This study aims to determine the effect of biochar from young coconut [Cocus nucifera L.] waste to improve the chemical properties of Ultisols and the growth of coffee [Coffea arabica] plant seeds. The research has been carried out at the Laboratory of Chemistry and Soil Fertility and Experimental wirehouse of the Faculty of Agriculture, Andalas University, Padang. This research used a Completely Randomized Design [CRD] with 3 replications. The formulation is biochar of young coconut waste/8 kg of soil ie: A = 0.0%; B = 0.5% [173 g]; C = 1.0% [348 g]; D = 1.5% [520 g]; and E = 2.0% [693 g]. The results of the utilization of young coconut waste as a source of biochar could improve the chemical properties of Ultisols. Addition 2% [693 g.8kg/lof soil] of biochar young coconut waste can increase pH and decrease Al and H-exch, so that increase available P, organic C and CEC by 1.70 ppm; 0.99% and 9.12 cmol[+].kg−1; compared to 0% of biochar. Application 1.5% [520g.8kg/lof soil] almost the same 2% of biochar young coconut waste to increase total N and exchangeable of the cation [K, Ca, and Mg]. Whereas addition up to 2% of biochar young coconut waste has not shown a significant increase in growth coffee [Coffee arabica L.] plant seed at the age of 3 months [12 after week planting].

Sub-bituminous coal [SC] activation with dolomite is the future technology in utilizing coal as an alternative organic material [Humic Substance]. This study aims to study the effect of SC activated with dolomite in improving the chemical properties of Ultisols and palm oil growth at the main-nursery stage [Elaeis guineensis Jacq.] In Dharmasraya. The experimental design was in Randomized Completely Block Design with three replications consisting of 6 treatments : A = 150g SC planting hole−1; B = 300g SC planting hole−1; C = 450g SC planting hole−1; D = 150g SC + 10% [15g] dolomite planting hole−1; E = 300g + 10% [30g] dolomite planting hole−1 and F = 450g SC + 10% [45g] dolomite planting hole−1. The results showed that the effect of activation on SC differs from those treatments without activation with dolomite. Effect of 450g SC activated with dolomite planting hole−1 is significant on the chemical properties of Ultisols, such as increasing in pH, available P, organic C, total N, CEC [Cation exchange capacity], and K, Ca, Exch-Mg, by 0.44 units, 1.33 ppm P, 0.44% C, 0.04% N, 0.25, 0.27, and 0.29 cmolckg−1, compared to 450g SC without activator and an increase in palm oil growth on height [12.33cm], stem diameter [0.84cm] and N, P, and K nutrient concentration from leaf of plant [0.014% N, 0.004% P, 0.002% K], compared to 450g SC without activator.

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<p>As an ameliorant, rice husk biochar (RHB) can improve soil quality and long-term carbon absorption and interaction with glyphosate during adsorption. This study investigated the ability of Inceptisol ameliorated with RHB to absorb glyphosate. Inceptisol ameliorated with 40^-t ha^-1 RHB increased the soil surface charge (ΔpH) by improving soil pH H₂O, electrical conductivity, cation exchange capacity, and soil organic matter. Linear and nonlinear models showed that fitting Langmuir and Freundlich isotherms is suitable for this study. The isotherm adsorption of glyphosate sequentially occurs in the Freundlich and Langmuir models (Inceptisol + 40^-t ha^-1 RHB &gt; Inceptisol), where the Freundlich model (R² = 0.938) is dominated by glyphosate adsorption on Inceptisol + 40^-t ha^-1 RHB with n of 0.46 and KF of 1.747 mg kg^-1, whereas the Langmuir model (R² = 0.8608) with Qm of 30.01 mg kg^-1 and KL of 0.08 L mg^-1 at a concentration level of 100 ppm and pH of the glyphosate solution 5.20 units. The glyphosate adsorption was also supported by changes in functional groups, where Fourier transform infrared spectroscopy shows a decrease in transmittance in the O-H; C=C; C-O; C-H, and mineral groups, indicating an increase in the adsorption capacity in Inceptisol ameliorated with 40^-t ha^-1 RHB. This study indicated that the physicochemical properties of Inceptisol are important in controlling the glyphosate adsorption ability of RHB in soils.</p>

Soil carbon is very important in food security, ecosystems, and environmental health, especially in the context of global climate change. This study was to determine the effect of carbon sequestration from bamboo biochar on increasing the productivity of marginal soils in the second planting season planted with soybean [Glycine max L.]. This study used a completely randomized design with 3 replications in 5 treatments: A = 0.0% [0g pot−1] B = 0.5% [173g pot−1]; C = 1.0% [348g pot−1]; D = 1.5% [520g pot−1] and E = 2.0 [693g pot−1] of bamboo biochar. The results showed that carbon sequestration from bamboo biochar had a significant effect on the chemical properties of Ultisols, such as increasing pH, available P, organic C, total N, CEC, and Ca-exch and could reduce Al-exch, by 0.90 units, 2.50 ppm P, 1.12% C, 0.13% N, 5.48; 1.79 and 0.88 cmolckg−1, compared to controls and increase in soybean growth and NPK nutrient uptake in stems and leaves [3.57g N, 2.61g P, 4.64g K], also in roots [0.93g N, 1.03g P, 0.94g K], compared to controls. Carbon sequestration from bamboo biochar with 2% application can increase the productivity of marginal soil [Ultisols] and soybean [Glycine max L.].