The growth of Brassica campestris, Solanum tuberosum L., Lycopersicum esculentum and Brassica junce in the field were promoted by the degraded soybean meal products (DSP). The root hair number of Brassica campestris was increased when 10 mul DSP (containing 30 mg peptides + amino acids ml(-1)) were added to 10 ml plant growth medium. A chemical fertilizer and an acid-hydrolyzed DSP did not show such an effect.