FERTILIZERS ON SANDY SOIL — SMITH. 127 



element. A sample of wheat straw was brought to our attention 

 from New Annan, Colchester County, and the farmer complained 

 that just at harvest time the straw, especially wheat, broke off just 

 below the head, and that he lost a considerable amount of grain 

 from this cause. When the straw was analysed it was found to 

 contain a large percentage of silicon in the upper internode just 

 below the head where it broke. Again the wood of our various 

 trees is surely strong, but it possesses scarcely any ash, and of 

 this ash only a small part is Silicon. The bark, however, which 

 is so brittle and weak often possesses a large percentage. 



Of the volatile parts of the plant only a word is required. 

 Plants obtain their nitrogen from the compounds in the soil. It 

 is possible that the clover maj^ obtain a little from sources that 

 are not available to other plants, but it is not necessary to dis- 

 cuss the point here. The most of our cultivated plants depend 

 on nitrates and ammonia, and can possibly use one or two of the 

 othei- forms of combined nitrogen in the soil. 



Of all the constituents of the plants mentioned above, only 

 three are usually in such small quantities or in such insoluble 

 forms in the soil that the plant cannot obtain them. In order to 

 be unavailable to the plant, they must be locked up in quite 

 insoluble forms, for the pkxnt is able in a measure to make its 

 own solution. It can undoubtedly dissolve out bases from the 

 hydrated silicates, and, proljably, also put double salts containing 

 potassium or ammonia in solution. Double phosphates contain- 

 ing alkalies are probably often soluble to the roots. 



Our soil is a sandy soil. These are held in bad favor by 

 popular opinion. They are called leachy. They are said to 

 possess all that a soil should not have, and none of those proper- 

 ties which a soil should have. Fortunately their reputation is 

 worse than they are. The effect of the application of fertilizers 

 to them would be in the highest degree to increase the absorp- 

 tive power for valuable constituents except nitrates. These it 

 might be expected would be washed out of sandy soils more 

 rapidh^ than from other soils. Every application of fertilizers 

 would increase its alisorptive power for other constituents. As 

 to how far these plant foods are likely to be washed out again. 



