INTRODUCTION, 37 



thrive in soils rich in lime and full of air ; they perish 

 in a wet sour soil. Thus the alfalfa filled all the soil 

 with its rootlets, going down- often as far as 6 feet, 

 no doubt, and numberless millions of bacteria work- 

 ing there were storing the soil with nitrogen drawn 

 from the air. The phosphorus supply may have 

 been somewhat deficient ; we bought phosphorus for 

 part of the land and added that. Then the land was 

 plowed ; the plow cut off millions of those big roots 

 and left the top soil one mass of roots, with also 

 many little rootlets and many leaves and stems that 

 had fallen down. And the subsoil was made porous 

 by being honeycombed by millions of the tap roots, 

 so the air penetrated all the more easily. Thus it is 

 seen that conditions for a big corn crop were almost 

 ideal. 



It would be an interesting thing to know just how 

 much richer Woodland Farm is than it was before 

 alfalfa began to grow upon it. It is safe to say that 

 the alfalfa, yielding on the average 300 tons of hay 

 per year for the past ten years, has added to the soil 

 plant food worth at least $3,000 each year, count- 

 ing the manure that has been returned and the work 

 of the roots; probably this is an underestimate, in 

 fact. Once we racked our brains to find manure 

 enough, and never did find enough. Now we rack 

 our brains again to find time to haul out the manure 

 that is made upon the farm. Gathering fertility by 

 the use of .alfalfa is like rolling a snowball — ^the 

 farther you roll it the faster it gathers. This would 

 not be true if the hay was sold off of the farm, but 



