788 Journal of Agricultural Research voi.xx.No.io 



Morse (4) analyzed samples representing four stages of growth and 

 reached the same conclusions, with respect to the protein and carbo- 

 hydrates, as the other investigators. 



Perhaps the most elaborate study of the subject was made by Jones 

 and Huston (2). Their study included the whole plant as well as the 

 stalks, leaves, and ears taken separately. Unfortunately their figures 

 for the whole plant are based upon yield per acre and so can not be com- 

 pared with those of the other investigators or with ours. 



EXPERIMENTAL WORK 



The crops for the experimental work were grown in a section of the 

 field at the Dairy Division Experiment Farm at Beltsville, Md., usually 

 devoted to silage corn. The preparation of the soil, the planting, and 

 cultivating were done under the supervision of T. E. Woodward, farm 

 superintendent. 



The sunflower plants were of the variety known as Giant Russian, and 

 the corn was Boone County White. The sunflower plants thrived well in 

 this soil (Bibb silt loam), reaching a height in many cases of 10 and 12 

 feet. 



In dividing the growing period of the corn plant into stages, more or 

 less arbitrary points must be taken. It is quite useless for the purpose 

 to select plants by their age or height, for it is easily possible to find at 

 any one time within a comparatively small area plants of the same height 

 and age at entirely different stages of maturity. Up to the time of tas- 

 seling, however, there are no easily recognized guides except height. 

 From that time until the plant is fully mature there are certain and 

 fairly distinct points that can be selected, based on the condition of the 

 silk and ears. 



The task of selecting stages of growth of the sunflower plant offers 

 more difficulty, and it is quite impossible to divide it into anything like 

 as sharply defined stages as in the case of the corn plant. We endeavored 

 to differentiate the stages first by the height and later by the condition 

 of the flower and seed, but at best these points are very arbitrary. 



The difficulties in selecting representative samples of whole plants for 

 chemical analysis are obvious. The plan we followed was to go through 

 a small area of the field and select from 6 to 20 plants of the proper 

 stage of growth and as nearly the same size and conformity as possible. 

 These were carefully wrapped in a specially prepared waterproof cloth 

 and taken immediately to the laboratory, where they were cut into 

 1 -inch lengths with a hand-power feed cutter. 



A 1 -kilogram subsample was weighed out and dried in the steam 

 closet for the determination of starch. The remainder was ground to a 

 pulp in a power meat grinder, and a subsample was taken for moisture, 

 albuminoids, and total-protein determinations. A further subsample 



