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Carmen Enid Martinez - One of the best experts on this subject based on the ideXlab platform.

  • Mineral colloids mediate organic carbon accumulation in a temperate forest Spodosol: depth-wise changes in pore water chemistry
    Biogeochemistry, 2018
    Co-Authors: Ekaterina Bazilevskaya, Douglas D Archibald, Carmen Enid Martinez
    Abstract:

    Mobile submicron mineral phases within soil pore waters are presumed to play a major role in the transport and availability of organic carbon (OC) in subsurface horizons. This work reports on the composition of the   95% of the total Fe and Al in SF-S are complexed with OC in all Spodosol horizons. In contrast with the SF-S, the SF-L had much greater OC concentrations and even lower M/C (

  • mineral colloids mediate organic carbon accumulation in a temperate forest Spodosol depth wise changes in pore water chemistry
    Biogeochemistry, 2018
    Co-Authors: Ekaterina Bazilevskaya, Douglas D Archibald, Carmen Enid Martinez
    Abstract:

    Mobile submicron mineral phases within soil pore waters are presumed to play a major role in the transport and availability of organic carbon (OC) in subsurface horizons. This work reports on the composition of the   95% of the total Fe and Al in SF-S are complexed with OC in all Spodosol horizons. In contrast with the SF-S, the SF-L had much greater OC concentrations and even lower M/C (< 0.01), except in the Bh horizon (M/C = 0.05). In Bh, major accumulation of organic matter occurred above the lesser-accumulating Bhs, the latter having higher pH, but much lower OC in all forms (soil, colloidal). Infrared spectroscopy indicates the SF-L fraction of soil pore waters contains both organic and inorganic constituents, including amorphous silica, the second-most abundant component after OC. Mineral-organic associations such as mineral crystallites embedded in OC are observed in the SF-L fraction by transmission electron microscopy (TEM). Transmission electron microscopy also reveal carbon-rich amorphous structures containing traces of Fe, Al and Si, and small (~ 100 nm) spherical amorphous SiO2 particles. These observations provide support for the main mechanism of OC accumulation in Spodosols being the downward movement of colloids (organic, OC-sorbed mineral and organo-mineral), followed by colloid immobilization due to a combination of increases in pH and M/C ratio. The occurrence of these three types of colloidal structures in pore waters seems to depend on the pH and the relative supply of OC and Fe + Al to pore waters. Similar colloidal structures might also contribute to the transport and availability of OC in subsurface horizons of soils that range in the accumulation of organic and organo-metallic compounds, that is, in the expression of spodic properties.

Ekaterina Bazilevskaya - One of the best experts on this subject based on the ideXlab platform.

  • Mineral colloids mediate organic carbon accumulation in a temperate forest Spodosol: depth-wise changes in pore water chemistry
    Biogeochemistry, 2018
    Co-Authors: Ekaterina Bazilevskaya, Douglas D Archibald, Carmen Enid Martinez
    Abstract:

    Mobile submicron mineral phases within soil pore waters are presumed to play a major role in the transport and availability of organic carbon (OC) in subsurface horizons. This work reports on the composition of the   95% of the total Fe and Al in SF-S are complexed with OC in all Spodosol horizons. In contrast with the SF-S, the SF-L had much greater OC concentrations and even lower M/C (

  • mineral colloids mediate organic carbon accumulation in a temperate forest Spodosol depth wise changes in pore water chemistry
    Biogeochemistry, 2018
    Co-Authors: Ekaterina Bazilevskaya, Douglas D Archibald, Carmen Enid Martinez
    Abstract:

    Mobile submicron mineral phases within soil pore waters are presumed to play a major role in the transport and availability of organic carbon (OC) in subsurface horizons. This work reports on the composition of the   95% of the total Fe and Al in SF-S are complexed with OC in all Spodosol horizons. In contrast with the SF-S, the SF-L had much greater OC concentrations and even lower M/C (< 0.01), except in the Bh horizon (M/C = 0.05). In Bh, major accumulation of organic matter occurred above the lesser-accumulating Bhs, the latter having higher pH, but much lower OC in all forms (soil, colloidal). Infrared spectroscopy indicates the SF-L fraction of soil pore waters contains both organic and inorganic constituents, including amorphous silica, the second-most abundant component after OC. Mineral-organic associations such as mineral crystallites embedded in OC are observed in the SF-L fraction by transmission electron microscopy (TEM). Transmission electron microscopy also reveal carbon-rich amorphous structures containing traces of Fe, Al and Si, and small (~ 100 nm) spherical amorphous SiO2 particles. These observations provide support for the main mechanism of OC accumulation in Spodosols being the downward movement of colloids (organic, OC-sorbed mineral and organo-mineral), followed by colloid immobilization due to a combination of increases in pH and M/C ratio. The occurrence of these three types of colloidal structures in pore waters seems to depend on the pH and the relative supply of OC and Fe + Al to pore waters. Similar colloidal structures might also contribute to the transport and availability of OC in subsurface horizons of soils that range in the accumulation of organic and organo-metallic compounds, that is, in the expression of spodic properties.

