May 27, 1918 



Boron 



453 



EFFECT OF BORAX AND COLEMANITE ON PEACH TREES 



Boron-treated and colemanite-treated manures were applied to the soil 

 of separate groups of peach trees {Amygdalus pcrsica) in an orchard at 

 Acampo, Cal., in November, 191 4. A third group of trees was fertilized 

 with untreated manure, and a fourth group was left unfertilized. A 

 total of 100 trees were included in the experiment. The work was done 

 under the supervision of Mr. R. I^. Nougaret, of the Bureau of Ento- 

 mology. The orchard was planted in the spring of 1913. The manure 

 was applied at the rate of 16 tons per acre. The amounts of boron and 

 colemanite added to the manure are given on page 451. In the fall of 

 1 91 5 the groups of fertilized trees could be easily distinguished from the 

 other trees in the orchard because of the vigorous growth and dark-green 

 color of the foliage. The dark-green foliage was particularly marked in 

 the case of the trees fertilized v/ith borax-treated manure, the foliage of 

 the trees fertilized with colemanite manure being somewhat less green, 

 while the foliage of the unmanured trees was the least green. Three 

 nurserymen having no knowledge of the nature of the experiment passed 

 judgment on the length of the growth of new wood, the fruit buds, and 

 the general condition of the trees. All of the trees treated with either 

 borax-treated or colemanite-treated manure were given the highest rat- 

 ings, while many of the trees fertilized with untreated manure or left 

 unfertilized were given lower ratings. 



Samples of soil from the experimental section of the orchard were 

 tested for boron. No acid-soluble boron was found in any of the soils, 

 but there was a small amount of total boron in all of the soils. .The 

 results are recorded in Table I and are in agreement with the results of 

 the analyses of other soils in showing the absence of detectable amounts 

 of soluble boron. 



Table I. — Percentage of soluble and total boron in soil samples, Acampo, Cal., igij 



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. 



Per cent. 

 o. 00003 

 . 0000 1 

 . 0000 1 



BARLEY EXPERIMENTS 



The effect of borax and colemanite on the growth of barley (Hordeum 

 spp.) was studied at Walnut Creek, Cal., by Mr. Nougaret. In these 

 experiments the manure was also applied at the rate of i6 tons per acre. 

 Three plots were used for the test, one fertilized with borax-treated 

 manure, one with colemanite-treated manure, and a third with untreated 



