30 HINTS ON SOILS AND FERTILIZERS 
in the spring. When sod land is to be plowed, 
it can best be plowed in the fall, as this gives 
the sod a much longer period of time to de¬ 
compose before planting time. Furthermore, 
fall plowing enables the soil to catch the winter 
rains and snows, thus preventing them from 
washing away. It also has a harmful effect 
upon certain crop pests that prey upon the 
crops and destroy them. Finally, it especially 
improves the tilth of heavy or lumpy soils, such 
as clay, for instance. By alternate freezing and 
thawing, these hard lumps are almost pulver¬ 
ized by spring. Thus we see that fall plowing 
has many very distinct advantages. 
Often it is impossible to do very much fall 
plowing, for one reason or another, and, as a 
result the bulk of the plowing is done in the 
spring. When this is the case, the soil 
(especially if a heavy clay) is quite liable to 
have a poor texture, if there are the usual 
spring rains. However, in some cases, spring 
plowing is to be preferred to fall plowing. Often 
it is advisable to sow a green manure crop, 
such as rye, on a piece of ground, after the 
crop has been removed. It can then be left on 
the ground until spring, when the rye can then 
be turned under, thereby supplying organic 
matter to the soil. Also, many sandy soils give 
best results when left until the spring to be 
plowed, as often this type of soil is subject to 
blowing if plowed in the fall. 
We have now quite a pretty fair comprehen¬ 
sion as to the meaning of good tilth. However, 
it must not be concluded that if a soil has 
good tilth that it is necessarily a fertile soil. 
