Friday, 27 May 2022 08:55

New pasture assessment booklet

Written by  Staff Reporters
Doug Edmeades, principal of soil science company AgKnowledge Lts, is behind the new booklet. Doug Edmeades, principal of soil science company AgKnowledge Lts, is behind the new booklet.

A new tool that enables farmers to assess the fertility of their soils by looking closely at the pasture quality, vigour and clover content has recently been released.

“It is an easy way to score pastures to determine whether these are up to speed and pulling their weight,” says Dr Doug Edmeades, principal of soil science company AgKnowledge Ltd, which is behind the new booklet.

Edmeades describes clover as ‘the canary in the soil fertility mine’.

“It is the first pasture component to disappear if the soil fertility is not optimal,” he explains. “For these reasons, the clover content of a pasture is a good proxy for the underlying fertility of the soil.”

Edmeades says where clover is growing in the pasture, its leaf size, abundance, colour and vigour, and the presence or absence excreta patches, are all important indicators of the underlying soil fertility.

This is where the Pasture Visual Assessment (PVA) booklet comes in. It uses these indicators to systematically score pastures on a 1-10 scale.

A poor pasture (say 1-2/10 on the PVA scale), contains < 5% clover, the clover has small leaves and is only growing in the nutrient rich dung and urine patches. Weeds and weed grasses dominate and the excreta patches are obvious.

In contrast, a 9-10/10 pastures comprises 30-40% clover and the companion grass is ryegrass. The pasture is uniformly green, and the excreta patches are not apparent.

“The PVA booklet provides a simple technical explanation of the system and contains a series of photographs showing the key features of the different types of pasture on 1 to 10 scale,” Edmeades adds.

“A farmer simply matches his own pastures against the photographs. Obviously if the pastures are no ‘up-to-scratch’ professional advice should be sought.”

The system, Pasture Visual assessment (PVA), has been developed with financial support from DairyNZ and Barenbrug.

The booklet is available at: This email address is being protected from spambots. You need JavaScript enabled to view it. ($20 plus postage) or from

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