In this study, waste human hairs discarded from beauty shops and barber shops were collected and hydrolysed with a mixture of 0.5 N KOH and 0.05 N $Ca(OH)_2$ by heating treatment for 20 min at $120^{circ}C$. The pH of the hydrolysate was adjusted to 8 using phosphoric acid. The final solid content of the hair hydrolysate was adjusted to 100 g/L based on hair weight. Nitrogen, carbon, hydrogen, sulfur, and oxygen contents in the hydrolysate were 13.68, 48.58, 6.46, 3.02, and 28.26%, respectively. When 0.5% (w/v) of forest soil was inoculated into 1% (v/v) of hair hydrolysate solution, 3% (w/v) of compost soil slurry, or a mixture of 1% (v/v) hair hydrolysate and 3% (w/v) of compost soil and incubated for 5 days at $25^{circ}C$, bacterial growth measured on the basis of the viable cell numbers was approximately 3 times higher in the hair hydrolysate and compost soil mixture than in the others. Based on these results, 100x diluted hair hydrolysate was used as an organic fertilizer for field tests. Hot pepper plants were planted in commercially purchased compost soil to produce identical field conditions before the field was fertilized with the hair hydrolysate. The community of the soil-intrinsic bacteria was increased based on the viable cell count, and more diversified based on the TGGE band number of DNA extracted from soil, in the fertilized field relative to the non-fertilized field. The growth of the hot pepper plant was increased more based on length and weight in the fertilized field than in the non-fertilized field. Fertilization with hair hydrolysates appears to protect the hot pepper plant against wilt disease in farm fields contaminated with Ralstonia solanacearum.