Potential of biochar bamboo and sub-bituminous coal as amendment of acid mineral soils for improving the growth of arabica coffee [Coffea arabica l.] seedlings

Abstract

Improvement the characteristics of acid mineral soil [Ultisols] is needed to support plant productivity. However, the utilization of biochar combined with sub-bituminous in improving ultisol is still limited. Therefore, this research was conducted by using treatments: 1] Control 0% Sub-bituminous [SBC] + 0% Bamboo Biochar [B]; 2] 100% SBC [20 ton.ha−1]; 3] 75% SBC + 25% B; 4] 50% SBC + 50% B; 5] 25% SBC + 75% B; and 6] 100% B [20 ton.ha-1] This study was designed using Completely Randomized Design [CRD] with 3 replications. The results showed that the application of combined biochar and sub-bituminous had a significant effect in improving ultisol’s fertility characteristics. There are two treatments that provide the most significant results for improving soil properties, namely 100% sub-bituminous treatment with a significant effect in increasing pH [1.3 pH units], Organic carbon [3.34%], Total N [0.12%], CEC [10.87 cmol/kg and Ca2+ [1.2%]. However, 50% sub-bituminous + 50% bamboo biochar treatment have a significant effect in increasing Available P [1.1 ppm], CEC [9.04 cmol/kg K+ [0.51 cmol/kg], Ca2+ [1.37 cmol/kg], and Mg2+ [1.27 cmol/kg]. In addition, application of 50% sub-bituminous + 50% bamboo biochar gave the best result for the plant height, branches and leaves of the coffee plants.