G30 EXPERIMENT STATION RECORD. [Vol. 43 



]arj;:e amounts of avuilabU' phosphorus in certain of the Bavarian soils wliicli 

 are rich in lime. 



It is also concluded that the action of heat and soil bacteria on the pro- 

 duction of carbon dioxid in soils has a marked effect upon the availability 

 of soil phosphates, and the use of organic matter as an aid in this action is 

 therefore recommended. 



Kaw rock phosphate v. acid phosphate, G. D. Cain (Louisiana Stas. Rpt. 

 1919. p. 31). — Experiments on a 3-year rotation are reported showing tliat raw 

 rock pho.sphate applied to corn at the rate of 2,700 lbs. per acre every third 

 year gave slightly better results than 16 per cent acid phosphate applied at 

 the rate of 300 lbs. per acre. Opposite results were obtained with cotton. 



Potash from kelp.— IT, The experimental distillation of kelp at low tem- 

 peratures, G. C. Spencer (Jour. Inilus. and Engin. Chem., 12 {1920), No. 7, 

 pp. 682-68.',, fig. l).—li\ a second contribution (E. S. R., 41, p. 508), studies of 

 the experimental destructive distillation of dried kelp, to determine whether or 

 not under carefully controlled conditions any relationship could be established 

 between the temperature at which distillation was taking place and the nature 

 of the distillation products, are reported. 



Sixteen distillations of dried kelp were made in an oil-jacketed wood retort 

 at temperatures not exceeding 320° C. These yielded aqueous liquor, tar, and 

 a nonintlammable gas. The residual charcoal was insufficiently heated either 

 for a good extraction of potash or for use as a filtering medium. This work has 

 demonstrated the necessity for distilling kelp at a much higher temperature. 



Experiments with sodium chlorid and potassium salts, H. R. Christensen 

 (Tidskr. Planteavl, 26 {1920), No. 5, pp. 137-823).— The results of the works of 

 others bearing on the subject are briefly reviewed, and experiments conducted 

 at the Danish state experiment stations on the fertilizing influence of sodium 

 chlorid and potassium salts on such root crops as mangolds, swedes, and 

 potatoes, are reported. 



The results indicate that under certain conditions sodium chlorid has a 

 very stimulating effect on the production of dry matter in crops, but this was 

 evident only in the case of mangolds for Danish crops. Raw Stassfurt salts, 

 kainit for instance, consistently replaced sodium chlorid in this respect. 



It is concluded that the more extensive use of low-grade potash salts is 

 justified and also the use of sodium chlorid. It is the opinion that the use of 

 these salts, sodium chlorid in particular, tends to offset the injurious effect of 

 summer droughts on the growth of mangolds. Sodium chlorid as a rule had 

 no effect on swedes, and there was no difference between the results obtained 

 with high and low grade potash fertilizers. High-grade potash salts were 

 preferable for potatoes, however. Kainit and sodium chlorid often had a 

 directly negative influence upon potatoes, as indicated by small production and 

 low quality. 



Lime in 1918, G. F. Loughlin and H. Insley {U. S. Geol. Survey, Min. 

 Resotirces U. S., 1918, pt. 2, pp. 813-856, pis. S, figs. 3).— Considerable statistical 

 data on the production, sale, and use of lime for different purposes, including 

 agriculture, in the United States during 1918 are reported graphically and 

 otherwise. 



The total quantity of lime sold in 1918 was 3,206,016 short tons, valued at 

 $26,808,909 — a decrease in quantity of 580,348 tons, or 15 per cent, but an 

 increase in value of .$3,001,032, or 13 per cent, compared with the production 

 in 1917. The average price per ton of lime increased from $6.29 in 1917 to 

 $8.36 in 1918. This was an increase of 33 per cent over the price for 1917 

 and of 113 per cent over the price for 1914. The greatest increase in price 



