370 ANNUAL. REPORT OF THE Off. Doc. 



and washing down the hillside, piteously pleading for humus to 

 give them the flush of fertility and plant roots to bind them in their 

 place. This condition brought about by neglecting to restore 

 humus, and often by excessive use of lime by which the little remain- 

 ing humus was burned out, must be speedily changed or some of the 

 proudest fields of the State will become practically barren. 



The difference between our fields to-day and the same fields when 

 our grandfathers looked upon the golden harvests that brought 

 them forty bushels of wheat, a hundred and fifty bushels of corn 

 ears or two or three tons of timothy hay per acre — the difference 

 between these old eastern fields and the vast prairie empires of the 

 west whose thundering train-loads of wheat and bet-f have sung a 

 requiem to our hopes, may be expressed with the one word — humus. 

 In the mineral elements of fertility no fields are richer than ours; 

 but to unlock this fertility, humus, in all its vital functions, is an 

 absolute necessity. And when we remember that the chief ele- 

 ment in building the foliage of the plant through which carbon is 

 gathered from the air, as well as in building the frame of the young 

 animal, is nitrogen; that this element in the forms available for 

 plants is not only the most important but the most expensive in 

 the rharket, and the most easily lost, we see the importance of 

 possessing a humus rich in nitrogen. With an atmosphere fifty-four 

 miles in depth, four-fifths of which is nitrogen, it is not necessary 

 to pay the dealer fifteen cents a pound for this element. The hand 

 that guides this inexhaustable store across the plains has given us 

 plants enabled by a mysteriously organized life to gather this ni- 

 tr.ogen from the soil atmosphere and prepare it for the plant. The 

 chief plants available in this latitude that possess this power are 

 the clovers — the common red, mammoth, crimson, white, alsike, 

 alfalfa and the vetches. The clover plant when turned into the 

 soil accomplishes all that we have seen accomplished by the non- 

 leguminous plants, and very much more. Its longer roots perforat- 

 ing the soil far below the average plow-depth, leave openings to ad- 

 mit the air, to break up the subsoil and oxidize the mineral com- 

 pounds, at the same time the plant pumps back much of the escap- 

 ing fertility, especially the phosphates and potash that was out of 

 the reach of the plants and roots of other crops. But its chief su- 

 periority consists in the fact that it adds to the soil, not only a 

 valuable bed of humus, but with it large quantities of nitrogen 

 taken from the air, while the non-leguminous plants simply add to 

 the soil what they had taken from it, with the exception of carbon. 



The amount of nitrogen appropriated by the clover plant differs 

 somewhat with varieties. An experiment by the Cornell Station 

 showed that after three months and four days' growth the crimson 

 had gained per acre 155 pounds of nitrogen, the mammoth 145 and 

 the common red 103. The alfalfa and vetches are much richer. 

 Thus a ton of red clover hay contains 41 pounds of nitrogen, alfalfa 

 48 and winter vetch 55. In the above experiment crimson clover 

 had gained per acre as much nitrogen as would be found in thirteen 

 tons of good stable manure or enough to produce sixty bushels of 

 wheat with its straw. 



It is not definitely known what part of its load of nitrogen is 

 taken from th6 air and what part from the soil, but enough is 



