Herbage testing can reveal a lot about what is happening in your soil, but timing and the right combination of tests are crucial. In this episode, Ewan and the team look at why mid to late spring can be such an important window for herbage testing in New Zealand, when multiple pasture species are actively growing and minerals can be better represented.

The conversation explores the relationship between soil tests, herbage tests and soil biology, including trace minerals such as cobalt, selenium, nickel, boron and iodine. They also work through an anonymised farm example, looking at nitrogen, potassium, calcium, silicon, aluminium and other minerals to understand what the numbers may be showing about the wider soil system.

They also revisit the response to the previous cropping episode, discussing how soil preparation, biology and nutrient cycling fit together, why plants such as wild turnip may be indicators of underlying soil conditions, and why soil testing should be the starting point when trying to understand what is limiting a farm.

In this episode:

• Why mid to late spring is an important time for herbage testing

• How different pasture species can affect the minerals showing in a herbage test

• Why some trace minerals are difficult to assess accurately through soil testing alone

• How herbage testing can provide an indication of soil biology and mineral availability

• The relationship between nickel, nitrogen and zinc

• Why silicon and aluminium are important when looking at weeds and soil conditions

• How soil tests and herbage tests can be used together

• What an anonymized farm herbage test can reveal about soil fertility

• Why soil testing should be the starting point when identifying limiting factors

• How soil biology can contribute to nutrient cycling after cropping

• What pasture plants and weeds may be telling you about the condition of the soil

• Why accuracy and observation matter when making soil fertility decisions