SOME CONDITIONS AFFFXTING THE COMPOSE 

 TION AND YIELD OF WHEAT. 



Experiments to ascertain the effect of different conditions upon 

 the composition and yield of wheat have been conducted mainly 

 along the following lines: 



(1) Stage of growth at which the grain is harvested. 



(2) Influence of immature seed upon the resulting crop. 



(3) Effect of climate. 



(4) Effect of soil. 



(5) Effect of soil moisture. 



(6) Influence of size or weight of seed upon the resulting crop. 



(7) Influence of specific gravity of seed upon the resulting crop. 



A brief summary of a number of these experiments is herewith 

 given. 



COMPOSITION AS AFFECTED BY TIME OF CUTTING. 



In 1879," and again in 1892,^ Dr. R. C. Kedzie conducted very 

 careful experiments to note the chemical changes that occur in the 

 wheat kernel during its formation and ripening. These agree in 

 the main in showing a gradual decrease in the percentage of total 

 nitrogen, albuminoid nitrogen, and non-albuminoid nitrogen from 

 the time the grain set to the time the kernel was ripe. The decrease 

 in all of these constituents was much more rapid during the first 

 than during the last stages of this development. The percentage 

 of ash decreased at the same time. 



In 1897 Prof. G. L. Teller^ carried on some experiments in which 

 he covered the ground already gone over by Doctor Kedzie and 

 also contributed to the knowledge of the subject some very important 

 data concerning the proportion of the various proteids contained 

 in the wheat kernel during the process of development. Teller 

 found that the proportion of total nitrogen in the dry matter steadily 

 decreased from the time the kernel was formed up to about a week 

 before ripening, but that, unlike Doctor Kedzie's results, it gradually 

 increased from that time on. He intimates that this increase before 

 ripening may have been due to defective sampling and hoped to 



« Report of Michigan Board of Agriculture, 1881-82, pp. 233-239. 

 '' Michigan Agricultural Experiment Station Bulletin 101. 

 '■ Arkansas Agricultural Experiment Station Bulletin 53. 



27889— No. 78—05 2 17 



