SOILS AND FERTILIZERS 109 



left on the surface of the ground, the soil does not re- 

 ceive all its fertilizing value, as part may wash away. 

 As fresh manure injures some crops, there is danger in 

 applying it in the spring unless thoroughly cured, or 

 rotted. Plants, if supplied with plant food in too great 

 abundance, are likely to overeat somewhat as animals 

 do, so it is better to apply the manure frequently in 

 small quantities on the land with comparatively long 

 periods between applications. 



The best results are obtained when rock phosphate 

 or acid phosphate and some fertilizer containing potas- 

 sium are applied with the manure. Wood ashes or sul- 

 phate of potassium will furnish potassium. 1 



Economy of Manure. --The cash value of animal 

 manure is usually estimated by ascertaining what the 

 same fertilizing value in commercial fertilizers would 

 cost. The price of nitrogen may be placed at 17 cents 

 a pound ; the other two elements are each worth about 

 6 cents a pound. A fertilizer containing 10 pounds 

 of nitrogen, 6 pounds of phosphorus, and 12 pounds of 

 potash, which is the proportion of these elements in a 

 ton of manure, would cost $2.78, which means that the 



1 Professor Chilcott has this to say of the application of manure : 

 " The farmer should fully understand that while the application of barn- 

 yard manure to the soil is certain to have a beneficial effect by adding to 

 the store of plant food, its effect may not be apparent in the results of the 

 first crop after application ; and that the immediate physical effects upon 

 the soil may be either beneficial or detrimental, depending upon the 

 character of the soil, the kind of manure, the time and method of applica- 

 tion, the nature of the crop and the character of the season as to moisture 

 and temperature. 



"The soil of the farm should be considered a bank in which the surplus 

 resources of the farm, in the form of plant food, should be deposited with 

 the understanding that the surplus cannot be withdrawn at once, but it is 

 to remain until such time as the conditions are favorable for its utilization." 



