The Bulletin. 15 



1906. — Land was broken June 11th, planted June 22d, and culti- 

 vated three times — July 11th arid 28th and August 13th. 



liun. — Land was broken June 22d, planted July 2d, and culti- 

 vated three times— July 23d, August 2d and 13th. 



In 1905, 1906, 1907 the peas followed wheat; in 1904 there 

 was no preceding spring crop, but corn was on the land in 1903. 



1908. — Land was broken July 11th, planted on the 15th, and 

 cultivated three times — July 28th, August 18th, and September 3d. 

 The peas this year followed oats. 



FERTILIZATION AND FERTILIZER MATERIALS USED. 



As already stated, fertilizer was applied in the drill just before 

 planting, the exact quantity of material for each row being weighed 

 out separately, so that each row would get its proper amount of the 

 several fertilizer constituents. Acid phosphate was used as the 

 source of phosphoric acid; dried blood as the source of nitrogen; 

 manure salt as the source of potash, and rock or building lime for 

 lime. The fertilizer materials were analyzed each year and the 

 applications made on basis of these analyses, so as to give the exact 

 quantities of nitrogen, phosphoric acid and potash required for each 

 plat. For the sake of simplicity and convenience in presenting the 

 results of a number of years' experiments, the fertilizer applications 

 are expressed in terms of acid phosphate containing 14 per cent 

 available phosphoric acid, dried blood containing 13 per cent nitro- 

 gen, and manure salt containing 20 per cent potash, which figures 

 represent the average composition of these materials. The fertilizer 

 applications in the fertilizer experiments are on basis of 300 pounds 

 per acre (for the normal plat W P K) of a mixture containing 8 

 per cent available phosphoric acid, 4 per cent potash, and 1 per 

 cent nitrogen. Lime is applied at the rate of 500 pounds rock or 

 building lime, or 1,000 pounds slaked lime. The fertilizer appli- 

 cations in the table, in addition to being represented in terms of 

 acid phosphate, dried blood, and manure salt, are also expressed 

 in terms of the symbols, N P K and L, which have the following 

 significance : 



N equals or represents nitrogen at the rate of 3 pounds per 



acre, or 23 pounds of 13 per cent dried blood ; 

 P represents phosphoric acid at the rate of 24 pounds per 



acre, or 171.4 pounds of 14 per cent acid phosphate; 

 K represents potash at the rate of 12 pounds potash per 



acre, or 60 pounds 20 per cent manure salt ; 

 L equals lime at the rate of 500 pounds rock, unslaked 



lime or 1,000 pounds slaked lime per acre. 



There are columns in the tables showing the exact weights in 

 pounds of phosphoric acid, potash and nitrogen applied to each 



