|
- Our soil is now about as saturated as it is likely to get this year. Sure
we will get more rain but we will also get fine days and the drying out
commences. Now is the optimum time to improve your drainage and condition
that heavy clay that passes as soil in this region.
- You may think that it makes sense to add sand to condition soil, but think
again before you commit that folly. It would take at least 5 times the
volume of sand to clay to make an impact. If that seems a reasonable
proposition, then you must own a sandpit somewhere. No, adding sand is not
an option.
- In this region we add a fine cream powder called gypsum. Never add
dolomite, even if the Mancurian and Mercurial Mr Cundall and ‘Backyard’
Don encourage you to. They are talking within their understanding of eastern
Australian soils that are fairly acidic in reaction. Add dolomite in
Adelaide and your soil is doomed to make most of your garden go a bright
yellow, from lime induced chlorosis.
- Gypsum is hydrated calcium sulphate, which is a plentiful and naturally
occurring compound in this state and it is pH neutral when added to our
alkaline soils. It has the action of causing clay particles to aggregate and
form ‘bigger lumps’ if you like. Water engineers use the term
flocculation, when they separate the turbid clay particle from our water in
the filtration process. Well gypsum acts like a soil flocculent, improving
drainage in the process.
- Gypsum also works in a short space of time and you do not need to dig it
in, but it is best spread on rough dug soil. Spread it at the rate of 300
grams per square metre on heavy clay or 150 grams per metre on clay loam.
- I add composted organic material at the same time, which saves one lot of
digging. Don’t dig the compost in too deep and make sure you add some
blood and bone or blood meal, if you follow me, so that you don’t suffer
short term nitrogen draw down. The compost acts as a great nutrient buffer
latter in spring, when you won’t be able to dig, because the garden beds
will be full of veggies and flowers.
|
