520 EXPERIMENT STATION RECORD. [Vol.38 



fertilizers, T. Remy {Landw. Jahrb., 49 {1916), pp. 685-728; abs. in Chem. 

 Zentbl, 1916, II, p. 766; Chem. Abs., 11 (1911), No. 15, p. 2253).— A description 

 is given of the so-called Rhenania phosphate, which is prepared from dicalciura 

 phosphate and phonolito, the phosphoric acid being rendered available to a 

 considerable extent and the potash made practically aa effective as potassium 

 chlorid. " Good Rhenania phosphate must contain 3 to 4 per cent K2O, 12 to 

 13 per cent P2O5, and at least 90 per cent of fine meal. Furthermore, at least 

 75 per cent of the PjOs must be citric acid-soluble and at least 50 per cent 

 citrate-soluble. Tables are given showing the solubility in various solvents of 

 the P2O5 and K2O in the raw materials, Rhenania phosphate, and two similar 

 preparations (Wolter phosphate and Gafsa phosphate)." 



Schroder's phosphate-potash, its preparation, manner of action, and 

 utilization, M. Popp {Landw. Jahrb., ^9 {1916), pp. 729-795; abs. in Chem. 

 Zentbl., 1916, II, p. 767; Chem. Abs., 11 {1917), No. 15, p. 2253).— Culture ex- 

 periments conducted at four experiment stations are reported with so-called 

 Schroder's phosphate-potash fertilizers which are prepared by heating raw 

 phosphate with calcium chlorid and magnesium chlorid. The potash was 

 found to act similarly to that of Stassfurt salts, the phosphate-potash fertilizer 

 having the same effect on cereals as 40 per cent potash salts. The yield of 

 potatoes was decreased, due to the action of the chlorin content. The Schroder 

 fertilizer and Thomas meal gave about equally valuable results. 



Potash from tule and the fertilizer value of certain marsh plants, P. L. 

 HiBBABD {California Sta. Bui. 288 {1917), pp. i87-i92).— Limited studies of 

 California marsh vegetation, particularly tule {Scirpus lacustris) but includ- 

 ing certain sedges and cat-tails, indicate that from 100 to 200 lbs. of potash 

 per acre may be obtained from a heavy growth of tule at an approximate cost 

 of from $5 to $10. The percentage of ash in samples of fresh material analyzed 

 varied from 1.8 to 6.6, averaging a little over 3 per cent, and the potash from 

 0.05 to 1.23, averaging about 0.67. Analyses of crude ash showed that 45.3 

 per cent of it was soluble in water, and that it contained from 7 to 15 per cent 

 of potash, mostly chlorid and sulphate. The crude ash is not deemed suited 

 for mixture with other materials to make high-grade fertilizers but is more 

 valuable for the extraction of high-grade potash salts. 



Fresh tule was found to contain about 6 lbs. of nitrogen, 2 lbs. of phosphoric 

 acid, and 12 lbs. of potash per ton, the proportion varying considerably with 

 the season, locality, and treatment, and it is regarded as comparable with 

 barnyard manure or Pacific coast kelps for fertilizing purposes. Three suc- 

 cessive leachings of one day's duration each extracted 85 per cent of the total 

 potash of the plants, and their harvesting before the leaching action of rains 

 sets in is deemed desirable. 



While potash recovery from tule may not be commercially profitable it is 

 thought that it may be of considerable local importance under present market 

 conditions. 



The importance of liming, J. Hughes {Jour. Bath and West and South. 

 Cotmties Soc., 5. ser., 11 {1916-17), pp. 27-Iflf). — The use of different forms of 

 lime on English soils is discussed. 



The action of precipitated magnesium carbonate on soils, W. P. Kellet 

 {Jour. Amer. Soc. Agron., 9 {1917), No. 6, pp. 285-297). — Experiments with two 

 light sandy loam soils, low in organic matter, are reported which showed "that 

 the effects produced by precipitated magnesium carbonate may differ widely 

 from those of magnesium sulphate. The addition of comparatively small 

 amounts of the former retarded the formation of nitrate to a marked degree, 

 while as much as 0.5 per cent of the latter produced no effect. It was also 



