Want optimal irrigation? Don't make assumptions
Farmer's Weekly|November 19, 2021
Plan, execute, control and verify. These are the four elements that constitute the irrigation approach of Indigo Fruit Farming in Mpumalanga, where every drop of water is used to its full potential. Farm manager Willem Kieviet spoke to Lindi Botha about his methods of irrigating to achieve the best crop yields.

“The days of starting the pump in an orchard and assuming the trees will be watered are long gone,” says Willem Kieviet, area manager of Indigo Fruit Farming on the outskirts of Mbombela, Mpumalanga.

Instead, he uses a meticulous method in which every decision is backed up by data, and any water applications are checked and double-checked.

“You need to think about how much water you’re applying and why. Ask yourself what time of the day is best for irrigating and what the expected outcome of the irrigation is, then measure whether it was achieved. Applications that rely on technology must be followed up by people, and vice versa.”

Indigo produces mandarins and seedless lemons, and has been using drip irrigation since 1997. Kieviet prefers this method to micro-irrigation, as it uses less water.

“With micro-irrigation, there’s more evaporation because you’re wetting a bigger surface area. Also, the water penetration isn’t necessarily as deep as with drip irrigation, so you lose a portion of the water you apply. Drip irrigation is more focused on a specific area.”

As the farms have mostly sandy loam soil, drip irrigation provides a further benefit: the drippers provide a suitable flow of water to top up the moisture levels without run-off.

The irrigation system differs somewhat from orchard to orchard, as new systems have been introduced on the farms since 1997. While some orchards are planted to a single row of trees with double dripper lines, others have double rows of trees with double dripper lines. The water flow also varies, ranging from 0,7ℓ/h to 2,3ℓ/h. The latter is used for single-row lines and provides water at a rate of 4,6m³/ha/h. The 0,7ℓ/h drippers are placed in double rows and provide 2,3m³/ha/h of water.

SLOWING THE FLOW

Kieviet says Indigo is moving towards reduced flow irrigation. The trees still receive the same amount of water overall, but their uptake is far better with lower flow over a longer period.

A booster pump is used for higher-lying blocks to ensure that the water reaches the irrigation system at the desired pressure.

The farm has a dedicated main line for each orchard so that water can be controlled from the pumphouse, rather than through valves in the orchards.

Each block has a dedicated main irrigation line so that the system can be managed from the pumphouse, rather than the orchard. There are also flow and pressure meters on each line to detect problems and accurately measure what is being applied.

The entire system is automated, which enables Kieviet to view all the irrigation applications at a glance, with problem areas showing up in different colours on his computer screen. Controlling the irrigation from the pumphouse on each farm simplifies management, as valves don’t have to be turned on and off in the orchards, which could be affected by human error.

The trees receive between 3 500m³ and 4 500m³/ ha/year of irrigation water. Citrus trees require about 6 500m³/ha/year. Rainfall in the area is about 820mm annually, which complements the scheduled irrigation, but Kieviet points out that not all rain provides effective irrigation.

“For example, it might rain softly for some time. Although this will count towards annual rainfall, it doesn’t really add much water for the trees. Conversely, storms bring a lot of water, but most of it flows away. We estimate that about 50% of the rain we receive is actually effective irrigation.”

Continue reading your story on the app

Continue reading your story in the magazine

MORE STORIES FROM FARMER'S WEEKLYView All

Why wetlands are vital for humans and nature: Part 1

Wetlands vary greatly in type, yet all are indispensable for purifying water and controlling its flow. They include mountain springs, midland marshes, flood plains, coastal lakes, mangrove swamps and estuaries.

2 mins read
Farmer's Weekly
January 07 - 14, 2022

‘COVID-19 deaths help drive up goat sales'

Communal goat farmers in South Africa can set their own prices due to a shortage of the animals brought about by COVID- 19-related deaths, according to Gugu Mbata, project manager of the Mdukatshani Rural Develpment Project.

2 mins read
Farmer's Weekly
January 28, 2022

SA breeder's new cultivar sparks fresh love for passion fruit

Mpumalanga-based granadilla breeder Darryn Stoltz has developed a delicious new passion fruit cultivar that offers several advantages over previous varieties. One of these is longer shelf life, enabling the export of better-quality fruit. He spoke to Lindi Botha.

7 mins read
Farmer's Weekly
January 28, 2022

The layperson's guide to ley farming

Over the past few years, monocropping has largely given way to the crop rotation system, and ley farming has gained popularity in grain-producing areas such as KwaZulu-Natal, Mpumalanga, the Free State and North West, where many farmers also produce livestock. Prof Chris Dannhauser spoke to Susan Marais about how the rotating of grain crops with planted pastures can be a highly useful practice.

8 mins read
Farmer's Weekly
January 28, 2022

The good and the bad of chimera

Chimera can be mistaken for a viral or bacterial infection, but it is actually a genetic disorder that could benefit some producers.

2 mins read
Farmer's Weekly
January 28, 2022

Massey Ferguson launches new tractor for orchards

With interest in the production of orchard crops on the rise, Massey Ferguson has launched the MF 3300 narrow-width tractor series in SA.

3 mins read
Farmer's Weekly
January 28, 2022

John Deere self-driving tractor is ready for commercial use

John Deere recently launched a fully autonomous tractor at the Consumer Technology Association’s show in Las Vegas, and it will be on sale in the US later this year.

2 mins read
Farmer's Weekly
January 28, 2022

Making it with medical cannabis

Thinking of producing medical cannabis? Glenneis Kriel spoke to industry pioneers about the opportunities and pitfalls for growers of this crop.

6 mins read
Farmer's Weekly
January 28, 2022

Indigenous veld goats: the ideal option for extreme conditions

Changing weather conditions and Africa’s severe poverty demand tough, easy-to-care-for livestock. The answer, says breeder Deon Vlok, is indigenous veld goats. Annelie Coleman reports.

4 mins read
Farmer's Weekly
January 28, 2022

Combating the effects of soil pollution

Soil pollution is a serious challenge worldwide, resulting in environmental damage and potential health hazards to people and animals. This report examines affordable ways in which farmers can limit its effects on their crops and reduce further soil degradation.

5 mins read
Farmer's Weekly
January 28, 2022