SOILS FEKTILIZERS. 215 



"The brine of one desiccated lake of souttiem California has been found to 

 contain suflBcient potassium to make it a possibly valuable commercial source 

 of potash." 



The theoretical possibilities in separating the potash from yarious types of 

 brine are pointed out in this bulletin and a review is given of proposed com- 

 mercial methods. 



The extraction of potassium salts from silicate rocks, W. C. Hancock 

 iChem. World, 2 (1913), No. Jf, pp. 118, ii9).— This is a brief review of methods. 



The importance of potash in feldspars for plants, B. Blanck {Jour. Land/to., 

 61 {WIS), No. 1, pp. 1-10). — The results of comparative tests in pot experi- 

 ments of various silicates of potash here reported confirm the results of previous 

 experiments (E. S. R., 27, p. 520) in showing that mica is a more available 

 source of potash for plants than feldspar. 



The action of ground phonolite in several years' fertilizer experiments, P. 

 Wagnek {Mitt. Deut. Landw. GcselL, 28 {1913), Nos. S, pp. 136-139; 9, pp. 151- 

 15It; 10, pp. 161-164)- — The results of cooperative field experiments with farmers 

 in continuation of earlier pot experiments (E. S. R., 20, p. 1118) using ground 

 phonolite in comparison with 40 per cent potash salt and potassium sulphate on a 

 variety of crops showed, in agreement with those obtained by many other inves- 

 tigators, that phonolite did not compare in effectiveness with the potash salts 

 and was not capable of supplsang plants with needed potash unless used in 

 amounts far exceeding those usually applied in practice. 



Kainit as a means of combating weeds, D. Dettweileb {Illus. Landw. Ztg., 

 SS {1913), No. 11, pp. 88, 89; abs. m Chem. Abs., 7 (191S), No. 8, p. 1399).— 

 Applied in pulverized condition when the dew is on the plants or shortly after 

 a rain, or in solution, kainit was found to be an effective means of combating 

 weeds. 



The use of lime on land, F. D. Gardn~eb (Proc. Amer. Soc. Agron., Jf {1912), 

 pp. 67-74)- — A briefer account of experiments here reported has already been 

 noted from another source (E. S. R., 28, p. 223). 



Influence of snlphur on the growth of potatoes and beets, K. Chancein 

 and A. Desbiot {Jour. Agr. Prat., n. ser., 23 {1912), No. 12, pp. 365-367). — 

 Experiments, in continuation of those already noted (E. S. R., 25, p. 519) with 

 these crops, in which sulphur was used at rates of from 200 to 400 kg. per 

 hectare (178 to 356 lbs. per acre), are briefly reported. The results indicate 

 some increase in yield as a result of the application of the sulphur. 



Kecent experiments on the fertilizing' action of sulphur, A. Desbiot {Jour. 

 Agr. Prat., n. ser., 25 {1913), No. 12, pp. 364, 565).— This is an account of 

 experiments in continuation of those noted above, sulphur being used in amounts 

 varying from 50 to 200 kg. per hectare (44.5 to 178 lbs. per acre) on beets, 

 potatoes, onions, and carrots. In case of the beets and potatoes the sulphur 

 was used in connection with manure alone and manure and a complete fertilizer. 



A green manure for tobacco, M. K. Bambee {Trap. Agr. and Mag. Ceylon 

 Agr. Soc., 40 {1913), No. 2, p. 85). — This article deals particularly with the 

 fertilizing value of the tulip tree {Thespesia populnea), which, it is stated, is 

 now largely used as a green manure for tobacco by the Cingalese. Analyses 

 are reported which show that sun-dried samples of this tree contained 2.2 per 

 cent of nitrogen and 10.3 per cent of ash, the ash containing 26 per cent of lime, 

 26.8 per cent of potash, and 5.4 per cent of phosphoric acid. Analyses of other 

 plants of value for green manuring are also reported, namely. Vigna catjang, 

 Crotalaria striata, PJiaseolus lunatus, Leuccena glauca, Tephros-ia purpurea,, and 

 T. Candida. 



