j tunney wrote:I am extremely interested in reintroducing Magnesium into our soils, and wondering if there is a way other than buying Epsom Salts to throw onto the land, so that it is available to what we are growing. Seaweed? What else?
I think for me it would depend on the existing soil structure and nutrient profile, as to what I used to add magnesium back to the soil. I would be hesitant to start broad-scale nutrient "fixing" without a decent soil analysis, because 1) most soil amendments are expensive and 2) if I'm just guessing, I could guess wrong and make a bigger problem than what I was trying to solve.
I wouldn't tend to use Epsom salts over a large area - I see them as more of a home garden "quick fix". Most people recommend using it as a foliar feed when plants are showing obvious signs of deficiency. It is a salt
, after all. Given that it's a highly soluble form of the mineral, I'm not convinced much would stay in the soil in a useful way.
Dolomite (dolomitic limestone) often has good amounts of magnesium (and calcium) in it. As it's used to fix acid soils, though, it may be best to skip it if your soil is already fairly alkaline. (Interestingly, alkaline soils tend to be higher in magnesium anyway. It becomes more bioavailable at higher pH, too.)
If I had animals that I was grazing on pasture, my preferred method of adding trace minerals (not just magnesium) would be in supplemental animal feed. My father is a beef cattle farmer in south-east QLD. He's been using a product range called NatraMin on his paddocks for the last 5ish years to add trace minerals back to the soil. He also supplements the cattle feed with it during drought (so most of the last five years...). Of course then he goes and burns the paddocks every year, which seems rather a waste to me, but that's a different problem. (If anyone knows how to convince an intractable, third-generation, "burn it all every year" farmer how to stop doing that, I'm all ears... 8-| )
I feel that putting the magnesium through an animal is probably the best way to add it to pasture for several reasons. First, you're supplementing the animal and keeping them healthier while the soils regenerate. In very bad conditions, this can be the difference between life and death.
Second, the magnesium is more likely to become bound up in a stable chemical form as it passes through the animal and exits as fertiliser.
Third, that fertiliser will be full of biological activity that will help both the soil structure as a whole, and the stabilisation of any other nutrients that are applied to the soil.