Aerating Your Soil Without A Machine? – Gerard Finnan

On a recent training course, we heard from a farmer and their consultant who was advocating the use of Gypsum, to add to a heavier sticky soil to help improve drainage and aeration.

Gypsum is naturally occurring in the soil and is quarried and mined in the UK.  It is basically Calcium Sulphate or otherwise used as plasterboard in buildings.  Heavier less free draining soils tend to be sticky and tighter because they are high in Magnesium.  By adding 2.5 t/Ha (legal limit is 1t/ha but the EA can give derogations) of gypsum, spread like lime, the sulphur removes the excess magnesium, whilst the calcium helps the soil to flocculate and improve in structure, opening up the airways.  This increases soil biology with water and roots travelling deeper in the soil.

Sufficient calcium is also considered essential for trace element availability and is particularly important for legumes.  The ideal percentages are 68 – 70% calcium and 10 – 12% magnesium.  The result is a drier soil earlier in the season and a soil with more water reserves deeper in the summer when there is a risk of drought.  If crops can be planted earlier or grass grazed over a longer growing season this will result in extra dry matter growth and utilisation.  You need to apply the gypsum for at least three consecutive years to see the cumulative positive effect.  We reckon it has the potential to produce a 200% return on investment per year.  Cost should be £30-£40/t delivered but will depend on delivery distances.

Though still in early March, wouldn’t we all like to see drier soils to enable turnout of livestock and get machinery working on the land?  Now you might not need to use the flat lifter or aerator in narrow weather/soil condition windows if you have the type of soil mentioned above.

It would also be useful to take a soil test to measure the calcium magnesium ratio of your soil before you start applying Gypsum to be able to quantify the amounts of gypsum to apply to produce the desired effect.

Speak with your agronomist or Gerard at for more information and ascertain whether this applies to your soil.