FIELD CROPS. 



205 



The following table sliows the nitrogen, pbosplioric acid, and potash in 

 the dry matter of tops, stnbble, and roots of crimson clover: 



Fertilizing constituents in dry matter of tops, stubhle, and roots. 



Nitrogen. 



Phosphoric acid. 



Tops. Stubble. Roots. Tops. Stubble. Roots. Tops. Stnbble.' Roots 



April 24. 

 May 12.. 

 May 24.. 

 May 31.. 



Per cent. 

 :^.6t) 



•i.TA 

 3.05 



2.03 

 1.94 

 1.95 



Per cent. Per cent, 

 2.61 I 0.85 

 2.91 1 1.02 

 2. 74 i 0. 72 

 2. 73 i • 0.67 



0.7G 

 0.49 

 0.52 



Per cent. 



0.87 

 0.99 

 0.76 

 0.87 



Per cent. 

 3.01 

 3.17 

 1.91 

 2.54 



Per cent. Per cent. 



1.81 



2.66 . 1.18 



1.13 I 0.82 



2. 88 1. 45 



Proximate analyses showed that the food constituents were not 

 widely different April 24 and May 12, but that after the latter date 

 there was a decided increase in liber and a consequent decrease in the 

 percentages of the other constituents. It is notable that in the tops 

 the albuminoids were relatively greatest in the immature plant, the 

 albuminoid nitrogen constituting 80.5 per cent of the total nitrogen 

 April 24, but only from 69.4 to 72 per cent at later dates. 



Value of crimson clover as a green manure (pp. 14^-23). — The following 

 table gives the average weights of green clover, dry matter, nitrogen, 

 phosphoric acid, and potash afforded by an acre of crimson clover cut 

 at different stages : 



Yield per acre of green clover, dry matter, nitrogen, phosphoric acid, and potash. 



"The table shows that by far the largest amount of orgauic matter and plant food 

 is contained in the tops, even at the first cutting, when the jilants were 6 in. higli, 

 and that there i.s practically no increase in the orgauic matter and fertilizer constit- 

 uents contained in the roots after that time. . . . 



"The gain of orgauic matter and fertilizer constituents iu the tops, including stub- 

 ble, constantly increased until maturity. Ou April 24, roughly, two thirds of the 



