Improving Clay Soil

[Pond Life]

I have started a patch of mixed veggies + several big buckets.

My soil seems quite fertile, but has a high clay content.

Some of the plants seem to like this (chillies, pumpkins) but others are having trouble penetrating the soil with their roots.

In particular some Durian seeds in pots started well but then stopped, on breaking the pot open I found they had developed a fat root about 10cm long but this was locked into a brick like clod of clay.

Also, if I plant multiple seeds in a pot its very difficult to separate seedlings for planting out without damageing the roots.

For some pots I've tried a mixture of 1/3 soil, 1/3 sand & 1/3 cow shit, this seems to help but the texture is more like grains of sand locked in clay than light crumbly stuff I'm aiming for.

Could anyone offer me a recipe for improving my soil either in bucket sized measurements or for a 4m x 4m patch.

Unfortunatly compost is in short supply at the moment (I hope to remedy this during the rainy season) & I'm a long way from garden centers for large quantities of comercial stuff.

Thanks

[btate]

Pond Life

I can't help much with the soil issue other than maybe add more sand, wood shavings etc.

Why would you want to start Durian????? Seedlings are readily available for peanuts in any area that supports durian growth. This would be an extra long project to "fruition"

[Pond Life]

The Durian is the girlfriends project, so i dont ask !.

The wood shavings idea sounds interesting, but where i am most woodwork is Teak, will Teak shaving work ?, Teak has a reputation for being rot proof.

[chownah]

I've been using manure and rice hulls in my garden to improve the soil and it has worked well for me. The rice hulls alone will tie up all the nitrogen at first so I add the manure to make up for this plus the manure adds phosphorus and potassium and lots of other stuff too. As time goes by the rice hulls will decompose and release the nitrogen they have tied up so adding rice hulls and manure will create a time release sort of situation for the nutrients as time goes by. After four years my garden soil has really changed (for the better) and now even my very sceptical wife is even impressed although she would never admit it.

When working with a clayey soil in pots it is important to first be sure the soil in the pots is really really saturated....this way the clay will be softer and easier to work with...but of course it will still be more difficult than with friable potting soil.

Mixing rice hulls and manure and composting it should work really well and if you water and turn the pile at the right times you should be able to make compost in 14 days with it. For information on making compost in 14 days google for "making 14 day compost"...or just "making compost" and you will find lots of information on what to do. The key to fast composting is that all materials used must be in small pieces...the manure is well masticated by the cows and the rice hulls are very small too so the combo works well. Anything else that has been shredded to small pieces can be added as well. Whole leaves on the other hand will mean that it will take about 6 weeks to get compost with proper watering and turning....more or less depending on the coarseness of the leaves.

Chownah

Edited April 12, 2007 by chownah

[ozzydom]

I have started a patch of mixed veggies + several big buckets.

My soil seems quite fertile, but has a high clay content.

Some of the plants seem to like this (chillies, pumpkins) but others are having trouble penetrating the soil with their roots.

In particular some Durian seeds in pots started well but then stopped, on breaking the pot open I found they had developed a fat root about 10cm long but this was locked into a brick like clod of clay.

Also, if I plant multiple seeds in a pot its very difficult to separate seedlings for planting out without damageing the roots.

For some pots I've tried a mixture of 1/3 soil, 1/3 sand & 1/3 cow shit, this seems to help but the texture is more like grains of sand locked in clay than light crumbly stuff I'm aiming for.

Could anyone offer me a recipe for improving my soil either in bucket sized measurements or for a 4m x 4m patch.

Unfortunatly compost is in short supply at the moment (I hope to remedy this during the rainy season) & I'm a long way from garden centers for large quantities of comercial stuff.

Thanks

Pond Life, the age old method of dealing with heavy clay soils is to add either gypsum or dolomite, clay soils are extremely rich in trace elements but plants cannot access them, gypsum and dolomite create a chemical reaction which separates the clay particles breaking them up and making the trace elements available.,also they dont have a huge impact on PH as does lime.

Adding humus etc means you have to continually dig and break up the clay and hope that whatever you add helps prevent the particles re-binding.

[Loom]

Ozzydome, I was thinking about spreading out lime as recommended in the makua forum and ran across bags of dolomite in a garden center. I thought dolomite was mostly calcium carbonate (lime) with some magnesium. Would it make a big difference to plant grow if the ph level is changed by adding straight lime?

