Laser-Induced Breakdown Spectroscopy (LIBS) is a method for measuring level of nitrogen (N) in the soil in the form of N-nitrate (NO3) rapidly without going through the process of sieving and drying. The sample soil in the form of pellets subjected to laser pulses using a wavelength of 532 nm, pulse duration 5.5 ns, repetition rate of 10 Hz, and Q-switch delay of 150 μs. Emissions are captured by the spectrometer with the wavelength range of 190-1130 nm. Spectrum characterization was processed through the second derivative in order to obtain a wavelength identity that could be rapidly used to estimate the nitrate content of the soil with a determination coefficient of (R2) 0.9254 and a coefficient of variation (CV) of 8.41%. The results of this study are very potential to be applied for rapid measurement of soil nitrate.
The increasing of population annually, needs to increase food availability. On the other hand, the productive land for agriculture have limitations because the large land conversion to non-agricultural land. The use of marginal land such as peat is an attempt to overcome the limited productive land for growing rice. Peat soils have low soil fertility level and acid soil reaction in nature. The conditions of peat soils require amelioration to improve soil fertility. The ameliorants that have potential to increase soil fertility are trass and volcanic ash. The purpose of this research was to examine the effects of trass and its combination with volcanic ash on soil chemical properties and rice growth. The research was conducted in a pot experiment using peat soils from Kumpeh, Jambi. Doses of trass as a single factor treatment were 0, 3, 6, and 9% or 0, 90, 180, and 270 gram/pot, and doses of the combination treatments between trass and volcanic ash were 0+7.5, 1.875+5.625, 3.75+3.75, 5.625+1.875, and 7.5+0% or 0+225, 56.25+168.75, 112.5+112.5, 168.75+56.25, and 225+0 grams/pot, the all treatments compared to standard fertilization. The research design was used Completely Randomized Design (CRD). The results showed that giving the trass as a single factor significantly increased the soil pH, Exchangable Al and Mg, available Zn and Mn, plant height, productive tillers, plant biomass, uptake of K, Si, and plant Zn. The combination trass with volcanic ash significantly increased the soil pH, Exchangable Al, total-N, Exchangable Na, available Zn and Mn, plant height, productive tillers, plant biomass, uptake of P, K, Si, and plant Zn. Beside that, combination trass with volcanic ash significantly improved the efficiency of P and K fertilization. Keywords: Peat, rice, trass, volcanic ash
Development of preminent commodity of rubber is one of Mandailing Natal Regency Government’s strategy to improve society prosperity. To support the mentioned things, this research was conducted with purpose of determining location suitability for the development of rubber plantation based on land evaluation, analysing of financial and marketing feasibilities of rubber smallholding, and analysing the directive of rubber smallholding potential development in Mandailing Natal Regency by using mapping and descriptive analysis. The research result shows that acreage of potential area for the development of rubber plantation in Mandailing Natal Regency is 460 849 ha (70.41%). Financially, the enterprise of rubber smallholding in every land suitability class is feasible. The market chain of rubber in Mandailing Natal Regency is not efficient enough. The location which is able to be recommended for the development of rubber plantation in Mandailing Natal Regency based on potential location, financially and relevant government regulations is 201 875 ha (30.84%). The performance of rubber smallholding plantation in Mandailing Natal Regency is influenced by agricultural extension service officer, the availability of farmer group, rubber productivity and availability of agricultural infrastructure. Nowdays, rubber processing factory should be built in Mandailing Natal, considering that raw materials are widely available and added value will contribute for regional development.
