260 SYSTEMS OF PERMANENT AGRICULTURE 



is usually marked on both clover and oats, the " increase " given 

 for phosphate must be regarded as quite unusual. Not more than 

 one tenth of the phosphorus applied would be removed in the two 

 crops. These results point toward the possibility of adopting 

 profitable systems of permanent agriculture; and yet the most 

 common fertilizer practice among the farmers of Ohio is to apply 

 about 7 pounds of soluble phosphorus per acre, with 3 or 4 pounds 

 each of nitrogen and potassium, in 200 pounds of "complete" 

 fertilizer about twice during a four-year or five-year rotation. 



In the Rural New Yorker for June 5, 1909,' Director Thorne 

 reports an average yield of 2440 pounds of clover hay with lime 

 applied, and 5112 pounds where rock phosphate is used, with no 

 other fertilizers; and where nitrogen or potassium had been applied, 

 the yield with lime was 2606 pounds and with rock phosphate, 

 5488 pounds, although where lime and a " complete " fertilizer, 

 including nitrogen, phosphorus, and 480 pounds of acid phosphate, 

 was used, the total yield of clover hay was only 4259 pounds. 

 The following comment is made by Thorne: 



"This experiment thus indicates that floats (raw phosphate) may be very 

 usefully employed for the combined purpose of carrying lime and phosphorus, 

 the increase over the limed land being more than enough in this one crop to 

 pay for one ton of floats per acre, which quantity has seemed to be as effective as 

 the larger quantity, although the two tons of lime have produced a larger 

 yield than the one ton, though not enough larger to pay the additional cost. 

 This experiment, therefore, is confirming those of the Maryland and Illinois 

 stations in showing that floats may be profitably used as a carrier of phos- 

 phorus on acid soils well stocked with organic matter, but the meager effect 

 produced upon cereal crops preceding clover would call for caution in de- 

 pending upon floats alone. " 



Of course, more clover means more humus and more nitrogen 

 if the clover is plowed under either directly or in manure; and, 

 while the cereal crops preceding clover are quite certain to be un- 

 satisfactory, they are sure to be increased after plowing under the 

 larger amount of clover or manure with phosphate. The data 

 reported by Thorne in these experiments do not show what increase 

 was produced by lime alone, all plots having been treated either 

 with lime or with raw phosphate, and consequently there seems 

 to be no support for the suggestion that the effect of the raw phos- 

 phate is in part due to the lime which it carries. In fact, the ordi- 



