470 ANNUAL REPORT OF THE Off. Doc. 



carried away in the rains that pass through it. A saving, there- 

 fore, may be effected by keei^ing the land constantly occupied with 

 growing crops, in order that food which is made available may be 

 absorbed by the roots of plants and converted into organic forms 

 which by their decay render it serviceable to other crops. The 

 methods of practice quite common in the East require that the 

 land lie bare at certain seasons of the year and some times for long 

 periods, during which severe losses of plant food may occur, the 

 chief element of which is the expensive constituent, nitrogen. 



Experiments conducted by Sir John B. Lawes, at Kothamsted, 

 England, showed that land in good condition, left bare from early 

 fall until spring, would lose an equivalent of 37 pounds of nitrogen 

 per acre. It was also shown that this could have been held and 

 appropriated by crops. This loss of nitrogen may not seem a 

 great matter at first glance, but a study of the losses in relation to 

 crop production shows that it is really very serious. In the first 

 place, this loss of nitrogen, which is possible and probable on good 

 soils left bare, is more than equivalent to the amount contained in 

 the average yield of wheat, rye, oats, corn or buckwheat; besides 

 the nitrogen which is carried away by the drainage water, is in 

 the very best form for feeding the plant, or it would not have 

 been lost, and thus its absence leaves the soil not only poorer in 

 this constituent element, but poorer in the sense that the remainder 

 of it in the soil is in a less useful form. While the amount and 

 time of rainfall cannot be controlled, its effect upon the soils in 

 causing loss may be largely governed if proper attention is given 

 to the matter of growing catch crops, in order that the land may 

 be constantly occupied. 



Another source of natural loss of nitrogen, is its escape as gas 

 into the atmosphere, due to the oxidation of vegetable matter, 

 which takes place very rapidly when soils rich in this substance are 

 improperly managed. In the system of continuous cropping which 

 is obeerved in certain sections of our country, the annual losses of 

 nitrogen are much greater than the amounts carried off in crops, 

 and while continuous cropi^ing is not so generally practiced in the 

 East the losses that occur, because of improper methods of rotation, 

 which leave the land bare for any length of time, are very consid- 

 erable. Indirect losses may occur, too, because the conditions are 

 made unfavorable for the activities that are present in the soil. 

 Take, for example, the rotation which allows the land to remain 

 bare from the early part of July until September, when the rota- 

 tion of corn, oats, wheat and grass is practiced. After the oat crop 

 is removed in July the land is frequently allowed to lie uncovered, 

 particularly in dry seasons, for a month or six weeks, during which 



