492 ANNUAL REPORT OF THE Off. Doc. 



early in the spring without interfering with the rotation, though nat- 

 urally the only gain will be the saving in the soil of food that would 

 be liable to be lost. The chief advantage of the nitrogen consuming 

 crops when used for this purpose, has been, as will be observed from 

 the previous discussion, is to hold fast to food that may be lost, as 

 the growth of the crops will not in anj^ large degree increase the 

 constituents in or improve the properties of the soil, as the oats 

 seeded early in the spring will prevent the crops from making any 

 considerable accumulation of food from soil and air. 



The next point to be considered is the protection of the soil, as 

 well as its possible improvement after the oats are harvested, and 

 before the succeeding crop is planted. It is preferable in this case, 

 of course, to use a plant which will accumulate nitrogen from the 

 air, renovating rather than exhaustive in its character, as the crop 

 which follows, namely, wheat or rye, is a nitrogen consumer, whose 

 entire and only source of nitrogenous food is the soil. A nitrogen 

 consuming crop, as millet, for example, or even buckwheat, would 

 use too completely the available food in the surface soil, converting 

 it into organic forms and hence make the conditions of soil less 

 favorable for the wheat in respect to available plant food, than if 

 the crop had not been grown. Furthermore, a crop must be grown 

 which develops rapidly, in order that a large accumulation of nitro- 

 gen and organic matter may be made in a short time, say six weeks 

 or two months. For this purpose, therefore, no better plants can 

 be suggested than the cow pea or soy bean. 



It is not necessary in the seeding of these plants that the land 

 should be plowed after the oats are removed, if the surface two or 

 three inches of soil can be made fine with a Cutawav harrow, in 

 fact, this is a better practice than to plow, as the losses of moisture 

 due to the preparation will be much less and the possible effect 

 of dry weather in part avoided. Hence, immediately after the 

 oats are removed prepare the land and seed cow peas or soy beans 

 at the rate of one and one-half bushels per acre; they may be broad- 

 casted, harrowed in, or put in with the grain drill, and preferably 

 dressed with 250 pounds per acre of a mixture of four parts of 

 acid phosphate and one part of muriate of potash. This added fer- 

 tility is to ensure an abundance of available mineral food, so neces- 

 sary in order that the plant may be induced to appropriate nitrogen 

 from the air. This, of course, will remain in the soil for the use 

 of the wheat or rye, which follows. At this season, if there is suffi- 

 cient moisture, the plants germinate quickly and grow rapidly and 

 will in six weeks make a considerable crop. 



The advantages of growing a crop of this character are, first, that 

 the soil is very soon covered with a plant of a large leafy growth. 



