How Hortgro helps with water

Stone- and pome-fruit growers need water — but so does everyone else. This is why water is high on the Hortgro agenda. By Anna Mouton.

Stone- and pome-fruit production in a relatively dry South Africa has always been constrained by water availability. The worrying consensus is that water will become even scarcer. “If you know that you’re already limited by water, and that water is going to become less, and that competition for water is going to increase, then you have to focus on water,” says Prof. Wiehann Steyn, general manager of Hortgro Science.

Hortgro recently conducted a foresight study to identify the main factors that will impact the fruit industry in future. According to Steyn, water was in the top five, and it was also in the top five in previous risk assessments.

“Water is critical — we’re not going to get away from that,” stresses Steyn. “You’re dealing with a permanent crop. You can’t just decide that one year you’ll turn off the taps to save water for the following year.”

Big-picture involvement

“Hortgro typically gets involved in all sorts of policy matters, including water policy — it’s about the allocation of water and who is awarded newly unlocked water,” says Mariette Kotzé, group operations manager at Hortgro. The goal is to ensure that growers have a seat at the table when decisions are made about water.

Kotzé cites the example of the upgrading of the Brandvlei and Clanwilliam Dams, which is expected to furnish additional irrigation water. Hortgro is on the committees that determine who is eligible for this water and how applications will be managed. “We play a proactive advocacy role, and we try to present the case of the growers,” explains Kotzé.

One tool that Hortgro uses to influence the policy environment is impact studies, to show how water use by the stone- and pome-fruit industry benefits South Africa. “Agriculture is such an integral part of the rural economy,” says Kotzé, “and an incredible number of people depend on it. If you limit agriculture, you limit the rural economy directly.”

In addition to working on big-picture issues, Hortgro has provided more immediate assistance to growers in the drought-stricken Klein Karoo. Together with Vinpro, the Canning Fruit Producers Association, Agri Western Cape, and Agri SA, Hortgro donated food parcels and financial aid to stone-fruit producers in 2019. Hortgro also teamed up with the Western Cape Department of Agriculture to support the re-establishment of 42 hectares of the estimated 300 hectares of orchards that died during the drought.

Although short-term humanitarian relief is important, Kotzé is clear about the need for long-term geospatial planning if the industry is to adapt to climate change. This includes quantifying water resources and rainfall patterns to inform decisions about infrastructure development as well as to optimise crop selection. She points out that some areas may eventually become better suited to livestock or annual crops than to deciduous fruit — what matters is that growers are empowered to manage their risk exposure.

Whereas stone- and pome-fruit production in certain areas is under threat, Kotzé believes that there are opportunities for expansion in others. She sees potential outside the Western Cape, but a lack of bulk infrastructure is a constraint, so Hortgro is actively motivating for the maintenance and upgrading of water-related infrastructure.

Science puts facts on the table

“You want to work with numbers when you’re talking about water use, not with estimates and outdated research,” says Steyn. “And you want to quantify water use in terms of water productivity — what are you doing with the water?” This was one reason for the knowledge-status survey on water use in stone and pome fruit that Hortgro commissioned in 2017.

“The idea was to synthesise knowledge, to be able to say what we know, and to identify gaps,” says the lead researcher on the survey, Dr Caren Jarmain. Jarmain is an agrometeorologist — she applies weather and climate information to support agriculture.

“Our focus was evapotranspiration — all water uses in an orchard,” explains Jarmain. “We didn’t just want to summarise the data, but we also wanted to find the drivers of crop water use.” Jarmain collaborated with Dr Nicky Taylor, senior lecturer in the Department of Plant and Soil Sciences at the University of Pretoria, to review the literature available for South Africa.

The main data source for the survey was FruitLook, which provides weekly actual evapotranspiration and biomass data that is obtained through remote sensing. FruitLook is funded by the Western Cape Department of Agriculture. “There’s few countries in the world where that type of dataset is available for free,” says Jarmain.

Prof. Adriaan van Niekerk from the Centre for Geographical Analysis at Stellenbosch University helped with the analysis of FruitLook data. The results showed that water use is driven by the complex interaction of the crop with the climate, the soil and management decisions. The most important factors will vary in different regions and on different sites.

The project report contains the estimated range of annual evapotranspiration and crop water use for different regions. Jarmain points out that different growers will need different amounts of water to achieve the same production. “You want to acknowledge that there are some combinations of factors — such as early or late cultivar, region, and soil type —where a farmer can get away with less water. The landscape that farmers have to farm — that canvas — is very variable.”

The survey also delineated pome- and stone-fruit production regions in a new map for the Western Cape, which was used to extract long-term statistics on rainfall, evapotranspiration, solar radiation, chill units, and heat units.

“We looked at what was found through other studies in South Africa,” says Jarmain, “and compared that to FruitLook data – and we did this per fruit type – and then we compared it to water requirements from SAPWAT.” SAPWAT is software that was developed with funding by the Water Research Commission and that is used to estimate irrigation requirements for planning purposes.

Several new projects have arisen from the knowledge gaps identified in this survey, including studies to determine the water requirements of specific fruit types. Hortgro Science has also been looking at ways to save water through applying mulches, deploying shade nets, and improving irrigation practices.

In a water-scarce world, growers can no longer ask how they can gain access to more water, says Taylor. “In this country, the question is really, how do I remain productive with lower amounts of water, and how do I get away with using less and less.”