66 Department of Soil Technology. 



3. The causes of the formation of soil granules, and the conditions 

 which are involved in these processes. 



Some of the facts brought out by these investigations are as follows : 



1. The growth of a legume with a non-legume gives the latter a greater 

 protein content than when it is grown alone. This is important from a 

 practical standpoint as it suggests a method for increasing the protein of 

 crops raised for stock food. 



2. The growth of alfalfa, and probably other legumes, increases the 

 nitrifying power of the soil for at least certain periods in the growth 

 of the crop. 



3. Not only legumes but also non-legumes were shown to have a 

 definite relation to the nitrate content of the soil on which they grow, 

 the relation differing with different crops. The data obtained have led 

 us to advance the hypothesis that certain non-legumes stimulate nitrifica- 

 tion during their period of most active growth, and later have a depress- 

 ing effect on the process of nitrate formation. 



4. The absorption of nitrate nitrogen by wheat plants grown in a rich 

 soil was found not to be proportional to the growth of the plants, but to 

 increase with a decrease in the soil moisture content and consequently 

 with a decrease in the crop. This will probably explain the high per- 

 centage of gluten in wheat grown in semi-arid regions. 



5. An investigation into the relation of lime to the growth of alfalfa 

 has disclosed the hitherto unnoted fact that the protein in alfalfa grown 

 on a limed soil is markedly greater than in that grown on soil in need 

 of lime. In the experiments on the University farm, this amounted to 

 eighty-eight pounds of protein per ton of alfalfa hay. 



6. Investigations involving the application of fertilizers at different 

 stages of growth of corn and oats have demonstrated that under certain 

 conditions and for certain crops the application of fertilizers after *the 

 crops are growing effects a substantial economy in the use of the 

 fertilizer. 



Another practical result was obtained from an experiment involving 

 the fertilization and manuring of crops in a six-year rotation of grain and 

 timothy hay. It was shown that the ordinary practice of fertilizing the 

 grain crops and not the hay results in a much smaller value of product 

 from the entire rotation than may be obtained by fertilizing the hay and 

 leaving the grain to obtain its nutriment from, the soil enriched by the 

 improved hay crop. 



