Test of viable seeds and plant propagules in sludge, bio-waste and soils (CEN/TS 16201: 2013 Standard).

The CEN/TS 1601 standard indicates a procedure for determining the content of seeds and propagules of unwanted weeds in crop substrates and soil improvers, which can also be applied to sludge and soils.

For its realization, the samples must be sieved to break up the lumps or agglomerates that may have formed by compression and that their particles are smaller than 10 mm, eliminating any foreign material such as plastics, metals or glass, mixing, and adjusting their pH and electrical conductivity, before determining the development of the plants, during an incubation period of 21 days under controlled conditions. The samples must not be added lime or fertilizers and must be free of seeds and plant propagules. Moisture loss should be avoided. The volume of the sample should be about 6 liters.

In addition, the samples must be treated to break the dormancy of the seeds. To moisten samples, they can be treated with gibberellic acid solution or potassium nitrate solution, instead of water.

The tests are carried out by distributing a minimum of 3 liters of the sample in a seed tray with holes with a perforated base. The trays are kept at adequate temperature and lighting, covered to prevent moisture loss. To verify that the development conditions are adequate, controls with barley seeds are included. If the controls show that the barley seeds do not develop correctly, it may indicate the existence of germination inhibitors, in which case a sample washing procedure can be carried out in a device that allows a flow of water, and this on another very small pore sieve to detect and collect undersized seeds.

The results are expressed as the total number of germinated seeds referred to a volume of 1 liter of original sample.