In the silty Lithuanian lakes are accumulated about 1,5 mlrd. m3 sapropel. Sapropel is valuable organic, limy matter, which can be used for fertilization and improving of soil. Lakes sapropel of various chemical composition a potential fertilizers were studied at the Voke Branch of the Lithuanian Institute of Agriculture during 1984-2008. Summarised results of a long-term experiment showed that calcareous sapropel reduced soil acidity, increased the amount of exchangeable bases. Under the influence of sapropel the contents of organic carbon and total nitrogen increased, as well. Experimental...