386 EXPERIMENT 8TATI0N RECORD. 



15-lG {1896), No. 18-19, itp. 1108-1110).— Tests of the alisorptive power of sterile and 

 hiimris soil for dextrin and gelatin are reported, showing tliat the presence of hnmus 

 greatly increases this pr(>i)ert> in soils. 



The conservation of moisture in the soil {(iarihn and Forest, (1S96), Xo. 450, 

 pp. 401, 402). 



The influence of growing plants upon soil moisture, E. D. .Sandehson {Souilurii 

 Itiiralist; Florida Farmer and Fruit (irotoer, 8 (189G), No. 41, pp. 045, 640). — A popular 

 article based upon experiments made in Germany and hy the stations in the United 

 States. 



FERTILIZERS. 



The assimilability of nitric and anmioniacal nitrogen by plants, 



Pagnoul {Ann. Ayron., ;J;J {J89(i), Xo. 10, pp. 485-490).— These two 

 forms of nitrogen were compared with each other on beets, cameline 

 {Camelina stifiva), clover, and oats grown in pots of about 25 liters 

 capacity filled with sterile sand. Three pots were devoted to each test, 

 the first receiving no fertilizer, the second phosphate of soda and nitrate 

 of potash, and the tliird ])liosphate of soda, muriate of potash, and 

 sulphate of ammonia. 



Tlie sulphate of ammonia proved decidedly superior to the nitrate, 

 giving yields nearly double the yield of beets, clover, and oats, and 

 over three times tlie yield of cameline produced by the nitrate. 



The unfertilized plants contained a small amount of nitrogen, but 

 the proportion was largely increased when fertilizers were ai)plied. No 

 trace of nitric nitrogen was found in the unfertilized plants. It was 

 abundant, however, in plants which had received nitrates and in much 

 less but still appreciable quantities in those which had received sulphate 

 of ammonia. 



The indications are that the ammonia salt was directly assimilated 

 and was more rapidly taken up than the nitrate. Examinations of the 

 crops on June 6 and 22 showed that during that period the nitric nitro- 

 gen had greatly decreased in the cases where nitrates were used, and it 

 is inferred that this nitrogen was used to build tissue. Ammoniacal 

 nitrogen was also determined. Very small amounts were found, on the 

 average a little more in the plants to which nitrates were ap])lied than 

 in those receiving the ammonia salt. 



The water content of the plants receiving sulphate of ammonia was 

 smaller than that of those fertilized with nitrates. 



The method used in determining nitric nitrogen in these investiga- 

 tions was as follows: Dry the material at 105° 0. and grind fine while 

 still warm. Place 2 gin. of the powder in a porcelain dish with a little 

 water and heat to boiling for a few minutes. Cool and add 6 to 10 

 drops of subacetate of lead, mix, and then add 1 gra. of animal black 

 which has been washed with acid. Let stand for 1 hour, shaking from 

 time to time, filter into a 50 cc. Hask, and make up to mark. Evaporate 

 5 cc. of this solution to dryness, add a dozen drops of i)henol-sulphuric 

 acid (10 gm. phenol in 70 of acid), mix thoroughly, add aJittle water, and 

 then ammonia. A yellow coloration due to j^icrate of ammonia appears 

 if nitric nitrogen was present in the origiiuil material. The amount of 



