Abstract:

Biochar is an environmentally friendly soil amendment due to its porous and high specific surface area. In order to study the effect of biochar on the water holding capacity of red clay and the growth of common slope grass species, the red clay in Guilin was taken as the research object, and the biochar of different raw material types and dosage was mixed into the red clay. The water holding capacity test, pot planting test and pH test were carried out, and the influence mechanism of biochar on the water holding capacity of red clay was explained by scanning electron microscopy (SEM). The results showed that the saturated water holding capacity and pH value of red clay increased with the increase of four kinds of biochar content, which effectively improved the environmental conditions of plant growth. The germination number and plant height of grass seeds increased after adding biochar, but the growth of grass seeds was negatively affected when the content was more than 5 %. Through microscopic tests, it was found that biochar was filled in the pores between red clay aggregates, and its porosity and hydrophilicity increased the saturated water holding capacity of red clay.

Key words: biochar, red clay, water-holding capacity, plant growth, microstructure