[ozzydom]

Ozzydome, I was thinking about spreading out lime as recommended in the makua forum and ran across bags of dolomite in a garden center. I thought dolomite was mostly calcium carbonate (lime) with some magnesium. Would it make a big difference to plant grow if the ph level is changed by adding straight lime?

Loom, Your right,Dolomite is a calcium manganese carbonate whereas lime is a calcium carbonate, the lime your referring to is probably processed lime as used in the building industry among other things,it is about twice as strong as dolomite and can cause burning if it comes in contact with plants,it is primarily used in agriculture to raise the PH of the soil,plants need a soil PH of about 5.5-6.5 in order to take up available nutrients.

Dolomite because of its K content is used as both a soil conditioner and fertilizer.it is much gentler and does not have to be dug in,It is semi soluble and will pass into the soil by rain or irrigation.

So if its only PH adjustment you want ,lime is ok just use care as a to high PH is as bad as a to low one

[Jamie]

Organic matter is alway one of the best ways to loosen up clay soils. I use good sieved black dirt (rotten manure). I also like to add a fair amount of sieved sand. If you can't get hold of good organic matter for the time being, sand is probably your best choice. I don't use a specific recipe as I have a large garden and bring in sand etc by the pickup load. I know the combination is about right when you can take the soil, roll it in to a ball and then press it. If it crumbles, it's right. If it just flattens and stays together, the clay content is still too high.

[Pond Life]

Sorry its taken so long to reply,

Thanks for all the suggestions.

Sounds like a I need a combination of things especialy getting my compost production into high gear.

The Gypsum/Dolomite idea sounds interesting, where would I buy it, garden centers or builders merchant ?

How much would I need for a 4m x 4m area of quite clay soil, are we talking handfuls or pickups full ?

My PH is at 6.5 so presumably I dont want to raise it, how much possibility of this is there with Gyp/Dol ?

Which is preferable Gyp or Dol ?

[JungleBiker]

The Durian is the girlfriends project, so i dont ask !.

Hi Pond Life,

FYI, you are unlikely to get any good fruit from trees grown from seedlings unless you use them as rootstocks and graft them with a good variety like Monthong, so I hope your girlfriend has some grafting skills.

JB.

[SAP]

Sorry its taken so long to reply,

Thanks for all the suggestions.

Sounds like a I need a combination of things especialy getting my compost production into high gear.

The Gypsum/Dolomite idea sounds interesting, where would I buy it, garden centers or builders merchant ?

How much would I need for a 4m x 4m area of quite clay soil, are we talking handfuls or pickups full ?

My PH is at 6.5 so presumably I dont want to raise it, how much possibility of this is there with Gyp/Dol ?

Which is preferable Gyp or Dol ?

OzzyDom is quite right about what he is sayig regarding Gypsum....But dolomite will actually increase your pH too. Generally in Thailand if you want raise your pH use dolomite, as you get the Mg free of charge. There is no real reason to use lime to raise pH in Thailand. (this advice actually came from my friend who works for Fert Co back home.

Pump on the organic matter

The other thing with hard clay soil, is never let it dry out, you should try to irrigate it every 1-2 days if you are growing vege. Drip line irrigation is the best for this.

Do you have salinity problem with your irrigation water?? If so may have to take some other measures.

[Pond Life]

OK, sounds like Gypsum & compost is the way to go.

Where do I buy Gypsum & how much do I need ? Also whats the Thai name ?

I doubt if I have a salinity problem, Im up in the mountains, water comes from river, thru irrigation klong, into my pond then onto the garden.

When theres enough water everything is nice & green no brown patches.

Thanks for all advice

[Khonwan]

...Where do I buy Gypsum & how much do I need ? Also whats the Thai name ?...

"Green Cal" agricultural gypsum: http://www.dktgypsum.com/flashmain.html

Retails for around 120 baht per 25kg bag. I've used it to clarify my pond water.

If you can't find it locally:

"YOU CAN CONTACT DIRECTLY TO OUR OFFICE AT BANGKOK

CONTACT PERSON: MR.JIRA PHANJIRAPHAK

TELEPHONE: 02-272-4051-3

FAX: 02-270-0879

MOBLIE PHONE: 08-1822-0821

E-MAIL:[email protected]"

[Pond Life]

Thanks for the site link,

That answered all my questions except :

Whats the Thai name for Gypsum, anyone ?

