192 ALFALFA FARMING IN AMERICA. 
thrive especially well in soils where the air can 
penetrate easily. The bacteria supply alfalfa with 
nitrogen. Thus deep plowing is equivalent to feed- 
ing the alfalfa with extra nitrogen. The heaviest 
growth of alfalfa that I have ever seen was on the 
ranch in Utah where I once lived, the plants stand- 
ing 48” high all over the field and very thick. The 
underlying soil there was of loam, interspersed with 
layers of loose sand and gravel, a soil that was too 
easily drained, not very fertile, but well filled with 
lime and other alkalies. With copious irrigation 
that land produced enormous crops of hay. 
Deep plowing in a manner imitates such a condi- 
tion by letting in the air and storing up more mois- 
ture as well. Of course one must use judgment. If 
his soil is of poor clay with only a thin skin of 
vegetable mould on top one dares not bury that 
deep under the clay and plant maize thereon, but 
it is probable that he could do it and plant alfalfa 
with success, especially if the land was well drained 
and limed. 
The water-holding power of deeply plowed soil 
is about double that of unplowed, or shallow plowed 
soil. This is important when it comes to getting 
maximum crops of alfalfa hay. The lack of mois- 
ture is usually the limiting factor in crop yield, a 
fact not half appreciated as yet. 
How to Plow Deep—tI have done some experi- 
menting ona hard clay soil with numerous small 
round boulders or ‘‘niggerheads’’ in it in trying to 
plow deep. It is not an easy task. In this especial 
