Seven agricultural waste biochars made from okra straw(HQK),wild rice stem straw(JB),rice straw(SD),waste edible fungus matrix(JZ),fig stem(WHG),swine manure(SM)and ricehusk(DK)were used to detect the effectsof different kinds and applicationrates(0.5%,1%,2% and 5%)of biochars on soilpH,water holding capacity and N adsorption.The results showed that at the application rates of2%,all the biochars significantly increased soilpH,in which JB and SD increasedmost,and significantly increased soil water holding capacity with the increasing rates of 2.87%～ 12.30%,in which SD increased most. Biochar could adsorb NH4+-N in soil solution,but the adsorption ability was not related to the application rates of biochar. WHG showed the strongest adsorption ability. The adsorption ability of JZ and HQK was the weakest. Adding biochars showed no effects on adsorption of NO3--N in soil solution.