[johnh101]

I saw a Thai documentary on this subject a few years back. A farang was having the exact same problem. He went to the local rock quarry and bought sacks of rock dust. He mixed it in to the clay soil with a rotovator and hey presto soon enough that area had double the crops of the untreated areas. I am not sure what the rock was but would suspect it was Limestone or possibly granite. This would also tie in with the other suggestions for applying lime to the soil.

[Robjg]

I have started a patch of mixed veggies + several big buckets.

My soil seems quite fertile, but has a high clay content.

Some of the plants seem to like this (chillies, pumpkins) but others are having trouble penetrating the soil with their roots.

In particular some Durian seeds in pots started well but then stopped, on breaking the pot open I found they had developed a fat root about 10cm long but this was locked into a brick like clod of clay.

Also, if I plant multiple seeds in a pot its very difficult to separate seedlings for planting out without damageing the roots.

For some pots I've tried a mixture of 1/3 soil, 1/3 sand & 1/3 cow shit, this seems to help but the texture is more like grains of sand locked in clay than light crumbly stuff I'm aiming for.

Could anyone offer me a recipe for improving my soil either in bucket sized measurements or for a 4m x 4m patch.

Unfortunatly compost is in short supply at the moment (I hope to remedy this during the rainy season) & I'm a long way from garden centers for large quantities of comercial stuff.

Thanks

[Robjg]

Vegetable Crops. A large number of vegetable crops were studied on phosphatic clay soil. Cultural practices and fertility needs for optimum production were identified. Some of the most promising vegetable crops, from a production standpoint, were cole crops such as broccoli, cabbage, and cauliflower which can be grown in the winter. Cucumbers and yellow squash were also productive and lend themselves to multiple cropping with cole crops. Sweet corn produced marketable yields in excess of state averages but problems with stand establishment and plant vigor were observed especially in the early spring. Okra was unusually productive on phosphatic clay soil as was zucchini squash and southern peas. One notable failure was sweet peppers. Numerous trials with sweet peppers resulted in low yields and poor quality of both plants and fruit. No cause or explanation has been found.

Grain Crops. Rice and soybeans performed well on phosphatic clay. Experimental rice yields were equivalent to yields expected in rice growing regions of Louisiana and Arkansas. Soybean yields were as high as 30 to 40 bushels per acre but were inconsistent. Yields of field corn, grain sorghum, wheat, and triticale were marginal. Best corn yields were observed when planted in early spring. Unfortunately, early spring planting requires the grain be harvested in June or July when normally frequent rains limit field access and increase the risk of total crop loss. The same is true of soybeans and grain sorghum.

You could try Layering in 25mm each of sand,pig manure,woodchip/dust and cross plough to a depth of about 250mm and seed through black plastic sheeting between rows obviously depending on the type of crop you are looking to grow and choose the right crop for the soil type. You can buy various addatives for all soil types. Most of the farmland in the regions have been depleted of its eco system and is low in nutricians. I would suggest introducing this method using a fallow feild rotation system to allow regeneration.

However for you personally with your 4 x 4 mtr patch you would be better off getting in a truck load of top soil from your local pig farmer much better than "cow shit" and grow a border of banana with suspended small guage netting for much needed shade.

[Loom]

Vegetable Crops. A large number of vegetable crops were studied on phosphatic clay soil. Cultural practices and fertility needs for optimum production were identified. Some of the most promising vegetable crops, from a production standpoint, were cole crops such as broccoli, cabbage, and cauliflower which can be grown in the winter. Cucumbers and yellow squash were also productive and lend themselves to multiple cropping with cole crops. Sweet corn produced marketable yields in excess of state averages but problems with stand establishment and plant vigor were observed especially in the early spring. Okra was unusually productive on phosphatic clay soil as was zucchini squash and southern peas. One notable failure was sweet peppers. Numerous trials with sweet peppers resulted in low yields and poor quality of both plants and fruit. No cause or explanation has been found.

Grain Crops. Rice and soybeans performed well on phosphatic clay. Experimental rice yields were equivalent to yields expected in rice growing regions of Louisiana and Arkansas. Soybean yields were as high as 30 to 40 bushels per acre but were inconsistent. Yields of field corn, grain sorghum, wheat, and triticale were marginal. Best corn yields were observed when planted in early spring. Unfortunately, early spring planting requires the grain be harvested in June or July when normally frequent rains limit field access and increase the risk of total crop loss. The same is true of soybeans and grain sorghum.

Robjg, Is there an online source for the study mentioned above? In a few of the previous posts soil ph was mentioned but this is the first I've seen that "clay soil" may tend to be phosphatic. This may have been the case for the study mentioned above, wherever it was done. Unless it's the case for all clay soils I suppose the only way to tell for sure is to test.

