PUBLICATIONS ON AGRICULTURAL BOTANY IN FRANCE. 941 



^ The inriiienco of the nature of soils upon ditteient crops was studied 

 by \'ille in 18(j0, Graudeau in 1808-88, and more recently by Kaulin,' 

 who has reported the results of his experiments with clover, beets, 

 wheat, and potatoes. The oi)timum composition of the types of soil 

 for the ditiercut crops as shown by his experiments were us follows: 



Optimum rrhttirc cumponiliun of soils. 



Such investigations will assist in determining the best relative pro- 

 portion of the soil constituents for each of our cultivated plants. 



Deherain and Denioussy^ have studied the circulation of air in the 

 soil, and have arrived at the conclusion that in order to secure the 

 proper aeration and circulation of water, soils should be mixed with 

 marl or lime, so that after a hard rain the water will be promptly car- 

 ried off. Deherain^ has recently discussed the practice of fallowing. 

 He has shown in experiments in boxes that fallowing may be profitable 

 where the supply of fertilizers is limited, and esi)ecially where weeds 

 are allowed to grow, but since the production of manure has so greatly 

 increased and nitrate of soda is so readily secured the practice of fal- 

 lowing can hardly be economically pursued. 



The same authors^ have shown that the oxidation of organic mate- 

 rial goes on rather actively at from 40 to OC^. From this it would 

 api)ear that in tropical regions soils tilled without the application of 

 fertilizers would become sterile through the disappearance of the 

 humus. In temperate regions this disappearance is slower, although 

 constant. In an experiment field at Grignou, Avhere different crops were 

 cultivated and where no fertilizer was used, the soil lost half its organic 

 matter in 10 years. Where manure is liberally used it is necessary to 

 stir the soil in order to admit the oxygen which renders the humus 

 available as plant food. 



Lechartier'' has made soil analyses by means of plants — alfalfa, 

 which was grown upon a variety of soils in different states of fertility. 

 It is claimed that by comparing the composition of imperfectly devel- 

 oped i)lants with that of normal plants the lack of fertilizing elements 

 in the soil may be ascertained. 



Fertilizers. — Claudel and Crochetelle" have reported experiments 



' Anil. Sci. Agroii., ser. 2, ami. 2, 1 (1896), p. 110. 



- Coiiipt. Reud., 122 (1896), p. 109; Ann. Agrou., 22 (1896). ].. 49 (K. S. K., 7, i.).. CI I. 751). 



'Ibid., p. 122; Ann. Agron., 22 (1896), pp. 297, 515 (E. S. R.. 7. p. 848). 



'U.id., 123 (1896;, p. 278 (E. S. R., 8, j). 208). 



5Jour. Agr., 1 (1896), p. 256; Compt. Rend., 121 (1895;, p. 866 (E. S. K'., 7, \^. 752.. 



"Ann. Agron., 22 (1896), p. 131 (E. S. R., 8, p. 55). 



