GROUP OF SAND SOILS. 
57 
fineness of grain and cannot be affected by any treatment it is 
practicable to give them. The water-holding capacity can be 
somewhat increased by increasing the amount of organic matter, 
but this is a comparatively slow process and the amount of or¬ 
ganic matter it is practicable to develop and maintain in these 
soils will increase their water-holding capacity only to a limited 
extent. 
The total content of the essential elements of plant food in 
these soils is moderate. The total phosphorus in the surface 8 
inches per acre averages between 750 and< 900 pounds and in 
the second 8 inches between 600 and 700 pounds. The total po¬ 
tassium in the surface 8 inches per acre is about 25,000 pounds 
in comparison with 50,000 or 55,000 pounds in the silt loam soils 
of that region. The total nitrogen content is between 1,200 and 
1,400 pounds in the surface 8 inches per acre. 
When a sufficient supply of active organic matter is devel¬ 
oped in these soils a considerable portion of the phosphorus and 
potassium will undoubtedly be made available, but the use of 
fertilizers containing these elements in a more readily available 
form is desirable whenever these soils are farmed. 
The starting point in the improvement of these soils is the 
development of active organic matter through the growth of 
legumes which are able to secure their nitrogen supply from the 
atmosphere. But before legumes can be grown with the great¬ 
est success the liming of the soil is necessary. The growth of 
a good crop of mammoth clover or soybeans through the use of 
lime and mineral fertilizers containing phosphorus and potas¬ 
sium is the best means of supplying this nitrogen and organic 
matter. In most cases this legume should be plowed under as a 
green manuring crop. 
Probably the best way to get clover started is to seed with a 
small grain. By using a light seeding of rye, disked or har¬ 
rowed in and seeded to clover in the spring, a good stand can 
usually be secured. The seed should be put in a little deeper 
than on heavy soils, and the drill should be followed by a cor¬ 
rugated roller, oil if this implement is not at hand, an ordin¬ 
ary roller, followed by a light harrow should be used. When 
clover is seeded with a small grain in this way the growing 
grain helps to hold the soil in place and prevent blowing of the 
loose soil by the wind. 
As the result of careful experiments on extremely sandy soils 
it appears that the best crop rotation for this class of land con- 
