Can you post the result by element/nutrient? Who did the test?

One reason for such a recommendation would be that the soil is sodic, which means it's high in sodium. The paper linked below may help.

Here is a link that might be useful: Managing Sodic Soils

This post was edited by TXEB on Tue, Aug 27, 13 at 2:37

Soils in arid areas such as Nevada tend to accumulate large amounts of Sodium since there is little rainfall to wash them out. Gypsum helps bind that Sodium and move them out with some irrigation. The link TXEB posted is a good source of information.

Actually, gypsum works by providing free calcium which can bind to the soils exchange sites (mostly on clay), which frees the sodium associated with those sites thus mobilizing it. If there is enough free lime in the soil then the addition of sulfur to lower the pH and, in turn, increase the free calcium will achieve the same result. If there isn't sufficient free lime, then the additional calcium required to mobilize the sodium needs to be supplied by something like gypsum. The keys to reclaiming or improving sodic soils are free calcium, and clean water to provide mobility.

Hi,

My alkaline soil with a of pH 7.8, was not tested for salt, but I know that our soils are infamous for having a high salt content. As a result, we flush it about twice per year. We have a lot of natural gypsum, thus the slightly high rating for calcium.

Lynn

Arid soils are typically high in sodium, and the alkalinity is separately derived from the carbonate that is usually associated with calcium, but can also be associated with any other metal cation (eg., magnesium, or sodium). Was the soil tested for sodium level and calcium, along with the pH ?

You can have "high calcium", but high is relative to the soils ability to bind and hold positively charged metal ions (that's CEC). As I noted in my previous post if you don't have free lime in the soil then reducing sodium levels is usually accomplished by adding more calcium. If the soil is alkaline, which arid soils that are sodic typically are, then you don't want to add more carbonate which would further raise pH, hence the use of gypsum which adds the calcium as a soluble and pH neutral sulfate instead of lime (calcium carbonate). If you have enough free lime, then adding sulfur along with using very clean water (low in both sodium and carbonate and pH neutral to slightly acidic) can do the job.

The recommendation to add both sulfur and gypsum suggests your soil is high enough in sodium that it is a concern for plant growth and health, and that the available calcium is not sufficient to mobilize the sodium. It further suggests that you don't have any appreciable free lime in the soil (mine has chunks of it - enough that adding sulfur at any reasonable rate won't much touch the pH).

The other culprit that plays a role in the whole thing is water quality. If your water is high in sodium then it becomes difficult to mobilize and remove sodium with that water source. If your irrigation water is very hard and alkaline with high calcium and carbonate levels (as is mine), then using sulfur to lower pH and effect free lime conversion doesn't really work (in my case I add ~0.5 lbs of lime per 1000 sq feet for every inch rain equivalent of irrigation).

So what was tested other than pH, and who did the analysis? Did they report analytical levels, (eg., ppm or lbs per acre)?

Lynn,

Here's another question for you (still want to know what was tested, results, and who did the work) - do you know which water district you're on?

The pH for my water is about 7.8 and it comes from the Colorado river. Dr. Good earth completed a basic soil test. Our soils are infamous for being high in salt content. My organic matter is low too. The company made suggestions. I need to add sulfur, gypsum and compost and blood meal.

Lynn

So I take it, no numbers on the soil test?

I looked at the water quality summary from the Las Vegas Valley Water District, and if that's where you get your water it's similar to the water I get, but even harder. Without all the numbers I can only guess, but my suspicion is that your soil is actually what would be considered saline/sodic. With the hard alkaline water it would be very difficult to mobilize Ca, so an increase in acidity is needed along with Ca, hence you need both the gypsum AND the sulfur to get the job done.

One more article for you - explains it a bit more.

Here is a link that might be useful: Alkaline, Saline & Sodic Soils

TXEb,

Thank you for the information. The company suggested products as well as the application rates. Unfortunately I did not have the information with me yesterday. Yes, Las Vegas Valley Water Disrict. I contacted them about 3 weeks ago and have a water report; somewhere. I am accustomed to folks being less specific regarding the water source and responded CO River.

Again thank you for the info. And the link.

The LVV Water District puts all of their reports online. As I learned, the water comes from the CO River via Lake Meade.

I don't mean this to sound negative, but don't get discouraged if you can't make much progress on pH, and I suspect you won't be able to. Neither can I. The water used for irrigation is a big part of the limitation. You can still grow a bunch of stuff - just stay away from that which really needs acidic soils.

Probably the best thing you can do to improve your soil quality over the long term is to start piling on the organic materials. Of course I suspect being is a desert makes supply and options a challenge.

Good luck!

Perhaps this from Colorado State University might be of some help.

Here is a link that might be useful: About arid soils