858 EXPERIMENT STATION RECORD. 



"The met I mil, therefore, should be of great value in comparing soils, the conditions 

 of which as to climate, etc., are similar. But its indications might lead to erroneous 

 views as tn the relative fertility of soils from tropical countries \\ hen compared with 

 those in temperate climates, since in the former a smaller amount of available plant 

 food in the soil, if renewed more rapidly, as it probably is, might furnish to the 

 plants an actually greater quantity of nutriment than would be yielded by a soil con- 

 taining a considerably larger amount of available food, but in which the processes by 

 which the unavailable become available went on more slowly. 



"( )f the probable truth of these conclusions the writer, from a comparison of his 

 analyses of the soils of the Transvaal with those of English soils, is fully persuaded, 

 although he fully realizes the favoring influences of abundant sunshine and high 

 temperature which affect the growth of plants in South Africa, and which help to 

 explain the fact that luxuriant crops are yielded by soils which, on analysis, appear 

 to be extremely deficient in plant food." 



The analysis of the soil by means of the plant, A. D. Hall {Jour. Ayr. 

 Sri., 1 (1905), No. 1, pp. (15-88). — This is a detailed account of observations which 

 have beeii briefly noted from another source (E. S. R., IB, p. 552). 



A contribution to the devising of a method of determining the fertilizer 

 requirements of soils by means of plant analysis, J. Hanamann (Ztschr. Landw. 

 Versuchsw. Oesterr., 7 {1904), No. 11, pp. 805-818). — A series of pot cultures with 

 barley, conducted according to the Helmkampf method, is reported, and the bearing 

 of the results on the accuracy of this method of determining the fertilizer require- 

 ments of soils is discussed. Ash analyses of the above-ground parts of the crops are 

 reported, and with analyses of the seed and soil are used in calculations of the bal- 

 ance of the fertilizing constituents. The results indicate that at least in ease of 

 barley the analysis of the straw will give a reliable indication of the fertilizer 

 requirements of the soil. 



Soil inoculation {Jour. Bd. Agr. [London], 11 (1905), No. 11, pp. 669-67 3). — A brief 

 account is given of methods of using the pure cultures made by Hiltnerand by G. T. 

 Moore of this Department. 



Nutrition of micro-organisms. The bacterial population of the soil, 

 L. Grandeau {Jour. Agr. Prat., n. ser., 9 ( t905), No. 8, pp. 237-239). — A brief sum- 

 mary of investigations by Duclaux, Fraenkel, Hold (E. S. R., 16, p. 553), and others 

 relating to the conditions favoring the development of micro-organisms in the soil. 



Nitrogen collecting bacteria, fallow, and exhaustive culture, T. Pfeiffbr 

 (.1////. Landw. Trust. Univ. Breslau, 3 (1!>04), Xo. 1, pp. 93-145). — This is a study of 

 the organisms of the soil which tix free nitrogen without association with leguminous 

 plants, and of the relation they bear to soil fertility under different conditions of 

 fallow and exhaustive culture. The results clearly confirm those of Rerthelot in 

 showing the existence and activity of such organisms. The exact agricultural 

 importance of these organisms is, however, not definitely known, it is shown that 

 the nitrogen supply of the soil is under favorable conditions so slowly utilized that 

 exhaustion is noted only after many years, and mi rich soils is scarcely noticeable 

 from year to year. Thorough aeration of the soil promotes the activity of the soil 

 organisms and hastens the exhaustion of the nitrogen supply. 



( )n bare fallow a large part of the nitrogen rendered soluble goes into the drainage 

 water and is lost. Fallow is in all cases an extreme form of soil robbery as regards 

 nitrogen, and its disadvantage in this respect is not compensated for by other minor 

 advantages in improving physical condition, etc., which it possesses. Such soil 

 robbery is not fully made good by the application of ammonium salts and nitrate of 

 soda. Barnyard manure appears to be the best means of restoring the fertility of 

 soils run down by exhaustive culture. 



On the treatment of soils with ether, carbon bisulphid, chloroform, 

 benzol, and hydrogen peroxid, and its effect on the growth of plants, F. 



