Know your Soils #7: The Respiration Test

Know your Soils #7: The Respiration Test 1358 772 Soilmentor

Welcome to the seventh instalment of our Know your Soils series sharing practical tips for monitoring the soil health on your land. Keep an eye out for our bitesize videos and fact sheets on simple tests you can do yourself on farm.

“If you can’t measure it, you can’t improve it.

How much biological activity is there in your soil?

Based on an AHDB GREATsoils video created by Soil Association and Earthcare Technical

The soil respiration test is a way to measure how much biological activity is occurring in your soil. When soil respires carbon dioxide is released by microbes, plant roots and soil fauna.

Decomposition of organic matter by microbes in the soil converts organic nutrients such as phosphorus, nitrogen, and sulfur into inorganic nutrients, which plants are able to absorb. This process is also known as carbon mineralisation, feeding the plants, and the soil.

Soil respiration is indicative of the soil’s ability to support living roots and plant growth. Low respiration rates show that there is a lack of soil organic matter and microbial activity in the soil. This could be down to the soil temperature, moisture, aeration or available Nitrogen.

Solvita has created a special field CO2 probe making it easy to test how much carbon dioxide is being released by the soil. It will give you a general idea of your soil’s natural metabolism and which farm management practises are affecting your biological activity.

In this GREATsoils video, find out how to do the test using the probe:

Soil samples need to be fresh from the field and slightly moist for this test — ideally the field will not have not been rained on for two days. It is interesting to sample fields of different uses such as pasture, arable and leys to see how the soil respiration differs.


For those in the UK can order kits from Solvita in the U.S. directly – please note prices are subject to change. Solvita field CO2 probes, gas tight jars and the CO2 colour chart are included in this set of 6 CO2 probes & jars for $99 (£75). You can get an idea of what the colour chart looks like in Solvita’s video. To stock up on probes you can buy 25 x field CO2 probes for $493 including shipping (£376) which is about $20 (£15) per test. The more you order the cheaper it gets: 50 is $714 (£544), so around $15 (£11) per test.

If you’re based in the U.S. you can link up with Will Brinton at Woodsend Labs to obtain advice and the Solvita equipment you need for this test.

If you’re based in the U.K. you can also get an in-depth assessment of your soil which includes the soil respiration test from NRM.

If you’re interested in trying this test at home why not club together with other farmers who would like to investigate their soil respiration.


See our free online soils guide for soil tests you can do at home and find out how our app Soilmentor helps you record & learn how your soil is changing.