Bone Meal, Stone Meal Etc

[lingling]

I asked this once before I think, but doesn't hurt to ask again. Does anyone know where I can buy bone meal or stone meal for soil improvement?

[chownah]

As I replied before, I would like to find a source of rock phosphate which is a ground rock product.

Chownah

[teletiger]

A little something....

The effectiveness, as a phosphate fertilizer, of granular reactive rock phosphate (carbonate substituted apatite from North Carolina, U.S.A.), granular triple superphosphate and partly powdered Duchess non-reactive rock phosphate (low carbonate apatite from north-eastern Australia) was compared in three field experiments on different soil types in different climatic regions of south-western Australia. Calciphos (finely ground calcined crandallite rock phosphate from Christmas Island) was included in one experiment. The rock phosphates were incorporated into the soil and their effectiveness was compared with both topdressed and incorporated superphosphate. Different species were grown at each site (barley, triticale and subterranean clover). As determined on the basis of relative amounts of fertilizer required for constant yield, the effectiveness of all the rock phosphates relative to incorporated superphosphate was very low at each site throughout the growth of each species. Fertilizer effectiveness of rock phosphates was about one-fifth that of superphosphate for barley, and one-tenth for triticale and clover. The maximum yield obtained from rock phosphate was generally 88-100% that obtained from superphosphate. Incorporation did not greatly affect the effectiveness of superphosphate.

Regards

[chownah]

Teletiger,

Thanks for that. I was not considering using rock phosphate for field crops like barley, triticale, or clover....by the way what the heck is "subterranean" clover? I would like to try some in my vegetable and fruit plots so I could apply much higher rates.

I have never used a rock phosphate product but I do know that there are alot of different types of rock phosphate and its effectiveness varies considerably depending on mineral type. I don't know enough about it to know if the types used in the experiments you referenced were good ones or not.

I do know that the rate at which soluble minerals are released from rock depends on mild acids in the soil to dissolve the mineral and make it available to plants. There are typically two sources for this acidity...mineral and organic.

In tropical soils the mineral character of the soils tends to make them acid and in many types of tropical soil if lime is applied it will effectively stop the decomposition of minerals and cut off a normally effective supply of several soluble nutrients. It is my belief (I don't know this for sure) that rock phosphate will be more effective if used in an acid soil and I'm not sure but I have suspicions that it might be that the soil in south western Australia is not very acid...being in the south it is probably not a tropical soil....but I know very little about the soils and climate of Australia so I could be wrong on this.

The process of organic matter breaking down in the soil creates organic acids. These acids help to dissolve minerals from crushed rock and make it soluble for plant use. It is my suspicion (I don't know this for sure) that rock phosphate will be alot more effective (be released quicker) in a soil with an abundance of organic material....like my vegetable and fruit plots.

And lastly....I don't know the details of the study but it is no surprise to me that superphosphate out performs rock phosphate in the way described because superphosphate is a chemical which dissolves almost immediately causing a spike in availability but alot of it will be leached into streams causing unnatural amounts of plant growth potentially (this is why phosphates are now banned from use in laundry powders in most places) and the application of superphosphate (from what I have read) will be gone in one or two seasons while the rock phosphate will continue to add nutrient to the soil for many years....how many depends on the type of rock, the soil it is placed into, the rainfall, and how fine the rock is ground.

I'm wanting to find more about rock phosphate and for me the best way is to get some and try it with my own approach to organic farming.

Chownah