CAMPBELL'S SOIL CULTURE MANUAL 247 



CHAPTER XXIX. 



SOIL MULCH OR DUST BLANKET. 



As the interest develops in Scientific Soil Culture there 

 are frequent instances where the innocent are misled in 

 unintentional ways. Among the more common is the refer- 

 ence to the name applied to the loose soil established by 

 the cultivator or harrow over the tilled fields. It is very 

 important that this question be fully understood, for much 

 difficulty and trouble may be avoided thereby. 



DUST BLANKET. 



The name Dust Blanket is an old one and is today 

 very commonly used, especially by the older writers, and 

 as a rule is taken by the farmer to mean literally what it 

 says, dust. The dust blanket in the older and more humid 

 sections of the east where the name originated, was con- 

 sidered by many to be necessary for the best protection 

 of moisture. This, however, has been found to be an error 

 in the more arid sections where the atmosphere is so much 

 dryer. It also was found to be the wrong idea by Prof. 

 King in his very elaborate experiments at the Wisconsin 

 Experiment Station during the early nineties. In the fol- 

 lowing, quoted from his book, "The Soil," on page 195, he 

 refers to the comparative effectiveness of a mulch of coarse 

 quartz sand that would pass a screen of 20 meshes to the 

 inch, but was retained by one of 40 meshes as compared 

 with pulverized air dried clay of equal thickness. It was 

 found that the evaporation from the soil with dust mulch 



