PLANT GROWTH IN DRY AREAS 119 



grows numerously in a crop of hard winter wheat, the 

 price paid will be lowered in proportion to the extent 

 to which such admixture is present. The difficulty found 

 in obtaining pure seed in dry areas is largely the out- 

 come of such volunteering of grains. 



The volunteering of grains may be greatly lessened : 

 (1) by early and prompt cutting of the crop; (2) by 

 careful handling of the same when cut, and (3) by the 

 gleaning of sheep and swine amid the stubbles. The 

 early and prompt cutting of the grain will prevent shat- 

 tering in the same to a very considerable extent, but it 

 will not in all instances entirely prevent it, providing the 

 grain is allowed to become sufficiently mature before it is 

 cut. Owing to the shortness of the grain crops in some 

 instances, the loss of heads is greater in the harvesting 

 process than it would be in the case of grains that were 

 of greater length. This loss is considerably increased if 

 the sheaves are handled in a careless manner. Sheep 

 or swine may subsequently gather many heads, but they 

 cannot gather them all, hence even under the most 

 favorable conditions there will be some loss from the 

 shattering and falling of heads in the harvesting process. 



The remedies for the volunteering of grain or 

 rather for the harmful influences that may result, are 

 the following: (1) summer-fallowing the land with suffi- 

 cient frequency ; (2) growing a cultivated crop with suffi- 

 cient frequency, and (3) modifying the rotation. The 

 frequency of the summer-fallowing will depend in a 

 considerable degree: (1) on the amount of the precipi- 

 tation ; (2) on the rotation, and (3) on whether the crops 

 are grown for feeding" or for being marketed. The 

 greater the precipitation, the less the necessity for the 

 summer-fallow in order to prevent volunteering, for 

 the more that the rainfall is, especially in the autumn, 

 the more will the grain sprout at that season, and when 

 thus sprouted it may be destroyed by subsequent cul- 



