No. 4.] CORN AS A GRAIN CROP. 339 



calorie. 1 On the basis of total heat energy produced, the products 

 per acre of some of the leading crops have the following relative valua- 

 tions: 2 — 



Calories. 



One acre of corn, 10,020,800 



One acre of mangels, ....... 6,801,760 



One acre of Swedes, 6,268,860 



One acre of potatoes, 6,024,600 



One acre of oats 3,578,660 



One acre of rye, 3,731,000 



On the basis of cost per acre on the college farm, 10,000 calories 

 of heat energy cost as follows: with corn as the crop, $0,033; with 

 mangels, SO. 112; with Swedes, $0.051 ; with potatoes, $0,083. Oats 

 and rye are not cultivated on the college farm, and it is impossible 

 to extend the comparison to these crops. It will be noticed that corn 

 far surpasses either of the other crops in the total number of calories 

 produced per acre, while the cost of 10,000 calories is far lower than 

 with either of the other crops. 



But, besides excelling other crops in its capacity to store up power 

 received from the sun in the shape of light and heat, and in the cost 

 of a given amount of food, corn surpasses most other crops in other 

 important particulars. It is remarkably free from disease. Seldom 

 is any considerable proportion of the crop destroyed either by disease 

 or by insect enemies, and, while it is considerably affected by season, 

 it is without doubt one of the most certain among the various crops 

 we can cultivate. From every point of view, therefore, it would seem 

 that corn is a crop deserving of greater attention than it receives on 

 the part of Massachusetts farmers. 



Botanical Characteristics. 

 Indian corn (Zca mays) is a native of the American continent, and 

 is believed to have descended from a wild form characterized by the 

 production of numerous very small ears on each of several joints. A 

 form discovered within comparatively recent times, to which the name 

 Zea canina was given, is believed by many to be the parent type. It 

 has sometimes been asserted that pod corn, the variety in which each 

 individual kernel is enclosed in a separate husk, is the parent form of 

 our cultivated varieties; but this theory is not now generally accepted. 

 Corn belongs to the great grass family, — the family which includes 



1 A calorie is the quantity of heat necessary to raise the temperature of a kilogram 

 of water one degree Centigrade. 



2 These figures for corn, mangels, Swedes and potatoes are from a paper on "Field 

 Crops" in "Agriculture of Massachusetts" for 1895, and are based upon crops upon the 

 college farm. The figures for oats and rye are calculated on the basis of the average 

 yields of these crops in Massachusetts. The figure for corn includes the entire plant in 

 the form of silage; those for oats and rye include straw as well as grain, assumed to 

 amount to a ton and a half per acre in each case. 



