341 



Value of Fertilizing Constituents op Weeds of Indiana. 

 Analysis of Ironweeds. 



By Frank Mathers and Miss Gail M. Stapp. 



This paper is the beginning of worlc to determine tlie value of weeds. 

 Ironweeds, wliich grow everywhere in great abundance, were selected for 

 analysis. Samples were collected from the university campus on Sep- 

 tember 29, 1911. They were cut into small pieces and dried for several 

 days iu the air. Finally the material was dried for sevei'al hours at about 

 00°. The analysis was made upon this dried sample, but the results were 

 calculated to the air dried njaterial. The loss on drying was 14 per cent. 

 The analyses' of several other substances are given in tliis table for com- 

 parison. 



Ironweeds 



Blue grass 



Oxeye daisy 



Wheat straw 



Foxtail 



Corn stover (fodder) ... 



Timothy hay 



Red top 



Red clover 



Per Cent of 



Nitrogen. 



1.29 

 1.28 

 1.19 

 0.28 

 0.59 

 1.54 

 1.04 

 1.26 

 1.15 

 2.07 



Phosphoric 

 Acid. 



0.66 

 0.63 

 0.40 

 0.44 

 0.12 

 0.44 

 0.29 

 0.53 

 0.36 

 0.38 



Potash. 



0.95 

 0.98 

 1.57 

 1.25 

 0.51 

 1.99 

 1.40 

 0.90 

 1.02 

 2.20 



Value per Ton. 



S6 50 



6 65 



3 28 

 2 87 

 8 45 



5 76 



6 24 



4 14 

 10 54 



*The values used for N, P2O5 and K2O are 18, 6 and 6 cents per pound respectively. 



These calculations do not consider the value of the organic matter, 

 v.'hich is really the thing of greatest importance iu manures and soiling 

 crops. The values assigned represent the cost of a commercial fertilizer 

 containing the same amounts of nitrogen, phosphoric acid and potash. 



' Yearbook of the U. S. Dept. of Agriculture, 20: 611 (1896). 



