Characterization of Treated Leonardites and Their Effects On Seedling Growth.

Seeds of two crops (soybean, corn) were treated in petri dishes with fulvic acid, humic acid, mixture of fulvic acid plus humic acid which derived from a leonardite (Neimeng province of China), and with 2 fractions of the same humic acid obtained by different membrane (©ƒ15KD, ©ƒ50KD). These 5 humic substrates were applied at 10, 50 and 200 mg C ·L^-1. Germination parameters such as the number of total germinated seeds, the velocity of seed germination, the fresh weight and dry weight of total seedlings were measured. We also measured chemical and physicochemical properties of humic substrates.  The germination (10 days) of 10 seeds (10 ml) were carried in controlled temperature, humidity conditions in a chamber, and early growth (30 days) of soybean and corn were carried using sand.