Douglas D Archibald - One of the best experts on this subject based on the ideXlab platform.

  • Mineral colloids mediate organic carbon accumulation in a temperate forest Spodosol: depth-wise changes in pore water chemistry
    Biogeochemistry, 2018
    Co-Authors: Ekaterina Bazilevskaya, Douglas D Archibald, Carmen Enid Martinez
    Abstract:

    Mobile submicron mineral phases within soil pore waters are presumed to play a major role in the transport and availability of organic carbon (OC) in subsurface horizons. This work reports on the composition of the   95% of the total Fe and Al in SF-S are complexed with OC in all Spodosol horizons. In contrast with the SF-S, the SF-L had much greater OC concentrations and even lower M/C (

  • mineral colloids mediate organic carbon accumulation in a temperate forest Spodosol depth wise changes in pore water chemistry
    Biogeochemistry, 2018
    Co-Authors: Ekaterina Bazilevskaya, Douglas D Archibald, Carmen Enid Martinez
    Abstract:

    Mobile submicron mineral phases within soil pore waters are presumed to play a major role in the transport and availability of organic carbon (OC) in subsurface horizons. This work reports on the composition of the   95% of the total Fe and Al in SF-S are complexed with OC in all Spodosol horizons. In contrast with the SF-S, the SF-L had much greater OC concentrations and even lower M/C (< 0.01), except in the Bh horizon (M/C = 0.05). In Bh, major accumulation of organic matter occurred above the lesser-accumulating Bhs, the latter having higher pH, but much lower OC in all forms (soil, colloidal). Infrared spectroscopy indicates the SF-L fraction of soil pore waters contains both organic and inorganic constituents, including amorphous silica, the second-most abundant component after OC. Mineral-organic associations such as mineral crystallites embedded in OC are observed in the SF-L fraction by transmission electron microscopy (TEM). Transmission electron microscopy also reveal carbon-rich amorphous structures containing traces of Fe, Al and Si, and small (~ 100 nm) spherical amorphous SiO2 particles. These observations provide support for the main mechanism of OC accumulation in Spodosols being the downward movement of colloids (organic, OC-sorbed mineral and organo-mineral), followed by colloid immobilization due to a combination of increases in pH and M/C ratio. The occurrence of these three types of colloidal structures in pore waters seems to depend on the pH and the relative supply of OC and Fe + Al to pore waters. Similar colloidal structures might also contribute to the transport and availability of OC in subsurface horizons of soils that range in the accumulation of organic and organo-metallic compounds, that is, in the expression of spodic properties.

George A. O'connor - One of the best experts on this subject based on the ideXlab platform.

  • Temperature Effects on Phosphorus Release from a Biosolids-Amended Soil
    Hindawi Limited, 2013
    Co-Authors: Maria L. Silveira, George A. O'connor
    Abstract:

    This study was designed to evaluate the effects of temperature on the potential leachable P pool and distribution of chemical P forms in a biosolids-amended soil. A P-deficient Spodosol was incubated with seven biosolids and inorganic P fertilizer at 20 and 32°C for 90 days. Amendments were applied to provide a total P concentration of 112 mg kg−1 soil, which correspond to a field application of ~224 kg P ha−1. Cumulative P mass leached during the 90 d study for any P source was

  • Fluctuating water table effect on phosphorus release and availability from a Florida Spodosol
    Nutrient Cycling in Agroecosystems, 2011
    Co-Authors: Augustine K. Obour, Maria L. Silveira, Joao M. B. Vendramini, Lynn E. Sollenberger, George A. O'connor
    Abstract:

