Department of Soil Investigation Ixxvii 



Any desired type of soil may be used, which is not possible with 

 ordinary field experiments. It is also possible to make a compari- 

 son of different soil types under any desired conditions, which may 

 be very serviceable in ascertaining the effect of those properties dif- 

 ferentiating these types upon certain factors in soil productiveness. 



The chief feature of the plan is that of keeping accurate records 

 of the factors affecting plant growth without producing artificial 

 conditions. 



The tube leading from the bottom of the tank is designed to 

 carry off the drainage water into a receptacle which will permit 

 the quantity to be measured and its constituents to be determined. 



Since the work of constructing these tanks was begun, the in- 

 stallation of similar apparatus has been commenced by two other 

 experiment stations. 



The following is an outline of the projects under investigation, 

 with comments on the nature and advancement of the work. The 

 first four projects are the old work begun by the Department of 

 Agronomy, and projects 8 to 14 are new work begun in 1909. 



Project I. Fertilizer experiments with timothy. — To ascertain 

 the best fertilizer treatment on the soil under experimentation for 

 a rotation consisting of timothy, corn, oats and wheat. In 1908 

 the experiment was extended to include a comparison of the prac- 

 tice of fertilizing for the grain crops alone, as is usually done, with 

 that of fertilizing for timothy alone. 



Project 2. Effect of weeds on corn. — The object is to ascertain 

 why weeds are injurious ; whether the injury is due entirely to the 

 removal of moisture or other food materials, or to some other cause. 



Field experiments on this may be discontinued after the present 

 summer if the results this year confirm those of the past two sea- 

 sons, which indicate that either one or both of the two causes first 

 mentioned are responsible for at least a large part of the effect, 

 and that if there is any other source of injury it is of very minor 

 importance. 



Project 3. Use of lime and inocculation for alfalfa. — This was 

 merely a field experiment designed to test in a practical way some 

 of the cultures of Pseudomonas radiccola dispensed for the pur- 

 pose of inocculation alfalfa land. The results are similar to most 

 of those reported by a number of experiment stations, and there 

 seems to be no reason for publishing them. 



Project 4. Examination of certain properties of an tui productive 

 soil. — We have shown that an accompanying condition of the less- 

 ened productiveness is deflocculation of the soil aggregates. The 



