GREEN MANURES AND COVER CROPS 
57 
of satisfaction. The customary sowing is about two 
bushels of seed to the acre covering with a harrow. 
101. Soy bean, also a legume, succeeds better on heavy 
soils and in cool climates than the cowpea and is, there- 
fore, valued by some northern growers as well as south- 
ern truckers for manurial purposes. The seed may be 
sown broadcast or in drills. Cultivation benefits the crop. 
A mixture of forty pounds each per acre of hairy vetch 
and winter barley is considered a valuable cover crop in 
some sections. Spring vetch and oats, timothy, and oats 
alone as an early spring or a late fall crop, are also used. 
Other soil improvement crops will doubtless be devel- 
oped and we may expect in the future to hear more about 
them from the vegetable growers’ standpoint. 
102. Fertilizing green manurial crops. — When crops 
for manurial purposes are grown on impoverished soils, 
commercial fertilizers should be used liberally enough 
to encourage a good growth. It may pay to use 500 
pounds to the acre of a high-grade fertilizer. Nitrogen 
is especially important for the nonlegumes. 
103. When to plow under green crops. — No very defi- 
nite advice can be given upon this question, because 
many factors must be taken into account, such as kind 
and age of crop, vegetables to follow, needs of the soil 
and seasonal conditions. The older the crop the more 
time will be required for its decomposition and the less 
benefit it will be to the next cash crop. Soil moisture 
problems are especially important in connection with 
green manures. When plowing is delayed too long, the 
ground may become too dry for successful sowing or 
transplanting. To prevent serious interference with the 
capillary movement of the soil moisture, the furrow slice 
should be stood on edge as much as possible rather than 
turned flat. Rolling or dragging immediately after 
plowing is regarded as valuable in preventing the devel- 
opment of soil acidity. 