Wife is interested in planting trees in similar type of soil so I wonder if testing for phosphate, ph, etc, is necessary and easy. I'm afraid that may depend on the type of tree.

To loosen up clay type soil on wife's land, neighbors have suggested putting in soybeans then ploughing them back into the topsoil after they've matured. Rgds,

[Jamie]

Clays do not have to contain phosphates, though phosphates do have an affinity (sorbtion)for clay.

[mobile69]

"Green Cal" agricultural gypsum: http://www.dktgypsum.com/flashmain.html

Retails for around 120 baht per 25kg bag. I've used it to clarify my pond water.

Can you add gypsum to a fish pond to clear the water, or would this kill all the fish?

[Khonwan]

"Green Cal" agricultural gypsum: http://www.dktgypsum.com/flashmain.html

Retails for around 120 baht per 25kg bag. I've used it to clarify my pond water.

Can you add gypsum to a fish pond to clear the water, or would this kill all the fish?

I rear fish in my pond (small scale - not commercially). Check out the link I provided! To save you time clicking through the links, go here: http://www.dktgypsum.com/cgi-bin/mainframe...showp=news.html

Don't use construction-supply gypsum for ponds - use agricultural gypsum. The construction stuff often contains impurities that can kill the fish. Green Cal is safe, and beneficial.

[ozzydom]

Vegetable Crops. A large number of vegetable crops were studied on phosphatic clay soil. Cultural practices and fertility needs for optimum production were identified. Some of the most promising vegetable crops, from a production standpoint, were cole crops such as broccoli, cabbage, and cauliflower which can be grown in the winter. Cucumbers and yellow squash were also productive and lend themselves to multiple cropping with cole crops. Sweet corn produced marketable yields in excess of state averages but problems with stand establishment and plant vigor were observed especially in the early spring. Okra was unusually productive on phosphatic clay soil as was zucchini squash and southern peas. One notable failure was sweet peppers. Numerous trials with sweet peppers resulted in low yields and poor quality of both plants and fruit. No cause or explanation has been found.

Grain Crops. Rice and soybeans performed well on phosphatic clay. Experimental rice yields were equivalent to yields expected in rice growing regions of Louisiana and Arkansas. Soybean yields were as high as 30 to 40 bushels per acre but were inconsistent. Yields of field corn, grain sorghum, wheat, and triticale were marginal. Best corn yields were observed when planted in early spring. Unfortunately, early spring planting requires the grain be harvested in June or July when normally frequent rains limit field access and increase the risk of total crop loss. The same is true of soybeans and grain sorghum.

You could try Layering in 25mm each of sand,pig manure,woodchip/dust and cross plough to a depth of about 250mm and seed through black plastic sheeting between rows obviously depending on the type of crop you are looking to grow and choose the right crop for the soil type. You can buy various addatives for all soil types. Most of the farmland in the regions have been depleted of its eco system and is low in nutricians. I would suggest introducing this method using a fallow feild rotation system to allow regeneration.

However for you personally with your 4 x 4 mtr patch you would be better off getting in a truck load of top soil from your local pig farmer much better than "cow shit" and grow a border of banana with suspended small guage netting for much needed shade.

I must have attended the wrong Ag School because Phosphatic clay is not a naturally occurring soil but a by-product of phosphate mining and although Thailand has phosphates in situ most of its requirements are imported. The study quoted from was one which was attempting to utilize the by-product.

[chownah]

Ozzydom,

Do you know where Thailand has deposits of rock phosphate...I'd like to find out.

Chownah

[ozzydom]

Ozzydom,

Do you know where Thailand has deposits of rock phosphate...I'd like to find out.

Chownah

Not sure, but there was an article in the Post not long ago that said several overseas companies had applied for licenses to mine and process Phosphate in LoS,

[chownah]

I know about the potash in Isaan but I haven't heard about phosphate....any info about where would be appreciated.

Chownah

[ozzydom]

I know about the potash in Isaan but I haven't heard about phosphate....any info about where would be appreciated.

Chownah

According to my fertilizer supplier,there are /were small mines in the Kalasin area that supplied guano type phosphate but he now gets it from China and South Korea as the local supply was spasmodic.

I use about 2 ton of triple superphosphate a year to green my pond water, I have read that there are deposits of marine type phosphate in the Sakhon Nakhon area as yet undeveloped