Monitoring soil organic matter
NRM Carbon Check soil analysis service
NRM is now offering a new Carbon check soil analysis service
which is along the lines that I advocated following my Churchill Fellowship. It appears to be very comprehensive and should be an invaluable means of reliably assessing soil organic matter (SOM) change over time provided that the sampling is consistent. That means sampling in a W, following the same route each time, I suggest 10 or 15 cores per sample (not 5 as suggested below) and if you want reliable trends then sample the same one or two representative fields every year. Random samples every 5 or 10 years are meaningless.
The potential to sequester carbon is dependant on soil type; clay soils have greater potential than sandy soils. Don’t expect dramatic changes in SOM levels, the results that I have from several farms show small increases in the order of 0.5 – to 1.0% SOM over 20 years of good organic practice. Results from one of the best-monitored farm systems trials at FiBL in Switzerland shows SOM levels are rather stable over 30 years of organic management, compared to a small decline under conventional management. Remember that SOM is more dependant on addition of organic matter than the negative effect of cultivations
So don’t get distracted by the persistent and misguided clamour for no-till organic – there is nothing wrong with shallow ploughing.
NRM sent me the following information on their service.
"We are offering Carbon Check as two versions, CarbonCheck and CarbonCheck Plus. The difference between the two packages is CarbonCheck Plus includes active carbon, a measurement of the active/ labile proportion of the soil carbon. Increasing active carbon is seen as a pre cursor to improving organic matter, but changes in the active carbon levels can be seen much more rapidly than traditional organic matter analysis.
Prices for the two options are as follows:
CarbonCheck - £25/sample excl VAT
CarbonCheck Plus - £35/ sample excl VAT
Active carbon is offered as a stand alone analysis for £13.50/ sample excl VAT
The SOM analysis method is Dumas.
The sample kit we can provide includes sample bags, analysis request forms and postage boxes/ bags. Note that the request form is different to a standard soil form. Just let me know how many samples you intend to submit and the address you would like this kit sent to, and I can get this dispatched.
Sampling for carbon follows many of the guidelines given to soil sampling for other nutrients. However it is recommended to take samples to a depth of 30cm, this may vary depending on the depth of your soil, and also if samples are being taken from different depths within the soil profile. Apart from this, sampling for carbon follows many of the guidelines in place for other nutrients:
Identify the different field areas, considering the environmental landscape, soil type, land use and areas of where different treatments have been applied.
Avoid patches with animal manure, animal pathways, field entrances, areas near water/ feed troughs and other unusual features.
A minimum of 5 cores should be taken at random within each strata and to make a composite sample, a ‘W’ pattern is recommended. Note that a greater number of cores provide a more representative sample, and the number taken should be appropriate to the size of the area covered.
If you have any other questions, please don’t hesitate to give me a call or email.
Business Development Manager
NRM Laboratories, A division of Cawood Scientific Ltd