BORON: ITS EFFECT ON CROPS AND ITS DISTRIBUTION 

 IN PLANTS AND SOIL IN DIFFERENT PARTS OF THE 

 UNITED STATES 



By F. C. Cook and J. B. Wilson, of the Animal Physiological Chemical Laboratory, 

 Bureau of Chemistry, United States Department of Agriculture 



INTRODUCTION 



The results reported in this paper are a continuation of the experiments 

 previously recorded (2, j, 4),* dealing with the effect on the growth of 

 crops of borax and colemanite (calcium borate) when added to horse 

 manure in amounts sufficient to kill the larvae of the house fly, with par- 

 ticular reference to the action of boron-treated manure when applied to 

 the same soil for two or three consecutive seasons. It was thought that 

 crops that had not been injured by the first addition of the boron-treated 

 manure might be injured by a second or third application. A study was 

 made of the effect on crops and soil of large amounts of boron-treated 

 manure such as might be used by truck growers to force crops. In this 

 way the tests covered the application of the largest possibly amounts of 

 boron-treated manure to soil which might possibly be made through any 

 combination of circumstances. 



GENERAL PLAN OF EXPERIMENTS ^ 



In all tests 0.08 pound of borax or 0.095 pound of colemanite per bushel 

 of manure were used. These quanities are sufficient to act as a larvicide 

 for the house fly. When 0.08 pound of borax is added to the bushel of 

 manure and applied at the rate of 16 tons to the acre, it is calculated, 

 by assuming that the weight of the upper 6 inches of soil per acre is 

 1,750,000 pounds, that 0.00176 per cent of boron as boric acid (H3BO3) 

 is present in the upper 6 inches of the soil. When the above quantity 

 of colemanite is added to the manure, 0.00232 per cent of boric acid is 

 estimated to be in the upper 6 inches of soil. If the treated manure is 

 applied at the rate of 24 and 40 tons to the acre, it is calculated that 

 0.00264 and 0.0044 per cent, respectively, of boric acid are present in the 

 upper 6 inches of soil when borax is added. When colemanite is added, 

 0.00348 and 0.0058 per cent, respectively, of boric acid are present in the 

 same amount of soil. 



The action of both borax-treated manure and colemanite-treated 

 manure on barley and peach trees in California and on wheat at Benton 



• Reference is made by number (italic) to " Literature cited," p. 470- 



2 The experiments were carried out with the cooperation of Mr. W. D. Hunter, of the Bureau of Ento- 

 mology. 



Journal of Agricultural Research, Vol. XIII. No. 9. 



"Washington, D. C. May 27, 1918 



no Key No. E-10 



(45^ 



