70 BULLETIN 355, U. S. DEPARTMENT OF AGRICULTURE. 
These windstorms usually do not have much chance to develop dur- 
ing the summer when the ground is more fully covered by growing 
crops. To prevent this danger of wind-blown sand the ground should 
be kept covered with growing crops as much as possible. Land 
on which potatoes have been grown may be seeded to rye at once 
after the digging of the potatoes, and, if desired, clover may be sown 
on the rye early in the following spring. In this way the ground is 
never exposed for any length of time to the wind. Fields on sandy 
farms should also be laid out in long narrow strips, so that the ground 
on which the tilled crop, such as corn or potatoes, is planted will alter- 
nate with strips bearing grain or grass which protects the ground. 
Fertility (Kef. No. 7, p. 415). — Sandy soils are low in the total 
amount of plant food they contain, and often what they do have is 
rather unavailable beoause of the coarseness of the grains of which it 
consists. It is particularly desirable that the organic matter of such 
soils be increased, partly because by so doing the nitrogen can be best 
increased, and partly because the organic matter acts on the mineral 
matter in the soil so as to make it available for growing crops. For 
adding organic matter legumes should be used as far as possible, since 
they have the power of gathering nitrogen from the air. In the 
growing of these legumes, such as clover, soy beans, etc., the use of a 
fertilizer containing potassium and phosphorus is important. Lime is 
also often needed to secure satisfactory crops of alfalfa or clover. 
These plants can secure much of their nitrogen from the atmosphere, 
but they require the mineral elements from the soil just as all plants 
do. However, it is important to notice that in the decomposition of 
organic matter produced by the growing and plowing under of legume 
crops the phosphorus and potassium which was used in their growth 
become available to succeeding crops, and this further increases the 
value of legumes as fertilizers. 
Crops for sandy soils. — The readiness with which sandy soils may 
be worked, even immediately following rams, especially adapts such 
soils to the growth of crops requiring considerable manual labor, such 
as vegetables and small fruits. The advantage which sandy soils 
have in this respect is so great that it offsets their low fertility and 
makes it preferable to use them for such purposes, even though fer- 
tilizers must be purchased in larger quantities than would be necessary 
on heavier soils. The low water-holding power of such soil also per- 
mits it to become warm much more quickly in the spring than heavier 
soils which contain much water, the evaporation of which keeps them 
cold. This higher temperature of sandy soils adapts them to certain 
crops requiring a high temperature, such as melons, tomatoes, and 
potatoes. The fact that sandy soils are subject to drought during 
periods of small rainfall in the summer makes them poorly suited to 
grass crops, which should grow all the season, especially when used 
