64 



FIELD CROP PRODUCTION 



plowing can be more thoroughly done, since it need not 

 be rushed by other work. At the same time it lessens the 

 work of the farmer in the spring when he is busiest. 



49. Weathering. — Increasing the depth of plowing 

 can be done more satisfactorily in the fall than in the 

 spring. The subsoil that is turned up in the fall will be 

 incorporated with the surface soil by freezing and thawing, 

 which are excellent agencies in pulverizing the soil. 



Fig. 17. — Afield of corn almost completely destroyed by grubworms. 



50. Killing of insects. — Many of the troublesome in- 

 sects injurious to field crops can be effectively combated 

 by fall plowing. Many insects spend the winter a few 

 inches below the surface of the ground, some in the egg 

 stage, some in the worm or grub stage. Fall or winter 

 plowing will break many of the eggs or egg sacs, bring the 

 caterpillar and pupa to the surface, where many will be 

 killed by freezing and others eaten by birds, or skunks and 

 other animals. The cut-worm and the grubworm pass 

 the winter in the ground in the partly grown stage. Fall 

 plowing has been recommended as one of the best methods 



