Study on Humus Status of Ferralsols Developed on Basalt under Coffee Planting in Dak Nong Province

Abstract

Soil humus and organic matters play important role for soil qualities and plant nutrition. They are strongly transformed in the tropical climate condition and human production activities. Ferralsols developed on basalt of Dak Nong province covers an area of 382,364 ha in which 64,424 ha under coffee cultivation. The intensive coffee cultivation influences soil humus status. The organic matters and humus status in Ferralsols under coffee cultivation in Dak Nong were characterized as follows: OC ranging from 1.75 to 3.81% (OM from 3.02 to 7.23%) in soil surface horizons and dramatically decreasing in deeper horizons; low humus content; low C/N ratio in a range from 9.21 to 13.81 (average was 11.18%); C_H/C_F ratio ranging from 0.20 to 0.62 in soil surface and from 0.19 to 0.29 in lowest horizons. Humus of Ferralsols in Dak Nong was fulvat and its reserves were low in surface horizons (55.71 ton/ha)