240 



The addition of the plaster had accordingly reduced the loss in organic 

 substances and also in nitrogen ; i. e., had exercised an arresting influence on 

 decomposition. The use of calcium compounds as a remedy against dis- 

 eases, in which an excess of nitrogen comes under consideration, will be 

 discussed under the individual cases of disease. 



3. THE DISADVANTAGES OF MOOR SOILS. 



The Acids in the Soil. 



Ramann^ explains as moors,— the formation of more moist regions in 

 temperate zones, in which soils poor in nutritive substances, with an acid 

 reaction, are covered with dwarfed bushes, grasses, mosses and peat-moss 

 (sphagnum), and also lichens. 



The humic acids* act freely here, and cause the acid reaction of the 

 soil. Acids are formed by the decomposition of the organic substances in 

 the soil to which fungi as well as bacteria surely contribute a share (Cepha- 

 losporium, Trichoderma, etc., according to Koning-). Formic acid, acetic 

 acid, butyric acid, etc., are produced which decompose rapidly in well 

 aerated soils. Besides these, however, the humic substances also form the 

 still little known crenic acid with its salts (crenates) which, widely dis- 

 tributed in soils and water, form a yellow, strongly acid solution, 

 drying to an amorphous mass. While its salts with alkalis and alkaline 

 earths are soluble, its ferric oxid remains insoluble. With the entrance of 

 air aprocrenic acid is produced from it, the salts of which are either in- 

 soluble or dissolve with difficulty. A great influence on the weathering and 

 the transportation of the accessible mineral salts may be ascribed to these 

 acids and their compounds\ Raw humus, peat and other soil substances 

 with a strong acid reaction lose only a part of their acids even after lying 

 sometime exposed to the air. Since even well aerated forest soil often 

 shows an acid reaction, it may be concluded that scant oxidation either does 

 not cause the production of the soil acids, or only at times produces them. 

 We must consider here also the work of definite bacteria in this acid for- 

 mation. Free acids are often absent in good soils, but poorer moor soils are 

 frequently rich in them and become even poorer because extensive leaching 

 and weathering processes constantly take place, due to the free acids. 



1 Ramann, Bodenkunde, 2nd. Edition. Jul. Springer. 1905. 



2 Koning-, Arch, n^erland. sc. ex. et nat. 1902 II, 9, p. 34. 



3 Ramann, loc. cit. p. 144. 



* In the light of recent investigations on the nature of the organic matter 

 of the soil it seems that we m<ust revise some of the older terminology. The term 

 '•humic acids" is rather to be regarded as a loose generic term applicable to a group 

 of organic compounds found in the soil. — Vide: — 



Mulder, The Chemistry of Vegetable and Animal Physiology, trans, by From- 

 berg, 1849. 



Schreiner, O. and Shorey, E. C, Bulletins 53, 74, and 88, Bureau of Soils, U. S. 

 Department of Agriculture. 



Jodidi, S. L. Jour. Amer. Chem. Soc. 34: 94. 1912: Jour. Franklin Inst. 175: 245. 

 1913. 



(Translator's note) 



