Judul: Characteristics of Physical Properties and Soil  Physical Quality Index of Post-Harvest Paddy Fields
Abstrak: Tanah sawah dapat mengalami penurunan kualitas tanah dan produktivitas akibat penggenangan dan pemberian pupuk anorganik secara terus menerus. Rotasi tanaman antara padi dengan palawija dapat menjadi alternatif dalam mempertahankan kesuburan lahan, produktivitas dan perekonomian petani. Karakteristik dan kualitas tanah penting dalam pengembangan pertanian. Kualitas tanah diukur dengan indikator kualitas tanah, salah satu indikatornya yaitu sifat fisik tanah. Penelitian ini bertujuan mengkaji karakteristik sifat fisik tanah sawah dan sifat fisik tanah yang berpengaruh terhadap Indeks Kualitas Fisik Tanah (IKFT), serta mengetahui IKFT dan potensi tanah sawah pasca panen untuk penanaman palawija di Kecamatan Sukaresmi, Kabupaten Cianjur. Metode yang digunakan yaitu PCA (Principal Component Analysis) untuk memilih MDS (Minimum Data Set) dari indikator sifat fisik tanah yang mewakili fungsi tanah. Hasil penelitian menunjukkan lokasi penelitian memiliki karakteristik tanah bertekstur lempung berpasir, lempung, lempung liat berpasir dan lempung berliat. Bobot isi berkisar 0,67-0,99 g/cm3 . Permeabilitas semua petak sawah > 12 cm/jam, pori drainase cepat dan pori drainase lambat berkisar 2,66-23,11% dan 1,17-33,66%. Air tersedia berada pada rentang 16,61-52,91%. Sifat fisik yang paling berpengaruh terhadap indeks kualitas fisik tanah adalah tekstur, pori drainase lambat, bobot isi dan permeabilitas. Nilai IKFT pada lokasi penelitian berada pada kisaran 2,80-4,50 dengan kategori agak buruk, sedang, agak baik dan baik. Lokasi penelitian memiliki indeks kualitas fisik tanah yang didominasi kategori agak baik. Hasil analisis karakteristik sifat fisik dan IKFT pada lokasi penelitian cukup sesuai dengan pengembangan tanaman palawija, untuk IKFT kategori agak buruk dan sedang dapat ditingkatkan dengan pemberian bahan organik., Paddy fields can experience a decrease in soil quality and productivity due to the continuous use and application of inorganic fertilizers. Crop rotation between rice and crops can be an alternative to maintain land fertility, productivity, and the economy of the farmers. Soil characteristics and quality are important in agriculture development. Soil quality is measured by soil quality indicators, one of the indicators is the physical properties of the soil. This study aims to examine the characteristics of the physical properties of paddy soil, determine the soil physical properties that have the most influence on the soil physical quality index (SPQI), determine the SPQI, and determine the potential of post-harvest paddy soil for crops in Sukaresmi District, Cianjur regency. The method used is PCA (Principal Component Analysis) to select the MDS (Minimum Data Set) of soil physical properties indicators that represent soil function. The results showed that the study site has the characteristics of textured soil sandy loam, loam, sandy clay loam, and clay loam. The bulk density is between 0.67-0.99 g/cm3 . The permeability of all rice plots > 12 cm/h, fast drainage pores, and slow drainage pores ranged from 2,66- 23,11% and 1,17-33,66%. Available Water Capacity (AWC) is in the range of 16,61-52,91%. Physical properties that most affect the physical quality index of soil are texture, slow drainage pores, bulk density, and permeability. SPQI value at the study site is in the range of 2,80-4,50 with the category of rather low, moderate, rather high, and high. The research location has a soil physical quality index that is dominated by the rather high category. The results of
Keyword: paddy fields, physical properties, crops, SPQI, quality soil

Judul: Evaluation of Characteristics of Physical Properties, Chemical Properties and Soil Quality of Post-Harvest Paddy Soil (Case Study: Tuban, East Java)
