52 Department of Soil Investigations. 



(h) Relation between the concentration of the soil-water solu- 

 tion, and the absorption of nutrients by the plant. 



(i) Effect of application of certain fertilizers on the density of 

 the soil-water solution. 



(j) Influence of absorption by the soil particles on the removal 

 by plants of salts from the soil-water solution. 



(2) Influence of certain atmospheric conditions on the absorption 

 of mineral nutrients by plants. Including 



(a) Relation of transpiration to atmospheric humidity, tem- 

 perature and intensity of sunlight. 



(b) Relation between transpiration, under these conditions, and 

 the acquisition of nutrients from the soil. 



(3) A study of certain unproductive soil with special reference to 

 the activities of its bacterial flora. 



(a) Effect of sterilization with steam, and with volatile anti- 

 septics on the soil in question, as well as upon others. 



(a) Effect on crop production. 



(b) Effect on physiological activities of ammonifying and nitri- 

 fying bacteria. 



(c) Effect on the relative number and activity of aerobic and 

 anaerobic forms. 



(d) Inoculation of sterilized and unsterilized good soil with in- 

 fusions of sterilized and unsterilized poor soil. 



(e) Inoculation of sterilized poor soil, and of good soil, with cul- 

 tures of bacteria peculiar to or occurring in large numbers in the 

 poor soil. 



(b) Effect of aeration on the bacterial processes in these soils, 

 the immediate effect of sterilization being to make the poor soil 

 more productive than the good. 



(a) An enumeration of the aerobic and anaerobic forms in the 

 aerated and unaerated soils. 



(b) Inoculation with cultures of the predominating forms of 

 bacteria from the unaerated soils. 



(c) Determination of the oxygen absorptive powers of the soils^ 

 and production of carbon dioxid. 



(4) The character and concentration of the aqueous extract of a 

 soil under different methods of treatment. 



(a) Extractions are being made of the soils on the various plats 

 occupied by the experiments in which timothy hay is being grown 

 under different methods of fertilization and in a rotation including 

 corn, oats and wheat. Determinations of nitrates are being made 



