846 ANNUAL REPORT OF THE Off. Doc. 



yet if there is a reasonable time elapsed after the application 

 of (he lime and the lime had been thoroughly incorporated with 

 (he soil before putting on the phosphate it would seem from 

 (heory and also from the results of practice that the lime would 

 aid in the forming of more desirable compounds with the soluble 

 phosphoric acid than would be formed by a union of phosphoric 

 acid with either iron or alumina. Again, on land that has been 

 limed, the precipitation or reversion of the soluble phosphates would 

 take place promptly and thus prevent harm that might come from 

 the acid condition of the soluble phosphates when they come in 

 close contact with young tender roots of plants and germinating 

 seeds. 



HOW SHALL PHOSPHATES BE APPLIED, BROADCAST OR IN THE HILL 



OR DRILL? 



The question is frequently asked as to how phosphates and, in 

 fact, fertilizers in general, should be applied. From what has al- 

 ready been said on the point of the desirability of thorough dis- 

 semination of phosphates of all sorts and of getting the soluble 

 phosphates incorporated with the soil so that reversion shall 

 promptly take place, and not subject the young and tender rootlets 

 to injury from the acid and soluble phosphates, it would seem that 

 there should be but little doubt but that the best way to apply 

 phosphates would be to broadcast them and to have the broadcasting 

 done so as to get as thorough a distribution as possible. 



Again, in the case of the soluble, or acid phosphates, the principal 

 value ultimately gained by the treatment with acid is the obtain- 

 ing of the phosphates in a very finely divided state and getting it 

 widely disseminated. The full value of these points is only obtained 

 by broadcasting the fertilizer. 



There is still another and very important point to consider in this 

 connection, and that is the means bj' which plants feed. Plants 

 obtain their food through the roots and the most active roots are 

 the young and fibrous ones. A study of the root systems of all 

 our common plants will be a great surprise to anyone who makes 

 tho shidy or examination for the first time. The area and depth 

 covered by the roots of all our plants will astonish most farmers 

 who have never considered the matter. When corn is but six or 

 eight inches high the roots of the plant will often be found to 

 be extended out tw^o or three feet in all directions, or to be running 

 from row to row and going much deeper than is ordinarily plowed. 

 The roots of a tobacco plant will almost always cover two or three 

 time as great a surface as the leaves of the plant can shade. Even 

 the roots of potato plants before maturity will extend from row 

 to row under the common system of planting. 



