Irrigation 101: How Orchards Differ From Field Crops

One of the most common mistakes farmers make when irrigating orchards is over-irrigation which deprives the plants of oxygen. Netafim agronomist Jovan Erasmus shares some welcome tips.


Regardless of your farm’s irrigation equipment and system design, if you don’t know how much water to distribute to each plant and when, you will never achieve optimal precision irrigation. Additionally, there are fundamental differences between scheduling irrigation in open fields and in orchards.

Netafim agronomist Jovan Erasmus explained in a previous article that some basic principles will always remain the same:

  • Your soil has a certain water-holding capacity based on the percentages of sand, silt, and clay, also known as soil texture.
  • A plant has a certain daily water requirement, which can be calculated or checked using standard formulas.
  • Different cultures have different rooting depths.
  • The primary goal of precision irrigation remains to deliver the right amount of water to the right place (in this case, the entire root zone but no deeper or wider than that), at the right time, as efficiently as possible. .

However, it is also important for farmers to understand the differences in approach when planning the watering schedule for their field crops or fruit trees.

Irrigation scheduling involves calculating how often and how long your farm's irrigation system will run.  Due to the depth of the roots, <a class=orchards generally need longer periods of irrigation. Photo: Supplied” class=”wp-image-100256″ data-srcset=”https://www.foodformzansi.co.za/wp-content/uploads/2022/09/GyroSA-2-1024×683.jpg 1024w, https://www.foodformzansi.co.za/wp-content/uploads/2022/09/GyroSA-2-300×200.jpg 300w, https://www.foodformzansi.co.za/wp-content/uploads/2022/09/GyroSA-2-768×512.jpg 768w, https://www.foodformzansi.co.za/wp-content/uploads/2022/09/GyroSA-2-750×500.jpg 750w, https://www.foodformzansi.co.za/wp-content/uploads/2022/09/GyroSA-2-1140×760.jpg 1140w, https://www.foodformzansi.co.za/wp-content/uploads/2022/09/GyroSA-2.jpg 1200w” sizes=”(max-width: 1024px) 100vw, 1024px”/>
Irrigation scheduling involves calculating how often and how long your farm’s irrigation system will run. Due to the depth of the roots, orchards generally need longer periods of irrigation. Photo: Supplied

Orchards vs open fields

Erasmus says root zones and plant spacings are some of the main differences between orchards and open fields.

“Orchards tend to have deeper root zones than field crops. Orchards also tend to have wider plant spacings – up to 6 or 7 m between plant rows and requiring two or three drip lines per row – compared to open field plant rows. Here the rows can be less than 1m apart and only need one drip line for one to two rows.

Due to the deeper root zones in orchards, farmers will generally need to irrigate longer to fill these root zones with water (but without wetting the soil beyond the root zone).

Orchard root zones are typically 40-60cm deep, compared to 10-40cm for vegetables.

Different stages of growth

Since any plant will require different amounts of water at its different stages of growth, it goes without saying that orchard planning will undergo significant adaptations as trees grow from saplings to fruit trees.

However, it is just as important to establish a good schedule in the early stages of growth as in later years.

“Young orchards tend to take time to generate a return on investment. Don’t neglect your orchard in the early years. This is important to ensure long-term productivity.

Due to spacing and deeper root zones, orchards often require two or even three lines of irrigation per row of plants.  Photo: Supplied
Due to spacing and deeper root zones, orchards often require two or even three lines of irrigation per row of plants. Photo: Supplied

Base every decision on accurate data

Erasmus believes that proper watering contributes by far most of the inputs needed for a good harvest. “Irrigate well first – before spending money on ‘miracle’ products”, is his advice.

And “getting it right” with the watering schedule involves crop- and zone-specific calculations, as well as continuous monitoring of soil moisture. This applies to orchards as well as open fields and will allow farmers to adapt the schedule to suit their needs.

If the data, for example, shows that the soil is too wet for the specific crop, you must adapt by reducing the hours of active irrigation. On the other hand, if the data shows that the soil is dry, the irrigation hours can be increased.

“You have to get to know your soil and you have to get to know your irrigation system,” Erasmus says. “Dig profile pits in your orchard to see how deep the root zones are. You can also use a hand auger to see how deep an irrigation event wets the specific soil.

“You can use a soil moisture probe, but then you need to make sure it’s installed correctly and calibrated for your specific soil and specific crop. If you don’t calibrate your probes correctly, you will end up using the wrong information to make the wrong decisions.

However, he issues a stern warning. “One of the main problems I see among farmers is over-irrigation in orchards. When plants are stressed, farmers often fail to give more water, but measure soil moisture and get data information will help you make better decisions.”

Netafim irrigation specialists warn that the water needs of trees should not be neglected when they are young, as water stress could impact for many years.  Photo: Supplied
Netafim irrigation specialists warn that the water needs of trees should not be neglected when they are young, as water stress could impact for many years. Photo: Supplied

Consult an expert

As always, the knowledge and experience of an industry expert can help farmers avoid costly mistakes. However, the choice of the expert is essential. “Do your homework. Consult with a reputable expert who can consider your unique scenario and will take into account things you may have missed.

“There are general guidelines, but never a single solution. The experts can make all the difference in ensuring that your investment is successful over the long term.

He leaves farmers with one final thought, saying that growing fruit is a long-term investment and early decisions could still have an effect decades later. “Farming may seem very lucrative and can be successful, but farming is not easy. Making sure you plan correctly is crucial before spending money on the investment. »

Farmers who want to gain more knowledge and practical advice on irrigation planning can visit Netafim’s Precision Irrigation Academy at www.netafim.co.za.

• To listen to a full Erasmus interview, listen to the latest episode of Farmer’s Inside Track. For more information on Netafim South Africa, click here.

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ALSO READ: Irrigation 101: Setting up the right watering schedule

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