ANNUAL REPORT, I'MO 13 



Th Effect of the Calcium Ion on the Development of Soybean Seedlings 

 and the Antagonism of This Ion to Arsenic, Boron, and Selenium Ions. 



(Walter S. Eisenmenger and Elvin T. Miles.) Farmers in certain regions 

 have in recent years suffered partial loss of their crop because of relative 

 scarcity of boron in the soil. This deficiency of boron was seemingly 

 augmented by the addition of lime to the soil. It seems that vi^hen small 

 amounts of boron are used on the soil to produce more normal plant 

 growth the application of calcium will reduce the efficiency of the 

 boron. This action of lime is not unlike that experienced when the cal- 

 cium is used to overcome the toxic efifect of overdoses of boron. Also in 

 certain sections of the country the residues of arsenic from applications 

 of sprays over a long period of time have been found to retard subsequent 

 growth of annuals. 



In an experiment designed to show growth of seedlings of soybeans in 

 single salt solutions of boron, arsenic, and selenium, it was found that 

 1 p. p.m. of arsenic, 1.5 p. p.m. of boron, or 4 p. p.m. of selenium in aqueous 

 solution produced a toxic reaction. In the presence of a neutral calcium 

 salt, however, arsenic produced toxic effects only when the arsenic was 

 present at the rate of 2 p.p.m. The toxic action of boron and selenium was 

 also depressed by the presence of a neutral calcium salt. On the other 

 hand it also holds true that the ions of arsenic, boron, and selenium will 

 counteract the toxic action of single salt solutions of neutral calcium ions. 



The Effect of Arsenious, Arsenic, and Antimony Oxides on Soil emd 

 Plant Growth. (Walter S. Eisenmenger and Hrant M. Yegian.) Pot 

 culture studies under greenhouse conditions on the effect of arsenious, 

 arsenic, and antimony oxides on Merrimac fine sandy loam and subsequent 

 crop growth are being continued. Five successive crops, barley and buck- 

 wheat alternating, have been grown in the same pots during 1939 and 

 1940, and the lightest applications of arsenious and arsenic oxides (500 

 p.p.m. and 250 p.p.m. respectively) are still toxic to barley, and 1500 p.p.m. 

 of arsenious oxide and 2,000 p. p. m. of arsenic oxide are toxic to buck- 

 wheat. 



It was found that by returning sufficient amounts of buckwheat and 

 barley tops to the pots arsenic toxicity could be overcome. A photograph 

 of the fifth crop, buckwheat, grown in pots treated with arsenious oxide 

 shows the value of organic matter in overcoming the arsenic toxicity very 

 clearly. (Page 57.) 



The antimony oxide treatment did not aflfect the yields of barley or 

 buckwheat, and the soil was not injured even temporarily by the heaviest 

 application (2000 p.p.m. antimony oxide). 



Sunflowers and Their Possibilities. (Karol J. Kucinski and Walter S. 

 Eisenmenger.) After the encouraging results obtained last year, the 

 experiment was continued. Although the season was exceptionally late 

 this year, sunflowers were planted on the 15th of May and grew to ma- 

 turity, forming exceptionally large seed heads. 



From the standpoint of seed production, fertilizer tests with sunflowers 

 show that apparently they are not very heavy feeders. Doubling the ap- 

 plication of fertilizer increased the yield of seed only about 5 percent. 

 The best plots yielded about one ton of good seed to the acre. Seedings 

 of one seed per hill every 18 inches in 36-inch rows proved to be better 

 than two seeds per hill in 36-inch check rows. Two seeds per hill 18 



