Introduction
With over 11,000 hectares of avocado orchards and rising production, irrigation is crucial for supporting New Zealand’s booming avocado industry. However, the unique physiology and growth habits of avocado trees present challenges for efficient irrigation management. By leveraging data and design principles tailored for avocados, next-generation smart irrigation systems developed by companies like Water and Irrigation Works are overcoming these obstacles. With innovations spanning soil moisture monitoring, variable rate application, and automation, precision irrigation can drive productivity while optimizing water use in orchards. And the avocado insights are translatable to designing effective systems for other high-value horticultural crops as well.
Why Avocados Are Tricky to Irrigate
Several inherent characteristics of avocado trees make them difficult to irrigate compared to other fruit crops. First, avocados have a shallow root system concentrated in the top 30 cm of soil. This leaves them highly vulnerable to moisture deficits that require frequent irrigation. However, shallow roots also risk damage and rotting if oversaturated for prolonged periods.
Additionally, avocados have an indeterminate flowering habit, meaning they can have flowers and fruit simultaneously at different stages of development. This diversity of growth phases on a single tree creates variable water needs. Flowers and young fruit require ample moisture for cell division, while mature fruit demands less frequent irrigation. Over or under-watering at key moments can profoundly affect productivity and fruit quality.
Finally, alternate bearing leads to extreme crop load fluctuations year to year. In one year following a small crop, the high fruit set has very high water demands. Overall, inconsistent soil moisture optimization from one season to the next hampers yields and makes irrigation recommendations difficult.
Precision Approach for Avocados
To address these challenges of optimizing avocado irrigation, a tailored approach is needed that monitors real-time tree water status and delivers water according to crop demands. This is the precision irrigation strategy taken by Katikati-based Water and Irrigation Works. Their smart irrigation systems are designed from the ground up based on extensive research into avocado soil moisture requirements and plant physiology.
At the foundation is AquaView, the company’s in-field soil moisture monitoring network. With sensors positioned at multiple depths corresponding to avocado root zones, AquaView provides a high-resolution moisture profile. This allows the detection of even mild deficits that could impair flowering, fruit set, and productivity if prolonged.
Tying into the AquaView data is IrriSoft, cloud-based irrigation management software optimized for avocados. IrriSoft incorporates weather forecasts, evapotranspiration models, and crop growth stage data to translate current soil moisture into irrigation decisions. Alternate bearing patterns are factored in to adjust recommendations seasonally based on crop load. This precision scheduling coordinates irrigation timing and amounts to the needs of flowers, developing fruit, and mature fruit simultaneously on the tree.
IrriSoft controls and automates irrigation equipment such as valves and pivots to match real-time requirements. Variable rate irrigation technology further tailors application within orchard blocks by zones. This accounts for soil type variability and microclimates like frost pockets.
Results and Benefits
Implementation of Water and Irrigation Works’ avocado irrigation systems has achieved impressive results in orchards across New Zealand’s main growing regions.
By eliminating unnecessary irrigation events based on soil moisture, water use efficiency has improved by over 25% compared to conventional timer-based schedules. Runoff and drainage are minimized along with pumping costs. Despite reduced water application, the precision timing centered on crop demands has increased flower production and fruit yields.
Alternate bearing impacts are also smoothed by maintaining optimal soil moisture despite fluctuating crop loads. Fruit quality benefits as well from consistent irrigation preventing moisture stress during critical growth stages.
The system automatically adapts recommendations to changing weather, plant growth cycles, and patterns like heat waves. And turnkey automation and monitoring reduce labour requirements for growers.
Beyond Avocados
While avocados present some unique irrigation challenges, the principles and technologies developed by Water and Irrigation Works are transferable to other crops. Soil moisture monitoring provides fundamental insights into actual plant water status for any horticultural production. And data-driven, variable-rate irrigation addresses spatial variability in soil, microclimate, and plant conditions prevalent in all orchards and vineyards.
The company is therefore expanding their precision irrigation beyond avocados into citrus, pip fruit, summer fruit, grapes, berries, and more. The equipment, modelling, and algorithms are adapted to each crop’s specific characteristics and irrigation needs. However, the same combination of real-time sensors, forecasting, automation, and variable rate technology optimizes water application, plant growth, and productivity.
As freshwater resources become more scarce globally, precision irrigation offers a path to sustainable intensification of horticulture. By designing irrigation around crop-specific moisture demands, companies like Water and Irrigation Works are leading the way in effective water management for orchards and speciality crops. Their innovations turn irrigation from an estimation into a data science that can maximize productivity per unit of water.
