Effects of coffee-husk biochar on the growth and yeilds of robusta coffee (Coffea canephora Pierre var. robusta) in the business stage

Abstract

Biochar is a carbon-rich organic material known to have the ability to improve the health of cultivated soil, growth, development, yield, and quality of various crop plants. This study was conducted to determine the effects of different dosage of coffee-husk biochar on the physical, chemical, and biological properties of soil for cultivating robusta coffee as well as on the growth, development, yield, and quality of coffee beans. An experiment consisted of 4 treatments (CT1: control, no biochar + 100% inorganic NPK fertilizer following the re-cultivation process for robusta coffee plants; CT2: 1 tons of biochar/ha + 80% inorganic NPK fertilizer; CT3: 2 tons of biochar/ha + 80% inorganic NPK fertilizer; CT4: 3 tons of biochar/ha + 80% NPK inorganic NPK fertilizer), with 3 replications, carried out in a completely randomized block design in a fourth-year robusta coffee plantation on basaltic red soil in Dak Lak province. The results showed that after 5 months of treatment, although the amount of inorganic NPK fertilizer was reduced by 20%, the treatments which applied 2 - 3 tons of coffee-husk biochar (CT3 and CT4) following the process showed the best effects on soil physical properties (porosity increased by 7.5 - 13.1%, moisture increased by 6.6 - 12.3%,) soil chemical properties (pHKCl increased by 1.05-1.17, SOM% increased by 16.9-21.4%, CEC increased by 25.0 - 30, 5%, Nts increased by 8.7 - 12.5%, P2O5dt increased by 15.9 - 17.1%, K2Odt increased by 3.6 - 3.7%) and soil biological properties (density of Pratylenchus sp. in coffee roots reduced by 61.5 - 73.1%, density of the pathogen Fusarium spp. reduced by 23.6 - 32.1%), contributed to enhancing the growth and development of coffee plants, leading to a yield increase of coffee beans by 17.2 - 24.5% compared to the control treatment. In the future, further studies are needed to evaluate the efficiency of higher doses of biochar and the long-term impact of coffee-husk biochar on the health of coffee crop cultivation soil as well as the growth, development, yield, and quality of coffee beans.