A Decision Support System for Rice Cultivation on Acid Sulfate Soils

Acid sulfate soils pose chemical, biological and physical problems for rice cultivation. The proposed amelioration for the study includes: 1) correct water management; 2) applying lime at appropriate rate and time; and 3) adequate fertilizer application. Those procedures were organized into an integrated decision support system (DSS), which used analytical methods and models. Main component for the model was production function as a response of those amelioration processes. The model used that function to simulate yield and in advance step, doing micro economic analysis by calculating profit in order to find the maximum one. In delivering production function, glasshouse experiment has been conducted using soil from acid sulfate soil area in Jelawat Rusa Irrigation Scheme, under Project Kemasin-Semerak (PERKASA), Kelantan. The result of glasshouse experiment showed that yield was significantly affected by the combination of lime and fertilizer (P<0.02). Water management and any of its combination did not affect yield. The highest yield was found on combination of GML at rate 4 t/ha using maximum fertilizer rate. Ameliorative assessment of lime and fertilizer have improved yield shown by increased soil quality and a better plant performance. Liming has increased soil pH, exchangeable Ca and exchangeable Mg, and these have decreased toxicity caused by of Al and Fe. Liming and water management has also improved rice yield by increasing grain weight and decreasing empty spikelet number. Field experiments, which include experimental plot and demonstration plot, have been conducted in that area for 2 seasons with the purpose of validating glasshouse experiment. Statistical analysis showed that yield of plot experiment on the first season was not significantly different (P>0.12). It was primarily because the first season of field experiment was disturbed by flood due to high rainfall and poor drainage system at the location. It may be also because lime is still not stably interacted with the soils to increase soil pH. Crop cutting test (CCT) in the second season of the field experiment showed a significant effect of lime treatment on the yield (P<0.07). The highest yield of 7.52 t/ha was found on treatment 6 using application of GML at 4 t/ha in combination with organic-based fertilizer (JITU). Treatment 5 using application of GML at 8 t/ha resulted on yield of 7.22 t/ha, which was not different from treatment 6 and this become the second highest value. Using field experiment, field adjusting factor (FAF) has been developed. It showed percentage of achieved yield on field trial from the potential yield (glasshouse experiment). The value of FAF was 0.40, which means only 40% of potential yield will be gained on the field. The 60% loss may be because of technical problems,inefficient harvester machines, incorrect fertilizer applications, pest and disease damages. Response curve as production function was formed using TableCurve 3D v4.0. From surface fitting process, an equation has been found (P<0.01). It consists of 4 parameters which were also significant at the same α of 5.00%. The value of r2 of the equation was 0.71, while the curve on initial data and the equation is quite similar. A model, RiCASS, used predicted yield from the equation to calculate the cost of inputs both fixed and variable, and to calculate the profit. It ran simulation under various inputs to find the optimum level that result in maximum profit under 4 different scenarios. Simulation showed that for the first general scenario, maximum profit margin was found to be $ 2,847/ha from predicted yield at 6.15 t/ha. It used lime at the rate of 6.50 t/ha and fertilizer index of 10. The second scenario in which total cost was limited to RM 1,500, maximum profit was found to be RM 2,024. Based on farmer’s cost, the maximum profit was found to be RM 3,624, while under limitation of cost below RM 1,000, the profit was found at RM 3,263. Validation carried out to evaluate the equation which consisted of paired comparison t-test and mean estimation error. Result showed that the equation was able to represent actual yield shown by insignificant difference with field experiment yield (average P>0.20) and small estimation error (2%)

MODEL KONSTRUKTIVISME UNTUK MENCIPTAKAN DISKUSI YANG EFEKTIF DAN PRESENTASI YANG INTERAKTIF DALAM PEMBELAJARAN MATA KULIAH INTRODUCTION TO RESEARCH IN ELT

Sebuah permasalahan muncul didalam kelas ketika proses diskusi dan presentasi tidak bisa berjalan dengan efektif dan interaktif. Penelitian ini bertujuan untuk menciptakan diskusi yang efektif dan presentasi yang interaktif dengan menggunakan model konstruktivisme dalam pembelajaran mata kuliah Introduction to Research in English Language Teaching di mahasiswa semester 5 program Pendidikan Bahasa Inggris Universitas Muhammadiyah Gresik. Metode penelitian ini menggunakan rancangan Lesson Study dengan menggunakan tiga landasan, yaitu merencanakan (Plan), implementasi pembelajaran (Do), mengobservasi dan merefleksi kegiatan pembelajaran (See) yang dilaksanakan dalam empat siklus pembelajaran. Hasil dari penelitian ini menunjukkan bahwa penggunaan model konstruktivisme ternyata mampu menciptakan sebuah diskusi yang efektif dan presentasi yang interaktif di dalam kelas. Beberapa saran dan rekomendasi untuk para pengajar dan peneliti selanjutnya juga di bahas dibagian akhir dari tulisan ini

