134 BOARD OF AGRICULTURE. 



plentiful amount in the soil, are phosphoric acid and potash. So 

 that of the thirteen elements of which a plant is made up, the 

 farmer lias to do with the supplying of only three. Hence the 

 problem of changing an infeitile soil to a fertile one is very much 

 simplified from what we formerly supposed it was. when we acted 

 under the belief that we had to suppl\- every one of these elementar\' 

 materials in order to render a soil fertile. We now have to look out 

 for nitrogen, phosphoric acid and potash. A soil may be lacking in 

 one of these ; a soil maj' be lacking in all of them. In passing, I 

 will say that no plant will grow unless it has within its reach ever\' 

 one of these thirteen elementary materials. This is not theory at 

 all — it is a scientific fact, which has been proved from practical 

 tests. By actual tests it has been found that our common agricult- 

 ural soils are frequently defective either in their supply of nitrogen, 

 of phosphoric acid, or in their supply of potash. Sometimes it is 

 one of them only ; but if only one of them, the soil utterly refuses 

 to produce crops, just the same as if all three were lacking. So it 

 is one, two or three of these substances which must be looked after 

 by the farmer and supplied, in order to change an infertile soil into 

 a fertile one. 



You will probably have in 3"our minds here that what we term an 

 infertile soil still is producing plant growth to a limited extent, 

 although not in profitable quantities. This comes from the fact that 

 all of our soils contain these materials, nitrogen, phosphoric acid 

 and potash ; but the trouble is that they are principally in such a 

 form that the plants cannot get hold of them and appropriate them 

 to their use. If they are unable to reach out and take hold of them 

 and appropriate them to their use, the plants will then refuse to 

 grow. But almost all of our soils do contain a small portion, at 

 least, of these elements, which is available, and thus crops still 

 grow, sufficient to cover the barrenness, it may be. but not sufficient 

 to make it profitable. These materials as found in the soil are in an 

 insoluble form. The materials which make up a plant must be in a 

 soluble condition or the plant cannot get hold of them. A plant 

 has to go into the soil and take these difierent materials and transfer 

 them into the different parts of the plant and assimilate them, so to 

 speak, into its structure. You see at once that that can only be 

 done when the}' are in a liquid form ; these materials must be 

 soluble in water, or else they are locked up beyond the reach of the 

 organs of the plant. This plant nutrition is obtained through and b}-* 



