Clay Soil Observations http://www.durgan.org/URL/?FOHEI 6 September 2009 Clay soil Observations. The garden bed is composed of good clay soil. To make the clay more useful for my requirement, it has been modified utilizing much compost over the last five years.Compost alone as a clay modifier still allows the soil to coagulate or lump. The addition of sand to the clay/compost appears to reduce the lumping problem. The thrust of my note is to suggest that compost alone is insufficient to adequately condition clay. Picture of the soils are presented to substantiate my views on the matter. It should be noted that the clay alone or with compost is still an excellent growing medium. The area is relatively small so modifying is practicable and feasible. Initially sand, screenings, peat moss each alone was tried as a mixing agent for making the clay more friable. These efforts were all failures. I am of the opinion that compost in large quantities is best for breaking up clay, then to make the mixture more friable sand should be added. It appears to be working well in my garden. My growing area is about 2000 square feet or 186 square meters. Note: I have also added wood chips, but consider these as compost, since they break down in a year and are no longer visible.
Hi, have you tried adding some source of calcium, eg gypsum or lime or a mixture, together with the organic matter? I am thinking of trying this myself as like you I feel organic matter is not enough on our heavy clay soils (= concrete for half of the year - no rain now for 3 months). As a child I remember one of my uncles using gypsum (on its own) to great effect where he lived. BTW, in relation to your other clay thread, I have added and dug in a small amount of sand in one part (left over from builders) perhaps only 3-4cm (~1.5"). To me, it appears to have had a benefit way beyond the quantity added (?did it have some lime or shell particles). Good luck! Boa sorte Brian
I have never used gypsum or even seriously contemplated applying it. Usually I attempt using what is readily available. For now I am satisfied with my soil structure, but time will indicate if this view is justified. Of course, compost will be added each year as a fertilizer, since this is readily available.
No, don't apply fertilizers or gypsum. I have the same soil, use manure and peat moss to amend it....compost is good to.
I live on a flood plain that has a high percentage of clay. Origanly I added pear moss but found it broke down and didn't contribute to the structure of the soil. For the past number of years I have been throwing sunflower canes and similar softer shoots on the garden over the winter month and letting the worms and bacteria in the soil do their job. Now I have a good base of humus and the soil is lighter enabling it to hold more water during the dryer summer months. Lime breaks down this humus to fast and just turns your soil into more clay if added to liberally.
Gypsum has its uses on certain clays. No doubt you would have heard or read about using gypsum to break up clay soils, it's even written on most packets. Gypsum can only improve clay soils that have sodicity. The sodium particles are displaced by gypsum from the clay. This is different to salinity where chloride is present. Only if it were that easy to just sprinkle some gypsum and problem solved, but farmers have long ago invested in ripping and organic green crops to till organic matter back into the soil. You can do a sodicity test, called the Emerson Dispersion Test to see if in fact your soil is sodic. http://www.durgan.org/URL/?DNAZT Read all about Gypsum. http://www.durgan.org/URL/?YZZLQ Sodic soil in the world. Scan down about half way on the page.There is little sodic soil in NA. Addition of gypsum is to no avail unless the soil is sodic. http://www.durgan.org/URL/?RHLIQ A field test for sodicity
To achieve the results that I have in my garden I did a little math as to quantities of material added to the clay. Since my thrust is for the home gardener I will use 10 square feet as the basic unit. Rototill the clay to about a depth of one foot, and insure it is small particles. Mix 1/2 to 1 cubic yard of good compost into the clay soil to about a foot depth. The clay should be reasonably dry to insure a good mix. Simply lay the compost over the clay and work in thoroughly using a rototiller. After this add about 25 liters (five gallon pail) of mason or play sand. This will make he compost/clay bed more friable, a desirable trait. A little sand goes a long way. Modify using your experience as necessary. My view is it is difficult to over do the addition of compost. I add some each year and the beds seldom rise in height, meaning the compost is breaking down or compacting. My beds were modified over about five years, but I see no reason why it could not be accomplished in one go.
Sphagnum Peat Moss as sold today is essentially useless in a garden. The moss is now being manufactured so that the particles are dust. Initially when desiring to break up clay I added about 16 large bags (3.4 cubic feet each) to a small area and the result was zero, zilch. I couldn't even find a trace after a year or less. For my seedlings I utilize coconut blocks reconstituted using water over about two days in the mix for water retention. This coconut material has some structure. It has only become common over the last two years in my area.
Here is some information about gypsum use in agriculture. Although this information is presented by the gypsum industry, there are references to the original research.
I suggest this is sales hype. The basic facts about the use of Gypsum is being ignored. Gypsum has its uses in Agriculture, but with caveats.
