Early season installation of N-Drip piping in a raisin grape vineyard in Kakamas, Northern Cape.
Introduction
Water sources are in distress globally due to climate change, population growth, pollution, and inefficient agricultural practices[i]. The Orange River is no different. Historically, the River has had an abundant supply of water, which has enabled the majority of farmers along its shores to use flood irrigation. However, farmers need to plan for the future where the allocated volume of water per hectare can be lowered due to water not being as abundant or as readily available as before.
Flood irrigation is still the primary irrigation method used for around 14 000 hectares of raisin grape vineyards along the Orange River, which account for more than 60% of all vineyards in the area.
Disadvantages of flood irrigation
Some of the disadvantages of flood irrigation include the following:
- Flood irrigation lacks precise control over the amount and timing of water application. This can make it challenging to adjust irrigation practices based on crop needs, weather conditions, or soil moisture levels. Plants are, therefore, either over-irrigated or under-irrigated.
- Water is only readily-available through capacity-constrained canal systems, so farmers have to irrigate their crops at specific times of the day. In warmer months, plants’ top roots dry out easily, while the buffer zones (deeper roots) stay mostly wet. As this is not ideal for crops’ optimal growth, farmers need more efficient (and cost-effective) irrigation methods.
- The combined effect of sediment, nutrients, and agrochemicals in run-off water can lead to a decline in water quality downstream.
- In the long term, flood irrigation can lead to nutrient leaching and soil degradation.
Challenges motivating alternative irrigation technologies
Availability of electricity
While South Africa grapples with its energy crisis, electricity supplied through the national electricity grid will not be a reliable resource for farmers to convert their flood irrigation systems to pressured irrigation systems. Although flood irrigation may seem like the “safer” option for now (as it can operate despite load shedding), there are realistic alternatives to consider.
Geographical position and infrastructure of farms
Most of the flood-irrigated farms in the Orange River region face unique challenges:
- Many flood-irrigated farms operate on small plots of land (consisting of alluvial soils and located on small islands in the Orange River).
- These farms require small-scale facilities as they do not have the space for large irrigation infrastructures.
- Accessibility also remains a challenge due to their locations on the banks of the River.
- Even without considering load shedding, most of these farms do not have electricity infrastructure that extends to farming blocks. Houses, drying facilities and farming blocks are located in separate areas of the farm: blocks are positioned closer to the river, while houses and other buildings are normally built on higher ground (away from flood-risk areas).
A likely solution
A low-pressure, low-flow system
In 2022, N-Drip, in collaboration with PepsiCo International, approached Raisins South Africa to conduct a research trial of its proprietary drip irrigation technology in the Lower Orange River Basin. The trial, which is being conducted at the Vine Academy and Model Farm in Kakamas, focusses on piloting a more water-efficient irrigation technique for raisin grape vineyards.
N-Drip is the first micro-irrigation solution powered by gravity alone (i.e., a low-pressure, low-flow system).
Benefits of the N-Drip system
The N-Drip system has several advantages.
- It’s an affordable investment as the capital outlay is low.
- The system operates solely on gravity, requiring no energy input.
- It’s highly efficient in its water use by slowly releasing water to the roots of the crops.
- As a high-precision irrigation system, it waters crops’ plants (not weeds around the plants). This means farmers can use less herbicides to control weeds effectively.
- Irrigation amounts due to seasonal or other environmental changes can be adjusted by increasing or reducing the length of an irrigation cycle.
- The irrigation pipeline includes IoT[ii] probes that monitor irrigation and nutrient levels at different parts of the blocks. Farm managers can use a mobile app to monitor crops virtually and communicate with N-Drip’s technical team via WhatsApp.
- N-Drip can reduce a farm’s carbon footprint (by using less water, electricity, herbicides and fertiliser) while producing better quality crops.
- It’s a regenerative farming practice that promotes soil health, which is crucial in the heavy, clay-type soils of the region.
