454 



Journal of Agricultural Research 



Vol. Xlir. No. 9 



manure. The amount of borax and colemanite added to the manure 

 is given on page 45 1 . 



No injurious effect of the boron was noticeable during the growing 

 period. The yields were not determined, but so far as could be esti- 

 mated, the borax and colemanite did not affect the yields. The crop 

 was harvested in June, 191 5. At the time of harvest samples of grain 

 and straw from each plot were analyzed for solids, nitrogen, and boric 

 acid. The results are given in Table II. 



Table II. — Percentage of solids, nitrogen, and boron in barley, grain, and straw, dry 

 basis, Walnut Creek, Cal., igij 



Boric acid added to upper 6 inches of soil. 



Per cent. 

 0.00176 as borax 



0.00232 as colemanite. . 



Control 



Control (between rows) 



Material. 



rStraw. 

 [Grain, 

 r Straw . 

 [Grain . 

 ("Straw . 

 [Grain . 

 ("Straw . 

 [Grain . 



Total 

 boron as 

 boric acid 



found. 



Per cent. 

 o 

 . 0000 1 

 . 0000 1 

 . 00002 



. OOOOI 



o 

 . 00002 



. OOOOI 



The nitrogen in the grain was practically equal in all samples, while 

 the two samples of straw grown on the boron-treated plots contained less 

 nitrogen than the two control straw samples. Only minute amounts of 

 boron were found in the barley, either straw or grain. The control 

 samples showed the presence of as much boron as there was in the barley 

 grown on soil to which boron was added. No injurious action of the 

 added boron was apparent. 



In this connection the difference in the effect of boron in nutrient 

 solution as compared with that in field experiments is illustrated by the 

 findings of Brenchley (/) at the Rothamsted station. She found boric 

 acid to be definitely poisonous to barley down to i part in 250,000. 



Samples of soil were taken from each of the three plots and analyzed 

 for soluble and total boron. The results are given in Table III. 



Table III. — Percentage of soluble and total boron in soil samples frotn Walnut Creek, 



Cal., 191 s 



Boric acid added to upper 6 inches of soil. 



Soluble boron 



as boric acid 



found. 



Total boron 



as boric acid 



found. 



Per cent. 



0.00176 as borax 



0.00232 as colemanite 



Control 



Per cent. 

 o. 00008 



. 000024 

 . 00004 



