Nutrients - Why do we care?

WHY DO WE CARE ABOUT NUTRIENT LOSSES FROM FARMS ANYWAY?  
AND HOW DO THEY GET INTO OUR WATERWAYS? 
AND WHERE DO THEY COME FROM?

Now that we have had a quick look at Overseer and Farm Environmental Plans, it is timely to take a step back and ask the question “why do we care about nutrient losses from farms anyway?”  But you also need to know how they get into our waterways, and where they come from in the first place.   This is my simple take on a number of complex and interactive cycles, but at the end of the day, we’re not all scientists, so I hope this helps put some context around why we are where we are today.

What do we care about?

Farming contributes four main pollutants to the environment: the nutrients nitrogen (N) and phosphorus (P), sediment, and faecal matter. So why do we care about these?

• Nutrient (N and P) enrichment of rivers, streams and other waterways can lead to unwanted growth of plants (waterweeds and algae), and this can be toxic to fish, but also other animals (think back to articles about dogs drinking river water and dying), and it’s not so good for humans either.   
• Excess sediment may cause siltation (which means that fish and aquatic plants get smothered), and degrade water clarity (makes it look dirty all the time!). 
• Faecal matter and its associated pathogens pose a risk to human and animal health through waterborne infectious diseases. 

How do they end up in our waterways?

N enters our rivers, streams and other waterways via leaching to groundwater.  Whereas sediment, faecal matter and P enter streams mostly in surface runoff. These two distinctions are important.

What are the on farm sources of these nutrients?

N comes primarily from urine patches.  P is primarily from P based fertilizer, solid animal excrement or stock having direct access to stream and other waterways.

Sediment and faecal matter is also from stock having direct access to streams, and run-off straight into waterways.

So, let’s put some context around this.  

We will take a farm which does dairy support from May to May.  Using Overseer, N and P losses can be determined.  The following table shows the outputs from this farm, using exactly the same inputs, but for varying topography and soil type.

Soil Type and Topography	N lost to water (leaching into groundwater) (kg per ha per year)	P lost to water (runoff)(kg per ha per year)
Light, free draining Lismore soil, flat land	27	0.3
Light, free draining Lismore soil, steep hill	27	0.1
Heavy, poorly drained Timaru soil, flat land	18	0.1
Heavy, poorly drained Timaru soil, steep hill	18	0.3

Thinking about how nutrients get into our waterways, the Overseer results confirm two things:  The first is that P losses are higher on steep land as opposed to the same farm on flat land.  The second is that N is more affected by soil type than topography – you get more leaching to groundwater in free draining soils as opposed to heavy, poorly drained soils.

The other thing you will notice is that N losses are much bigger numbers than P losses, but any small increase in either number can have a big impact on waterways – it is generally many small increases that create a big problem – death by 1,000 cuts!

Therefore, when we are looking at how we manage nutrient losses on our farms, understanding the source of the nutrients, and how nutrients get into our waterways is critical.  Looking at possible mitigation options will be next time’s topic.

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

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

Introducing: KERI JOHNSTON

As today is International Women’s day it seems fitting to be introducing our new inspirational H2Grow contributor - Keri Johnston director of Irricon Resource Solutions. Irricon won the Rural Women New Zealand’s Enterprising Rural Women Award in 2014 and Keri was a finalist in the Women of Influence Awards in the Rural category in 2015. Not surprisingly the H2Grow team are bubbling with excitement to have Keri sharing her great depth of knowledge and expertise with us all!

Keri Johnston

Hello everyone, and thank you to H2Grow for having me.  So, a little bit about me.  I was born and bred on a North Otago sheep and beef farm.  After leaving school I completed a Bachelor of Engineering degree in Natural Resources, specialising in water and land management.   I wanted a job that meant I wasn’t going to be stuck inside all the time, and I hate the sight of blood, so doctor or vet was off the table. While the degree starts at Canterbury University, the last two years were spent at Lincoln University. During this time, I met and fell in love with my now husband, who was dairy farming on Banks Peninsula at the time.  

