Judul: Penggunaan Rhizobium dan bakteri pelarut fosfat pada tanah mineral masam untuk memperbaiki pertumbuhan bibit sengon (Paraserianthes falcataria (L.) Nielsen)
Abstrak: The main problem of acid soil is the availability of nutrients and high exchangeable A1 content. Soil acidity will reduce many legum plant growth, decrease number of rhizobia and nodule initiation and inhibit the function and growth of ndule. Based on these problems, the experiment was cmducted to obtain the acid and A1 tolerant strain of Rhizobium isolated from sengon nodules, and to obtain the effective strain of Rhizobium in fixing atmospheric nitrogen, and phosphate solubilizing bacteria in increasing P availability, thus support plant growth. The study was focused on three aspects: ( I ) Research on Rhizobim consist of (a) collection of Ahitobiurn strains from sengon nodules, (b) screening Rhizobium toward acidity and high concentration of Al, (c) screening Rhizobium based on their ability to fix nitrogen, (d) marking the selected Rhizobim with antibiotic, and screening the resistant mutants, (e) assesing the effectiveness of the selected Rhizobim on acid soil in greenhouse; (2) Research on phosphate solubilizing bacteria, consist of (a) isolation of phosphate solubilizing bacteria, (b) selection of phosphate solubilizing bacteria in dissolving P from rock phosphate and Alms in liquid medium and acid soil, (c) identification of selected phosphate solubilizing bacteria, (d) determination of organic acid produced by selective phosphate solubilizing bacteria, (e) assessing the effectiveness of selected phosphate solubilizing bacteria in greenhouse; (3) winmulation between Rhizobim and phosphate solubilizing bactetia in greenhouse and field experiments., Permasalahan yang utama dari tanah masam adalah cadangan unsur hara kesuburan tanah yang rendah, kandungan Al dapat ditukar tinggi, dan mempunyai kapasitas retensi P yang tinggi. Kemasaman tanah pada tanaman leguminosa akan menyebabkan terganggunya pertumbuhan tanaman, jumlah rhizobia dan pembentukan bintil akar berkurang serta terhambatnya fungsi dan perkembangan bintil.
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Judul: Penggunaan Rhizobium Dan Mikrob Pelarut Fosfat (MPF) Untuk Memperbaiki Pertumbuhan Bibit Akasia (Acacia mangium dan Acacia crassicarpa)
Abstrak: The increasing of paper raw material requirement is caused by the development of raw material. Therefore, it is needed a method to produce a high quality and quantity of paper. Acacia is one of paper raw material. To increase the growth of acacia seed, an effective usage of Rhizobium and Phosphate Solubilizing Microbe (pSM) seedling inoculant is one of strategies to produce good acacia seeds. The Rhizobium and Phosphate Solubilizing Microbe seedling inoculant can reduce anorganic fertilizer usage and increase the growth of acacia seed. The aims of this research were to select Rhizobium which has an ability to fix atmosphere N2 air and local Phosphate Solubilizing Microbe in dissolving phosphate, also to test the ability of those isolates in increasing the growth of acacia seedling. This research was conducted in the Soil Biotechnology Laboratory, Department of Soil and Land Resource Science, Faculty of Agriculture, Bogor Agricultural University and RAPP greenhouse (Pelalawan and Pangkalan Kerinci R&D Nursary) in Riau. Plant media is cocopit. The experiment consisted of 15 Rhizobium treatments isolated from peat soil, which was planted with A. crassicarpa, and mineral soil, which was planted with A. mangium; 16 Phosphate Solubilizing Microbe treatments taken from peat and mineral soil with 5 replications . The research resulted 2 Rhizobium isolates from IS tested isolates, which could increase the growth of A. crassicarpa effectively, those were Rh Ac S and POS-RIS, and 2 Phosphate Solubilizing Microbe from 16 tested isolates, those were BPF 4 and FPF S. While on A. mangium, there were 2 isolated out of 15 Rhizobium isolates which could increase the A. mangium growth effectively, those were M32-M33-R2N and M45-R2N; also 3 isolates out of 16 Phosphate Solubilizing Microbe, those were M32-BP3, FRK2, and M33-FP2. The characteristic of effectiveness could be seen from the plant height, the amount of leaves, the dry root wight, the dry plant weight, the diameter of bar and the root compactness; so that the usage of Rhizobium inokulan, Rh Ac 5 and P05-RIS equal to the usage of 0.1 kgll Monopotassiumphosphate fertilizer and better than control. Meanwhile the usage of MPF, BPF 4 and FPFS equal to the usage ofO.SI1 kg of Osmocote fertilizer and better than control.
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Judul: Uji Robust T2-Hotelling dengan Menggunakan Penduga Minimum Covariance Determinant
Abstrak: Hotelling’s T2 statistic is a good statistic for inference about the mean of a multivariate normal population. In Hotelling’s T2 statistic, approximation with Bonferroni confidence intervals provides shorter interval than T2 confidence intervals. Therefore, to find the mean of a multivariate normal population, simultaneous t-intervals based on the Bonferroni method is often applied. However, hypothesis test and confidence intervals based on T2 statistic can be significantly affected by outliers in a set of multivariate normal data. Therefore, to find a good estimator for the mean of a multivariate normal population, the Minimum Covariance Determinant (MCD) estimator is used. To increase the efficiency of the MCD estimator, this test statistic is applied using the reweighted MCD which gives weights to the mean and covariance based on the robust of the observations.
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