Judul: The Effects of Tractor Traffic and Organic Matter On Soil Compaction and Tillage Draft
Abstrak: The amendment of organic matter into soil can improve the soil condition and prevent soil compaction caused by tractor traffic. The aims of this research are to know the influence of tractor traffic and organic matter to nature of physical mechanic of soil, analyze the influence of organic tractor traffic and organic matter to performance of soil tillage and to know the influence of soil compaction to performance of peanut crop. This research was conducted in Leuwikopo farm (dry land) and in the laboratory for soil analyzes. The result shows that tractor traffic and organic matter treatment have effect to soil compaction and performance peanut crop. The highest value of bulk density is 1.2 g / cm3 there is at 6 traffic with the organic matter doses 4 ton / ha treatment and lowest is 0.93 g / cm3 at without traffic with the organic matter 4 ton / ha treatment. the biggest sum of pods is 25 pod / tree there is at 2 traffic with the organic matter doses 6 ton / ha treatment and the smallest pods is 8.6 pod / tree at 6 traffic without organic matter treatment.
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Judul: Kapasitas Maksimum Kepadatan Tanah pada Berbagai Distribusi Ukuran Partikel dan Kadar Bahan Organik Tanah dalam Kondisi Kering Udara dan Kapasitas Lapang
Abstrak: Soil consists of mineral and organic matter. The particle size distribution of soil affects the physic characteristics, while soil organic matter is important to improve the soil characteristics. One of the physical change that may occur in soil, as a result of certain forces worked to it, is soil compaction. This research aimed to determine the effect of soil particle size distribution and organic matter in soil compaction, in relation with soil physic characteristics, also to determine the influence of water content in soil compaction and its relation to soil physical properties. The simulation of soil particle size distribution and organic matter content conducted using soil, quartz, and compose. Soils collected from Ciampea, Bogor. The analysis carried out in Laboratory of Departement of Soil Science and Land Resources, Faculty of Agricultural, IPB. The research was set up using randomized design with two factors with three replications. Factor A, which consists: heavy clay, clay, sandy loam, and sand. Factor B consist of: organic matter content 0,5%; 2,5%; 5,0%; and 7,5%. Water content treatments for compaction analyzed using t-student test to compare between the dry air with field capacity compaction. The result showed that the soil particle size distribution and organic matter in soil compaction provide real effect on the maximum soil density and soil physic characteristics, which include: bulk density, total drainage pore, available water pore, permeability, penetration resistance, and compaction energy. The finer soil texture, the smaller of soil bulk density, soil permeability, and soil drainage pore. The organic matter content has an effect in decreasing bulk density, soil permeability, and increasing the available water pore. Soil moisture content has influence on soil compaction. The increase in water content during compaction caused energy required to compaction decreased. The density of soil can be seen from the soil bulk density and penetration resistance.
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Judul: Embriogenesis ikan buta (Astyanax fasciatus)
Abstrak: Ikan buta Astyanax fasciatus adalah spesies ikan unik dari famili Characidae yang menempati perairan dalam gua di Wilayah La Cueva Chica-San Luis Potasi-Mexico. Ikan ini memiliki mata yang tereduksi (Blind Cavefish) dan warna kulit merah muda, pucat serta mengkilap.
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