Agriculture accounts for roughly 70% of global freshwater withdrawals. In many of the world’s most productive growing regions, that proportion is considerably higher. As aquifers drop, river allocations tighten, and climate patterns shift, the pressure on agricultural water use is intensifying from every direction simultaneously.
For growers, this creates a genuine dilemma. Water is both the resource they need most and the resource facing the most pressure. Reducing irrigation without a yield penalty is the goal, but in practice it requires understanding how crops use water at a physiological level, not just how much they receive.
This is where water use efficiency (WUE) becomes a critical concept, and where ISKAMAR with PSI 433 Precision Technology provides a measurable, practical solution.
What Water Use Efficiency Actually Means
Water use efficiency is the ratio of yield produced to water consumed. A crop with high WUE produces more biomass or marketable yield for every litre of water it transpires. A crop with low WUE requires proportionally more water to achieve the same result.
WUE is not fixed. It changes with temperature, humidity, crop growth stage, and the physiological condition of the plant. Under heat or drought stress, WUE typically falls because the plant’s internal water management systems become less efficient: stomata close erratically, carbohydrate transport slows, and cellular damage begins to accumulate.
Improving WUE is therefore not simply a matter of applying less water. It requires either improving the conditions under which the plant uses water, or enhancing the plant’s internal systems so that it extracts more productive output from each unit of water it absorbs.
How ISKAMAR Improves WUE
ISKAMAR is built around a complex of marine oligosaccharides derived from chitosan, enriched with calcium and organic acids. These molecules are engineered using PSI 433 Precision Technology to activate specific water management mechanisms inside the plant.
Stomatal Optimisation
Stomata are the plant’s primary mechanism for managing the trade-off between gas exchange and water loss. Under water deficit, poorly regulated stomatal closure reduces photosynthesis more than necessary, limiting yield while not fully conserving water. ISKAMAR improves stomatal regulation, allowing the plant to maintain a more productive balance between gas exchange and water retention throughout periods of stress.
Relative Water Content
Relative water content (RWC) is a direct measure of how well a plant is retaining the water it has absorbed. In a season-long potato trial under significant agricultural drought, ISKAMAR-treated plants consistently maintained higher RWC at every measurement point than untreated controls, even as the soil moisture deficit increased. Higher RWC means the plant stays metabolically active for longer and continues to allocate resources to productive growth rather than triggering a full stress response.
Carbohydrate and Calcium Mobility
Water stress impairs the movement of carbohydrates and calcium through the plant. Calcium is critical for cell wall integrity and fruit quality. Carbohydrates drive fruit fill and sugar accumulation. ISKAMAR improves the transport of both under water deficit conditions, helping the plant continue productive development even when its overall water status is compromised.
The Yield Evidence
Across replicated field trials under water deficit conditions, ISKAMAR delivered an average yield increase of 15.4% in stressed crops compared to untreated controls.
In the potato drought trial, marketable yield increased by 16.1% with ISKAMAR treatment. This was directly correlated with the improved RWC data, confirming that the mechanism is real and the yield benefit is causally linked to improved water use efficiency, not random variation.
The Sustainability Dimension
The sustainability case for improving WUE is straightforward. If a grower can produce the same yield with 25-35% less water, that is a direct reduction in extraction pressure on aquifers and river systems. It also reduces energy costs for pumping, lowers the risk of soil salinisation from over-irrigation, and in regions with metered water allocations, it can reduce direct input costs significantly.
ISKAMAR’s application protocol for structured deficit irrigation programmes, three foliar sprays at 3 L/Ha distributed across vegetative phase, flowering, and fruit set, is specifically designed to support growers who are already managing reduced irrigation volumes. It provides a biological underpinning for the agronomic practice of deficit irrigation, giving crops the physiological tools to perform well under deliberate water restriction.
A Balanced Programme for Water-Stressed Regions
Water stress does not occur in isolation. In many regions, it coincides with heat stress, salinity from saline irrigation sources, or both. Brandon Bioscience’s product range is designed to address these overlapping challenges through complementary mechanisms.
ISKAMAR addresses water use efficiency and drought tolerance. BLOCSAL addresses salinity stress and ion toxicity. MARTELLO addresses heat stress and thermal protection during the reproductive stage. BARRAMAR and MARTELLO are the two products that we have used in combination programmes the most, the others, the data is limited
All three products are backed by peer-reviewed publications. Explore the full programme at our solutions page or read the science on our published research page.
