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W Texas | Will sulfates in irrigation water break down any calcium from a calcareous soil?
I know the literature says Calcium Carbonate has low solubility at high pH, but what if your calcium levels are 20,000lbs+/acre? I've seen some literature that basically says calcareous soils have an endless buffer against sodicity of irrigation water, others say the calcium is unavailable.
Reason I am asking is some of my wells have an SAR up to around 11. Very high sulfates, often 300+ppm.
Wondering if I need to add gypsum or just leave it alone. I do used MAP and 28-0-0-5 for fertilizers, which probably only helps a bit.
Salinity tests will average about 4-6 EC and around 15 SAR. pH very high, 8+.
Soils are productive as long as I stick with adapted crops (barley, triticale, cotton, alfalfa). Water infiltration seems fine as long as the soil is covered/shaded. Hot sun and high wind will cause any soil to crust here.
Only time I have seen severe dispersion is when it used to be flood irrigated, which I attribute to excess leaching of salts, leading to a non-saline, sodic soil. Whereas under furrow or pivot it is typically a saline, sodic soil.
All No-Till, FWIW. CECs around 40. | |
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High Sulfates in Sodic irrigation water, irrigating calcareous high pH soil.