Kendala terbesar kegiatan evaluasi lahan di Indonesia adalah ketersediaan dan kelengkapan data sumberdaya lahan skala semi detil maupun detil. Meskipun data sumberdaya lahan pada skala tersebut tersedia namun data mengenai sifat kimia dan biologi tanah seringkali tidak lengkap. Untuk mengantisipasi permasalahan tersebut, penelitian ini bertujuan untuk mengkaji penerapan metode evaluasi lahan alternatif untuk identifikasi lahan sawah, yaitu metode ekstrapolasi. Metode ekstrapolasi dimulai dari identifikasi karakteristik lahan yang mencirikan keberadaan lahan sawah, penentuan kelas dan skor karakteristik lahan penciri menurut tingkat kecocokan lahan sawah, identifikasi nilai skor total berikut klasifikasi tingkat kecocokan lahan sawah akhir yang terjadi di lahan sawah, dan ekstrapolasi spasial tingkat kecocokan lahan sawah akhir ke seluruh area kajian. Hasil penelitian menunjukkan bahwa karakteristik lahan yang mencirikan keberadaan lahan sawah adalah kemiringan lereng, curah hujan, jarak dari jalan, dan jarak dari sumber air. Perbandingan metode ekstrapolasi dengan metode evaluasi kesesuaian lahan maupun evaluasi kemampuan lahan menunjukkan bahwa metode ekstrapolasi dapat direkomendasikan sebagai metode evaluasi lahan alternatif karena memiliki representasi keberadaan lahan sawah yang paling tinggi, yaitu 97,5 %. Kata Kunci: Evaluasi Lahan, Ekstrapolasi Spasial, Lahan Sawah. ABSTRACT The main obstacle in land evaluation in Indonesia is the availability and completeness of land resources data, both in semi-detailed and detailed scale. Eventhough land resource data on semi-detailed and detailed scale are obtainable but chemical and biological soil properties data is often incomplete.To anticipate such problems, this research aimed to review the application of alternative land evaluation method for paddy field identification, which is called extrapolation method. The extrapolation method started from the identification of land characteristics that could indicate the presence of paddy field, fortitude class and score of identifier land characteristics according to the paddy field suitability, identified total score and paddy field suitability level that occured in paddy field, and extrapolated paddy field suitability level spatially throughout the study area. The results showed that the land characteristics that could be used as identifier characteristic were; slope, rainfall, distance from the road, and distance from the water source. Comparison extrapolation method with land suitability evaluation and land capability evaluation method showed that extrapolation method could be recommended as an alternative method for land evaluation because it had the highest paddy field representation, which was 97.5%. Keywords: Land Evaluation, Spatial Extrapolation, Paddy Field.
<p>Acid soil is commonly grown with cassava, which in general, tolerate low soil fertility and aluminum (Al) toxicity. However, without any improvement efforts such soil will become worse. Intercropping cassava with <em>Brachiaria decumbens </em>(BD) which adapts to acid soil and tolerates low fertility soils as well as application of arbuscular mycorrhiza (AM) and organic matters are among the important efforts to rehabilitate this soil. The experiment was conducted to examine the impact of BD, AM, and potassium (K) enriched rice straw compost on exchangeable Al, available K, and stability of soil aggregates. Experiment was arranged in a completely randomized design with three factors and three replications. The first factor was BD as cassava intercropping, the second factor was AM, and the third factor was 2 t ha-1 rice straw compost enriched with 0 kg, 50 kg, 100 kg, and 200 kg KCl ha-1. Brick pots (1 m length x 1 m width x 0.45 m depth) filled with Kanhapludult soil was used for growing cassava in which row of BD was planted at 60 cm from cassava stem. K-enriched rice straw compost and AM (10 g per stem) were applied around cassava stem at 2 and 12 days after planting, respectively. BD was cut every 30 days and the cutting was returned to the soil. Soil exchangeable Al was analyzed at 0, 3, 6 and 9 months after planting (MAP), while Al and K contents as well as aggregate stability were measured at 6 MAP. The results showed that planting BD decreased 33% exchangeable Al, which means that the root exudates of this grass was effective in detoxifying Al3+. Treatment of BD and/or in combination with AM was effective in preserving K added to the soil, increasing total polysaccharides, and improving soil aggregate stability. This indicated that planting BD and applying AM and Kenriched rice straw compost improved acid soil fertility, and therefore can be recommended in cassava cultivation.</p>
