Preliminary Study of a Method for Obtaining Brown Coal and Biochar Based Granular Compound Fertilizer

A purpose of the research was to develop a method for the preparation of novel organo-mineral fertilizers with the use of brown coal and biochars as organic additives. Brown coal was blended simultaneously together with inorganic materials used for the process of urea superphosphate production in a laboratory scale using a pan granulator and in larger scale using a rapid mixer granulator. Biochars were used for the coating purposes of the urea superphosphate granules on a laboratory scale using a pan granulator. Moreover, the aim was to measure and evaluate the physico-chemical properties of organic materials and the obtained organo-mineral fertilizer products and to study the effects of these products on the selected yield components of spring wheat such as grain yield per plant, spike number per plant, and plant height, in pot trials. Results showed that brown coal and biochars can be used as raw materials for production of fertilizer products. Brown coal contained about 50% of total humic acids while biochar contained nearly 6% of total humic-like substances. Brown coal based compound fertilizer granules produced in the large scale were characterized by particle hardness from 15.80 to 23.3 N while those produced in the laboratory scale were classified as "soft" (particle hardness below 2.3 N). The application of brown coal based fertilizers and two studied biochar coated fertilizers had a positive impact on the grain yield per plant of spring wheat.