Judul: Keanekaragaman makrofauna tanah di beberapa ekosistem alami dan budidaya di kabupaten Pelalawan, propinsi Riau
Abstrak: As part of land ecosystem, soil macrofauna have several certain roles. Some of those roles are as obliterator of soil organic material, bio indicator, and increasing soil porosity and aeration. Palm oil fields have been rapidly developed in Indonesia. This rapid development is presumed will change the natural ecosystem into artificial ecosystem which impact to soil macro fauna. In accordance to that presumption further study of soil macrofauna need to be done in palm oil field and other surrounding habitat. The purpose of this research are to acknowledge the diversity of soil macrofauna in several natural and cultivation ecosystems and to find out the composition of macrofauna community in several different habitat, that are palm oil field, natural forest, rubber field and residential. This research was conducted in palm oil field in Pelalawan Regency, Province of Riau. The macrofauna specimens were taken from each location by using purposive sampling method and were taken from each plot by using hand sorting method. The soil macrofauna specimens furthermore were taken for documentation and identification.
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Judul: Abundance of Soil Macrofauna on Several Land Covers in Balangan Regency, South Kalimantan Province
Abstrak: Keberadaan makrofauna tanah memiliki peran penting dalam mempertahankan dan mengembalikan kesuburan tanah. Penelitian ini bertujuan menganalisis kelimpahan makrofauna tanah dan pengaruh jenis vegetasi, serta lingkungan terhadap kelimpahan makrofauna tanah pada beberapa tutupan lahan di Kabupaten Balangan, Kalimantan Selatan. Pembuatan petak dengan ukuran 20 m × 20 m secara purposive sampling. Analisis data dilakukan dengan uji Beda Nyata Terkecil (BNT) dan uji korelasi Pearson. Kelimpahan makrofauna tanah secara keseluruhan terdiri atas 15 ordo dan 27 famili dengan total individu sebanyak 370 individu/m². Hasil uji BNT menunjukkan kelimpahan makrofauna tanah berbeda nyata di hutan sekunder dan lahan kosong, sedangkan kelimpahan makrofauna tanah tidak berbeda nyata antara hutan meranti dan kebun karet. Berdasarkan uji korelasi Pearson, faktor klimatis kelembapan tanah memiliki hubungan positif yang sangat kuat terhadap kelimpahan makrofauna tanah, serta faktor edafis seperti porositas, C-organik, respirasi, berat basah, berat kering, dan kadar air juga memiliki hubungan positif yang sangat kuat terhadap kelimpahan makrofauna tanah., The existence of soil macrofauna has an important role in maintaining and restoring soil fertility. This study aimed to analyze the abundance of soil macrofauna and the influence of vegetation type, as well as the environment on the abundance of soil macrofauna in several land covers in Balangan Regency, South Kalimantan. Plots measuring 20 m × 20 m were made using purposive sampling. Data analysis used the Least Significant Difference (LSD) test and Pearson correlation test. The overall abundance of soil macrofauna consists of 15 orders and 27 families with a total of 370 individuals/m². The BNT test results showed that the abundance of soil macrofauna was significantly different in secondary forests and empty land, while the abundance of soil macrofauna was not significantly different between meranti forests and rubber plantations. Based on the Pearson correlation test, the climatic factor of soil moisture has a very strong positive relationship with the abundance of soil macrofauna, and edaphic factors such as porosity, C-organic, respiration, wet weight, dry weight, and moisture content also have a very strong positive relationship with the abundance of soil macrofauna.
Keyword: climatic, edaphic, formicidae, secondary forest, vegetation

Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf