FERTILIZERS. 



201 



FERTILIZERS. 



The relative value of phosphoric acid from different sources, 



C. E. Thokne aiidJ. F. Hickman (^>///o Sta. Bui. rj3, pp. o'l, 3;,').— The 

 followiu^^ table gives the average increased yield per acre on plats 

 devoted to the continuous culture of corn, wheat, and oats, and fertil- 

 ized with different forms of phosphoric acid, the tests extending over 

 6 seasons in the case of corn, 5 for wheat, and 4 for oats: 



Increased yield per acre ivUh different forms of phosphoric acid. 



Fertilizer per acre. 



320 lbs. dis-solved boneblack 



320 11)8. aciil phosphate 



3U0 lbs. basic slas 



lucrease of grain. 



Corn. 



Bushels. 

 4."3 

 7.3 

 7.2 



Wheat. 



Bushels. 

 4.0 

 4.2 

 4.6 



Oats. 



Bushels. 

 5.0 

 5.5 

 7.0 



Increase of straw. 



Corn. Wheat. 



Pounds. 

 383 

 867 



bounds. 



1,509 



945 



1.017 



Oats. 



Pounds. 

 233 

 507 

 444 



"The plat receiving basic slag has had a somewhat larger total quantity of phos- 

 phoric acid per acre and that receiving acid phosphate a somewhat smaller quantity 

 than that applied iu the boneblack, but apparently the jihosphoric acid found iu 

 . . . the Carolina rock is equally efficacious, pound for pound, with that found 

 in bones . . . when both have been converted into su])erphosphate, and the 

 mineral phosphoric acid of the basic slag is not inferior to the most active forms of 

 the same substance as derived from bones. 



"Should some way be discovered by which the greater growth of [wheat] straw 

 produced by the boneblack superphosphate may be made to bear a proiiortional* 

 (juantity of grain, a greater value would have to be assigned to that form of phos- 

 jthoric acid than the results thus far attained will justify; but at present this 

 excessive production of straw must be looked upon as a disadvantage, in the light 

 of the results in 1891, when every plat dressed with boneblack superphosphate 

 gave a smaller yield of grain than the unfertilized plats adjoining, although the 

 straw was enormously increased, while the rock and slag phosphates gave a more 

 moderate increase of straw with a small increase of grain.'' 



On the conservation of animal manure in the climate of Sao 

 Paulo, Brazil, F. W. Dafert (KeJat. Inst. Agron. Sdo Paulo, Brazil, 

 1>^93, pp. 73-75). — The losses during 2 months under different ways of 

 keeping manure were briefly as follows : 



Loss of dry matter and nitrogen in manure. 



stored under cover and kept dry. . . 

 Stored under cover and kept moist 

 Exposed to the sun and kept dry.. 

 Exposed to the sun and kept moist 



6210— Ko. 3 3 



Loss of dry matter. 



Without I With 

 plaster. I plaster. 



Per cent. 

 30.3 

 22.6 

 19.5 

 29.0 



Per cent. 

 50.8 

 35.7 

 31.7 

 53.1 



Loss of nitrogen. 



Without Witli 

 plaster, plaster. 



Per cent. 

 44.3 

 13.9 

 33.8 

 21.0 



Per cent. 

 12.4 

 33.9 

 10.2 

 37.0 



