

THE EFFECT OF DUST FROM CEMENT MILLS ON 

 THE SETTING OF FRUIT 



PAUL J. ANDERSON 



Cornell University, Ithaca, N. Y. 



Fruit growers in the vicinity of Hudson, New York, in the 

 spring of 1910 complained that their crops were seriously dam- 

 aged by dust from large cement mills which had recently been 

 located there. They noticed particularly a decrease in the amount 

 of fruijb that was set on trees within the dust zone. They also 

 feared permanent injury to the foliage and young shoots. The 

 investigations recorded below were undertaken in order to 

 determine the nature and extent of the alleged injury and, if 

 possible, to find a remedy. 



Appearance of the foliage. The foliage in the dust zone is cov- 

 ered with a fine, gray, gritty dust mixed with minute black gran- 

 ules (evidently cinders). The coating is heavier near the mills 

 but is plainly noticeable at a distance of two miles. A green- 

 house located a mile away was so heavily coated within a month 

 after the plant started operations that the passage of light 

 through the glass was seriously interfered with. Hard rains 

 wash the coarser part of the dust from the leaves and while they 

 are wet they appear green, but, on drying, become white again 

 from a thin film which cannot be washed off. On a rigid surface, 

 however, such as a greenhouse roof, the dust collects and sets 

 very rapidly, forming an opaque covering which can be removed 

 only by the use of acid. Under certain weather conditions the 

 same hard crust is formed on the leaves and remains on them 

 throughout the season. 



Source of the dust. That the dust comes from the mills — not 

 from the roads or soil — is evident from the following considera- 

 tions: (1) It is found nowhere else except in an area about the 

 mills; (2) it falls just as heavily when the ground is soaked and 



THE PLANT WORLD, VOL. 17, NO. 3, 1914 