    Spodosols in Florida exhibit a unique hydrology including a fluctuating water table that can often reach the surface horizon during the summer months. This paper evaluated the effects of fluctuating water table on P fluxes and availability in a typical Florida Spodosol. The study was conducted on an established bahiagrass (Paspalum notatum Flugge) pasture grown on a Smyrna sand (sandy, siliceous, hyperthermic Aeric Alaquods). Phosphorus fluxes were measured using suction cup lysimeters installed at depths of 15, 30, 60, 90, and 150 cm. The 15- and 30-cm deep lysimeters were located above the spodic (Bh) horizon, whereas the remaining lysimeters (60-, 90- and 150-cm) were below the Bh horizon. A pressure transducer was installed at the center of the experimental site to monitor changes in water table depth. Two anion exchange membranes (2 × 6 cm) were buried in each plot at a 15-cm depth to estimate in situ P availability. During the 2-year study, leachate P concentrations in the lysimeters above the Bh horizon increased as water tables rose in the months of August and September. Conversely, P concentration measured in the lysimeters below the Bh horizon remained relatively constant (0.02 mg L−1). Soil P availability also increased (from 3.2 μg cm−2 in June to 9.2 μg cm−2 in August) in response to rising water table. Results showed that the fluctuating water table conditions experienced during the summer months in Florida cause upward flux of P from the Bh horizon, which increased soil P availability and susceptibility to off-site transport.

  • A Phosphorus Budget for Bahiagrass Pastures Growing on a Typical Florida Spodosol
    Agronomy Journal, 2011
    Co-Authors: Augustine K. Obour, George A. O'connor, Maria L. Silveira, Joao M. B. Vendramini, James W. Jawitz, Lynn E. Sollenberger
    Abstract:

    Despite evidence that forage crops can access P from the Bh horizon, routine soil testing focus only on P concentrations in the top 15 cm. We evaluated the role of the Bh horizon on the overall P budget for 2 yr in a bahiagrass (Paspalum notatum Fliigge) pasture grown on a Spodosol. Treatments consisted of three P rates (0, 5, and 10 kg ha -1 ) arranged in a completely randomized design with each plot receiving a basal application of 56 kg N ha -1 and 47 kg K ha -1 . Phosphorus application had no effect on bahiagrass P uptake (P = 0.2). Average P mass leached below the 45-cm soil depth was 0.08, 0.08, and 0.09 kg P ha -1 for the 0, 5, and 10 kg P ha -1 treatments, respectively. In 2007, the net balance of P in the Ap horizon was -10.8 kg P ha -1 for the control and -0.8 kg P ha -1 for the 10 kg P ha -1 treatment. The same treatments had net P balances of -6.6 and 7.2 kg ha -1 in 2008. When soil P held in the Bh horizon was included in the P budget computation, the net P balance was positive for all treatments including the control. Results indicate that soil P concentrations were sufficient to maintain bahiagrass production with no additional P fertilization required. Phosphorus held in the Bh horizon is a significant supply of P to low-input pastures growing on Spodosols in Florida and should be considered in nutrient management programs for perennial grasses.

  • Evaluating phosphorus loss from a Florida Spodosol as affected by phosphorus-source application methods.
    Journal of environmental quality, 2008
    Co-Authors: Sampson Agyin-birikorang, George A. O'connor, S. R. Brinton
    Abstract:

    Incorporating applied phosphorus (P) sources can reduce P runoff losses and is a recommended best management practice. However, in soils with low P retention capacities, leaching can be a major mechanism for off-site P loss, and the P-source application method (surface or incorporation) may not significantly affect the total amount of off-site P loss. We utilized simulated rainfall protocols to investigate effects of P-source characteristics and application methods on the forms and amounts of P losses from six P sources, including five biosolids materials produced and/or marketed in Florida, and one inorganic fertilizer (triple superphosphate). A typical Florida Spodosol (Immokalee fine sand; sandy, siliceous, hyperthermic Arenic Alaquods) was used for the study, to which the P sources were each applied at a rate of 224 kg P ha(-1) (approximately the P rate associated with N-based biosolids applications). The P sources were either surface-applied to the soil or incorporated into the soil to a depth of 5 cm. Amended soils were subjected to three simulated rainfall events, at 1-d intervals. Runoff and leachate were collected after each rainfall event and analyzed for P losses in the form of soluble reactive P (SRP), total dissolved P (TDP), total P (TP), and bioavailable P (BAP) (in runoff only). Cumulative masses (runoff + leachate for the three rainfall events) of P losses from all the P sources were similar, whether the amendments were surface-applied or incorporated into the soil. The solubility of the amendment, rather than application method, largely determines the P loss potential in poorly P-sorbing Florida Spodosols.

