LEGUMES AND SOIL FERTILITY i8i 



turned under each year with the result that the soil gained as an 

 average 177 pounds per acre of total nitrogen, which is the quan- 

 tity of nitrogen found in three 40-bushel crops of wheat, provided 

 the straw is returned to the soil. Work on the soil of the Nephi 

 Experiment Station (Utah), with a rotation of wheat and peas 

 where the peas were plowed under, showed a gain in total nitro- 

 gen of 240 pounds in four years. That is, in addition to furnish- 

 ing the nitrogen required by the wheat crop the peas had added 

 to the soil an average of sixty pounds of nitrogen per year. 



The second method of maintaining the nitrogen and organic 

 matter of the soil — the combined rotation and livestock method — 

 is the more practical, and if systematically practiced will not only 

 maintain the nitrogen of the soil but will prove of great economic 

 value to the individual following it. It consists of a rotation in 

 which the legume plays a prominent part. The legume to be 

 fed and all the manure returned to the soil. This would mean 

 the selling from the farm the hay crop in the form of butter, 

 milk, or beef which carries from the soil only a fraction of the 

 nitrogen stored up by the legume. Moreover, it brings for the 

 producer much greater returns than does the system in which the 

 legume is completely removed from the soil. 



It must be remembered, however, in this system that only three- 

 fourths of the total nitrogen of the feed is recovered in the dung 

 and urine. So that in place of three tons of alfalfa adding 150 

 pounds of nitrogen to the soil from the air, it would add only 112 

 pounds — and this where all of the liquid and solid excrements 

 are collected ?nd returned to the soil. However, where the alfalfa 

 is to be fed and the manure returned to the soil the legume can 

 occupy a much longer period in the rotation, and that with greater 

 economy than where the legume is to be plowed under directly. 



Hence, we find that if these principles which have been estab- 

 lished for soils even low in nitrogen be systematically applied to 

 the soil it will result in greater revenue from an increased live- 

 stock industry and will maintain the soil rich in nitrogen and 

 organic matter in place of depleting it of its stored-up nitrogen, 

 as is so often the case with the present methods. 



