Indonesian Journal of Agricultural Science
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EFFECT OF PHOSPHATE ON NODULE PRIMORDIA OF SOYBEAN (Glycine max Merrill) IN ACID SOILS IN RHIZOTRON EXPERIMENTS
Get PDFTo clarify whether P had a direct or indirect effect on the nodulation process of soybean grown in acid soils from Sitiung, West Sumatra, Indonesia, a series of rhizotron experiments, with special attention given to formation of nodule primordia, was conducted at Laboratory of Microbiology, Wageningen University in 1998-2000. It was shown that Ca and P were essential nutrients for root growth, nodule formation, and growth of soybean in the acid soils (Oxisols). Ca increased root growth, number of nodule primordia, nodules, and growth of the soybean plant. This positive effect of Ca was increased considerably by the application of P. Ca and P have a synergistic effect on biological nitrogen fixation (BNF) of soybean in acid soils. Ca is important for the establishment of nodules, whilst P is essential for the development and function of the formed nodules. P increased number of nodule primordia, thus it also has an important role in the initiation of nodule formation. From this study, it can be concluded that Ca and P are the most limiting nutrients for BNF of soybean in the acid soils of Sitiung, West Sumatra, Indonesia
IDENTIFICATION AND EVALUATION OF FIBER HYDROLYTIC ENZYMES IN THE EXTRACT OF TERMITES (Glyptotermes montanus) FOR POULTRY FEED APPLICATION
Get PDFFoot rot disease of black pepper caused by Phytophthora capsici had been reported in Batangas and Laguna, Philippines. The plant was recovered following the application of crop residue (organic substrate) and intercropping with other crops. This study was aimed to isolate, identify, and determine the soil mycoflora from the rhizosphere of black pepper grown on various cropping patterns in Batangas and Laguna. Antagonistic activity of mycoflora isolates was tested against P. capsici using dual culture technique. The result showed that 149 colonies of soil mycoflora isolated were belonging to 14 genera; three of them, i.e. Penicillium, Paecilomyces and Aspergillus, were the most dominant. All of the mycoflora isolates were able to inhibit the growth of the pathogen. Eighteen of them were the most promising antagonists, based on their inhibition growth of more than 60%. It is suggested that antagonistic mechanism of Mucor isolate (1001), Trichoderma (125, 170, 171, 179, 180, 181), Gliocladium (109), Cunninghamella (165, 168), Mortierella (177), and Aspergillus (106) was space competitor (competition for nutrient) since they rapidly overgrew the pathogen. Aspergillus (67, 79, 81, 83, 108, and 202) isolates inhibited the pathogen apparently by producing antibiotic, whereas Trichoderma (125, 170, 171, 179, 180, and 181) isolates were able to penetrate the hyphae of the pathogen. The organic matter percentage in the soil was significantly correlated with the number of antagonistic mycoflora in rhizosphere (R2 = 0.1094), but the cropping pattern wPoultry are not able to digest fiber in the diet. Hydrolytic enzymes including cellulases and hemicellulases have been used as poultry feed supplement. Termites (Glyptotermes montanus) have the ability to digest wood that contains high fiber. The purpose of this experiment was to identify the cellulase and hemicellulase of termite extract. The hydrolytic (saccharification) activity of the termite extract on feedstuffs was then evaluated. It contained high endo-β-D-1,4-glucanase (CMCase) activity, but the activities of avicelase, β-D-1,4-mannanase, β- D-1,4-xylanase, and β-D-1,4-glucosidase were very low. The activities of the enzymes were higher in the fresh extract than those extracted after drying at 40oC with blower oven. CMCase (as cellulase), β-D-1,4-mannanase (as hemicellulase), and β-D- 1,4-glucosidase (as glycosidase) were reevaluated further to determine the optimum pH and temperatures for maximum activities. The optimum pH for CMCase, β-D-1,4-mannanase, and β-D-1,4-glucosidase were 6.2, 5.0, and 5.8 respectively, while the optimum temperatures were 45-50oC, 50-55oC, and 42-45oC, respectively. The enzyme mixture or cocktail was more appropriate in digesting feedstuffs with high lignocellulose (fiber) such as rice bran and pollard than feedstuffs with more soluble starch such as soybean and corn meals. The extracted enzyme could be immobilized with pollard, but CMCase recovery was low (28.6%), while β-D-1,4-mannanase and β-D-1,4-glucosidase recoveries were 89.2% and 272.9%, respectively. Termite extract contained enzyme cocktails of lignocellulases that potentially be used as feed supplement. However, its use is limited by its low activity.as negatively correlated. This study suggests that organic matter increased antagonistic mycoflora in black pepper rhizosphere, which will reduce severity of the disease
EFFECT OF BIO FERTILIZER ON MATURE OIL PALM IN NORTH SUMATRA AND RIAU
