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.

Contamination of mercury (Hg) in ex-gold mining soil is the impetus for the development of amelioration technology that utilizes Indonesian sub-bituminous coal to study the soil surface charge and the chemical properties of ex-gold mining soil. This research was aimed to study surface charge and chemical properties of ex-gold mining soil ameliorated with Indonesian sub-bituminous coal. The experimental design used in this study was a Completely Randomized Design with three replications. The treatment was implemented in a pot with the equivalent dose: A = 0 (0.0g); B = 10 (0.5g); C = 20 (1.0g); D = 30 (1.5g), and (E) 40 t ha−1 (2g 100g−1 soil). The results showed amelioration technology with Indonesian sub-bituminous coal, at the application of 40 t ha-1 on ex-gold mining soils, could increase the soil surface charge (ΔpH) by 0.60 through changes in chemical properties of the ex-gold mining soil, where there was an increase in pH (H2O) EC, CEC, and SOM, respectively of 0.37; 0.04 dS m−1; 2.14 cmol kg−1 and 7.83% compared to the control. Soil surface charge was supported by soil minerals [Quartz (SiO2)] and an increase in the chemical properties of the ex-mining soil ameliorated with Indonesian sub-bituminous coal which caused Hg to decrease by 2.50 mg kg−1 compared to the control.

Liming increases soil fertility through improved soil conditions in acidic soils (Ultisols). This study aimed to determine the effect of limes [CaO; Ca(OH)2; CaCO3 and CaMg(CO3)2 ] on the chemical properties of Ultisols of Limau Manis Padang. Treatments tested in this study application of four types of lime, i.e. A = CaO; B = Ca(OH)2; C = CaCO3; dan D = CaMg(CO3)2. on an Ultisol. A control treatment with no application of lime was also included in this study. After incubation of the soil-lime mixtures for two weeks, the results of the study showed that liming using dolomite [CaMg(CO3)2] was more effective in improving the chemical properties of Ultisols, compared to other types of lime [CaO; Ca(OH)2; CaCO3]. The effect of dolomite on 1*exchangeable Al (1 me Ca 100 g-1) improved chemical properties of an Ultisol from Limau Manis Padang such as pH H2O by 0.35 unit, available P by 1.03 ppm, exchangeable Al by 0.91 cmolc kg-1 ; exchangeable H by 0.92 cmolc kg-1 ; CEC by10.49 cmolc kg-1 ; exchangeable K by 0.03 cmolc kg-1 ; exchangeable Ca by 0.44 cmolc kg-1 and exchangeable Mg by 1.34 cmol ckg-1 , compared to control.

In the northern area of Mount Talang with some steep slopes (more than 30°), the local community implements an intensive monoculture agricultural system that can accelerate land degradation in the long term. Study was aimed to examine the soils physicochemical properties of monoculture land on several slopes in the northern foothill of Mount Talang. Survey method and soil sampling were implemented in this research, using a purposive random sampling toward the monoculture land on slopes> 45%, 25-45%, 15-25%, 8-15%, and the forest as control, at 0-20 cm and 20-40 cm depth. The results revealed that the soil texture that dominates the forest and monoculture cropping system is sandy loam. In addition, soil water content increases by the increased soil layer depth as well, with highest level observed in monoculture cropping system 25-45% (73.72%). Soil bulk density ranging from 0.4-0.6 g / cm3, or have the same tendency at both soil depths. The total pore space of forest land and monoculture agricultural land is 75%, categorized as high. The highest soil organic C content was found in monoculture agricultural land with a slope of >45%. The value of pH for all land uses was 5.15-5.29 on acid criteria. The cation exchange capacity was above 40 me / 100g and the total N content is 0.8-1.6%, so both of them are categorized as very high. Based on the data, the soils physicochemical properties of monoculture cropping system on several slope classes similar to the forest. The land quality for monoculture cropping system is still maintained, even though it is on the upper slopes of the foothill of Mount Talang. However, in the monoculture cropping systems will trigger the loss of soil organic matter, so the addition of soil organic matter content should be prioritized, especially in the agricultural land management of this area.