446 EXPEKIMENT STATION RECORD. [Vol.37 



The wheats of Baluchistan, Khorassan, and the Kurram Valley, Gabbieluc 

 L. C. HowABD {Mem. Dept. Agr. India, Bot. Ser., 8 {1916), No. 1, pp. S8, pis. 2. 

 fig. 1). — This is a botanical classiQcation and detailed description of the wheats 

 of Baluchistan, Khorassan, and the Kurram Valley, and a brief description of 

 the barleys of Khorassan. 



Third annual seed laboratory report, 1915-16, W. L. Oswald {Minnesota 

 l?ta. Bui. 165 {1917), pp. 12, figs. ^).— During the year 9.5G4 voluntary samples 

 and 104 official inspection samples were tested for germination or purity, or 

 both, and the results reported in tabular form. A 3-year summary of the seed- 

 testing work is included in this report 



Seed impurities, A. H. Cockayne {Jour. Agr. [Xew Zeal.], 13 {1916), No. S, 

 pp. 208-212). — This is a list of 225 extraneous seeds found in commercial 

 samples of seed on the New Zealand market, together with a key showing the 

 relative frequency of occurrence and harmfulness of each. 



Weeds on arable land and their suppression, Winifred K. Brenchley {Jour. 

 Roy. Agr. Soc. England, 76 {1915), pp. 1^-37, pi. 1, figs. iO).— This is a general 

 discussion of weeds on cultivated land, including a glossary of 76 weeds men- 

 tioned in the paper. 



Weed control with pulverized kainit, H. Lijjdeman {Tijdschr. Planten- 

 ziekten, 22 {1916), No. 5, pp. 107-121, pis. 10). — This is a general discussion of 

 weed control with the application of finely ground kainit including a com- 

 parison of kainit with ferrous sulphate in weed control. 



HOETICTJITTJRE. 



The persistence of lawn and other grasses as influenced especially by the 

 effect of manures on the degree of soil acidity, B. L. H.vbtwell and S. C. 

 Damon {Rhode Island Sta. Bui. 170 {1917), pp. S-2i, pis. 4).— This bulletin 

 briefly reviews earlier work of the station on the subject (E. S. R.. 20, p. 144), 

 and reports in detail further experiments that have been in progress for a 

 number of years. The effect on different kinds of grasses of changes in the 

 degree of so-called soil acidity has received special attention. Soil acidity was 

 modified not only by liming but by applying fertilizer combinations having acid, 

 neutral, and alkaline reactions. Observations are also given on the effect on 

 mixed herbage of variations in the amount of different nutrients, (»n the 

 relative effect ivenps.s of different sources of nitrogen used as top-dressings, and 

 on the nature of the turf from different individual grasses and mixtures which 

 were seeded in 1905. 



The study as a whole has shown that with other conditions equal variations 

 in the supply of individual nutrients may be expected to cnu.se changes in the 

 proportion of different gras.scs in a mixture. The most potent factor leading 

 to the replacement of one grass by another appears to ho variation in tlio detrree 

 of so-called soil acidity. The most common example of variation in herbage 

 caused by modifications in the degree of acidity is the gradual replacement 

 of timothy by redtop when manurial substances which are physiologically acid 

 are applied and vice versa when alkaline .substances are added. That the 

 differences are not due merely to the physical and nutrient effects of the 

 fertilizer was indicated in experiments where these effects were eliminated by 

 the maintenance of optimum physical and nutrient conditions. 



Having added at the time of seeding sufficient lime to create a soil reaction 

 thought to he suitwl to the kind of grass adopted, any changes in reaction 

 which are subsequently desired may be made by modifications in the annual 

 top-dressing. The authors point out, however, that even when the specific 



