THE CHEMICAL DEVELOPMENT OF ALFALFA. 169 
TABLE NO. LXXV. 


POUNDS REMOVED IN AN ACRE CROP 


Potash Phosphates | ;. 3 i 
CRs) | "eesOer® | Bime (cso) | Magnesia 
BNitaltalElayss. .sde.s-cs0c-2s 206 58 | 89 | 22 
BELOVED EL AY. cocc-osceee0 <-cos 66 28 | 76 | 17 

Alfalfa draws most heavily on the lime and potash, re- 
sembling clover in this respect, but because of its heavier 
yield per season, a greater quantity of these ash constituents 
is removed. Most of the soil of Minnesota is well supplied 
with these ash constituents. If the alfalfa is fed on the farm 
and the manure well preserved and returned to the land, but 
little fertility is lost. If it happens that soils are poor in 
these constituents, fertilizers of lime in the form of land 
plaster and potash in the form of wood ashes can be profit- 
ably applied. The ash of alfalfa seed is rich in potash and 
phosphates; the samples analyzed contained 32.77 per cent 
potash and 44.29 per cent phosphate. It will be seen that 
when the seed is sold a considerable amount of this valuable 
ash material is removed from the farm. 
With the aid of nitrogen gathering bacteria, alfalfa, like 
clover, can use the free nitrogen of the air, still it must not 
be inferred that a fair supply of nitrogen in the soil is un- 
necessary or that the application of nitrogenous fertilizers 
is always wasteful. Professor Bernard Dyer* of England 
has shown by careful experiments that ‘‘Theuse of moderate 
quantities of nitrate of soda has been decidedly remunera- 
tive.’ He found that in five years, an annual dressing of 1 
ewt. of nitrate of soda per acre gave an increase of nearly 
three tons of green alfalfa fodder per acre per year, while an 
annual dressing of 2 cwt. per acre gave an increase of four 
and a half tons of fodder per acre per year. From this he 
calculated that there was an annual profit dueto the nitrate 
of alittle more than four doJlars per acre in the first case 
and over six dollars per acre in the second case. 
* Reprint from the ‘Transactions of the Highland and Agricultural Society of 
Scotland,’ Fifth Ser., Vol. XIV, 1902. 