Get PDFChemical fertilizers have routinely been applied at oil palm plantations to maintain soil fertility. Due to the increase of chemical fertilizer prices, some efforts have been done at such as to reduce cost and increase efficiency in chemical fertilizer application at oil palm plantations include the use of bio fertilizer (BF). The objective of experiment was to evaluate the effect of reducing oil palm standard dosage of chemical fertilizers combined with BF on mature oil palm yield. The experiment was carried out in 2002-2003 covering an area of 4367 ha at PTPN IV in North Sumatra and of 515.58 ha at PTPN V in Riau. The planting material was Dura x Pasifera variety and planted in 1980-1995. A randomized block design was used having three fertilizer treatments: (A) 100% chemical fertilizer (normal dosage), (B) 75% chemical fertilizer + BF, and (C) 50% chemical fertilizer + BF. The replications at PTPN IV and V were 11 and 7, respectively. The BF was applied firstly in May 2002. Dosage of BF was 250 g tree-1 yr-1. The BF was given in pockets with four pockets per palm tree. The parameters observed were fresh fruit bunch (FFB) weight, average of bunch weight, and average of bunch number. Results of the experiments showed that palm yield treated with 75% chemical fertilizer + BF and 50% chemical fertilizer + BF were both not significantly different with palm yield treated with 100% chemical fertilizer. The application of 75% chemical fertilizer + BF and 50% chemical fertilizer + BF gave benefit of Rp509,093 and Rp1,231,535 ha-1 yr-1, respectively. Technically, nutrients given as chemical fertilizers using combination of 75% chemical fertilizer + BF are still higher than the nutrients transported into 26 tons palm FFB ha-1 yr-1. Fertilizer treatment combination of 50% chemical fertilizer + BF will technically be safe only for palm yield of <16 tons palm FFB ha-1 yr-1, since nutrients given as fertilizer are still higher than those transported into the palm yield
IDENTIFICATION OF LEAD AND CADMIUM LEVELS IN WHITE CABBAGE (Brassica rapa L.), SOIL, AND IRRIGATION WATER OF URBAN AGRICULTURAL SITES IN THE PHILIPPINES
Get PDFUrban agriculture comprises a variety of farming systems, ranging from subsistence to fully commercialized agriculture. Pollution from automobile exhaust, industrial and commercialactivities may affect humans, crops, soil, and water in and around urban agriculture areas. The research aimed to investigate the level and distribution of lead (Pb) and cadmium (Cd) in white cabbage (Brassica rapa L.), soil, and irrigation water taken from urban sites. The research was conducted in Las Piñas and Parañaque, Metro Manila, Philippines. The field area was divided into three sections based on its distance from the main road (0, 25, and 50 m). Irrigation water was taken from canal (Las Piñas) and river (Parañaque). Pb and Cd contents of the extract were measured by Atomic Absorption Spectrophotometry. Combined analysis over locations was used. The relationship between distance from the main road and metal contents was measured by Pearson’s correlation. Based on combined analyses, highly significant difference over locations was only showed on Cd content in white cabbage. Cd content in white cabbage grown in Parañaque was higher than that cultivated in Las Piñas, while Cd content in the soil between both sites was comparable.The average Pb content (1.09 µg g-1 dry weight) was highest in the white cabbage grown right beside the main road. A similar trend was also observed in the soil, with the highest concentration being recorded at 26 µg g-1 dry weight. There was a negative relationship between distance from the main road and Pb and Cd contents in white cabbage and the soil. Level of Pb in water taken from the canal and river was similar (0.12 mg l-1), whereaslevels of Cd were 0.0084 and 0.0095 mg l-1, respectively. In general, the concentrations of Pb and Cd in white cabbage and soil as well as irrigation water were still in the acceptable limits. In terms of environmental hazards and polluted city environment, it seems that big cities in Indonesia especially Jakarta and Surabaya have the same problem with the Philippines. Therefore, it is suggested that the study on heavy metal contaminationin several crops, especially those grown along the main road, should be conducted
KINETICS OF COLOUR CHANGE OF TOMATOES DURING DRYING
Get PDFColour is one of the pharameters determining the quality of dried tomatoes. The changes in colour of the skin of tomatoes during drying in an experimental dryer at various temperatures were measured every two hours by using Minolta CR 200 colorimeter and the colours were represented in Hunter-Lab scale. The objective of this research was develop a model for predicting colour changes of tomatoes during drying. The decrease in darkness as represented by dL value varied from 10 to 16%, while decrease in chroma value (dL) varied from 20 to 37% of initial values. An empirical logarithmic equation with six constants was derived to fit the data of chroma changes during drying at various temperature and times. The model of colour change of tomatoes can be used for determining the optimum drying temperature to produce acceptable colour of dried tomatoes at reasonable cost
