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 Fertiliser 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.^QnQ must not rashly 



