If you don’t have time to go out and sample your soils or find it too hard, then this is the test for you.
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.
This test includes soil sampling by Envirofield. To book them, please email the sample forms and what3words locations as explained in the instructions that will be send with the order confirmation. Please book them as early as possible to ensure they will be able to sample, particularly if you live in remote areas of the UK.
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.