Five treatments were performed to examine the effects of biochar and compost, applied separately or in combination, on plant growth of mung bean (Vigna radiata) and soil properties in a semi-arid area of northeast China. The results showed that biochar and compost produced positive impacts on both the plants and the soil, with these effects dependent upon the biochar to compost ratios. In addition, the changes in biomass and growth indices vary according to the growing phases: with the medium to late growing phases showing more prominent responses than the early phase. The total organic carbon and electric conductivity were increased by the soil amendments, especially in the biochar-compost combination treatments (P<0.05). Addition of biochar-compost lowered the soil bulk density relative to the control (P<0.05). Also notably, the biochar-compost treatment enhanced the water holding capacity, which is highly desirable for sandy soils. In short, synergic effects of biochar and compost were documented in promoting plant growth, biomass accumulation, yield and in improving soil properties. (C) 2016 Friends Science Publishers