Keri Johnston

As a new graduate I began my career working for Meridian Energy at Manapouri power station and was then based at Twizel working on dam safety.  I turned down a transfer to Wellington to get married and go dairy farming in Canterbury- I didn’t fancy the idea of a long-distance marriage!  

In Canterbury I took a job with the Regional Council working on consents. A job ironically, I disliked, but one that has stood me in good stead as it gave me real insight into the resource consent process and requirements.

I then moved within the organisation to a role carrying out the environmental management of river works.   At the same time, I had two children, and we were continuing to grow their farming business by moving to increasingly larger farming operations.  It has been a continual drift south, starting in Banks Peninsula and via several farms now settled in Geraldine, on our own 80ha dairy support and beef block near Geraldine.

In 2007, whilst on the drift south, I started Irricon Resource Solutions, an environmental consultancy. Irricon now has 15 staff stretching from North Canterbury to Duntroon and a head office in Timaru.  I still work mostly from home, around kids and the farm.  It also means I can sneak in a lunchtime horse ride or YouTube yoga session!  

I am passionate about what I do.  Helping farmers work out how all these new regulations affect them and trying to get them involved in the limit setting process early on.  This stuff is not going away, and you are better off to be at the table having the discussions.   After all, if you’re not at the table, chances are, you’ll be on the menu.  

Keri Johnston - Irricon Resource Solutions. 

EM surveying - Knowledge is Power... (and Potential profit!)

An Electromagnetic Survey is one of the key layers required on the precision farming journey. Precise location and understanding of soil types is a key piece of information in driving decisions around water use and nutrient placement. Not only can an EM survey be used to reduce water inputs it can form the basis of other decisions related to plant health, production and nutrient uptake. Turning the pretty maps into useful data requires some powerful software. That is where VA Gateway comes in. Gateway allows for in depth analysis of multiple layers, including Yield and EM. All Agri Optics customers have access to VA Gateway and AgCloud the online version.

With the software we create reports on the various layers of data collected. Clients get information on two EM soil profiles, one measuring the conductivity in the top 0-50 cm of soil and the other looking at changes in the top 0-125cm of your soil profile. Our report explains our findings on each layer with an explanation of what you are seeing. Depending on the variability arising from the survey, we then create different management zones based on the range in EM units. These zoned maps can then be imported into your variable rate irrigation (VRI) software if they are used for irrigation or into your VR seed drilling control box if you are using it for variable rate seeding based on your soils.

Figure 1. Top left is a shallow EM map and to the right of it a zoned map of that layer. Below is the same but for the deeper EM (0-125cm).

We also report on topography features. As we log the EM data at 2cm accuracy we are also mapping these features. This data set in its own right is very useful and gives you the surface characteristics of the area surveyed in the form of six additional maps, slope, elevation, landscape change, aspect, any depressions and witness index (which way water will move in a rain or irrigation event). This data can be a powerful management tool. The water movement models can help highlight potential areas of issue, so they can be addressed, be it nutrient movement or run off.

Figure 2. Gateway software generates water movement models based on the topography data.

The elevation data can also be used to create contour maps that can be used in the design stage of your centre pivot system, e.g. when calculating tower spacing's or to help with budgeting for any required earth works.

Figure 3. Gateway software can be used to create 3D contour maps.

We can also create moisture probe placement maps based on your EM and elevation data to find your optimum site within each management zone. These sites can also be used as ground-truthing sites with HydroServices neutron probe to put actual specific values to the different zones water holding capacities and then convert the EM map into a water holding capacity map.

A further report can be created to gauge the likely payback time from the installation of VRI based on your soil variability, the crop you are growing, its value per unit and the cost of your VRI system. This is proving very helpful for those who are unsure as to whether they have enough variability in the surveyed area to warrant VRI.

All our data is collected using strict protocols, with the highest standards in continuity and quality every time. This ensures our clients have powerful, solution-focused information. For more details check out our website www.agrioptics.co.nz.

Post credit to Chris Smith.