Seed treatments have long been an important part of agriculture - adding significant value to a sown pasture or crop in some cases.

One good example is rhizobium inoculation of lucerne that enables nitrogen fixation to occur.  

This drives forage yield and boosts nitrogen levels for following crops.

In recent years the range of seed treatments available to producers has grown.

Rhizobium and fungicide treatment are well proven and commonly used these days, with newer technology targeting issues such as insect control and micro-nutrients.

Seed coatings may also be used to improve the ability of seed to be handled with modern machinery, often referred to as "ballistic properties" and used on seed that is excessively light or fluffy.

For some pasture species the use of seed coating to improve the ballistic properties is the only practical means of establishing the pasture.

Producers should undertake their own research before investing in any seed treatment - looking for sound evidence that proves the value of the treatment.

While pot and glasshouse trials are useful indictors of how a treatment can add value to sown seed, they may not take into account all of the variables present when sowing a paddock.

Field trials are generally a better way to assess value due to the large number of field factors that can influence the establishment outcome.

In some cases a treatment that works well in a glasshouse may be ineffective when subjected to the full field environment.
Additionally, some seed treatments will add significant weight to the seed.

Sometimes this can be as high as 80 per cent of the bagged weight, so the sowing rate at the combine may need to be adjusted to achieve the targeted plant population.

For example, lucerne has approximately 440,000 seeds per kilogram.

If you sow a lucerne pasture at five kilograms per hectare of bare seed you would expect to sow about 220 seeds per square metre.

However, if the coating comprises 80 per cent by weight of the product there is only 200 grams of seed for every kilogram of coated product.

You would need to sow the coated seed at 25/kg to achieve the same 220 seeds/m2.

Consequently, if you are purchasing coated seed rather than bare seed, make sure that you allow for the increased sowing rate where the coating adds significant weight to the seed.

In the above example, if bare lucerne seed is worth five dollars per kg then treated seed should cost $1/kg.

If field trials have proven the seed coating increases the establishment percentage of seed sown compared to bare seed, then the sowing rate of coated seed can be adjusted by this amount.