SOIL / SENSOR PROCUREMENT
Questions to answer before requesting a soil-moisture sensor quote
Define the measurement, data path, operating costs, and acceptance check before comparing soil-moisture sensing quotes.
- soil moisture
- sensor selection
- procurement
- telemetry
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Start with the decision, not the device
Ask suppliers to quote the measurement method, the full data path, and the work needed to keep the system useful. A quote is comparable only if it says what is measured, where readings will come from, how they reach the person making irrigation decisions, which recurring costs apply, and who will maintain the system.
Write down the irrigation decision the reading is meant to support. For example: Will this block need water within the next application window? That question helps distinguish a system that tracks water content from one that tracks soil-water tension or potential. University of Minnesota Extension describes these as different measurement approaches with different interpretation and installation limits. Utah State University advises interpreting trends with field capacity or refill points, crop response, and field observations. These sources are starting points, not local advice for a specific crop and soil.[1][2]
- Which measurement does this system provide: water content, tension or potential, or a profile measurement?
- What should the manager compare the reading with before acting?
- Which soil, salinity, temperature, installation, bulk-density, or calibration conditions can change the reading or its interpretation?
- What field observation or reference check should be used when the graph and the crop do not agree?
Define the zone and depth plan before asking for a count
The equipment count has no meaning without a zone and depth plan. Ask the supplier to separate the quoted hardware from the advice needed to define representative management zones, depths, and exceptions. This table asks the supplier to state the quote scope. It is not a placement prescription; use the linked placement guide for that field decision.
| Question | Why it changes the quote |
|---|---|
| Which blocks or management zones need separate readings? | One location may not represent a field with different soils, crops, or irrigation behavior. |
| Which depths will be measured and why? | A shallow reading and a root-zone profile answer different questions. |
| What crop stage and rooting-depth assumption is being used? | The useful range changes as roots develop. |
| What access, installation, and protection work is included? | Installation can require more than the sensor hardware. |
Ask for the whole data path
A sensor reading is one part of the working system. Request a diagram or written list that follows the reading from the probe to the operator. Include the sensor, cable or radio path, logger, gateway, power source, software or portal, alerts, data export, and the person who receives a failed-communication notice.
Ask the supplier to name the exact model and logger pairing. METER lists DDI serial and SDI-12 for TEROS 12; IRROMETER lists SDI-12 and 0 to 3 V adapter paths for WATERMARK; Acclima lists SDI-12 for TDR-315N; and Sentek lists RS232, RS485, SDI-12, and Modbus paths for Drill & Drop configurations. Those are manufacturer interface statements, not proof that a proposed field system is compatible. Confirm the supplier's compatibility statement in writing for the proposed logger, gateway, region, and firmware version.[3][4][5][6]
- Does the quote include a logger, gateway, cellular service, radio hardware, software subscription, and data export? List each excluded item and its expected recurring cost.
- What happens when power, communications, or a subscription fails? Who sees that condition, and how is the gap recorded?
- Can the operation export readings in a usable format if it changes software or service provider?
Separate purchase price from operating cost
Do not compare a sensor-only price with a system price. A fair quote separates hardware, installation, communications, telemetry, subscription, training, support, and maintenance. It should mark price as a listed price, dealer quote, or estimate and give the date, currency, region, and taxes or freight assumptions. Recheck price, availability, warranty, firmware, and compatibility against a current written quote and official documentation before ordering.
| Field | Record |
|---|---|
| Measurement and system shape | |
| Exact model and documented interfaces | |
| Sensor hardware | |
| Logger, gateway, and power | |
| Communications and subscription | |
| Installation and commissioning | |
| Training, support, and maintenance | |
| Warranty and exclusions | |
| Data export and account ownership | |
| Price type, date, region, and quote expiry |
Operating standard
Define the acceptance check before purchase
Before signing, ask the supplier to state how the operation will know that the installed system is reporting and being interpreted as intended. The acceptance check should include a communication test, a named person responsible for reviewing data, a comparison with field observations or another agreed reference method, and a response when readings conflict or are missing.
This is not a promise that the system will improve irrigation outcomes. It makes the first operating check visible. If the operation cannot name the decision, data path, recurring-cost boundary, and acceptance check, pause the purchase and resolve those gaps before comparing sensor models.
This is desk research. FarmHub has not purchased, installed, or tested the named equipment and had no documented affiliate, sponsorship, reseller, free-unit, or paid-placement relationship with METER, IRROMETER, Acclima, or Sentek on 2026-09-25. Before ordering, recheck product specifications on the relevant official product page or in a written supplier quote.[3][4][5][6]
Research record
Sources
Every factual claim in this note is tied to the numbered evidence below.
- [1] university extension[1] University of Minnesota Extension, Soil moisture sensors for irrigation scheduling. Measurement categories, interpretation and installation limits, sensor conditions, data loggers, and using readings with other scheduling tools. Accessed 2026-09-29.
- [2] university extension[2] Utah State University Extension, Irrigation Technology Cost/Benefit Analysis Calculator. Using field capacity or refill points, crop response, and field observations to interpret soil-moisture trends. Accessed 2026-09-29.
- [3] manufacturer[3] METER Group, TEROS 12. Manufacturer-published TEROS 12 interface statements. Not independent compatibility evidence. Accessed 2026-09-29.
- [4] manufacturer[4] IRROMETER, Soil Moisture Sensors. Manufacturer-published WATERMARK interface-path statements. Not independent compatibility evidence. Accessed 2026-09-29.
- [5] manufacturer[5] Acclima, Digital TDR soil moisture sensors. Manufacturer-published TDR-315N SDI-12 statement. Not independent compatibility evidence. Accessed 2026-09-29.
- [6] manufacturer[6] Sentek Technologies, Drill & Drop. Manufacturer-published Drill & Drop interface-path statements. Not independent compatibility evidence. Accessed 2026-09-29.
Continue through the archive
Related operating questions
Choose a soil-moisture sensing approach before requesting quotes
A desk-researched field guide for selecting a soil-moisture measurement method, checking the whole data path, and turning a reading into a cautious irrigation decision.
Place soil-moisture sensors where they represent the root zone
Choose representative management zones, depth bands, and in-row locations before treating a soil-moisture reading as an irrigation decision input.
Schedule Irrigation With Soil Moisture and ET
Use a root-zone water budget, representative soil-moisture readings, and field observations together to decide whether to irrigate, wait, investigate, or adjust depth.