SOIL PROPERTIES OF THE EASTERN TOPOSEQUENCE OF MOUNT KELIMUTU, FLORES ISLAND, EAST NUSA TENGGARA AND THEIR POTENTIAL FOR AGRICULTURAL USE
No full textKelimutu stratovolcano is one of the young volcanoes extensively found in Flores island. Studies on volcanic soil properties and their suitability for agricultural development in the whole island are lacking. The research was conducted to evaluate the relationship of elevation and soil properties, and suitability for agricultural development. Five representative pedons at elevation of 550, 1,000, 1,200, 1,400, and 1,600 m above sea level (asl), respectively, were studied in the field, and 22 soil samples were analyzed in the laboratory. The results indicated that elevation significantly affected soil properties and degree of soil weathering. With decreasing elevation, sand content, amorphous material content, and phosphate retention decreased. Concomitantly, clay content, H2O-pH, exchangeable Ca and Mg, base saturation, and soil-CEC increased. A highly positive correlation was shown between P retention and NaFpH, Al, and (Al+0.5 Fe) contents extracted by acid ammonium oxalate. Soil-CEC also showed significant positive correlation with clay and silt contents, organic carbon, and exchangeable Ca and Mg. Degree of weathering increased with decreasing elevation as reflected by decreasing silt/clay ratio. Soils developed from Entisols (Lithic Udorthents) at 1,600 m asl, to Andisols (Typic Hapludands) at 1,000-1,400 m asl, and Mollisols (Typic Hapludolls) at lower elevation down to 550 m asl. Soils at 1,400-1,600 m asl are unsuitable for agriculture. Soils at 1,000-1,200 m are moderately suitable for food crops, horticulture, and estate crops. Dominant limiting factors are steep slopes and P retention. Soils at 550 m asl are suitable for food and estate crops, and also lowland horticulture
KINETIC EVALUATION OF ETHANOL-TOLERANT THERMOPHILE Geobacillus thermoglucosidasius M10EXG FOR ETHANOL PRODUCTION
Get PDFThermophiles are challenging to be studied for ethanol production using agricultural waste containing lignocellulosic materials rich in hexose and pentose. These bacteria have many advantages such as utilizing a wide range of substrates, including pentose (C5) and hexose (C6). In ethanol production, it is important to use ethanol tolerant strain capable in converting lignocellulosic hydrolysate. This study was aimed to investigate the growth profile of ethanol-tolerant thermophile Geobacillus thermoglucosidasius M10EXG using a defined growth medium consisted of single carbon glucose (TGTV), xylose (TXTV), and a mixture of glucose and xylose (TGXTV), together with the effect of yeast extract additionto the media. The experiments were conducted at the School of Biotechnology and Biomolecular Sciences of The University of New South Wales, Australia on a shake flask fermentation at 60°C in duplicate experiment. Cultures were sampled every two hours and analised for their kinetic parameters including the maximum specific growth rate (µmax), biomass yield (Yx/s), ethanol and by-product yields (acetate and L-lactate) (Yp/s), and the doubling time (Td). Results showed that this strain was capable of growing on minimal medium containing glucose or xylose as a single carbon source. This strain utilized glucose and xylose simultaneously (co-fermentation), although there was glucose repression of xylose at relatively low glucose concentration (0.5% w/v), particularly when yeast extract (0.2% w/v) was added to the medium. The highest biomass yield was obtained at 0.5 g l-1 on glucose medium; the yield increased when yeast extract was added (at 0.59 g l-1). The highest specific growth rate of 0.25 was obtained in the phase I growth when the strain was grown on a mixture of glucose and xylose (0.5% : 0.5% w/v) medium. Diauxic growth was shown on the mixture of glucose, xylose, and yeast extract. The strain produced low level of ethanol (0.1 g l-1), as well as low level (0.2 g l-1) of by-products (L-lactate and acetate) after 15 hours. The results suggests its potential application for fermenting lignocellulosic agricultural wastes for ethanol production
THE STEM BORER INFESTATION ON RICE CULTIVARS AT THREE PLANTING TIMES
