234 ALFALFA FARMING IN AMERICA. 
a field or plant is inoculated. If it is of a rich 
green color, if it is growing fast, if it looks healthy 
and happy, be pretty sure that it is inoculated, 
whether you did it or Nature did it. If, on the other 
hand, it looks pale and yellow and unhappy and is 
crowded by weeds and altogether miserable, be sure 
that it is not inoculated. 
Inoculated Soil a Fertilizer Laboratory.—Consider 
what is doing in an inoculated soil where conditions 
are right and alfalfa is growing thereon. Take the 
yearly growth at only 4 tons per acre. Four tons 
of alfalfa hay contain about 176 pounds of nitro- 
gen, 40 pounds of phosphorus and 128 pounds of 
potash. Nitrogen is sold for about 15 cents per 
pound in various forms, often for a much higher 
price. Phosphorus is sold at a low price for 5 cents 
per pound. Potash is worth about the same price. 
Thus in the crop of 4 tons of hay we find nitrogen 
largely gathered by the bacteria worth $26.40, 
potash worth $6.40, phosphoric acid worth $2—all 
these from one acre yielding only 4 tons of alfalfa 
hay. The total-is $34.80. The manurial value of 
this yield is vastly more than this amount, since the 
humus contained is worth more to the soil than one 
can well estimate. And the value to the soil is nearly 
double this estimate since we take no account of the 
root growth, also stored with nitrogen. Prof. Voor- 
hees estimates the fertilizing value of an acre of al- 
falfa well grown to be about $65, in comparison of 
course with commercial fertilizers bought. 
Soil Building with Alfalfa—One must not rashly 
