402 AGRICULTURAL ECONOMICS 



wheat, hay, corn, and tobacco. When the field labor on this farm 

 is charted, it becomes obvious that during May, June, and a part of 

 July, corn and tobacco are competitive. The labor is some days on 

 the one crop, some days on the other, and knowing the character of 

 the crop it is fair to assume that had he planted more corn and no 

 tobacco, the time put on the tobacco during the period of planting and 

 cultivation would have been put on the corn (Figs. 18 and 19). 



When the three small grains are compared with corn and tobacco, 

 it is clear that they are sowed before the time for planting corn or 

 tobacco; also that they are harvested in the latter part of July, 

 apparently after the tilled crops were laid by. This suggests that 

 these small-grain crops are complementary to the tilled crops from 

 the standpoint of demand for man and horse labor. It is known also 

 that these groups of crops are complementary from the standpoint 

 of the demands of a good system of crop rotation. The small grains 

 may provide nurse crops for grasses and legumes. The tilled crops 

 clean and give tilth to the land. 



In studying the demands of the various crops upon the time of 

 the farmer, operations should be divided into two classes: (i) those 

 which must be done within very narrow limits of time, such as seeding 

 and harvesting of small grain, the planting and cultivation of tobacco, 

 and (2) those which can be done equally well at any tune through a 

 period of considerable length, such as plowing and thrashing. Labor 

 of the former class should always take precedence over that of the 

 latter class, but labor of the second class should not be put off until 

 it must be done when labor of the first class is demanding attention. 

 If plowing is left too long, it may delay the planting ; if threshing is post- 

 poned too long, it may conflict with tobacco harvest or silage cutting. 



Passing from these more general conditions shown by the chart 

 to the further details of each of these groups, it is interesting to note 

 the way in which this farmer employed his labor on the three spring- 

 grain crops. The wheat and the oats were seeded and harvested so 

 nearly at the same time that they appear to be strictly competitive. 

 The barley, however, is sown later and harvested earlier. Barley has 

 a shorter season. By a proper combination of barley with the other 

 spring grains, both the seedtime and the harvest were spread over a 

 longer period. This might have been accomplished by selecting two 

 varieties of oats which vary in length of their period of growth. 



While corn and tobacco appear to be competitive during the season 

 when corn is cultivated, it appears that they are complementary in 