A Decision Support System for Rice Cultivation on Acid Sulfate Soils in Malaysia

Ameliorative steps to put acid sulfate soils into productive use can be organized by a decision support system. The model uses microeconomic analysis to get an optimal rate of lime and fertilizer in maximizing profit. A glasshouse experiment was conducted on an acid sulfate soil in Malaysia to get the potential yield. A field trial was conducted for validation purposes. The recommended rate of fertilizer application of 150-200 kg ha-1 N. 20-30 kg ha-1 P and 150-200 kg ha-1 K were applied during the critical stage of the rice growth. Field Adjusting Factor (FAF) of 0.40 has been found and this was used to analyze the production function. Using TableCurve 3D software. an equation for production function was established. Validation using experimental data showed that the equation has a good capability. shown by the value of p&gt;0.2 (t-test) and MEE of 2%. The model. named as RiCASS (Rice Cultivation on Acid Sulfate Soil) was developed and successfully simulatedthe maximal profit under 4 different scenarios. The recommended rate of lime (GML) was 6.5 t ha-1 for maximal profit and 2.5- 3.0 t ha-1 for the farmers, practice. Keywords: Acid sulfate soil. decision support system. field adjusting factor. lime. ric

Alleviating an Acid Sulfate Soil Cultivated to Rice (Oryza sativa) Using Ground Magnesium Limestone and Organic Fertilizer

Rice yield on acid sulfate soils in Malaysia is very low, presumably due to AI and/or Fe toxicity. This study wasconducted to ameliorate an acid sulfate soil in the Kemasin-Semerak Integrated Agricultural Development Project, located in Kelantan, Peninsular Malaysia, for rice cultivation. Rice variety, MR 219, was used as the test crop. Treatment included the use of various rates of ground magnesium limestone (GML), with or without an organic fertilizer. This acid sulfate soil had an initial pH of < 3.5 at depth below 45 cm. Exchangeable AI in the soil was high, especially in the subsoil. The first crop of rice was disturbed by floods. The result for the 2"d crop showed a promising trend; applying 4 t GMUha in combination with an organicfertilizer, the topsoil pH had increasedfrom 3.95 to 4.21, increasing the exchangeable Ca and Mgfrom 1.58 and 0.48 cmol/kg soil to 2.57 and O. 79 cmol/kg soil, respectively. In this treatment, the rice yield was 7.5 tlha, which was much higher than that produced by farmer's practice of about 2 tlha. The increase in yield was due to the combined effects of increasing pH and exchangeable Ca and Mg and of lowering AI and Fe concentration in the soil solution

The Online Global Quarantine Conversation Club as the Way to Trigger Students' Ability in Speaking English

Global Quarantine Conversation Club (GQCC) is a speaking practice program that involves more than 20 countries across the world. Since the English subject has not attracted students' attention yet, this program is expected to trigger the students in learning English. The study purposed to describe the implementation of GQCC, to analyze the students' perception toward the implementation of GQCC, and to analyze the teacher's reflection toward the implementation of GQCC. This study belonged to qualitative research approach with case study design. One English teacher and two students of a senior high school in Gresik, Indonesia, were selected as the subjects of the study. The instruments used in this study were observations, interviews, and documentations. The result showed that (1) the teachers and the students' activities were doing briefing and rehearsal in pre-program, doing presentation and group discussion during program and doing evaluation and reflection in post program, (2) the students found that the GQCC program gave positive impact on their English as well as gave them new cultural knowledge, and (3) the teacher was becoming aware about the need of improving the students' speaking skill through some accelerated programs as well as the technology literacy. This study gave some recommendations for both school and further research

The growth of oil palm, cocoa and rice in Malaysia as affected by acid sulfate soil infertility.

Soils along the coastal plains in Malaysia usually contain pyrite (FeS2). When these areas are drained, pyrite in the sediments oxidizes releasing acidity and A1, and jarosite is formed. This paper summarizes the results of studies on the acid sulface soils planted to oil palm, cocoa and rice. A glasshouse study conducted to test the growth of oil palm on acod sulfate under waterlogged and well drained conditions indicated that the best growth was observed on the non-jarositic freely topsoil. Oil palm was found to be moderatley yolerant to soil acidity. The growth was only affected if A13+ activities were aboved 100uM and pH below 4.3. The result from our study indicated that cocoa was sensitive to the presence of A1 in acid sulfate soil. As the amount of A1 in the cocoa leaves increased, the relative plant height of cocoa seedlings decreased. The critical value for A13+ activities in the soil were 10uM. A study was conducted in the Kelantan Plains, in the Northeast coast state of Peninsular Malaysia to determine the effects of line and organic fertilizer application on rice yield planted on an acid sulfate soil. After applying 4 t of ground magnesium limestone per ha in combination with 0.25 t per ha of organic fertilizer, a rice yield of 7.5 t/ha was obtained in the 2nd season. This is comparable to the rice production in the gragary area of Malaysia. If properly managed, acid sulfate soils in Malaysia can be used for cultivation of oil palm and rice