724 EXPERIMENT STATION RECORD. 



The gi neral soil and cultural conditions are described, with suggestions as to improve- 

 ments, and the physical and chemical properties of the soils, based on analyses of 

 samples from typical virgin and cultivated areas, are discussed, the attempt being 

 made "to describe, classify, and indicate the best method of manuring the tea soils 

 of each district in the Brahmaputra Valley." It is shown that the. soils used for 

 tea culture in this valley vary from micaceous sand and gravel to stiff red clays. 



The field observations as well as the analyses reported show a deterioration of the 

 soils under continuous culture in tea as regards both yield and quality of product. 

 This deterioration is considered to be largely due to decline in fertilizing constitu- 

 ents, especially organic matter and nitrogen, and may, to a large extent, be remedied 

 by the judicious use of local supplies of fertilizing materials. "Tea requires for its 

 successful cultivation a considerable quantity of organic matter and nitrogen in the 

 soil — the best results being obtained only when more than 35 per cent of the non- 

 sandy portions of the soil consists of organic matter and 0.8 per cent of nitrogen. 

 Provided this is present, tea can be cultivated with success in presence of a minimum 

 quantity of other constituents, notably phosphoric acid and potash; but to obtain 

 high-quality tea these latter materials must exist in the soil in larger amount, and, 

 other things being equal, the larger the quantity of phosphoric acid (in presence of 

 sufficient nitrogen) the better will be the tea. . . . One might say that in general 

 terms if on analysis a soil presents ( 1 ) less than 35 per cent of organic matter, or 

 (2) less than 0.8 per cent of nitrogen, on the nonsand}"^ portion of the soil it needs 

 these constituents as manure; (3) less than 0.25 per cent of phosphoric acid, calcu- 

 lated in the same way, it needs phosphates, and if high-quality tea is to be produced 

 0.4 per cent should be present; (4) potash in amount less than 3 per cent of the oxid 

 of iron and alumina, taken together, it needs potash manures. . . . Potash runs 

 parallel with phosphoric acid, but is probably present in ample quantity in Assam 

 soils. In short, much nitrogen with little phosphoric acid will produce rank growth 

 with medium tea only — much nitrogen with nnich phosphoric acid will give luxuri- 

 ant growth and high-quality tea— little nitrogen with much phosphoric acid will give 

 high-quality tea, l)ut comparatively little of it — and if there is a deficiency in both, 

 tea can never be profitable. Other constituents besides the three named may possi- 

 bly have an intimate connection with the quality of the tea. Lime probably has 

 little or none — and is in any case present in ample quantity everywhere." Iron and 

 manganese appear to be present in sufficient quanity in the Assam soils. Whether 

 they exert any important influence on the growth of tea has not yet been definitely 

 determined. ■ 



"The methods of manuring recommended are based on the necessity for the addi- 

 tion of organic matter and nitrogen in almost every case, of phosphates often, and 

 occasionally of potash. In a heavy soil generally speaking green manuring crops 

 previously manured with phosphates give the best method; in a light one usually 

 cattle manure or oil cake, also with green manuring, form the best addition, taking 

 into consideration the ultimate object of all manuring — the maximum improvement 

 of the crop at the minimum of cost." (See also p. 749. ) 



A chemical study of the phosphoric acid and potash contents of the wheat 

 soils of Broadbalk field, Rothamsted, B. Dyek (PliiJ. Trans. Ro}/. Soc. [Lonfhni], 

 ser. B, 194 {1901), pp. 2S5-290) .^T!h.\s gives in full the paper which was noted in 

 abstract (E. S. R., 13, p. 30). 



The Eocene deposits of Maryland, AV. B. Clark, G. C. Martin, et al. {Mary- 

 land Geological Sarrei/: Eocene. Baltimore: Johns Hopkins Press, 1901, pp. 3S1, pis. 

 64). — This includes a historical review of the literature of the subject with a list of 

 113 references to articles on the subject; discussions of the general stratigraphic rela- 

 tions of the deposits, distribution of strata, general classification of the deposits, 

 origin of the materials, stratigraphical and paleontological characteristics, geological 

 and geographical distribution of species, correlation of deposits, and systematic 