Abstrak: Tanah sawah pasca panen memiliki sifat yang berubah dan berbeda dengan kondisi ketika sawah diairi, meskipun merupakan kelanjutan dari sifat sebelumnya. Sifat yang berbeda perlu dievaluasi untuk mengetahui kualitas dan tingkat kesuburannya. Penelitian bertujuan mengevaluasi karakteristik sifat fisika dan kimia tanah sawah pasca panen di Tuban, Jawa Timur dan menentukan kualitas tanah serta potensinya untuk penanaman palawija. Metode penelitian menggunakan metode Principal Component Analysis (PCA) dan Minimum Data Set (MDS) dari parameter yang mewakili fungsi tanah untuk analisis kualitas tanah. Parameter yang dianalisis adalah tekstur, bobot isi, pori air tersedia, permeabilitas, C-organik, N total, P-tersedia (P2O5), Kalium dapat ditukar (K-dd), dan Kapasitas Tukar Kation (KTK). Berdasarkan hasil penelitian menunjukkan lokasi penelitian bertekstur klei yang masuk kedalam kategori sedang. Bobot isi berkisar pada 0.8 – 1.4g/cm3 . Pori air tersedia berkisar pada 7.37 – 41.47%. Permeabilitas berada pada rentang 0 – 39.88cm/jam. Kadar C-organik dan Nitrogen relatif rendah. P-tersedia, K-dd, KTK relatif tinggi. Berdasarkan analisis PCA didapatkan tiga parameter sebagai MDS yaitu tekstur, Pori Air Tersedia (PAT), dan permeabilitas. Nilai IKT berkisar 2.60 – 3.43 yang masuk kategori agak rendah dan sedang. Indeks Kualitas Tanah yang dominan pada daerah penelitian adalah sedang. Hasil analisis menunjukkan lokasi penelitian sesuai untuk pengembangan tanaman palawija dan IKT yang rendah dapat ditingkatkan dengan pemberian bahan organik., Post-harvest paddy soil has changed properties and is different from the conditions when the paddy soil is irrigated, although it is a continuation of the previous properties. Different properties need to be evaluated to determine their quality and fertility rate. The study aimed to evaluate the characteristics of physical and chemical properties of post-harvest paddy soil in Tuban, East Java and determine soil quality and its potential for planting crops. The research used Principal Component Analysis (PCA) and Minimum Data Set (MDS) method to select parameters for soil quality analysis. The parameters analyzed were texture, bulk density, available water pores, permeability, C-organic, total nitrogen, available phosphor (P2O5), exchangeable Potassium, and Cation Exchange Capacity (CEC). Based on the result showed that the location of the study has a clay texture which included in the moderate category. Bulk density ranges from 0.8 – 1.4g/cm3 . Available water pores ranges from 7.37 – 41.47%. Permeability ranges from 0 – 39.88cm/h. C-organic and total nitrogen level are relatively low. Available phosphor, exchangeable potassium, and CEC are relatively high. Based on the PCA analysis, there are three parameters obtained as the MDS that are texture, available water pores, and permeability. The Soil Quality Index values range from 2.60 – 3.43, which included in the slightly low and medium categories. The dominant soil quality index in the study area is medium categories. The results of the analysis showed that the location of the study is suitable for the development of secondary crops and SQI low category can be improved by the provision of organic matter.
Keyword: oil Quality Index, Minimum Data Set (MDS), Principal Component Analysis (PCA)

Judul: Grup dan Homomorfisma Grup pada Rubik Revenge
Abstrak: Rubik cube is a kind of puzzle game. A player must arrange rubik sides, which have been disordered, back to the position where every side has the same colour. This paper does not focus on the settlement solution, but instead on proving the existence of a group homomorphism between rubik movement group and S96 symmetric permutation group in rubik revenge. Firstly, it has been proved that rubik movement set is a group. Then, it also has been proved that the M set, which contains numeric labels of 1 until 96 in cubinos sides, is S96 symmetric permutation group.
Keyword: