154 STORRS AGRICULTURAL EXPERIMENT STATION. 



POT EXPERIMENTS WITH NITROGENOUS 

 FERTILIZERS IN 1901. 



BY C. S. PHELPS. 



The chief difficulties met with in field experiments with fer- 

 tilizers are variations in the soil of the different plots, irregu- 

 larities of sea.son, particularly in the amounts of rainfall, and 

 the impossibility of applying fertilizers in such ways that the 

 plants shall get the full benefit of them and at the same time 

 not get plant food in varying quantities from other sources. 

 In order to overcome these difficulties as far as possible, and to 

 verify the results of the field experiments by investigations in 

 which the conditions influencing the grovvth of the crops might 

 be more under control, the Station for several years has carried 

 on experiments in which plants were grown in a prepared soil 

 in pots in a special vegetation house. In these experiments all 

 the pots are filled from a lot of soil that has been very thor- 

 oughly mixed and is therefore quite uniform; the plants are all 

 watered artificially so that the amount of moisture in the soil 

 can be kept within certain limits; and the fertilizers are applied 

 in such ways that there is little, if any, chance for loss of plant 

 food. 



A detailed account of these experiments, describing the pots 

 and soil used, the method of applying the fertilizer and the 

 water, the shelter house and the care of the plants during the 

 growing season, the sampling and analyzing of the crops, etc., 

 and giving the results obtained during several years with dif- 

 ferent crops, is given in the Report of the Station for 1900. In 

 the present article, which reports the results of the experiment 

 for 1901, these details are briefly -recapitulated, and any varia- 

 tions in the methods of conducting the experiments are included. 



Shelter house and pots. — The plant shelter is a light frame 

 structure with a large number of windows. It has a gravel 

 floor on a level with a yard at the west side and is fitted with 



