52 ILLINOIS STATE DAIRYMEN'S ASSOCIATION 



tion of the acid phosphate to $4.13. By one system of com- 

 puting the increase, the acid phosphate gave the larger increase 

 per acre, and where the other method was used the raw phos- 

 phate gave a larger increase. In either case the raw phosphate 

 gave a larger increase for the money invested. As I figure it, 

 from these two methods, every dollar gave the following re- 

 sults. By the one method the computation was $6.35 returned 

 for raw phosphate, while the acid phosphate gave $5.10 for 

 every dollar invested. By the other method of computing every 

 dollar gave a return of $7.23 for raw phosphate, and of $3.90 

 for acid phosphate. I don't care which form of phosphate you 

 use — both give g'ood results. If the soil is pretty poor in or- 

 ganic matter, use the acid phosphate, but with organic manures 

 the raw phosphate does without question give good results. 



Question: Does acid phosphate have any injurious effect 

 on the soil?" 



Dr. Hopkins : It does increase the acidity of the soil, but 

 not in any very large way, because the amount applied is not 

 large. Where bone meal has been used side by side with acid 

 phosphate, with no lime applied, it does not take very long, on 

 many soils, before the clover is better on the bone meal plots. 

 It is also better on the raw phosphate plots. Clover is particu- 

 larly sensitive to acid soils, and so is alfalfa, but it does not take 

 very much lime to destroy this acid. 



Question : Would it injure the physical character of the 

 land? 



Dr. Hopkins : Not to any important extent. 



Question : In applying the lime to acid soil, will it show 

 results the first thing? 



Dr. Hopkins : Yes. I think I have seen it show within 

 four weeks for clover. If you put it on in the winter, as' soon 

 as the clover has a fair start, you may see the difference if your 

 soil is greatly in need of lime. 



