CULTURE OF WHEAT 79 



The value of the latter will depend largely upon the needs of the 

 soil and the character of the manure used. 



III. CULTURAL METHODS. 



126. Time of Plowing. — It is generally conceded to be good 

 practice to plow for winter wheat as early as practicable after 

 the previous crop has been removed. This allows the soil to 

 become compact before the seed is sown, prevents weeds from 

 going to seed, and conser^-es the soil moisture by preventing the 

 growth of vegetation, by the pulverization of the surface soil and 

 by enabling more of the rainfall to be absorbed. In this con- 

 nection the pulverization of the surface after each heavy rainfall, 

 preferably with a spring tooth harrow, is extremely desirable 

 in order to prevent surface evaporation. 



The experiment made by the Oklahoma Station^ is a fair 

 illustration of what may be expected in the drier climates 

 or the drier seasons of the more humid sections. Plats were 

 plowed on July 19th, August 15th and September nth. The 

 early plowed plat turned up moist and mellow; the medium 

 plowed somewhat dry and lumpy, while the late plowed plat was 

 weedy, turned up lumpy and was dry to the full depth of plowing. 

 Disking, harrowing and rolling was necessary to the extent that 

 it was estimated that about eight times as much labor was put 

 on it as would have been necessary had the ground been plowed 

 when moist. All sections were seeded September 15th. In the 

 early plowed plat germination was prompt and growth good. 

 On the late plowed portion many plants suffered from lack 

 of moisture ; the following summer the crop matured later, was 

 more seriously affected by blight, and the grain was more 

 shrivelled. The following yields were obtained : 



Date of plowing Yield per acre, ba 



July 19 S'^-s 



August 15 23.5 



September 11 15.3 



1 Okla. Bui. 47 (1900), pp. 26-48. 



