124 



THE RIPENING OF WHEAT. 



THE GROSS PEODUCT PER ACRE AT EACH CUTTING, 



Tlie amount of grain as influenced by the period of cutting is a question of 

 practical importance to the farmer. In making this estimate I confined my 

 attention to the weight of perfectly dry berry, because I was satisfied that any 

 variation in amount of grain, attendant upon changes during growtli, arises 

 from variation in the size and weight of the berry, and not from any change 

 in the number of grains growing on a given area, since new grains would not 

 form during the period of ripening, and all those already formed would pass 

 through the successive stages of development more or less completely. In 

 this way there were eliminated several sources of error incidental to measur- 

 ing the grain produced on a given area, such as the loss of grain in handling, 

 and from incomplete threshing, varying productiveness of different plots of 

 soil, etc. All broken kernels and foreign substances of every kind were 

 removed, but no grains were removed in consequence of imperfect develop- 

 mcTit. The grain was then poured into the scale-pan of a delicate balance, 

 and ten grammes carefully weighed out and the number of grains of wheat 

 counted. This was repeated ten times for each specimen and one-tenth of 

 the sum of the whole was taken as representing the number of kernels of 

 wheat for the weight of ten grammes. 



The gross product of grain at the several stages of growth would be directly 

 as the weight of the kernels, and inversely as the number of kernels required 

 to produce a given weight. 



The average number of grains of wheat required to weigh ten grammes at 

 the several periods of cutting is given in the following table. I have also 

 estimated the number of bushels of grain at the different periods of cutting, 

 on the supposition that eacli variety of wheat produced thirty bushels to the 

 acre as its maximum. The table also contains the percentage of nitrogen, 

 cellulose, and ash, at the different periods of growth: 



TABLE I. 



