No abstract

The research about “Incubation of titonia for organic acid production in rice field”  has been conducted in soil laboratory Agriculture Collage Andalas University Padang, since  January to August 2005.  The objective of this research was to determine the best method of using titonia to produce organic acids in rice field.  The research had 2 factors, 3 series of titonia application and 5 levels of titonia dossages with 3 replications.  The series are: A1 =  Titonia was mixed with soil and then, the soil was directly flooded;  A2 =  Titonia was mixed with soil and then, let them stay on soil surface for 3 weeks before being flooded; A3 = Titonia was mixed with soil and then, the soil was moistened until field capacity for 3 weeks before being flooded.  The second factor was titonia dossages (0,000; 1,250; 2,500; 3,750; 5,000 g  dry weight of titonia per kg soil). The result showed that organic acids of the soil had been changed as a consequence of titonia application and the incubation with soil.  The highest organic acid production was found  at combination of titonia incubation with soil at field capacity for 3 weeks, that was malat acid (184-489 mgl-1). The others detected were citrate, tartarate, malate, and benzoat acids, butt fenolate acids was not detected.  Keywords: incubation, organic acids, rice field, titonia.

Abstr actThe purpose of this research is to study interaction of humic substances extracted from subbituminus coal with P fertilizer on the chemical properties of Ultisol and crop production of corn (Zea mays L.). The experiment was designed in completely randomized design having 2 factors (4 x 4) with 3 replications. The first factor was dose of humic substances (A) which consists of 4 levels (A1 = 0 ppm, A2 = 400 ppm, A3 = 800 ppm, and A4 = 1200 ppm). The second factor was level of fertilizer P (B) (B1 = 100% recommendation, B2 = 75% recommendation, B3 = 50% recommendation, and B4 = 25%). The result showed that : 1) There is no interaction between humic substances and P fertilizer on the chemical nature of Ultisol and crop production of corn (Zea mays L.) 2) Use of humic substance for 800 ppm with some level of P fertilizer could improve some chemical properties of Ultisol such as decreased in content of Al-exch by 0,38 me/100 g soil, increased in P-available by 22,16 ppm, CEC by 8,42 me/100 g soil and P nutrient by 0,10 %, as well as corn yield by 25,67 g/pot compared to soil without humic substances 3) The use of SP-36 for 50 % with some level of humic substances increased in plant height by 26,58 cm, P nutrient by 0,11 %, and the use of 75 % SP-36 increased corn yield by 5,84 g/pot compared to 25% of P recommended.

A research was carried out at glass house and at Soil Laboratory of Faculty of Agriculture, Andalas University Padang. The experiment was aimed to determine the interaction between humic material from compost and P fertilizer on some chemical properties of Oxisol, nutrient uptake and corn production. This experiment consisted of 2 factors (4 x 4) with three replications which were allocated in completely randomized design (CRD). The first factor was humic material having 4 doses (0, 400, 800, and 1200 ppm) and the 2nd factor was P fertilizer having 4 doses (100%, 75%, 50%, and 25% of recomendation (R)). The result showed that there was : 1) Interaction between humic materials and P fertilizer for the quality the corn seeds. Application of 800 ppm humic material improved the quality of the seeds even though at low level of P fertilizer. 2) Then, it also increased availability of P by 23.03 ppm, N total by 0.09 %, and decreased Al-exch by 0.53 me (100 g) -1 and Fe-exch by 25.62 ppm compared to threatment without application of humic material. Likewise, nutrients (N and P) uptake by plant also increased by 0.28 and 0.03 %, respectively. 3) Application of P fertilizer at 75 % R increased soil P availability by 3.77 ppm, N and P content of plant by 0.43 % and 0.06 %, and seed weight by 13.20 g and decreased Fe-exch by 21.16 ppm, compared to 25 % R of P fertilizer.

<p>Tujuan penelitian ini untuk mengetahui apakah strategi pembelajaran konflik kognitif berbantuan <em>software wingeom</em> dapat meningkatkan kemampuan pemecahan masalah matematis peserta didik. Jenis penelitian ini merupakan penelitian Quasy Experiment Design. Populasi dari penelitian ini adalah seluruh kelas VIII SMP Negeri 22 Bandar Lampung tahun ajaran 2016/2017. Teknik pengambilan sampel dalam penelitian ini menggunakan teknik <em>Cluster Random Sampling</em>. Teknik pengumpulan data yang digunakan adalah tes kemampuan pemecahan masalah matematis peserta didik. Teknik analisis yang digunakan dalam penelitian ini adalah analisis variansi satu jalur sel tak sama. Berdasarkan hasil analisis variansi satu jalur dengan sel tak sama, diperoleh hasil bahwa terdapat perbedaan antara strategi pembelajaran konflik kognitif berbantuan <em>software wingeom</em> dalam meningkatkan kemampuan pemecahan masalah matematis peserta didik.</p>