Thursday, 29 September 2016

Improving Irrigation Efficiency for Only $50

Dr Anthony Davoren is renowned as one of New Zealand’s leading irrigation consultants, establishing Hydroservices in 1983. If you have a question about irrigation management, soil and soil water assessment or surface and groundwater water resources then Tony will have the answer. What sets Tony apart is his practical, hands-on approach and the way he communicates information in a way that farmers can easily understand and relate to… I mean how many other speakers will you find presenting from a hole in the ground!

The Waihao Wainono Group and Morven Glenavy Irrigation recently hosted a field day focusing on improving irrigation efficiency. H2Grow is lucky enough to be able to share with you some short videos from this day. In the first in this series Tony explains how the root depth of the pasture or crop you are growing should be considered when deciding on the most appropriate soil moisture measuring equipment for your property.

Considering Root Depth when Measuring your Soil Moisture Levels

Keep a look out for the next video in this series where Tony explains how to measure drainage so that you can better manage your irrigation and prevent irrigation water, and nutrients, draining through the soil... and his top tips of how to greatly improve your systems irrigation efficiency for as little as $50!

Thank you to Dr Anthony Davoren, Waihao Wainono Group and Morven Glenavy Irrigation.

Wednesday, 21 September 2016

Soil Properties Critical when Applying Effluent

Dairy effluent is a great source of nutrients for growing pasture. But if not managed properly effluent can also be a significant source of contaminants which harm our waterways. Understanding how soil properties affect nutrient loss is a key to maximising the benefits of effluent on farm and minimising its impacts on waterways.

Soil texture and structure determine the amount of water that can enter and be retained within a particular soil, and the rate of transmission of excess water through that soil. So effluent irrigation systems should be matched to soil properties to minimise runoff and leaching. The rate at which effluent can be applied to the land for maximum production benefit is determined by the soil’s properties including structure, porosity and infiltration rate.

The nature of the effluent and cattle treading on soils can affect the infiltration rate. Treading damage, which occurs most when the soils are wet, significantly reduces the infiltration rate. For some soils this can result in accumulation of effluent below slopes and in hollows. It can then enter surface waterways.

Movement of water through soil pores is generally described as hydraulic conductivity. When hydraulic conductivity of the soil is low, irrigation of effluent will result in ponding and run-off once the total water capacity of the soil is exceeded or if application rate exceeds infiltration rate.

Low rates of hydraulic conductivity are found in soils that are poorly drained, and ponding and runoff often occur with high rainfall. Many of these soils are artificially drained to reduce the incidence of ponding and water-logging, and this carries a risk that effluent can bypass the soil and be directed rapidly into waterways

Leaching occurs as excess water moves through the soil. So soils with lower water holding capacity are more susceptible to leaching, while soils with high water holding capacity (deep silt loams) can store significant quantities of effluent.

The soils that have low available water holding capacities, are the shallow to moderately deep soils, as well as sandy or stony soils. Effluent irrigation on these soils is likely to result in leaching unless it is applied at low rates and in small doses. The irrigation system on these soils must be capable of low rates of application to gain the maximum nutrient benefit.

Drainage and the level of biological activity of the soil at the application site are important. Aim to apply effluent at a rate that keeps it in the root zone so that the nutrients can be utilised by pasture.

Permeable soils with a deep water table and no drainage limits are best for putting effluent on. However, on stony soils the risk of effluent draining directly to ground water would be an issue to consider. In such situations, application depths and rates should be adjusted to account for this risk.

Another issue is "bypass flow". When effluent application rates are higher than infiltration rates, water can enter continuous macro-pores that are open at the soil surface, and then move very rapidly via so-called "bypass flow" through a relatively dry soil matrix. This means little opportunity for the water to be retained within the root zone and high leaching of nitrate is likely to occur. Bypass flow of farm dairy effluent can occur in soils that undergo shrinkage and fissuring during drying, especially when these soils have been previously compacted by treading.

Efficient effluent storage provides flexibility when it comes to application and helps maximise nutrient uptake (image: DairyNZ)
A key to avoiding over application can be having adequate effluent storage so that irrigation can be deferred if conditions aren’t right. DairyNZ has released a new smart-phone app to help farmers apply effluent more efficiently. The Dairy Effluent Spreading Calculator app provides dairy farmers and effluent spreading contractors with guidance around nutrient application rates based on the depth and type of effluent they apply.

H2Grow would like to thank Bala Tikkisetty for this blog post. Bala is a sustainable agriculture advisor at the Waikato Regional Council.

If  you are keen for further information about best practice for applying effluent you will find a raft of useful information on the Waikato Regional Council website.

Or alternatively contact Bala directly, email or call (freephone) 0800 800 401.

Wednesday, 14 September 2016

Introducing: NICOLE MESMAN

Today's contributor profile introduces Nicole Mesman. Nicole's energy is inspiring. Her intellect and fortitude to challenge the conventional are just two of many reasons that we hope she does not spread her wings too far astray in the future, as agriculture is sure to benefit from retaining talent of her calibre.


I am a born and bred Cantabrian, from Christchurch, however I am continuing to spread my wings and experience the rural Mid-Canterbury. My childhood was filled with tramping, skiing and hunting holidays and from a young teenager I would say that I wanted to work with and in the environment and outdoors. Aside from rabbit shooting and hunting I never really did a lot on farms growing up. Lincoln drew me in at the end of high school, not for agriculture though but for biogeoscience (which I would realise was a fancy name for soil science). 

Once I got to Lincoln though my perspective and direction started to change. It’s hard not to get roped into agriculture when at Lincoln. Especially when your friends are doing projects like putting nappies on cows, monitoring cows grazing throughout the night and separating different swards of grass from endless piles of clippings. They were always looking for helpers, the fun we had!

It was a third year soils paper that introduced me to precision ag. We were out digging holes at Craige Mackenzie’s to create a soil map and also determine if the properties of the soils we found agreed with his EM map (the relationship was a good one I will add). After this I spent my summer making cakes out of soil, sand and water to review soil moisture sensors and then continued with my honours which analysed the effect of grazing and irrigation on soil physical properties. 

After Lincoln I worked for Lindsay as a summer student looking at their irrigation systems and EM mapping on various farms before going on to work for Ballance Agri-Nutrients. I am constantly learning more about agriculture and farming and I love it. Whenever I can find out about someone’s operation, learn from them and likewise share what I have learnt with them is a very good day.

Nicole fills up most of her weekends with outdoor pursuits; tramping, skiing, hunting and learning the ropes of day-to-day farm jobs

Nicole Mesman

Monday, 12 September 2016

Introducing: NICK EVANS

Second in our series of H2Grow contributor profiles we would like to introduce Nick Evans. Nick is a Precision Ag Technician at Agri Optics NZ based in Methven. His enthusiasm and fresh perspective coupled with learnings through his Lincoln University studies are an asset to the H2Grow Team.


Nick analysing EM survey data of an irrigated area for a customer 
I grew up in rural town Ashburton so exposure to agriculture was certain. Once getting under way in high school and after getting sick of washing trucks for my parents my dad sorted me out with a job working for a friend of his out in Wakanui. From then my interest in ag progressed. It wasn’t long before I would show up in the school holidays, be given a list of jobs to do and was left to looking after the farm whilst the boss went off on holiday.

After all of this exposure during my school years I was tossing up between engineering and a B Com Ag at Lincoln. Lincoln obviously won the day and I started my first three years of study. Meeting a huge range of people from all parts of the country meant that some strong friendships were also created. One of the perks of these friendships are the all-important farm tours when I go to visit. 

After the BCom I completed a Master of Management in Agribusiness over 18 months. This grew my skills and knowledge particularly around how to understand and interpret scientific papers and studies. Agricultural innovations were a part of the course and this was my first real exposure to Precision Ag. It was from there that my interest in the area grew.

On a day to day basis you will find me enjoying my time the most when I get the opportunity to work with farmers to implement Precision practices. The challenge is in tailoring it to meet the needs and requirements of the farm and the farmer. 

Nick Evans - Agri Optics NZ Ltd

Friday, 9 September 2016

We Have a Winner [COMPETITION]

We are very happy to announce that the winner of the Garmin GPSMAP64s is... 


Congratulations Simon, we're sure you'll be chuffed with this very handy handheld GPS unit. 

From the whole H2Grow Team we'd like to thank everyone that entered this competition, and we hope that you find something of interest in this blog in the future.

We would also like to apologise for the delayed competition winner announcement, this was due to unforeseen circumstances. Apologies for any inconvenience this may have called.