ĐÁNH GIÁ KHẢ NĂNG HẤP PHỤ LÂN DỄ TIÊU LÊN ĐẤT ĐỎ BAZAN (HUYỆN KRÔNG BÚK TỈNH ĐẮK LẮK) ĐƯỢC CẢI TẠO BẰNG THAN SINH HỌC CÓ NGUỒN GỐC TỪ VỎ CÀ PHÊ Ở CÁC NHIỆT ĐỘ NHIỆT PHÂN KHÁC NHAU

Tóm tắt

Biochar from agricultural residues plays an important role in improving the efficiency of nutrient use for
plants, including available phosphorus. Study on the characteristics of biochar derived from coffee husk,
which was prepared at different temperatures, was made. Similar study on the ability to adsorb available
phosphorus from basalt red soil (Krong Buk district, Dak Lak province) and soil with biochar supplement
was also conducted. Coffee husk were prepared at temperatures of 300, 450 and 600 °C with a
temperature increase of 10 ºC / min and a 2-hour holding time. Soil (control sample) and soil
supplemented with 4% biochar were mixed with P solution at different concentrations until equilibrium.
Physical and chemical properties such soil (pH, OC, easily digested P content, moisture content) and
biochar (recovery efficiency, OC, pH, pHpzc, H+, OH- group numbers, CEC) were collected and
evaluated. The results showed that the parameters of adsorption equilibrium process are consistent with
Langmuir and Freundlich isothermal model. The maximum P adsorption capacity on soil (control
sample), the soil supplemented with 4% biochar at temperatures 300, 450 and 600 °C is 2.97; 2.97; 2.94
and 5.48 mg.g-1. Kinetics of adsorption of available P in biochar supplemented soil at temperature of
600 °C follow pseudo second order kinetic model with constants k = 0.25 g.mg-1.hour-1, R2 = 0.95.
Research results showed that the addition of biochar from coffee husk prepared at 600ºC increases the
adsorption of available phosphorus to basalt red in Krong Buk district, Dak Lak province.