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Ri

I've been googling for advice on Bentonite as a soil amendment to improve water retention, and hit a previous message on this board. Can anyone tell me how much Bentonite powder to add to how much soil?
Thanks?

12/19/2006 9:33:16 AM

Anamosa, IA BPIowegian@aol.com

Around here we use bentonite to seal up leaky ponds. 1 pound per square foot, mixed in the top 12" of soil will seal up a pond tight. It is a volcanic clay that swells about 20X when saturated with water. It also shrinks and cracks when dried out. I would be real careful about putting very much in your soil. If you hit a dry period and didn't water enough, it could shrink, crack the soil and break roots. If you got too much rain, it could turn your patch into a swamp. I prefer organic matter to hold moisture.

12/21/2006 1:42:40 PM

Mill Bay, British Columbia

I've used it to add clay to my non-clay, high OM soil. See post at;

http://www.bigpumpkins.com/MsgBoard/ViewThread.asp?b=20&p=101143

1/1/2007 4:00:35 PM

Kalamazoo, MI (Jpwrhse@charter.net)

So I guess I'm still a little unsure here. My CEC is low and needs to be improved. I posted my soil test results a little while ago they're also listed below. I added lime at the rate suggested by the lab and I intend to add manure in the spring but I don't want to add too much manure either, I've heard that can be as bad as not adding any at all. But could my soil benefit from mixing in some unscented clumping cat litter when I till in the spring? If so how much? Or should I just use Manure and again how much should I put on? i.e. should I just sprinkle on a thin coating og the cat litter, or spread the manure an inch thick and till in? Still learning about this whole soil ammending thing and want to do it right.

PH - 6.1
P - 100 ppm
K - 112 ppm
Mg - 89 ppm
Ca - 520 ppm
CEC(OM) - 4.8 meq/100 g

% of Exchangeable Bases
K - 7.9
Mg - 20.4
Ca - 71.6

1/1/2007 8:36:01 PM

Mill Bay, British Columbia

I just used the bentonite to give my soil some added clay which was recommended based upon my soil test and my soil texture and structure. From my understanding of bentonite clay, it will assist in improving your CEC, in my case I don't think it was a fix all, but was part of the program along with manures and composts and other ammendments. From your soil test, one cannot tell what kind of soil you are dealing with and whether or not you need the additional clay from adding kitty litter or not. My OM has been very high in the past few years so I added several hundred pounds to my roughly 1000 sq. ft but also added "Turface" calcined clay cause I was in a patch buying frenzy a few years ago and it seemed like a logical addition.

I guess what I am leading to is, I only added the clay products cause in the mountains where I live, there is more just plain soil and rocks and some glaciel till but just not much clay.

So, when you dig down do you find clay?

1/1/2007 9:01:22 PM

Mill Bay, British Columbia

Sorry, meant to post this link so that you can test your soil for texture and decide whether or not your patch (or planting area) would benefit from the bentonite.

http://www.taunton.com/finegardening/pages/g00164.asp

1/1/2007 9:11:10 PM

Ontario, Canada.

Jp. I would suspect that your OM is low and most likely very near background levels of approx 4%. Is your soil also sandy?

You can add lots of well rotted manure right now. 3 to 6" will get you going. Get it in ASAP. The ground is still open and snow free with little frost. Now is a good time.

To raise CEC, yes you can use Cat litter(Calcined Clay) but I would prefer a product called Profile. It is used on baseball diamonds as a water absorbant and golf course greens to prevent soil compaction and moisture retention. Also CEC can be raised using vermiculite and perlite too.

1/1/2007 9:37:49 PM

Mill Bay, British Columbia

Thanks Russ for chiming in, the product (profile) you mentioned is the same turface stuff that I used from them for both my patch and our league's fastball and softball fields.

http://www.taunton.com/finegardening/pages/g00164.asp

http://www.profileproducts.com/sports_fields/index.cfm?lp=gb&bhcp=1

1/1/2007 11:37:38 PM

Kalamazoo, MI (Jpwrhse@charter.net)

If you dig down deep somewhere around 18 to 24 inches you will hit sand. The top soil is nice dark dirt that needs to be atlieast some what dry to be able to till, but does seem alittle sandy once dried. I didn't expect my CEC to be as low as it was though. I'm still trying to find a local farm to get large amounts of manure from, but was also concerned about adding too much. If 3 to 6 inches is ok, I guess I won't be that concerned about adding too much anymore. Should I till in now or wait until spring? I had also considered mixing in vermiculite and had considered asking the question on here but was going to check into price to see if it was practical first.

1/2/2007 8:50:51 AM

Garden State Pumpkins

With that being said...If your soil is sitting on that much sand then water retention is obviously a problem. I take it you could lay a hose down running without getting a puddle? Confusion comes from the CEC number and equating that to OM. Come on down to NJ..I'll give ya all the clay ya need for some of that sand..LOL..I would think any clay you could add would help with your cec numbers. I would also venture to say that that type of soil leaches nutrients as fast as any I have heard of. The local growers will Know how to handle that the best I'm sure.

1/2/2007 10:42:09 PM