USING CHEMICAL MANURES 



37 



that if supplied with everything else that was necessary, the fol- 

 lowing amounts of manurial ingredients were removed from the 

 soil by 1,000 pounds of field-cured hay, free from clover: 



5.6 to 5.8 pounds of nitrogen. 



14.7 to 16.2 pounds of actual potash (K 2 O). 



3.3 to 3.5 pounds of phosphoric acid (P 2 O 6 ). 



"The early application of top-dressing is of vital importance in 

 a dry season such as that of 1900, when, notwithstanding the severe 

 drouth, 4.1 tons of field-cured hay were harvested per acre. At 

 present the great drawback to profitable grass culture in New Eng- 

 land is the neglect systematically to top-dress mowing lands and a 

 general lack of knowledge of the relative quantities and absolute 

 amounts of chemical manures to apply. If every one of the 78,824 

 acres of grass land in Rhode Island were treated in an intelligent 

 and economical manner, the increased revenue to the state would 

 be enormous. The facts presented ought to emphasize the impor- 

 tance of chemical manures." 



In 1902 the experiment was continued, each plot re- 

 ceiving phosphorus, potassium and two of them nitro- 

 gen. Below are given the quantities of nitrate of soda 

 applied per acre, and the amounts of actual nitrogen con- 

 tained therein : 



"The following are the amounts of field-cured hay harvested 

 in 1902, upon each of the three plots: 



