Soil fundamentals library

[SD51555]

Given my failure to score some ag gypsum.....do you imagine calcitic lime to be of benefit for me? Much lower in magnesium than dolomitic lime, plenty of calcium, and I've got "room" to afford a bit of a pH boost. I believe this would be much easier to accomplish than gypsum procurement.
My CA:MG ratio really sucks.

Speaking of cation exchange, fwiw - by far the best performing portion of this ground (in terms of plant growth) was the portion headed "Jumbo S N", which also had the lowest cation exchange factor.

I think you could with your Jumbo N spot. You've got a 5.7 pH with a 6.5 buffer pH. Looks like you could put on 1.5 tons/ac of calcitic lime. A good calcitic lime is gonna be 30-35% or so calcium. I would look for a lime with a little (under 5%) magnesium in it. 3000 pounds would get you at least 900 lbs of calcium, or 450 ppm Ca rise. That would leave you right in the strike zone of good Ca to Mg balance. Your new Ca to Mg would be 1210 Ca to 127 Mg (assuming no Mg in the lime). If you can find a lime that is 2-4% magnesium and 28-32% calcium, you could go a little longer too. But I think 3000 pounds would put you in the low 6's for pH, and that's a pretty good spot to get good micros uptake and no pH drag.





If I could pick a pH, I like to aim for 6.3-6.5. That seems to be where it can all get in.

 

[SD51555]

Speaking of cation exchange, fwiw - by far the best performing portion of this ground (in terms of plant growth) was the portion headed "Jumbo S N", which also had the lowest cation exchange factor.

Randy Dowdy, the guy that won the national corn yield contest year after year grew his 600 bushel corn in soil that had a CEC of like 4 or 5. It was very sandy if I remember it right. Now keep in mind, this guy is spoon feeding foliar nutrients all season long through a pivot, but so could anyone else. I think with an extremely sandy soil and the ability to put on good water, he never wished for moisture, and he had more oxygen in his soil that anyone else.

I think pore space/oxygen is the yield limiting factor for all crops in heavy soil. In sandy non-irrigated soil, there is tons of oxygen and the yield limiting factor is moisture. This is also why I bang the drum so loudly for the sandy guys to focus on growing a solid duff layer to hold the temp down and keep it moist. I think those plots would deliver legendary yields if it could be kept from the sun. The moisture efficiency of a plot with a heavy duff layer is almost 100%. A little water lasts a long time that way.

 

[SD51555]

I went out and checked my sweet clover plot tonight. We’re finally starting to green up up here. I’ve got the duff layer, and we’re not getting the moisture to catch up after 5 years of drought.

Here’s my duff going into year 5 of our drought. I will say, after no snow this winter, I did get an inch three weeks ago, and another 7/10ths this week. That's enough to get me off to a good start, and probably carry me to far enough to get an early summer canopy, but I'll need another inch or two after August 15th to get a fall crop.

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