Fisiologi Lentinus Spp. dengan Reaksi Oksidasi pada Medium Agar Asamgalat, Agar Asamtanat, dan Agar Tirosin

Hutan tropis Indonesia kaya akan jenis jamur (Mushroom). Keragaman ini merupakan faktor pendo-rong perlunya dilakukan USAha mengidentifikasi dari jamur-jamur yang ada, salah satunya Lentinus spp. Ada enam Lentinus yang telah diteliti dan dipublikasikan tetapi hanya satu yang berasal dari daerah tropis (Kame-run), yaitu Lentinus squarrosulus. Lentinus berpotensi sebagai makanan atau pencampur makanan. Selain itu juga berpotensi sebagai obat-obatan, diantaranya berkhasiat sebagai antibakteri dan antifungi disamping kha-siat lainnya. Penelitian ini bertujuan untuk mengetahui sifat-sifat fisiologi jamur Lentinus spp. berdasarkan reaksi oksidasi pada medium Agar Asamgalat, Agar Asamtanat dan Agar Tirosin. Data fisiologi ini dipakai se-bagai acuan untuk penelitian selanjutnya dalam produksi senyawa antimikroba. Tahap pelaksanaan meliputi pembuatan stok kultur dan peremajaan biakan murni, melihat reaksi oksidasi pada medium asamgalat agar (AAG), agar asamtanat (AAT), dan agar Tirosin (AT). Hasil penelitian memperlihatkan semua isolat Lentinus spp. menunjukkan reaksi yang positif pada medium AAG, AAT, sebaliknya menunjukkan reaksi negatif pada medium AT. Hal ini ditandai dengan terbentuknya zona coklat terang sampai coklat gelap pada medium AAG dan AAT di sekitar hamparan koloni. Sedangkan pada medium AT tidak ditemui adanya zona hitam di sekitar hamparan koloni

Soil Enzyme Activities and Their Relationship to Total Soil Bacteria, Soil Microbial Biomass and Soil Chemical Characteristics of Organic and Conventional Farming

Soil properties such as physical, chemical, biological, microbiological and biochemical aspects affect on soil quality. Soil microbiological activities directly affect stability of ecosystems and soil fertility. The research aimed to determine soil microbial activities through soil enzyme activities and their relationship to total soil bacteria, soil microbial biomass, and soil chemical characteristics. The research was conducted at Laboratory of Soil Microbiology, Indonesian Soil Research Institute, Bogor from July 2015 to January 2016. Soil samples 0-10 cm depth were taken from organic and conventional farming of some commodities (tomato, carrot, maize, broccoli) from Bogor Regency, while those of rice were taken from Tasikmalaya Regency. Soil dehydrogenase, urease and cellulase activities were determined using some modified methods. The results showed that soil dehydrogenase and cellulase activities in organic farming were higher than those in conventional farming, whereas the soil urease activity in organic farming was lower than that in conventional farming. The total soil bacteria and soil microbial biomass were significantly and positively correlated with soil dehydrogenase, urease, and cellulose activities. Soil dehydrogenase, urease, and cellulose activities were very significantly and positively correlated with all soil characteristics tested, i.e. soil organic C, total N, potential P and K, available P and K, CEC, and pH, except that soil urease activity was very significantly and negatively correlated with soil pH. The results of this research indicated that organic farming is recommended for maintaining soil fertility and plant productivity; however, small use of urea fertilizer is still needed in the farming

Soil Chemical Characteristics of Organic and Conventional Agriculture

Use of chemical fertilizers and pesticides on intensive land of both lowland and upland food crops have been shown to increase agricultural productivity significantly. Research aimed to study soil chemical characteristics and soil pesticide residues at some crops of organic and conventional farms. The research was carried out in  Laboratory of Soil Chemistry, Indonesian Soil Research Institute and in Laboratory of Agrochemical Residue, Indonesian Agricultural Environment Research Institute, Bogor from February to July 2015. Soil samples at 0-10 cm depth were taken compositely from broccoli (Brassica oleracea), carrots (Daucus carota), maize (Zea mays), and tomatoes (Solanum lycopersicum) farms in Bogor Regency as well as from rice field in Tasikmalaya Regency at both organic and conventional farms. Soil chemical characteristics were analyzed include: soil organic-C (Walkey and Black), total-N (Kjeldahl), potential-P (HCl 25%), available-P (Olsen), potential-K (HCl 25%), available-K (NH4OAc 1 N pH 7), CEC (NH4OAc 1 N pH 7), and pH (soil : water = 1: 5), while pesticide residues included levels of organochlorine (lindane, aldrin, heptaklor, dieldrin, DDT, endosulfan); organophosphates (diazinon, fenitrotin, metidation, paration, profenofos); and carbamates (carbofuran, MIPC, BPMC) in the soil by using Gas Chromatography method. Results showed that levels of soil organic-C, total-N, potential and available-P, potential and available-K, CEC, pH  at organic farms were higher than those at conventional farms. Some pesticide residues compound (organochlorines, organophosphates, and carbamates) were detected at conventional farm, while those at organic farm were not detected (trace).Keywords: Conventional farm, organic farm, pesticide residues, soil properties. [How to Cite: Muhammad AA, F Hazra, S Salma and D Nursyamsi. 2016. Soil Chemical Characteristics of Organic and Conventional Agriculture. J Trop Soils 21: 19-25. Doi: 10.5400/jts.2016.21.1.19][Permalink/DOI: www.dx.doi.org/10.5400/jts.2016.21.1.19]&nbsp