Seed Testing
Seed moisture content is one of the most important factor influencing seed quality and storability. Therefore, its estimation during seed quality determination is important. Seed moisture content can be expressed either on wet weight basis or on dry weight basis. In seed testing, it is always expressed on a wet weight basis, the method for its calculation is given later. Seed moisture content can be determined either by air oven or moisture meter. However, if prescribed standard for moisture content is less than 8%, air oven method shall be used.
(1) Air Oven method: In this method, seed moisture is removed by drying at a specified temperature .The moisture content is expressed as a percentage of the original weight (wet weight basis). It is the most common and standard method for seed moisture determination. The formula to be used is
M2-M3 Loss in weight
M= --------- x 100 = -------------------- x 100
M2-M1 Initial weight of seed
Where M = Seed moisture content
M1 = Weight of the empty container with its cover
M2 = Weight of the container with its cover and seeds before drying
M3 = Weight of the container with its cover and seeds after drying.
(2) Moisture meters: A variety of moisture meters are available in the market. These meters estimate seed moisture quickly but the estimation is not as precise as by the air-oven method. The meters should be calibrated and standardized against the air-oven method.
100 gm for species that have to be ground and 50 gm for all other species is the sample to be submitted in polythene bag of 700 gauge for moisture estimation.