steps growers can take at any time to help reduce tracking problems.”

Following good maintenance practices is the first and most cost-effective step in reducing tracking problems. Melvin suggests:

• Check the owner’s manual and adjust the tyre pressure accordingly. When the pressure is too high, the tyres will make deeper tracks and if it’s too low, the tyre may come off the rim.

• During the first pass of the year, run the pivot around dry on a day when the soil is fairly moist but does not stick to the tyres or squeeze out. These conditions are optimum for packing the soil in the wheel track. During the second pass, apply 6 - 12mm of water. This will help compact the soil and reduce the depth of the pivot track during the season. 

• Over-watering and keeping the irrigated area too wet often leads to deep tracking problems, so it’s important to maintain a good irrigation schedule. Apply the largest practical irrigation depth, without runoff, and allow the paddock surface to dry more before the next pass. 

In areas where conditions create significant problems, Melvin said growers have additional options, including:

• Adding a three-foot extension in the pivot pipe at the pivot point every other year, which allows the wheels to move out of the old tracks for a year. This gives the soil an opportunity to firm up before moving back the following year.

• Adjusting the sprinkler configuration around each tower to direct water away from pivot tracks or applying water after the pivot has passed.

• Integrating Variable Rate Irrigation technology (VRI) for pinpoint control of irrigation systems. With VRI technology, problem areas can dry out, reducing the depth of the tracks throughout the growing season. For more information visit growsmartprecisionvri.co.nz.

• Increasing tyre footprint by switching to larger tyres, NFTrax or radials to minimise the kg's per square centimetre the wheel puts on the soil.

To access the complete article that Melvin wrote about track management options, visit www.ksre.k-state.edu/irrigate/oow/p16/Melvin16.pdf.

For information about tracking solutions, including NFTrax, talk with your local Zimmatic dealer or visit www.zimmatic.com/tracking-solutions. 

This helpful guide to managing wheel track rutting has been adapted from a recent Zimmatic by Lindsay blog article (Managing Wheel Track Problems) and posted today by Sarah Elliot from Lindsay NZ.

The Road to Complete Control from your Mobile Device

Here's an insight to the development pathway from the world's first true variable rate irrigation system through to the release this year of Growsmart® Precision VRI with FieldNET® - complete remote pivot management, with VRI control, monitoring and reporting. 

For more information visit precisionirrigation.co.nz/fieldnet.

This video clip has been shared with you by Sarah Elliot from LindsayNZ.

Irrigation NZ Conference Summary

The Irrigation NZ Conference was held in Oamaru from the 5^th to 7^th of April. There was a huge range of speakers and presentations all relating to different aspects of the industry. Some of the important and recurring topics are summarised below.

Irrigation has benefits to communities and the environment.

The pre-conference tour took a bus load of delegates on a tiki-tour through the Waitaki valley to see first hand the irrigation schemes that draw water from the mighty river. It is readily apparent that irrigation water has benefits to farmers and community.  An example being a storage pond which is held in a trust to allow the public to use it for recreational use. A great example of the community and irrigators coming together to prosper together.

MGI Intake off the Waitaki River.

Also highlighted on the trip was how irrigation can have benefits to the environment.  The frequent droughts experienced by the Waitaki Valley prior to irrigation meant that rabbits and dust storms were free to wreak havoc on the area. Now, with irrigation, soil is no longer lost in howling Nor’Westers and improved soil structure has resulted in reduced sediment loadings in water ways. This draws some similar parallels to Keith Cameron’s talk at the PAANZ Conference (see: http://www.h2grow.nz/2016/03/inaugural-paanz-conference-summary.html)

The future is a scary place…

Synthetic meat and massive urban greenhouse skyscrapers are set to be realities in the future. The value and limited supply of the world’s natural resources was something that really hit home in Julian Cribb’s talk and it gave serious weight to the fact that efficient irrigation and water use is extremely important.

Another guest speaker, Peter Biggs detailed the concept of the volatile, uncertain, complicated and ambiguous world that we live in today. Complexity and uncertainty are two concepts that are a big part of the irrigation scene in New Zealand. How do we keep an eye on the future when such complex issues confront us at home on a daily basis?

Engaging with the public is important for success.

Nicky Hyslop, Chair of INZ made us aware of something we are all possibly guilty of. Not listening when we should. The idea that more often than not we just need to “shut up and listen” when dealing with the public on issues related to irrigation and agriculture and go forward in a dynamic, proactive way. The key message being that we must “engage” with the public rather than lecture them if any change is to be bought about.

 

Waitaki Irrigators Collective to bring together all irrigators in the Waitaki Valley

Management and measurement to improve efficiency.

The growth of technology in the sector is seeing efficiency gains left, right and centre. From improved efficiency of infrastructure that delivers water to the farm gate to the use of VRI and soil moisture management, irrigators have plenty of scope to lift performance. The level of data that can be easily captured from an irrigation system such as; flow, pressure and energy used is high. Not only can irrigators make use of this data to reduce energy costs but also water use efficiency. Dan Bloomer presented on how simply it is done with 2 dozen buckets to actually measure what water your irrigator is putting on the ground. Ultimately what gets measured gets managed.

This weeks post was bought to you by Nick Evans of Agri Optics. To find out more about Nick or to get in touch with Agri Optics check out our website: http://www.agrioptics.co.nz/meettheteam/