Geochemical examination of lake sapropels used as fertilizers and fodder additives, U.S.S.R.

Abstract

In recent years sapropels have been increasingly used as fertilizers and fodder additives in Byelorussia and in other regions of the Soviet Union. Thorough geochemical investigations are required to elucidate the essential differences in the composition of lake sapropels. At the same time, a rather wide range of element concentrations permits the selection of lakes and deposits with the most valuable proproties for these uses. The agrochemical effectiveness of sapropels is determined by the content of N, P, K, a number of trace elements, the silty fraction, the amount of biologically active substances, and the level of exchange acidity. It is also important to know the content of harmful components, e.g. pesticides, benzopyrine, a number of heavy metals (such as Pb, Hg and Cd) and the presence of pathogenic microorganisms. The content of mobile forms of elements, which the authors investigated by the method of successive extractions and isolation of humic and fulvic acids, is very essential for the utilization of sapropels as fertilizers and fodder additives. Three limno-geochemical provinces, differing in the types of deposits and ion the chamical composition of sapropels, were defined in Byelorussia. This led to more efficient prospecting and identification of the occurrence of sapropels with specific properties.