HOETICULTUEE. 139 



weed seeds in farm lands and to discover the relation of their prevalence to 

 cultural conditions. Samples of soil were taken from fields in Ontario, Sas- 

 katchewan, and Alberta. 



The average number of vital seeds per square yard 1 in. deep was found to 

 be in the surface inch 1.107, in the second inch 457, and at from 5 to 7 in. l)elow 

 the surface 331. The average number of vital seeds in 20-oz. samples of sod 

 aged 5 to 10 years was in the first inch IS, in the second inch 14, and at a depth 

 of from 5 to 7 in. 7*. In sod 10 to 15 years old the seeds at the respective depths 

 were 15^, 0, and 3-J, and in sod 15 to 20 years old, 20, 24, and 2*, respectively. 



In a field which had grown barley and oats continuously from 1904 to 1912 

 20 oz. of soil in the surface inch showed 134 weed seeds, the second inch showed 

 1.33, and at from 5 to 7 in. 112 seeds were found. A field under a good cropping 

 system since 1905 showed only about one-fourth as many weed seeds as one 

 under continuous grain cropping. 



The destruction of weeds by the use of sulphuric acid, E. Eabate (Prog. 

 Agr. et Vit. {Ed. VEst-Centre), 36 {1915), No. 3, pp. 59-67).— This article dis- 

 cusses the work of several years (E. S. R., 30, p. 441) on weed destruction, and 

 gives results of recent trials in which sulphuric acid was successfully used in 

 the destruction of wild mustard, buttercups, shepherd's purse, whitlow grass, 

 w.illfiower. feverfew, bindweed, knotgrass, trefoil, and ^ledicago apiculata in 

 fiolds of cereals. 



Weeds: How to control them, H. R. Cos {U. 8. Dept. Agr. Fanners' Bui. 

 660 {1915), pp. 29, figs. 27). — This gives methods of control of weeds and a 

 desc-riptive list of the 50 worst weeds of the United States. 



HORTICULTURE. 



Experiments in growing greenhouse croijs on muck or humus soils, 11. C. 

 Thompson (Jour. Amer. Peat Soc, 7 {1914), No. 4, pp. 191-207. figs. 7).— The 

 results are given of experiments conducted by the author during the seasons 

 1912-13 and 1913-14 to determine the value of muck or humus soils in growing 

 greenhouse crops and the adaptation of different crops to these soils. The 

 work the first season was confined to one representative tyiie of pure muck soil 

 taken from a cultivated field in northern New Jersey and the growing of let- 

 tuce, cauliflower, and tomatoes. An additional type of muck from a cultivated 

 field near Kalamazoo, Mich., was used the second sea.son and roses and carna- 

 tions were also grown on the New Jersey muck. Yields for the various plats 

 are here presented in tabular form and discussed. 



No definite conclusions are drawn, but the results for two seasons indicate 

 that a good type of cultivated muck soil is valuable for greenhouse crops. Raw 

 muck soil gave much lower yields than the cultivated soil. The greatest value 

 of muck is for crops grown for their foliage, such as lettuce, although cauli- 

 flower and tomatoes produced large yields on pure muck and on mixtures con- 

 taining from 25 to 75 per cent of muck. Pure muck should not be used with 

 ro.s3s, as the foliage growth is too great and the flowers not satisfactory. A 

 mixture of muck soil and clay produced large numbers of flowers of good color 

 with long stems and excellent foliage. With carnations the muck soil did not 

 give as good results as a clay-sand-manure mixture. The flower stems on plants 

 in the plats containing 50 per cent or more of muck were longer and heavier 

 than on the plants in the regular greenhouse soil, but the number of blossoms 

 produced was not as large. 



Grafting the eggplant on Solanum torbum, H. A. van Hermann {Modern 

 Cuba, 3 {1915), No. 3, pp. 54-57, fig. i).— The author calls attention to the 

 98262°— No. 2—15 1 



