WATER SOILS. 



727 



Experinient.s with sugar beets gave the following results: 



Assimilable plant food in the soil corresponding with different yields of sugar beets. 



High yield 



Mediiim yield 

 Low vield 



Nitrogen. 



Per cent. 

 0.0140 

 .0069 



Phosplioric 

 acid. 



0. 0026 

 .0008 



Experiments with white mustard showed that, while it resembles 

 oats and barley with respect to assimilating nitrogen and phosphoric 

 acid from the soil, it is strikingly sensitive to the sulphuric acid con- 

 tent of the soil. Other things being equal, the yield was increased 

 1^ to 2 times when a fertilizer containing sulphuric acid was added. 



From his own results and from those of Hellriegel, the author has 

 prepared the following table, which indicates the contents of easily 

 assimilable substances in the soil in the cases of low, medium, and high 

 yields of oats and other plants which do not differ strikingly from one 

 another in their plant-food requirements: 



Assimilable plant food in the soil^ corresponding tvith different yields of oats and plants of 



similar requirements. 



High yield . . . 

 Medium yield 

 Low yield 



Nitrogen. P^°^R^«"« Potash. 



Per cent. 

 0. 0108 

 ! .0000 



. 0021 



acid. 



Per cent. 

 0.0050 

 .0022 

 .0010 



Per cent. 



0.0060 



.0020 



.0010 



— P. FIREMAN. 



The amount of humus in soils and the percentage of nitro- 

 gen in the humus as affected by applications of air-slaked 

 lime and certain other substances, H. J. Wheeler, C. L. Sar- 

 gent, and B. L. Hartwell {Rhode Island Sta. Rpt. 1890, pjy. 

 lo2-159). — This is an account of studies of the changes in humus and 

 nitrogen content of soil which had lieen used in pot experiments with 

 corn, oats, and rye during 1893, ISOi, and 1895. Humus was deter- 

 mined by treatment with hj^drochloric acid according to Hilgard, fol- 

 lowed b}^ extraction with ammonia according to Huston and McBride's 

 method. 



"The nitrogen in the humus was determined by using a 2 J per cent solution of 

 potassium hydroxid in place of the solution of ammonium hydroxid of like strength, 

 which was employed in the determination of humus. Aliquot portions of the extract 

 were then neutralized with sulphuric acid, and after evaporating to dryness in a 

 K-eldahl flask, the nitrogen was determined as usual by the method of Kjeldahl. 

 The soils were air-dried before analyzing, and the different samples contained from 

 2.00 to 2.75 per cent of water determined at 100° C." 



^Calculate" I to dry matter. 



16466— No. 8—01 3 



