Pasture cover measurement, explained
Pasture cover — kilograms of dry matter per hectare — is the single most useful number on a grazing farm. Here is what it means, the main ways to measure it, and how to do it from a phone photo.
What is pasture cover?
Pasture cover (also called herbage mass or feed available) is the amount of dry matter standing in a paddock, expressed as kgDM/ha. Average farm cover — the mean across all paddocks — tells you how much feed is in front of the stock, and comparing it with demand tells you whether you are heading into a surplus or a deficit.
Target covers depend on your system and season: dairy platforms typically watch average cover closely through calving and drying off, while sheep and beef systems track it to set stocking policy through winter and lambing. Whatever the system, the principle is the same — you cannot manage what you do not measure.
The main measurement methods
Visual assessment is the oldest method: trained estimators score paddocks by eye. It is free but drifts between people and over time. The rising plate meter measures compressed sward height and converts it to cover with a formula — consistent, but it assumes sward density and only captures height. The falling plate meter and pasture probes work on similar principles, and cut-and-dry quadrats are the laboratory reference but impractical for weekly farm walks.
Photo-based measurement is the newest method. A model reads the sward in an image — height, density, colour, species and structure — and estimates cover directly. Pasture Ai uses this approach and adds feed quality (DM%, CP%, MJME, NDF%) from the same photo.
How to measure pasture cover with your phone
Open Pasture Ai, stand over representative pasture, and photograph the sward from a consistent height and angle in even light. The app returns a cover estimate in seconds and saves it against the paddock automatically.
For a steadier paddock figure, take up to 10 assessments across the paddock and let the app average them. Repeat weekly on the same round and you get the two numbers that drive grazing decisions: average cover and growth rate.
Getting reliable cover measurements
- Measure weekly, on the same day and roughly the same time
- Keep photo height and angle consistent from week to week
- Take multiple assessments per paddock and use the average
- Calibrate the app to your grazing type and season
- Track average cover and growth rate, not single readings
- Record every walk — history is where the value compounds
Frequently asked questions
What is a good pasture cover?
It depends on your system, stock class and season. Dairy systems manage average cover against targets that change through the year; sheep and beef systems set cover targets around lambing and wintering. The app tracks your covers over time so you can compare against your own targets.
How often should I measure pasture cover?
Weekly is the standard for active rotational grazing. Fortnightly measurement still builds a useful growth curve; less often than that and the wedge and growth rate lose reliability.
What units does pasture cover use?
Kilograms of dry matter per hectare (kgDM/ha) in New Zealand and Australia. Pasture Ai reports cover in kgDM/ha along with feed quality metrics.
Can I measure cover without equipment?
Yes — photo-based measurement needs only a phone. Download the app, photograph the sward, and the cover estimate returns in seconds.
Measure your first paddock today
Start the 7-day free trial, photograph a paddock, and see your first pasture cover reading in under a minute.
A card is required to start the trial. Cancel anytime from your Account page or email support@pastureai.ai.