White paper
Whitepaper: A Methodology for Measuring and Rationing Irrigation Water
The full technical method: how crop demand is computed by FAO Paper 56, how moisture thresholds are set, and how a saving is documented so that it survives audit.
A technical paper written for the agronomist and the farm manager rather than the general buyer. It sets out the calculation in equations - reference evapotranspiration, the crop coefficient by growth stage, effective rainfall and application efficiency, as given in FAO Irrigation and Drainage Paper 56 - and then applies them to a fully worked example, step by step.
The second section deals with soil moisture thresholds: how field capacity and wilting point are derived from soil texture, where the irrigation trigger sits between them, and how that trigger differs between establishment and fruiting for the same crop.
The third section is about documentation: what has to be recorded for a saving figure to remain auditable a year later - dated raw meter readings, running hours, and the weather events that moved them - and why keeping the monthly reports without the data underneath them is not enough.
The paper closes by stating the limits of the method plainly: what it is not suitable for, and where the expected error is largest (soil that varies sharply within a single plot, and saline irrigation water that imposes an additional leaching fraction).
Where should we send it?
An email address, and the file opens on the next screen. We send the link a second time to that address so you still have it next week.