N-Drip is especially useful to small-scale farmers as it gives them access to drip irrigation systems without incurring the capital (setup costs) or operational (ongoing, running costs) expenses needed by an electricity infrastructure.
N-Drip also addresses the negative impacts of flood irrigation, such as soil desalination, deteriorating water quality (due to drainage flowing back into rivers), fertiliser/herbicide wastage (due to them being scattered around crops’ bases), and the risk of oxygen shortage in root zones due to over-irrigation. Farm managers can add fertiliser to the N-Drip system for a more targeted dosage to plants’ root systems.
The App
The N-Drip mobile app includes dashboards that show how the IoT-probes monitor different parts of the blocks to ensure optimal irrigation conditions. See below screenshots from the App.
Maintenance
Existing irrigation systems consist mostly of micro dripper systems, and often use high-pressure filter systems to separate debris and other contaminants from the water supply.
Because low-pressure irrigation systems are more likely to get clogged up with debris settling in their pipes than high-pressure systems, the N-Drip system requires farm managers to:
- Stimulate sedimentation with peroxide and hydrochloric acid (HCL) during each irrigation cycle. The chemical compounds are added to a dosage canister that is suspended in the water tank or dam.
- Clear the irrigation pipes and drippers by rinsing them frequently* and removing weeds around the drippers’ openings.
(*the frequency will depend on the quality of water).
The research trial
For a perennial crop like raisin grapes whose harvest quality is determined in the flowering period (in the case of raisin grapes, it is 15 months before the harvesting period), it was essential to start the N-Drip trial 15-24 months before the crop’s harvesting period and to run the trial until the end of the harvesting period.
The N-Drip research trial in Kakamas includes both young vines (starting from one year of age) and older vines (up to ten years old) as long as the vines have established root systems. The trial’s objective is to convert a vineyard’s flood irrigation to N-Drip’s low-pressure, low-flow system without compromising the crop’s yield and quality. Additionally, the trial has a control group for each block that continues to use flood irrigation, enabling the research team to compare the results of the two types of irrigation systems over time.
Before the trial started, an international, high-skilled team from N-Drip analysed the crop’s soil composition, water quality, and irrigation requirements. This was done to establish a baseline for the trial and to ensure that the N-Drip system is calibrated and installed correctly.
The research team reviews the crops’ irrigation statistics in real time. The N-Drip dashboard uses data from various sources (including onsite flow meters, irrigation probes, and weather data) to analyse and report on whether irrigation is evenly distributed throughout the crop. N-Drip’s technical team may suggest necessary alterations to the system via a local WhatsApp group and has weekly virtual meetings with the local management. N-Drip has an agent in Eswatini who also regularly visits the trial.
The project is well-resourced to ensure that it provides scientifically validated feedback by the end of the trial.
N-Drip provides similar support as described in this section to irrigation farmers who would like to try out the N-Drip system on their farms.
The results
One of the key research objectives of the trial is to determine N-Drip’s overall effectiveness over multiple seasons. During the first season of the project, the initial crop was of good quality, and no significant differences were observed. The project is, however, still in its early phase and the research team recognises that multiple factors can affect crop performance. Research findings are expected to become more comparable for the upcoming season (2023/24).
The trial represents a positive step forward in proactively addressing our country’s future water needs. N-drip could be an alternative to flood irrigation that will impact irrigation farming globally.
Contact details:
N-Drip
https://ndrip.com/contacts/
Raisins South Africa
Stefan Jordaan
stefanj@raisinsa.co.za
+27 54 495 0283
[i] https://www.worldwildlife.org/threats/water-scarcity; https://www.cfr.org/backgrounder/water-stress-global-problem-thats-getting-worse
[ii] Internet of Things (IoT) probes/sensors are wireless pieces of hardware that detect changes in an environment at a specific point and collect data. The sensors use secure radio signals (such as LoRaWAN) to connect with internet-based servers that analyse and report on the data. IoT sensors can help farmers monitor their crops in real-time so that they know exactly how much water and nutrients crops need at any given time.