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Abstract. In productive oil palm plantation areas, poor vegetation is generally caused by low light intensity. This condition causes excessive erosion and decreases soil fertility. One of the efforts for soil and water conservation at oil palm plantations is through increased vegetation diversity. The changes of soil and plant nitrogen, phosporus, and potassium content, observed by planting two types of herbs under oil palm tree, with different compositions. Vegetation composition was set as: Arachis glabrata 100%; Stenotaprum secundatum 100%; Arachis glabrata 50% + Stenotaprum secundatum 50%; Arachis glabrata 75% + Stenotaprum secundatum 25%; Arachis glabrata 25% + Stenotaprum secundatum 75%. The shoot and root fresh/dry weight, nutrient content (nitrogen, phosphor, and potassium) of each cutting were measured at the end of the experiment. Ten of treatment plant were harvested and divided shoots and roots after washing out of soil. Biomass samples were dried at 70 °C for 48 h and weighed. The total N and its proportional concentration (N%) were analyzed with the microKjeldahl method. Potasium analyzing with flamephotometry, and phosphor and from samples was determined by analyzing with spectrophotometry method. The results showed the highest shoot growth of A.glabarata if planting was mixed with S. secundatum, but the result was different with S.secundatum being superior if planted with monoculture system. Combination of interrow cultivation is more recommended for soil conservation and nutrient maintenance in palm oil trees were A. Glabarata 75% + S.secundatum 25%.

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The Gogo rice is a food crop that contributes to food self-sufficiency. Food demand, especially rice continues to increase along with population growth. Because of the higher food needs and the narrowness of fertile land, due to the land conversion function. So the utilization of sub-optimal lands / landed with appropriate food crops. The potency of the sub-optimal area in South Sulawesi is 274,549 hectares. The purpose of this research is to know how sub-optimal land used and farmer appraisal to gogo rice. This research was conducted in Wajo and Jeneponto Regencies from January to December 2017. The research used survey method and display of gogo rice plant NSV of Agricultural Research Agency in the field. The number of farmers taken as a sample of 80 farmers. The technique of collecting data by interview method and observation of vegetative and generations of display gogo rice plant. The collected data are then tabulated and then analyzed descriptively and test the agreement and business feasibility. The activities of rice farming on sub-optimal land are done by farmers that have the productive age. The application of rice farming technology to suboptimal land has not been intensive yet. Display gogo rice plant VUB resulted from Agricultural Research Agency appropriate to be planted with / out sub-optimal land of dry land and irrigated rice fields limited. Understanding farmers on superior gogo rice are not optimal (77.50%). Farmer's preference to superior gogo farmers. Rice farming of farmers provides income (implicative). Rp 4.575.000/ha, (explicit). Rp 7.245.000/ha and R/C (implicative ) 1.62 and (explicit ) 2.53.

This study aimed to determine the increase in students’ interest and achievement of science in the 8th graders of SMP Negeri 1 Watampone, Bone Regency Indonesia, when using outdoor activities. This study applied Classroom Action Research (CAR), which consists of two learning cycles following the procedural phase such as planning, implementation, observation phase, and reflection. The sample was taken using a purposive sampling technique class. The data collected included data about the students’ science achievement before the implementation of the action, data about the students’ interest in learning science, data about the students’ science achievement in the cycle I and cycle II, and data on the observations/notes of the teacher in each research cycle. Data were obtained through a questionnaire asking about students’ interest in learning science, students’ achievement result test before the implementation of the action, students’ achievement test in cycle I and cycle II, and student learning observation sheet. Data then analyzed using quantitative and qualitative descriptive analysis techniques. The results showed that there was an increase in students’ achievement, both in cycle I and in cycle II. Students’ mastery level in science materials was in the high category and their readiness, sincerity, and activeness in participating in the learning process were increased. Recommendation and direction for further research are included in the study.

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Biochar is a negatively charged recalcitrant carbon that has the potential to adsorb heavy metals. This research aim was to identify the best type of biomass with a simple combustion process (Kiln) in producing carbon, base cations, organic acids, the highest surface area and pores with more porous morphology. The type of biomass used was paddy straw, rice husk, coconut fiber, oil palm empty fruit bunch. Instrument to observe the morphology, carbon content and a number of Biochar bases using Scanning Electron Microscope (SEM-EDAX), to observe the surface and pores (m2 / g) using Brunauer Emmet Teller (BET), and to observe functional groups type using Fourier Transform Infrared Spectroscopy (FTIR). The research results showed that coconut fiber biomass had the highest surface area of 23.9145 m2 / g but rice husk had a larger pore volume and pore size of 0.026962 m3 / g and 63.6994 4V / A respectively. The highest percentage of carbon was found in rice husk biochar by 77.18% with an atomic percentage of 86.43%. The functional group was dominated by Phenolic (OH), Carboxyl, Ether and Esters groups with a frequency of 1050-1300 and the highest frequency was in Rice Husk Biochar. Cation in biochar was dominated by K+ with the highest percentage of rice husk by 2.75%, Na+ was also found in rice husk by 1.07%, while Mg2+ was in Biochar of oil palm bunches by 0.63%. Porous morphology was seen in rice husks with ˃ 1000 magnification, so rice husk biochar has the best potential as heavy metals adsorption. Contribution/ Originality:This study is one of very few studies which have investigated utilization straw, husk, coconut fiber and palm empty bunch as biochar, potential was showed by morphology, surface are, pore size and functional group.Recently the abundant use of organic biomass has been converted into biochar, and has given hope for a reduction in carbon emissions. In addition, biochar which is rich in negative carbon provides a strong ability to adsorb metal such as Cu, Cd, Pb on the soil thereby reducing pollution [2].

Toba highlands is unique and covers a large area. Peat plays an important role as a carbon sink, and is currently utilized for agricultural purposes, use as firewood, and left to degrade. The use of peatlands will impact the maturity of peat, and the emission of carbon dioxides and other gases caused by the decomposition process of microbes. A brief transformation of organic carbon from peat into carbon dioxide negatively impacts the environment, especially in increasing the greenhouse gas emissions. C-organic and C-microbial biomass was observed in peatlands of the Toba Highlands in Humbang Hasundutan, employing the Walkey and Black method, and fumigation and extraction methods to calculate the microbial population involved in the decomposition process or called C-microbial biomass. Moreover, descriptive method were used to map their distribution in the peat areas. The results showed that the highest C-organic was found in barren land at 22.05% and soil C-microbial biomass population was 3.24 µg g−1 soil, whereas the least C-Organic was found in peatland transferred to coffee fields, at 5.23% while the least C-microbial biomass was in peatland transferred to onion fields at 0.28 µg g−1 soil. There was a relatively small amount of organic matter and C-microbial biomass in paddy field, shallots, and grasses. Therefore, the results indicated that converting peatland into agricultural land would likely change the value of organic matter and C-biomass population.