RECENT WORK IN AGRICULTURAE SCIENCE. 



CHEMISTRY. 



Chemical methods for the determination of the fertility of the soils with 

 respect to phosphoric acid, K. K. (Ikdroitz {Zliur. Opujtri. Ai/roii. [Jour. Expt. 

 lAtndiv.], 4 {1903), No. 4, pp- 403-432). — The author reviews his previous investiga- 

 tions on this subject, and reports further pot experiments with oats and mustard on 

 19 widely different soils. The pots contained 5 kg. of dry soil and were fertilized 

 with various amounts and combinations of nitrogen, phosphoric acid, potash, and 

 lime. 



The phosphoric acid was determined separately in the straw and grain of the 

 harvested crops, as well as in the roots in a few cases. The solubi'lity of the phos- 

 phoric acid of the soil in 2 per cent citric and acetic acids was also determined. 

 From a comparison of the data thus obtained the conclusion is drawn that ])lants 

 vary widely in their capacity for utilizing the phosphoric acid of the soil. There 

 was no close agreement between the amounts utilized by the oats and mustard 

 on the same soil, and similar results are reported for 12 different kinds of plants 

 grown on the same soil, namely, sandy chernezem. 



It was further shown in studies on 19 different samples of soil that there was no 

 agreement between the availability of the phosphoric acid of the soil as measured 

 by solubility in 2 per cent citric or acetic acid and the amounts taken up by jilants. 

 In studies of the relative assimilability of the phosphates of iron, aluminum, and 

 calcium by flax, oats, and mustard, as compared with their solubility in citric and 

 acetic acids, it was found that as regards the yield produced the relative efficiency 

 of these phosphates was, beginning with the highest, aluminum phosphate, calcium 

 phosphate, and iron phosphate. As regards solubility in 2 per cent acetic acid, the 

 order was calcium phosphate, aluminum phosphate, and iron phosphate, the latter 

 being almost insoluble in acetic acid. The aluminum and calcium phosphates were 

 about equally soluble in 2 per cent citric acid, thus showing a closer agreement 

 with the actual availability of these phosphates as determined by means of the 



plant. — p. FIREMAN. 



Studies in soil analysis, A. Atterberg {K. Landt. Akad. Ilandl. oeh T'uMr., 42 

 {1903), No. 3, pp. 185-253). — A discussion of methods of mechanical soil analysis, 

 and suggestions for a new terminology of soil grains. The relation of soil particles 

 of different diameters to hygroscopicity, air content, volume, weight, caijillarity,. 

 etc., were studied experimentally, as well as the rapidity of drying out, the floccu- 

 ;ati(jn of fine sand grains, the relation of sandy soil to plant roots, etc. — f. w. woll. 



On recent efforts to simplify soil analysis, Emmerling {Oesterr. Chem. Ztg., 6 

 {1903), No. 18, p). 412). — This is a brief note on an address before the International 

 Congress of Applied Chemisti-y at Berlin in 1903, and refers to Rodewald's method 

 of determining the fineness of the particles of a soil by means of its hygroscopicity, 

 the importance of tlie determination of the loss on ignition, the comparatively little 

 value of determinations of nitrogen by means of the Kjeldahl method, and the sub- 

 stitution of weaker solvents for stronger acids like hot hydrochloric acid in the chem- 

 ical analysis of soils. 



549 



