No. 1, July, 1920] SOIL SCIENCE 245 



pletely inhibit it. The damage Beems to !>'■ due to the inability of the plant to secure water 



with sufficient rapidity. — William ./. linbl, ins. 



L633. 11i;ssi;i,\i an, IIkmuk. Studier over de norrlandska tallhedarnas ftfryngringsvlllkor. 

 II. [Studies of natural reproduction in the pine heaths of Norrland.| Skogsv&rdsfftrenillgi 

 Tidskr. 17:29-76. Fig. I t8. L919. 



1631. PaBKBB, R. C. Testing seed potatoes on Long Island. Potato Mag. 2 2 : 8, 22 -23; 

 2<: 19, 27 -28. 1 fig. 1919— See Bot. Absts. 3, Entry 2721. 



1635. Sim, T. II. Soil erosion and conservation. South African Jour, [ndust. 2: 1034- 

 1042. 1919. — Within or in the vicinity of undamaged forest, erosion is rare. It is not usually 

 the root mass which holds the soil, but the surface sponge which prevents water from running, 

 or from gaining force if it docs run. Certain classes of grass-veld are naturally tending toward 

 the tree veld and should be in trees rather than in grass. — E. P. Phillips. 



1636. Stbinkobnig, L. A, Relation of fluorine in soils, plants, and animals. Jour. Indust. 

 Eng. Chem. 11 : 163-465. 1919. — The percentage of fluorine in plants seldom rises above 0.002 

 per cent and most times it is below 0.001 per cent. [See also Bot. Absts. 4, Entry 2716.] — 

 H, Schmitz. 



1637. Swanson, C. O., and W. L. Latshaw. Effect of alfalfa on the fertility elements 

 of the soil in comparison with grain crops. Soil Sci. 8: 1-39. 1919. — Analyses are reported for 

 the nitrogen, phosphorus, calcium, and organic and inorganic carbon of the soil from old 

 alfalfa fields, old cultivated fields and virgin sod wherever they could be found in close prox- 

 imity. About 40 comparisons involving approximately 100 soils were made. In the humid 

 and sub-humid sections of Kansas the alfalfa fields contained less nitrogen than the virgin 

 sod but more than the cropped fields. In the semi-arid section the alfalfa fields contained 

 more nitrogen than the virgin sod. The cropped fields contained less than the sod. In all 

 three sections the alfalfa fields contain less organic carbon than the sod but more than the 

 cropped fields. The phosphorus content of cropped soil was less than that in alfalfa or sod. — 

 William J. Robbins. 



1638. Walker, S. S. The use of nickel crucibles for the J. Larence Smith fusion in deter- 

 mining soil potassium. Jour. Indust. Eng. Chem. 11: 1139-1140. 1919. — It is found that the 

 same results for soil potassium are obtained whether the soil is fused in a platinum or nickel 

 crucible, but that the nickel crucibles are attacked by the fusion mixture and are therefore 

 not as satisfactory. — Henry Schmitz. 



1639. Walster, H. L. Soil conditions and plant growth. [Rev. of: Russell, E. J. 

 Soil conditions and plant growth. 3d ed. 243 p., 14 fig. Longmans, Green and Co.: New 

 York, 1917.] Bot. Gaz. 67: 171-173. Feb., 1919. 



INFLUENCE OF BIOLOGICAL AGENTS 



1640. Allen, E. R. Some conditions affecting the growth and activities of Azotobacter 

 chroococcum. Ann. Missouri Bot. Gard. 6: 1-44. Fig. 1-2. 1919. — See Bot. Absts. 4, 

 Entry 1532. 



1641. Barthel, Chr. Forsok med Dr. A. Kiihns U-culturer. [Tests of Dr. A. Kuhns' 

 U-cultures.] K. Landbr. Akad. Handl. och Tidskr. 1919: 85-95. 1919.— A review of work on 

 soil inoculation with cultures of free-living, nitrogen fixing bacteria and a presentation of bac- 

 teriological and cultural investigations with a "universal-culture" put out by Dr. A. Kuhn 

 of Berlin. U-cultures contain a mixed bacterial flora similar to that found in ordinary soil. 

 No beneficial effect was found from its use in tests with oats, potatoes, and cabbage. Sub- 

 stantiates the belief of soil bacteriologists that, aside from the specific nodule bacteria of 

 legumes, introduction of nitrogen fixing bacteria into normal soils is ineffective since these 



