What is not rain, not sunshine, not bugs and not fertiliser but makes a Gippy milkmaid’s grass grow?
Lime! This is the first 30 tonne load of a 210 tonne order I placed the other day. High in calcium, lime helps to balance the natural acidity of our soils. Why does it matter? You can read all about it on a DEPI acid soil factsheet but here are the basics:
- a low pH binds up the soil’s nutrients, making them less available to the plants
- there’s a greater risk of manganese toxicity in acidic waterlogged soils
- the nitrogen-fixing organisms in the soil suffer
- plant roots become stunted in acidic conditions, making them more vulnerable to dry spells and root-eating pests
- aluminium becomes more soluble and affects plant growth
Some of our paddocks are fine but others are desperately low, both in calcium and pH. Last year’s finances were just too tight to do much about it but, with a better milk price this year, I’m making up for lost ground.
It will take years to see any impact. In three applications over the last seven years, for example, we’ve spread a total of 7.5 tonnes/ha of lime on the paddock around the house because it’s one of the most acidic on the farm. Despite such a heavy dose of lime, we’ve only managed to lift the pH from 4.0 (that’s in CaCl2, not water, for the aficionados) to 4.5, which still qualifies it as highly acidic.
Just goes to show that Giza wasn’t built in a day.