A Botanical and Economic Study. 173 



receiving no nitrogenous manures were of a light green 



color, and during the first half of the season the same 1 on- 

 dition of the plant was noticeable on the plats receiving 

 ammonium sulphate. 1 The light green color of a crop wili 

 indicate, generally, that the soil is deficient in available nitro- 

 gen. It is evident that chlorophyll formation has a close 

 connection with the proper assimilation of nitrogen, but that 

 the increased carbon assimilation does not take place unless 

 with this additional chlorophyll sufficient mineral matter is 

 present. The corn plant docs not respond to heavy applica- 

 tions of nitrogenous manures. It is therefore easy to apply 

 too much. 2 



The use of large quantities of nitrogen above the quantity 

 utilized by the plant is a direct waste of money: 1 The use of 

 superphosphates alone on corn is unsatisfactory. 1 The use 

 of potash alone is unadvisable,"' and of doubtful value. "The 

 yield of ear corn on the two unmanured plats were respectively 

 thirty-four and forty bushels per acre ; on the three plats re- 

 ceiving fertilizers containing no potash, from thirty-three to 

 thirty-six bushels, and on those receiving potash fertilizers, 

 from sixty-five to seventy-six bushels ; the largest yield was 

 with the combination of potash and nitrogen." ,; When pot- 

 ash was used, there was a marked increase of crop (twenty- 

 eight to thirty-nine bushels per acre), and the greatest in- 

 crease was with a manure composed of potash and nitrogen 

 (thirty-nine bushels). There was a profit in every instance 

 where potash was used, and a loss (financially) where that 

 element was left out. 7 Mixed superphosphate, potash and 

 nitrate of soda yielded the best results." The yield in all 

 cases was larger when potash and superphosphate were ap- 

 plied with nitrogenous fertilizers.' J Nitrogenous manures, 



1 Massachusetts Stat., - Rep., 1889, 148; Exp. Stat. Rec, 11, 579. 

 - South Carolina Stat., 2 Rep., 1889, 210-26S : Exp. Stat. Rec, 11, 550. 

 ; Connecticut, Storr's Stat., 2 Rep., 1889. 

 4 Georgia, Stat. Bui., 10, 1890, 20. 



South Carolina Stat., 2 Kep., 1889, 210-26S. 

 c Kentucky Stat. Bui., 33, 1891. 

 ; Exp. Stat Rec. 11, 725. 

 8 Georgia Stat. Bui., 10, 1890, 20. 

 '•' Georgia Stat Bui., 15, 1891: Exp. Stat. Rec, in. 604. 



