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2.2.2 Soil Mineral Nitrogen Plus Test


Soil Mineral Nitrogen Plus (SMN) including “N now” and “N Later”.

SKU: SNT-1016 Category:

Please note: if you are a regular customer on a monthly invoice account, go directly to the SMN Plus Portal to create your sample forms (Step 2).

The SMN Plus Test measures both “N Now” and “N Later”. N Now is soil mineral nitrogen (SMN) which is the form of nitrogen in the soil directly available for crop uptake at the time of sampling. N Later is the additional nitrogen that will become available through mineralisation of organic matter and taken up by the crop between time of sampling and harvest. Measuring SMN Plus where soils have a high organic matter or after manure inputs or after eg grass or vegetables can potentially reduce fertiliser inputs. 

The courier collection of the samples and box delivery are included in the price of this test, so no need to add these extra to your basket. The sample depth for this test is 0 – 60 cm or to the depth of the top soil if the soil is shallow.

The best sampling times are before applying Nitrogen fertiliser, usually from the end of January. If N fertiliser or organic manures have been applied, please wait at least 4-6 weeks before sampling. 

Soil samples for SMN Plus have to remain cold in a fridge below 4 °C, but not frozen. If they are not kept cold, mineralisation will take place which will result in an overestimation of the result. It is therefore important to send the samples in insulated boxes with frozen ice packs to keep them cold in transit. 


For sampling instructions, click here

To order a polystyrene sample box, click here

For the sample form to send with the samples, log into your account first, then click here

For the courier booking form, click here