Irrigation and fertigation: water and nutrients where crops need them

Fertigation incorporates fertilisers into irrigation water to supply nutrients during applications. Its performance depends on water quality, solution preparation, distribution uniformity and scheduling. Automating schedules is one part of the system, not a guarantee that every plant receives the intended application.

When a sector shows uneven growth, increasing irrigation time can seem the quickest response. First check whether emitters deliver similar volumes and whether the applied solution matches the nutrition programme. Correcting distribution problems with more time may overwater locations already receiving enough.

Uniformity is verified at the installation

A practical assessment measures volumes delivered by different emitters over the same interval, including points near and far from the sector inlet. The aim is to identify differences, investigate their causes and repeat measurements after corrections.

Oregon State University describes uniformity assessment using collected volumes and highlights maintenance and operating pressure as parts of diagnosis. Its guide concerns sprinkler systems: checking distribution is a useful principle, but the procedure must be adapted to the system assessed. Oregon State University, Measuring irrigation uniformity.

For CiberAgro, this means sizing the network together with filtration, pressures, sectors and emitter types. Engineering should define how delivery will be verified, not merely which components will be installed.

Water analysis comes before the recipe

pH, alkalinity and electrical conductivity provide different information. Conductivity relates to dissolved-salt concentration but does not identify individual nutrients. Nor does pH replace alkalinity measurement.

UMass Extension recommends analysing source water and using pH and conductivity measurements to follow its behaviour and treatment results. It also stresses the importance of instruments that can be calibrated. UMass Extension, Water Analysis.

Penn State highlights the particular importance of water quality in small substrate volumes and hydroponics. The same technical solution should therefore not automatically be transferred between plugs, large pots and other systems. Penn State Extension, Interpreting Irrigation Water Tests.

Schedule for the crop and verify the response

Programme design should combine crop, stage, substrate, available root volume, environmental conditions and the responsible agronomist’s criteria. An irrigation schedule can be a starting point; reviewing it requires information about what actually happens.

One application is to enable irrigation within time windows and use substrate measurements as an additional condition. Another is to maintain different programmes for sectors with different needs. Choices require thresholds, operating limits and a response when a measurement becomes unavailable.

Integration with Sinthesis depends on the sensors, valves and modules included in the project. Measuring pH or conductivity does not itself imply automatic dosing: that function requires specific equipment and configuration.

Assessing system impact

Before modifying the system, record a baseline. Then compare periods and sectors under reasonably equivalent conditions:

• Water volume applied per sector and unit area.
• Delivery differences between measured points.
• Fertiliser consumption alongside the concentration or recipe used.
• Deviations from defined solution parameters.
• Drainage, where measured, and observed changes in crop uniformity.

Reducing litres without maintaining the agronomic objective is not an improvement in itself. Assessment should relate resources to quality and results, distinguishing changes in weather, crop and management.

In research, recording applications and conditions helps describe the treatment carried out. The platform can facilitate records, but trial validity also depends on the experimental protocol.

Tell us how you irrigate today and let’s assess what should improve.

Frequently asked questions

Does fertigation replace water analysis?

No. Source water forms part of the final solution. Analysis provides information needed to define nutrition programmes and assess treatments.

Does conductivity reveal each nutrient?

No. Conductivity reflects the combined behaviour of the ions present; it does not replace analysis identifying composition.

Can an existing system be improved?

It can be assessed. A survey must check components, condition, distribution and automation capability before defining what to retain or replace.

Apply these criteria: explore irrigation and fertigation and integrated control. Discuss your project.

Sources and scope of evidence

• Oregon State University, Measuring irrigation uniformity: distribution assessment for sprinklers; adapt the method when assessing drip irrigation.
• UMass, Water Analysis: water quality and pH/conductivity monitoring.
• Penn State Extension, Interpreting Irrigation Water Tests: interpreting water parameters for protected cultivation.