Judul: Pengaruh Kadar Air dan Pemberian Pupuk terhadap Dekomposisi Bahan Gambut
Abstrak: Peat land has often been used for large scale farming and plantation. Thus the technology on its utility has been improved and shows a bright prospect. However, the use of those technology upon the peat land has received many critics. Many scientists suggest that the decreasing of ground water levels in peat land will cause the increase of CO2 emission; the lower the groundwater surface, the more emission will be. However, this theory is only based on chemistry and physics reactions, while in fact the decomposition process is determined by biochemical reactions where microbes hold an important role. The objective of this research is to know the effect of water content combined with the addition of fertilizer on the peat decomposition and its composing materials based on its respirations. The respiration was measured by Jar Method. Respiration measurement was done every 10 days until the level of respiration rate was constant. The result showed that 2 times water holding at field capacity (WHFC) treatment has the highest respiration value as compared with 1 times WHFC and 0.5 times WHFC. The addition of urea fertilizer whether alone or combined with SP-36 has an effect to the value of the respiration. The addition of litters on sieved peat (GS) or the sieved peat combined with woody materials (GBS) also showed high respirations value. The high value of respiration was affected by the population of bacteria and fungi. This is supported by suitable environment and adequate food supply. Result of final analysis after incubation showed C/N and C/P ratio may not figured the rate of decomposition.
Keyword: water content, respiration, peat composing materials, peat decomposition

Judul: Pengaruh Trichoderma sp. dan Molase pada Pengomposan Sampah Daun dalam Lubang Resapan Biopori terhadap Laju Pengomposan dan Laju Peresapan Air
Abstrak: Trichoderma sp. is typical microorganism that could increase the decomposition rate of organic materials, whereas by-product of sugar processing molasse can be used as energy source for support their growth. The aim of this research was to study the effect of Trichoderma sp. and molasses addition on rate of litters decomposition within biopore infiltration hole and water infiltration rate. This research used rendomized block design with three replications. The treatments applied, are (i) control (without leaf litter, P0), (ii) leaf litter (P1), (iii) leaf litter + molasses (P2), (iv) leaf litter + Trichoderma sp. (P3), and (v) leaf litter + combined Trichoderma sp. and molasses (P4). During the decomposition process, carbon (C) concentration in leaf litters was tended to decrease. The lowest carbon concentration contained in compost was found in treatment of P4 (18% C), whereas total nitrogen was varied among the treatments. The highest total nitrogen concentration was observed in treatment of P3 (0.72% N). The lowest C/N value was resulted in treatment of P3 (26.41). Phospore (P) and potassium (K) in compost was decreased during the decomposition process. All treatments with organic materials addition resulted in the increase of infiltration rate of biopore infiltration hole.
Keyword: water infiltration rate, Trichoderma sp, molasses, decomposition, compost

Judul: Invers Drazin dari Matriks Toeplitz Singular
Abstrak: Matriks Toeplitz adalah matriks yang setiap unsur pada diagonal utama bernilai sama dan setiap unsur pada subdiagonal yang bersesuaian dengan diagonal utama juga bernilai sama. Matriks singular adalah matriks yang tidak bisa ditentukan inversnya. Akan tetapi, dapat diupayakan untuk ditentukan inversnya menggunakan invers matriks yang diperumum. Invers Drazin merupakan salah satu jenis invers matriks yang diperumum. Pada karya ilmiah ini ditentukan invers Drazin dari matriks Toeplitz singular dengan menggunakan metode Leverrier Faddeev. Kemudian, ditentukan invers Drazin dari matriks Toeplitz singular yang direpresentasikan sebagai penjumlahan segitiga bawah dan segitiga atas matriks Toeplitz berdasar pada teorema Gohberg dan Semencul., Toeplitz matrix is a matrix in with element on the main diagonal has the same value and on the subdiagonal corresponding to the main diagonal also has the same value. Singular matrix is a matrix that has no inverse. However, it can be attempted to determine the inverse using a generalized inverse matrix. Inverse Drazin is a type of generalized matrix inverse. This paper discussed the inverse Drazin for a singular Toeplitz matrix using the Leverrier Faddeev method. Then, the Drazin inverse of the singular Toeplitz matrix which is represented as a sum of products of lower and upper triangular Toeplitz matrix based on Gohberg and Semencul theorem.
Keyword: inverse Drazine, singular Toeplitz matrix