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Nuts about low-flow drip irrigation

Nuts about low-flow drip irrigation

“Low-flow drip irrigation has given me full control over every aspect of irrigation and Nutrigation™ in my macadamia orchards.” Sean Doveton buzzes with excitement as he talks about his passion for low-flow drip irrigation and the impact it has had on the Doveton Farm.

The Dovetons have been on the family farm in the Port Shepstone area for more than 30 years. “We produced sugarcane and later moved into bananas. We then discovered that we had panama disease in our banana plantations. This, combined with the realisation that we had to move to a more productive crop, compelled us to switch to macadamia production,” Sean explained.

Gary Frances, technical advisor for Netafim South Africa in KwaZulu Natal, with Sean Doveton in his macadamia orchards.
Doveton Farms planted their first macadamia trees in 1999 and later realised that they needed a top-notch irrigation system to take the macadamia orchards to the next level.

Sean sat down with Gerhard Mostert of AgriWiz. “Gerhard said that he could give me different options, but that I had to consider low-flow drip irrigation if I wanted a solution where technology will take the farm forward.

I had to trust him, as I did not know the system and had no idea what the outcome would be. We decided to go with low-flow drip irrigation, although it had never been done in our area. It was a risk, but it has paid off without doubt. The system is fantastic.” said Sean. “The biggest challenge has been to get my mind around the low-flow way of thinking.”

A challenging start
Sean and his team now had to install a new irrigation system onto existing and varying orchards. This posed quite a challenge. “We had varying tree ages and we had to plan out blocks according to tree age, topography, variety and more. We knew we had to get it right and did a lot of calculations and research to ensure that we do. We also travelled all over the country to look at other farms where low-flow drip irrigation is already successfully implemented in macadamia orchards.”

Ideally, Sean adds, you would start from scratch and plan out the entire farm according to soil types and other aspects. This would allow you to divide the farm into irrigation blocks. “It is however never too late to install a low-flow drip irrigation system in your orchards.”

A year after his first discussion with Gerhard, Sean installed low-flow dripperlines in the first orchard blocks. Within 8 months the entire farm had been converted to low-flow drip irrigation.

From reject to rejoice
During the planning phase, Sean and Gerhard considered the future of each tree. “There were quite a few blocks where I told Gerhard that the trees needed to go, that we had to take them out, cut our losses and start anew. He however encouraged me to let the system do its job and wait to see what the right move will be.”It was worth the wait, as many of these trees are now delivering incredible and consistent results. “We can now pick out single trees with poor performance, rather than being concerned over entire blocks. With this level of irrigation and Nutrigation, we can also single out these trees much earlier as the rest of the orchard has such incredible and consistent growth.”

Sean said that it is still early days, but that the impact on yields and crop quality looks very promising. “We have been using low-flow drip irrigation for the past two to three years. Many of the young trees are now going into their first production season, so we are very excited to see the results. Although I cannot credit it to the irrigation system alone, we have seen a 35% yield increase from the previous to the latest crop.”

He adds that the greatest impact to date has been the fact that trees are flowering and entering production much sooner. “Isn’t that what it is all about? We spend a lot of money – earlier and higher returns on investment is exactly what our bottom line wants. Low-flow drip irrigation allows you to push the tree harder, and it produces accordingly.”

Exciting technology
“The technology behind low-flow drip irrigation is what really excites me,” said Sean. As the irrigation industry evolves, low-flow drippers are increasingly used, and improved technology is constantly available. Netafim, a leader in precision irrigation, defines low-flow drip irrigation as irrigation systems where drippers with flow rates of 1ℓ/h and lower are used.
Advantages of low-flow drip irrigation include better depth management, improved water distribution, the possibility of longer irrigation periods, higher performance from poor soil areas, simultaneous irrigation of larger areas, a resulting better soil-water-air ratio and the prevention of fertiliser leeching. All of this makes the system more accurate and efficient than other irrigation systems.

The concept of continuous irrigation has flowed from the availability of low-flow drippers. This is irrigation at a very low-flow over a longer period of time. Drippers with higher flow rates have led to short irrigation periods with regular intervals as water delivery was too fast and too deep. As the flow rate is decreased, longer irrigation period becomes the norm.

Game-changing practices
Sean and his team can now irrigate the entire farm at once and the orchards are irrigated 365 days a year, come rain or shine. Irrigation during rainfall is known as a technical irrigation. This is a very short irrigation done with the sole purpose of applying fertiliser.

This, of course, goes for the Nutrigation as well, adds Sean. “We used to fertilise the trees four to six times a year. We are now fertilising 365 days a year with small amounts of fertiliser. Instead of the tree drawing its nutrients directly from nutrients inherent in the soil, you have an open hydroponics system on your whole farm, where the nutrients can be applied daily on demand, just like the water is applied daily on demand.

This has been a game changer as the trees have responded very well. The young trees are producing earlier, the older trees are recovering and coming back into high production. We have total control over how much fertiliser we apply how often, where and when we apply it and how deep we apply it.”

Another great advantage is that a breakdown in one block, does not affect water and nutrient delivery to other blocks on the farm. It is also advantageous that the entire cycle takes place in 24 hours. This means that tomorrow is a new day and any mistakes made can be rectified.”

“I have embraced this technology and now I no longer have to settle for second best. I can push the trees and the trees respond. I do not think that we have hit the ceiling yet, and I am excited to see where this system can take us.”

Passion and attention needed
Sean admits that taking on the low-flow challenge is overwhelming, as it requires significant investment. You must also do the necessary math to make sure you are doing it right. At the same time the system must be meticulously managed and maintained. “The resulting control is no doubt worth all of this.

“I must stress that it is important that you work with someone who has a passion for low-flow drip irrigation and that you make the commitment to managing and maintaining the system on the level that it requires. If not, it will not work. I have no doubt that low-flow drip irrigation works and can take your orchards to the next level – if it receives the necessary attention.”

Monitor meticulously
As mentioned, the system will fail without the necessary management. An important part of this is monitoring, an aspect of irrigation and Nutrigation management that should never be underestimated. Without monitoring, all irrigation planning and management become mere guesswork.
“We are now doing proactive irrigation scheduling using the Agriwiz platform, which takes the ETo (reference evapotranspiration) for the area for the period in question into account. With the combination of the versatility of the irrigation system, the scheduling programme, the soil moisture probes and soil solution EC value monitoring, we believe that we can strive for even better results.”

We have access to excellent monitoring technology, but I am especially looking forward to new developments in this regard. The more data we probe from the soil, the better we can adjust our scheduling and management.”

More with less
As irrigation trends change in the macadamia industry, and as the industry is forced to adapt to climate change and water-scarcity, the entire industry has been surprised at how little water macadamia trees can manage with.
“I believe that the control low-flow drip irrigation allows us, combined with excellent irrigation and Nutrigation management can take the macadamia industry to a next level. We have to give each tree, according to variety, age, area, soil type and other aspects, exactly what it needs at the right time. We have the tools to do this and must use these tools to our advantage.”

Sean cannot say enough about the importance of adopting new technology in farming. “Within three years, technology and management has taken us from merely surviving, to this incredible point where we are now asking – what next?He admits that technology is moving really fast, making it difficult to know when to invest and when to hold out for the ‘update’. “This should however not hold us back.”

“We have learned a lot throughout the entire low-flow process. As we are now over the initial cost shock of setting up an entire irrigation system in a year, we are smiling all the way. It would have been easy to say – let’s rather fix what we have. That would have however been a massive mistake.”

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