Browsing by Author "Artacho, Pamela"

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    CHEMICAL FRACTIONS OF Al IN VOLCANIC SOIL AMENDED WITH CELLULOSE WASTE
    (2013) Borquez, Carlos; Arellano, Eduardo; Artacho, Pamela; Bonomelli, Claudia; Canales, Camila; Antilen, Monica
    The cellulose industry generates a great volume of organic and inorganic waste, one of these wastes are called dreg (D) and grits (G). These residues have a high content of calcium carbonate, positioning them as potential bleachers in acid soils. Due to the important content of Al in the residues, a sequential extraction was done to establish the metal chemical fractions such as exchangeable, adsorbed, organic carbonated, and the ones associated to sulfurs, in incubated samples (2, 4, 8, and 32 days at 60 degrees C) of an Andisol amended soil with Grits, Dregs + Grits and lime in 1, 2 and 3 ton/ha doses. The results revealed that there was a significant increase in the amount of Al in all fractions, in comparison to the control soil. On the other hand the incorporation of these residues through a Dregs (70%) + Grits (30%) mixture provoked a pH increase, always higher than the commercial lime.
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    Nitrogen Application in Irrigated Rice Grown in Mediterranean Conditions: Effects on Grain Yield, Dry Matter Production, Nitrogen Uptake, and Nitrogen Use Efficiency
    (TAYLOR & FRANCIS INC, 2009) Artacho, Pamela; Bonomelli, Claudia; Meza, Francisco
    Field experiments were conducted in the major rice growing area of Chile to evaluate the effects of nitrogen (N) fertilization and site on grain yield and some yield components, dry matter production, N uptake, and N use efficiency in rice cultivar 'Diamante'. Two sites (indicated as sites 1 and 2) and six N rates (0, 50, 100, 150, 200, and 300 kg N ha-1) were compared. Nitrogen fertilization increased yield, panicle density, spikelet sterility, dry matter production, and N uptake at maturity. 90% of maximum yield was obtained with 200 kg N ha-1 in site 1 (12,810 kg ha-1) and with 100 kg N ha-1 in site 2 (8,000 kg ha-1). These differences were explained by lower panicle density, and the resulting lower dry matter production and N uptake in site 2. Nitrogen use efficiency for biomass and grain production, and grain yield per unit of grain N decreased with N fertilization. While, agronomic N use efficiency and N harvest index were not affected. All N use efficiency indices were significantly higher in site 1, except grain yield per unit of grain N. The observed variation in N use efficiency indices between sites would reflect site-specific differences in temperature and solar radiation, which in turn, determined yield potentials of each site. On the basis of these results, cultivar 'Diamante' would correspond to a high-N use efficiency genotype for grain yield.
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    Seasonal pattern of root growth in relation to shoot phenology and soil temperature in sweet cherry trees (Prunus avium): A preliminary study in central Chile
    (2012) Bonomelli, Claudia; Bonilla, Carlos; Acuna, Edouard; Artacho, Pamela
    C. Bonomelli, C. Bonilla, E. Acuna, and P. Artacho. 2012. Seasonal pattern of root growth in relation to shoot phenology and soil temperature in sweet cherry trees (Prunus avium): A preliminary study in central Chile. Cien. Inv. Agr. 39(1): 127-136. The period between flowering and harvest in the sweet cherry (Prunus avium L.) is shorter than most fruit trees; thus, competition for assimilate and nutrients occurs early in the season. To properly supply water and nutrients during this critical period, optimal growth and root development are necessary. To characterize the root growth pattern of cherry trees in relation to shoot growth and phenology, a study was conducted on a 'Bing' cherry orchard on Gisela 6 rootstock at fourth leaf, located in central Chile (34 degrees 70 degrees S, 70 degrees 43' W). During the 2009-2010 season, the shoot length and fruit diameter were measured on eight trees, and the root length was quantified by installing rhizotrons on two trees. Additionally, a two-tone (black/white) plastic cover was placed in the row over one tree with a rhizotron to analyze the effects of the plastic cover on soil temperature and root growth. The results showed three peaks of root growth during the season. The first peak occurred 43 days after full bloom (DAFB), corresponding to the phenological stages of the fruit turning from green to straw color. This peak occurred at 326 accumulated degree days (ADD) in the soil and 212 ADD in the air. The second peak was observed after harvest at 97 DAFB, when the shoot growth had stopped, and the soil and air had accumulated 932 and 692 degree days, respectively. The third and last peak occurred at 167 DAFB, with 1887 ADD in the soil and 1361 ADD in the air. The plastic cover increased the average soil temperature by approximately 1 degrees C, thereby increasing the ADD by 105.2 units during the study period. However, this increase was not enough to affect the root growth pattern.
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