SOILS FERTILIZERS. 921 



vations on a niiniher of farms in the rcjiion of Leijtsic as to the effect of rain- 

 fall from the time of seeding to the time of blooming on the action of various 

 fertilizers (nitrate of soda, potash salts, and suixM-ithosphate) on the growth 

 of oats during the dry year of 1904. The rainfall during the growing period 

 (38 days) of 1!X)4 was 126.8 mm., or- 118.2 mm. less than the normal for the 

 region. 



The broad general fact was brought out that the greater the rainfall during 

 the growing jieriod the smaller the action of the easily soluble and the greater 

 the action of the ditficultly soluble fertilizers. The distribution, as well as the 

 amount of the rainfall, was of great importance. Ditficultly soluble fertilizers 

 gave best results when there were a few days of heavy rainfall rather than 

 many days of light rainfall. Nitrate of soda was found to be effective as a 

 fertilizer only when the average daily rainfall during the growing period was 

 at least 2.5 mm. Potash salts and superphosphate required 3.5 mm. Since 

 only about 40 per cent of rainfall is on the average used by plants, it is of 

 great practical value to determine the limits of efficient rainfall for each 

 locality. By application of the method of least squares the probable effect of 

 the fertilizers under different rainfall conditions was calculated. These calcu- 

 lated results agreed quite well with those actually obtained in the field 

 experiments. 



Some results of the use of chemical fertilizers in Carnia, Z. Bonomi (Ann. 

 R. Staz. aS'/kt. Agr. Udine, i) (WOS), pp. 27^0). — A comparison on natural per- 

 manent meadow is here reported of mineral superphosphate alone and com- 

 biniHl with nitrate of soda and with nitrate of soda and sulphate of potash. 

 The superphosphate (12 to 14 per cent phosi)horic acid) was used at the rate of 

 540 lbs. per acre, the nitrate of soda at the rate of 135 lbs. ]>er acre, and the 

 sulphate of potash at the rate of 180 lbs. per acre. Two plats were used for 

 each combination and for check plats. The complete fertilizer gave the largest 

 absolute gain, but the best result economically was obtained from the super- 

 phf»sphate and nitrate of soda. 



Investigations on the composition of Peruvian guano, J. (i. Maschhatjpt 

 (Enf/rais, 23 {1908), A^o. 51, p. Ul)). — The results of 40 analyses of Peruvian 

 guano are summarized, showing the variations in soluble potash, phosphoric 

 acid, oxalic acid, uric acid, anmioniacal nitrogen, nitrogen in form of sul- 

 phate of ammonia, and total nitrogen in jnire guano, leached and decomposed 

 guano, and mixtures of guano and sulphate of ammonia. It is shown that the 

 composition even of pure guano is so variable that it is impracticable to fix a 

 standard for it. 



Studies on the preparation of nitrate, J. Jorgensen {BoJ. Sac. Fomento 

 Fabril [ChUc], 25 ( lOOH), Xo. It, pp. 6-2/-626).— Studies of the solubility at dif- 

 ferent temperatures of caliche containing varying proportions of sodium 

 nitrate, sulphate, and chlorld are reported. Thes" caliches are divided into 3 

 general groui)S : (1) Those containing a large amount of sodium i-hlorid : (2) 

 those containing a large amount of sodium" suli)hiite; and (.'>) those containing 

 carl)onate (lei) in addition to chlorid and sulphate. 



The first group presents no difficulties. For the second group the use of steam 

 of low pressure is recommended. The preparation of the third group is com- 

 plicated and not more than 50 j»er cent of the nitrate is usually recovered. 



The author states that considerable nitrate is lost in the liquid remaining 

 after the i)resent jirocesses of extraction are complete, and that much of this 

 loss may l)e jivoided by careful cheniic:il aii:ilyses and improved methods. 



Experiments on the action of nitrate of soda, ammonium salts, lime nitro- 

 gen, nitrogen lime, and the Norwegian lime niter, W. Schneidewind et al. 



