Patrick Rahilly wrote:Mr. Morgan,
I realize your post was made last December, sorry if this gets to you late, however, I hope to give you some thoughts to think about prior to this coming Aussi Summer.
South Australia. I don't intend to second guess you, but are you certain the soil is acidic? Do you happen to be in the Murray-Darling basin? East, West? Climate type?
you should look at the surrounding Veg on the adjacent parcels/ hillsides? Other crops in the area.
I would guess with the white clay sub soil you are probably dealing with a very old soil potentially in a very high moisture area or perhaps now dry, with a historically wet history/ancient flood plain/wetland (billabong) which has leached out all the irons and metals leaving essentially a clay/silicon matrix which can be acidic. the dusty top soils darker color from organic matter (OM) from what plants have grown there recently (last couple hundred years). The dusty-ness makes me think it is more alkaline or sodic in nature, and if you are in a flood plain/historic lake/billabong this is more likely the case than acidic. Its hard to say without knowing climate and spatial proximity in Auz.
My best suggesting to you, regardless of further details, is to look around at the adjacent veg, bushes, shrubs and trees especially. If you are not opposed to planting these in your pasture (with a little more info I can offer some help/suggestions) in broadly spaced rows (trees and shrubs) (think silvo-pasture) this may be the best way to to add OM to the sub-soil, add soil structure, increase grass rooting ability, increase water infiltration/percolation/holding capacity, decrease ET associated with wind, perhaps even build soil by collecting soil that blows off your neighbors lands. Trees/shrubs not only can access deep nutrients that have leached out of surface soils and deposit them on the surface through litter drop and shallow root turnover, but they can also bring deep soil moisture to the surface (a plant phyx anomaly).
Also, where is the water table? shallow? Water quality of the table, salty?
Anyhow, more info would be good to better ascertain your situation.
R. Morgan wrote:I have a hard white clay subsoil with a small amount of dusty brown soil on top. Grass struggles and is slow growing. Soil is acidic.
I am thinking of adding lots of horse manure to improve soil structure , moisture holding capacity and fertility. This is a smallish area
of irrigated pasture (in South Australia) which I need to establish. I need to find out what deep rooted plants to put in the mix, where to get the seeds for
it in small enough quantities and really.......... everything
All ideas appreciated.