i60 EXPERIMENT STATION BECORD. [Vol.38 



Inaf-cuttins bees. The yield of seed varies from 1 to 15 bii. per acre, experi- 

 enced growers usually obtaining from 4 to 7 bu. per a«re. Directions are given 

 for harvesting and marketing the seed crop. 



Barley for New York, H. H. Lo\t: and F. P. Busseix (N. T. State Col. Agr., 

 Cornell Univ. Ext. Bui. 13 {1911), pp. ^61-472, figs. 3).— Variety tests with 2- 

 and 6-rowed typos of barley, begun in 1913, are reported for the 4-year period 

 1913-1916. 



Of the 6-rowed varieties Featherston No. 7 gave the highest average yield for 

 the 3-year period 1914-1916, amounting to 50 bu. per acre, while Manchury 

 Selection N. D. A. C. 2125 was second with a yield of 45.4 bu. Guy Mayle 

 was lowest with 25.3 bu. per acre. Manchury X Champion of Vermont No. 2 

 was best of the 2-rowed types, with an average yield of 47.1 bu., and Champion 

 of Vermont second with 43.8 bu. per acre. Primus (Svalof) was lowest with 

 29.2 bu. The average yield of the 5 best 6-rowed varieties for the 3 years 1914r- 

 1916 was 45.6 bu. per acre as compared with an average yield of 44 bu. from 

 the best 5 2-rowed types. Commercial types deemed superior in yielding quali- 

 ties include Champion of Vermont, Common Six-Row, Oderbrucker, Common 

 Two-Row, and Silver King. 



The effect of hydrogen and hydroxyl-ion concentration on the growth of 

 barley seedling's, D. R. Hoagland {Soil Sci., S {1917). No. 6, pp. 547-560).— 

 Having measured the hydrogen-ion concentrations of various soil suspensions 

 representing soils of acid, alkali, and slightly alkaline types, investigations 

 were undertaken to study the effect of similar hydrogen and hydroxyl ion con- 

 centrations in nutrient media where the numerous other variables of the soil 

 could be eliminated. 



Barley seeds were sprouted between layers of white paper toweling, and the 

 seedlings transferred to 150-cc. bottles containing the culture media and grown 

 for 14 days. The effect of the various solutions on the seedlings was deter- 

 mined from the general appearance of the roots and tops, the development of 

 lateral roots and root hairs, and the dry weights of tops, roots, and residual 

 seeds. In many of the experiments the fresh weight and average length of the 

 tops were noted and microscopic examinations made of the roots. The 

 hydroxyl-icm concentration of the solutions was controlled by varying the pro- 

 portions of KsPOi and KsHPO*, and the hydrogen-ion concentrations by the use 

 of KH2PO4, supplemented in one set by 1 per cent of HsPO*. Neutral solutions 

 were used as checks. The hydrogen-ion concentrations of all solutions were 

 ascertained by electrometric measurements. 



The general effect of the higher concentrations of the hydroxyl ion was to 

 decrease the fresh and dry weights of the tops and the average length. The de- 

 velopment of lateral roots was almost entirely repressed, while microscopic 

 examinations of the root tips indicated unquestionable injury. The leaves also 

 gave evidence in many cases of toxicity. Concentrations of the hydroxyl ion 

 greater Wian about 1.8 X 10"' are considered detrimental to barley seedlings, 

 while concentrations greater than 2.5 X 10"* are considered extremely toxic. 



Acid conditions are said to be favorable to the growth of seedlings in con- 

 centrations as high as 0.7 X 10'° hydrogen ions. The- fresh and dry weight of 

 the tops and the average length increased over that of the neutral solutions. 

 Lateral root development was good and microscopic examinations showed no 

 evidence of injury to the root tips. These results substantiate those obtained by 

 Tottingham (E. S. R., 31, p. 425) as shown by electrometric measurements of 

 solutions similar to those employed by him in studies with wheat. Decided 

 injury, accompanied a hydrogen-ion concentration of 0.3X10"', resulting in a 



