Evidence brief: closing the irrigation feedback loop
How can a grower distinguish a correct watering decision from successful water delivery?
Scope of this review
Drip-irrigated crops in containers or substrate slabs, with moisture sensing and zone flow measurement. Open-field scheduling and nutrient recipes are outside scope. The examples are conceptual, not Hamfy trial results.
How we assessed the evidence
Sources reviewed on 8 October 2026. We checked the original study or university guidance, separated its setting from transferable principles, and developed an operating checklist. This is an editorial review, not a systematic review or a Hamfy field trial. Worked examples use stated assumptions.
What the evidence supports
Demand and delivery are different evidence
A moisture value can request irrigation, while flow and pressure help check execution. Local emitter and substrate observations are still needed because a zone total can hide unequal delivery.
The control principle has experimental support
The 2006 study demonstrates sensor-triggered feedback in a defined potted-plant system. Hamfy’s proposed commissioning sequence adds explicit checks for stale data, bounded pulses and missing response.
Simple arithmetic can reveal an investigation
The assumed 10 L pulse is a transparent reference calculation. It cannot diagnose the cause of a discrepancy without timing, pressure, meter and local-delivery evidence.
What this review does not establish
- Neither the hypothetical moisture trace nor the pulse calculation supplies a crop-specific irrigation target.
- The cited experiment does not predict savings for a different commercial crop or installation.
- Failure response must be agreed for the crop, hydraulic system and operator availability.
Hamfy’s proposed next step
Commission one clearly defined zone. Validate measurements and delivery first, then compare a bounded feedback programme with the existing schedule while retaining crop-quality checks and an operator recovery route.
Evidence to collect for a real project
- Crop, container and substrate specifications plus sensor calibration and placement records.
- Timed valve, pressure, zone-flow, emitter-output and substrate-response records.
- Comparable water use, drainage, crop quality and operator interventions across repeated periods.
Source notes
- Research / technical guidance · 2006An automated system for controlling drought stress and irrigation in potted plantsKrishna S. Nemali and Marc W. van Iersel · Scientia Horticulturae
Original 2006 potted-plant experiment by Nemali and van Iersel. It supports the feedback principle, not universal moisture thresholds.
- Research / technical guidance · 2016Drip Irrigation Checklist: Start-UpChavez, Coolong, Wells and Porter · UGA Cooperative Extension
University checklist for hydraulic inspection and startup checks; the field context must be adapted to the greenhouse zone.