The influences of chemical fertilizers and a nitrification inhibitor on greenhouse gas fluxes (N2O and CH4) in a corn field in Indonesia were investigated using a closed chamber. Plots received 45+45 kg-N ha −1 of nitrogen fertilizer by split applications of urea, a single application of controlled-release fertilizer (CRF-LP30) or urea+dicyandiamide (DCD; a nitrification inhibitor), and no nitrogen application (control). Cumulative amounts of N2O emitted from the field were 1.87, 1.70, 1.06, and 0.42 kg N2O-N ha −1 season −1 for the urea, CRF-LP30, urea+DCD, and control plots, respectively. The application of urea+DCD reduced the emission of N2O by 55.8% compared with urea. On the other hand, the soil acted as a sink for CH4 in the CRL-LP30, control, and urea+DCD plots with value of −0.09, −0.06 and − 0.06 kg CH4-C ha −1 season −1 , respectively. When the viability of AOB (ammonia-oxidizing bacteria) and NOB (nitriteoxidizing bacteria) were monitored, AOB numbers were correlated with the N2O emission. These results suggest that 1) there is a potential for reducing emissions of N2O by applying DCD, and 2) corn fields treated with CRF or urea+DCD can act as a sink for CH4 in a tropical humid climate.

Penelitian ini bertujuan untuk mengembangkan strategi blended learning pada perkuliahan Biologi Dasar dalam bentuk media pembelajaran online. Penelitian ini termasuk penelitian deskrptif dengan pendekatan R & D. Pengembangan produk  berupa e-learning dilakukan dengan mengacu pada model instruksional ADDIE. Penelitian ini dilaksanakan di Jurusan Biologi FMIPA UNM  tahun akademik 2018/2019 pada mata kuliah Biologi Dasar. Data dikumpul dengan menggunakan lembar validasi dan angket. Data penelitian dianalisis secara kuantitatif dengan persentase. Hasil penelitian diperoleh media  e-learning mata kuliah Biologi Dasar yang telah divalidasi. Dengan demikian disimpulkan bahwa blended learning mata kuliah Biologi Dasar memenuhi kriteri validitas dengan kategori sangat valid dan praktis dengan alamat laman www.muhiddin.web.id. Dari hasil penelitian tersebut,disarankan kepada dosen-dosen agar dapat menggunakan e-learning dalam perkuliahan.

Abstract. This Research and Development (R and D) concerns on learning media development regarding electronic magazine (e-magazine) for Plant Growth and Development subject. The R and D’s model used Analyze, Design, Develop, Implement, Evaluate (ADDIE). Validity test obtained from two expert validators and Practicality test obtained from the using of media by teacher and students. The Develop stage of this study conducted by validating e-magazine for further be implemented on SMAN 10 Gowa, Class of XII4 Natural Science. The number of subjects comprised of 29 students. Data collected from interview, observation and questionnaire. The result of validity test showed the average of media feasibility percentage is  82%. While the subject matter feasibility gained 81%. Both of these result showed very decent category which was meant that the media is feasible to be used. The average of teacher and students respond gained 83% and 81 % respectively toward positive respond. From the point of feasibility which had been evaluated by validity and practical test, this study can be conclude that emagazine is valid and practice learning media to be implemented in learning process. Keywords: e-magazine, validity, practicality, plant growth and development

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This research was conducted during one semester in four different classes that were taught biology by using four different teaching strategies: Problem-based learning (PBL), Jigsaw, PBL integrated with Jigsaw (PBLJigsaw), and direct teaching. This research explored the correlation between metacognition (metacognitive awareness and metacognitive skills) with cognitive retention of students in the four different strategies, and compared the four regression lines whether or not they are parallel. There was no correlation between metacognitive awareness and cognitive retention in the four teaching strategies in biology classroom, while the correlations between metacognitive skills and cognitive retention were significant. The results of the analysis of variance related to the regression equation in the four different strategies were parallel and did not coincide; the regression line of PBLJigsaw strategy was at the highest position. It indicated that this strategy has the potency to empower metacognitive skills and simultaneously increased cognitive retention. Key words: metacognitive awareness, metacognitive skills, cognitive retention, problem-based learning, jigsaw, regression line.