Get PDFStem borer is the second important rice pest after rats in Indonesia. A field trial was conducted in Karawang, West Java in dry season of 2003 to study the effect of planting time on the stem borer infestation on seven rice cultivars. The rice cultivars tested were Fatmawati (new plant type cultivar), Gilirang (semi-new plant type cultivar), Maro and Intani 3 (hybrid rice cultivars), and IR72, Cilosari and IR62 (inbreed rice cultivars). The three planting times (PT) were: (1) the early PT, 14 days before farmer’s PT, (2) the common PT, simultaneously with farmer’s PT, and (3) the late PT, 14 days after farmer’s PT. The trial was arranged in a split plot design with four replications. Planting time is the main plot and rice cultivar is the subplot. Fourteen-day old rice seedlings were transplanted at 25 cm x 25 cm planting distance in a 5 m x 6 m plot size. Species and fluctuation of rice stem borer were determined by using water traps containing four synthetic sex pheromone lures of rice stem borer species as attractant. Results showed that the dominant species of stem borer was yellow stem borer (Scirpophaga incertulas Wlk.). Degree of stem borer infestation depended upon the planting time. Stem borer infestation at the first planting time was higher (average 37.90%) compared to those found at the second and third planting time, i.e. 0.65% and 0.54%, respectively. Rice yields of Fatmawati, Gilirang, Maro, Intani-3, and Cilosari cultivars correlated with the degree of stem borer infestation, but did not correlate with planting time. Cilosari cultivar showed the most tolerant under heavily stem borer infestation. The present study implies that adjustment of planting time is the most feasible effort to reduce stem borer infestation because none of the seven rice cultivars tested were able to minimize damage under heavily infestation of yellow stem borer
THE INFLUENCE OF CULTURAL PRACTICE ON POPULATION OF PEA LEAFMINER (Liriomyza huidobrensis) AND ITS PARASITOIDS IN POTATO
Get PDFPea leafminer (Liriomyza huidobrensis) is the major pest of potato crop in Indonesia. The use of insecticides to control the pest is ineffective and harmful to the natural enemies. The study aimed to find out a promising cultural practice for leafminer management on potato crop. The study was conducted at a farmer’s field in Bali in 2004. Potato plants (Granola variety) were grown in a raised-bed plot of 10 m x 1 m. The treatments evaluated were standard cultural practice (C), C plus reflective plastic mulch (RPM) (CM), farmer’s practice (F), vermicompost (V), and V plus RPM (VM). All treatments were arranged in RCBD with five replications. From each plot, 10 plant samples were randomly taken to observe the presence of larvae, mines, and adults. Larvae and adults of leafminer and mines were separately counted from the top, middle, and bottom parts of the plant samples. Parasitoids were collected from the infested leaves of the plant samples. Emerged parasitoids were counted and put into vials with 70% ethyl alcohol and then identified. The results showed that the population of adults, larvae of L. huidobrensis, and mines were less in C, CM, V, and VM treatments compared to farmer's practice (F). However, RPM (CM and VM) treatments significantly reduced population of leafminer and mines. The highest population of adults, larvae, and mines on RPM treatment were less than 1.5, 8.5, and 10 per plant, respectively compared to other treatments which were greater than 3.2 for adults, 12.4 for larvae, and 12.7 for mines. Parasitoid population and parasitism level were more in vermicompost treatments (V and VM) compared to other treatments (C, CM, and F). The results showed that application of pesticides was ineffective against leafminer and reduced parasitoid population; in the other hand RPM was effective to control leafminer although the effect on parasitoids was not clear. Parasitoid species that were found associated with potato crop were Hemiptarsenus varicornis, Neochrysocharis sp., and Opius sp. Combination of RPM with standard practice and vermicompost are prospective for leafminer management in potato crop, however, VM is friendlier to environment regarding sustainable agriculture
MECHANISM OF ALUMINUM TOXICITY AVOIDANCE IN TROPICAL RICE (Oryza sativa), MAIZE (Zea mays), AND SOYBEAN (Glycine max)
Get PDFPlanting Al tolerant crops is an economically justifiable approach in crop production on acid soils. Experiments were conducted to study the mechanisms of Al tolerance among species and varieties of tropical rice, maize, and soybean with previously known levels of Al tolerance. These varieties were hydroponically cultured in 0, 5, 10, and 30 mg l-1 Al with complete nutrient solution at pH 4. The results show that root/shoot ratio of dry weight at 10 mg l-1 Al treatment was an important parameter to indicate differential Al tolerance in maize. Oxalic acid exudation from roots cannot always explain the Al tolerance. Total organic acid concentration in roots at 10 mg l-1 Al treatment indicated a difference of Al tolerance in soybean and lowland rice. Aluminum translocation from roots to shoots was lower in tolerant varieties than in sensitive varieties of soybean. Increased Al concentration in shoots with increased Al level in the solution was larger in soybean and maize than in lowland or upland rice. Among varieties of soybean, the Al concentration in shoots increased drastically in Wilis (Al-sensitive variety) with increase Al level, while in Kitamusume (Al-tolerant variety) it did not