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The Effect of Substituted Cations in the Soil Complex on the Decomposition of Organic Matter
Author(s) -
Smith F. B.,
Whitehead Thomas
Publication year - 1941
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1941.036159950005000c0043x
Subject(s) - citation , decomposition , session (web analytics) , organic matter , computer science , library science , chemistry , sociology , organic chemistry , world wide web
TV /f ICROBIOLOGICAL action in soil is affected 1V1 by several factors, one of which is hydrogen ion concentration. The decomposition of organic matter may take place under widely varying conditions, depending upon the pH of the soil, numbers and kinds of organisms, available nutrient elements and water and air relationships. Because of the known harmful effects of strong acids on living tissues the early soil microbiologists believed that any acidity was detrimental to the soil microorganisms, especially to the bacteria. Consequently it was thought by some that the beneficial effects of lime on soils was due principally to the neutralization of soil acids. Subsequently it was found that many soil microorganisms tolerate slight acidities and that optimum conditions for some bacteria are actually strongly acid. As a matter of fact, optimum reactions for most of the physiological processes in plants and animals seem to be obtained on the acid side of neutrality. Because of this there has been a tendency in some quarters to discount the importance of lime as an agent to neutralize soil acids. However, there are some who still consider that an important function of lime under .certain soil conditions is to neutralize acidity. Albrecht and his associates (i, 2., 3, 4, 5, 6, 9, io) have contributed much information concerning the relation of calcium and the hydrogen-ion concentration to the growth and nodulation of soybeans. Killinger and Smith (7), in a study of the importance of soil colloids to soil microorganisms, found that colloidal suspensions added to culture media brought about notable increases in the growth of Rhizobium leguminosarum, Bacillus radiobacter, and Asotobacter chroococcum. McCalla (io) investigated the effect of adsorbed ions of colloidal clay as a factor in nitrogen fixation by Azotobacter and found that the amount of nitrogen fixed was influenced by the kind and quantity of ions adsorbed by the clay. Kononova (8) has studied the influence of exchangeable bases on the decomposition of organic matter in soils. Unfortunately, the details of Kononova's investigations are not readily available and there is still a need for more information on the effects of the adsorbed ions of the colloidal complex on the decomposition of organic matter in soils. The purpose of the work reported here was to determine the rate of decomposition of organic matter in soils saturated with different cations and to observe the effects of the decomposing organic matter on the pH of the soil.