Peat soil amelioration has important role on improvement of soil peat fertility such as on increasing soil pH, reducing organic acid and toxic ions, and also increasing nutrients availability. Soil amelioration with polyvalent cations (Fe Al Cu Zn) namely slag, lateritic soils, and river mud are effectively reducing harmful effect of phenolic acid. The objectives of the study were to determine the effect of soil amelioration on peat soil chemical properties, optimum temperature amelioran tras and dolomite to increase Si concentration in peat soil, also to determine the effect of soil amelioration on increasing crop productivity (both biomass and yield). The study was consisted of two sets of experiments, namely soil incubation in the laboratory and greenhouse experiment with 4 replications of CRD (complete randomized design) plot design. The result of the study showed that the application of slag and dolomite are significantly different to increase pH, base saturation, and (Ca, Mg) content, meanwhile slag application was more complex and stable on improving chemical properties of peat soil. Slag was also improving pH, KB, and Ca, Fe content as well as silica and ash. Tras and dolomite burning were not significantly different on increasing silica in peat soil. Slag application was significantly increased both dried crop biomass and yield on rice. The best ameliorant was slag compared to tras, dolomite, and mixed tras dolomit with slag.Keywords: Ameliorant, organic acids, paddy, peat soil
The physical quality of NPK fertilizer is very important, good physical quality, as indicated by the low potential of caking and absorption-penetration of water so that NPK fertilizer can be stored for a longer time and easier in handling. In this study, the granulation test used NPK 15-15-15 + 5S formula with the percentage filter pressmud 0%, 60%, 70%, 80%. 90% and 100% in two types of K sources: MOP (KCl) and SOP (K2SO4). Granulation was carried out using the wet granulation method using pan granulator, 2 kg batch-1 capacity, rotation speed 23 rpm and 50o pan slope. The purpose of this study was to determine the effect of filter pressmud addition on the tendency of caking NPK 15-15-15 + 5S products during storage. The results showed that the addition of pressmud filler in the production of NPK fertilizer was obtained: the addition of filter pressmud as a filler in the production of 15-15-15 + 5S NPK fertilizers can reduce the potential of caking by 1.77% -44.31% depending on the formulation of raw materials used.
Pekebunan kelapa sawit di Indonesia telah berkembang secara signifikan dalam 20 tahun terakhir. Perluasan areal perkebunan kelapa sawit telah mengarah ke lahan-lahan marjinal seperti lahan sulfat masam dan gambut. Lahan marjinal untuk pengembangan perkebunan kelapa sawit bukanlah suatu pilihan, tetapi karena keterbatasan lahan semata. Reklamasi lahan sulfat masam dengan mendrain lahan rawa akan membuat kemasaman tanah meningkat drastis dan dapat mengganggu pertumbuhan tanaman. Selain itu drainase juga dapat membuat sejumlah besar hara ikut tercuci. Penelitian bertujuan untuk mengetahui pengaruh kedalaman pirit terhadap beberapa sifat kimia tanah serta produksi kelapa sawit. Penelitian dilaksanakan melalui survei lapangan di perkebunan kelapa sawit PTPN VII, unit usaha Bentayan, Sumatera Selatan. Analisis contoh tanah dilaksanakan di Laboratorium Kimia dan Kesuburan Tanah, Departemen Ilmu Tanah dan Sumberdaya Lahan, Fakultas Pertanian, IPB. Pengamatan dilakukan pada blok-blok dengan kedalaman pirit < 30 cm, 30-60 cm, dan > 60 cm, produksi dikumpulkan pada blok-blok tersebut dan diambil contoh tanahnya. Selain itu juga diambil contoh tanah berpirit yang belum dan telah mengalami drainase. Hasil penelitian menunjukkan bahwa kedalaman pirit < 30 cm memiliki pengaruh yang sangat nyata terhadap meningkatnya kemasaman tanah, Al yang dapat dipertukarkan, berkurangnya N-total, K dan Zn serta penurunan produksi tanaman kelapa sawit. Drainase menyebabkan kecenderungan terjadinya penurunan kadar P, Ca, Mg, dan Cu, serta kejenuhan basa.
