Judul: Soil Quality Assessment for Vegetable Management Practice with KMnO4 Oxidizable Method
Abstrak: A simple method of estimating biologically active soil organic carbon (SOC) can accelerate determination of soil quality related to soil organic matter (SOM) content. Changes in biologically active SOC can be used in evaluating the impact of vegetable management and other agricultural practices on soil quality. Regional estimates of SOC changes can only be obtained by analyzing very large number of samples over large areas due to the strong spatial variability in SOC contents. Visible and Near Infrared Spectroscopy (VNIRS) provides an alternative to chemical analyses. The benefits of this technique include a reduction of the sampling processing time, an increase of the number of samples that can be analyzed within time and budget constraints, hence an improvement of the detection of small changes in SOC stocks for a given area. This study report on a highly simplified method in which neutral dilute solutions of potassium permanganate (KMnO4) reacts with most of the active fractions of SOM, changing the deep purple color of the solution to a light pink color. Pearson correlation was used to compare laboratory and field-kit protocol with other soil quality indicators. Results from the laboratory and field-kit protocols were nearly identical (r=0.99, R2=0.98), not significant t test, not different CV (range 10- 14%), and not different coefficient of correlation.
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Judul: Korelasi Ekstrak Kalium Tanah Ultisol dan Oksisol dengan Respons Tanaman Jagung
Abstrak: Ultisol and Oxisol are two kinds of soil that have widcly distribution in Indonesia, which is potential to the developed in crop agriculture like C0111. Low level of potassium nced fertilized that appropriate with thc plants demand. The selected extraction method to measure the potassium needed were detennined through the correlation test between the concentration of potassium soil and the plants response. This expcriment were conducted in Ultisol and Oxisol soil Balambangan Pagar, Lampung Utara to select the best extraction method of potassium soil for corn. The experiment used five status potassium levels, that is very low (OX), low ('1,X), medium (VoX), high Oc.X), very high (X), which X = 631,68 mg KCllpot or equivalent with 1287,32 kg Kel/ha, that is the potassium demand to reach the very high potassium content. Each POk1ssium levels was fertilized with 0, 40, 80, 160, 320 mg KCllpot. Respectively plants response were correlated with the potassium soil that estimated by five method, HCI 25%, Olsen, Morgan Wolf, Morgan Vanema, and NH4-asetic pH 7,0. The result showed that fertilization of K significantly increased the plants only in very low level ofpotassiulll soil as 19,8% in Ultisol and 28,6% in Oxisol. For the increasing height weight of dry pbnts was 1,87-27,27% in Ultisol and 0,26-18,74% in Oxisol. The capability of each method in determining the potassium in soil could be different. Hel 25%, Olsen, Morgan Wolf, Morgan Vancma, dan NH.l-asclic pH 7,0 method were selected to estimate K fertilizer needed in Ultisol for corn,and in Oxisol soil was Olsen and NH4-asetic pH 7,0 method.
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Judul: Konstruksi Hukum Grup Kurva Eliptik Atas F3m
Abstrak: Elliptic curves upon F3m can be divided in two cases, i.e. supersingular and nonsupersingular case. Based on group laws on elliptic curves, a new arithmetic upon F3m can be formulated as an addition process of two random points on the curve. This addition process can then be applied to the ElGamal algorithm.
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