  • Runoff and leachate losses of phosphorus in a sandy Spodosol amended with biosolids.
    Journal of environmental quality, 2008
    Co-Authors: Luís Reynaldo Ferracciú Alleoni, Scott R. Brinton, George A. O'connor
    Abstract:

    Florida Spodosols are sandy, inherently low in Fe- and Al-based minerals, and sorb phosphorus (P) poorly. We evaluated runoff and leachate P losses from a typical Florida Spodosol amended with biosolids and triple superphosphate (TSP). Phosphorus losses were evaluated with traditional indoor rainfall simulations but used a double-deck box arrangement that allowed leaching and runoff to be determined simultaneously. Biosolids (Lakeland, OCUD, Milorganite, and Disney) represented contrasting values of total P, percent water-extractable P (PWEP), and percentage of solids. All P sources were surface applied at 224 kg P ha(-1), representing a soil P rate typical of N-based biosolids application. All biosolids-P sources lost less P than TSP, and leachate-P losses generally dominated. For Lakeland-amended soil, bioavailable P (BAP) was mainly lost by runoff (81% of total BAP losses). This behavior was due to surface sealing and drying after application of the slurry (31 g kg(-1) solids) material. For all other P sources, BAP losses in leachate were much greater than in runoff, representing 94% of total BAP losses for TSP, 80% for Milorganite, 72% for Disney, and 69% for OCUD treatments. Phosphorus leaching can be extreme and represents a great concern in many coarse-textured Florida Spodosols and other coastal plain soils with low P-sorption capacities. The PWEP values of P sources were significantly correlated with total P and BAP losses in runoff and leachate. The PWEP of a source can serve as a good indicator of potential P loss when amended to sandy soils with low P-retention capacities.

Journal Admin - One of the best experts on this subject based on the ideXlab platform.

  • PEMBERIAN GUANO WALET DENGAN PENGURANGAN PUPUK SP-36 TERHADAP PERTUMBUHAN DAN HASIL TANAMANKUBIS BUNGA (Brassica oleracea var.botrytis L.) PADA TANAH Spodosol (The Application Of Guano Walet With Reduction Of SP-36 Fertilizer To Growth And Yield Of F
    'Universitas Palangka Raya', 2019
    Co-Authors: Journal Admin
    Abstract:

    ABSTRACTThe aim of this study was to determine the interaction between guano walet administration and reduction of SP-36 fertilizer on growth and yield of flower cabbage; to find out the effect of guano walet on the growth and yield of flower cabbage; and to find out the effect of SP-36 fertilizer reduction on growth and yield of flower cabbage. The study was conducted from May to August 2018. This study used a completely randomized design (CRD) consisting of 2 factors namely guano walet with a reduction in SP-36 fertilizer, 4 x 4 factorial pattern with 3 replications. The variables observed were the number of leaves, flowering age, plant wet weight, fresh weight of flowers, and diameter of flower crop. The results showed that the combination of 100% guano walet administration with a reduction of SP-36 0% on Spodosol soil gave the best results for the number of leaves with an average value of 16.00 strands at 6 weeks after planting and fresh flower weight of 166, 76 g. Guano walet administration on Spodosol soil with a dose of 100% gave the best results on the number of leaves by 25.83 strands at the age of 9 weeks after planting, flowering age of 79.33 day, plant wet weight of 326.82 g and the results showed that the combination of 100% guano walet administration with a reduction of SP-36 0% gave the best results for the diameter of flower cropwith an average value of 12,15 cm.Key words: cabbage flower, guano walet, SP-36 fertilizer, SpodosolsABSTRAKTujuan dari penelitian ini adalah untuk mengetahui interaksi antara pemberian guano walet dengan pengurangan pupuk SP-36 terhadap pertumbuhan dan hasil kubis bunga; untuk mengetahui pengaruh pemberian guano walet terhadap pertumbuhan dan hasil kubis bunga; dan untuk mengetahui pengaruh pengurangan pupuk SP-36 terhadap pertumbuhan dan hasil kubisbunga.Penelitian dilaksanakan mulai dari bulan Mei sampai Agustus 2018. Penelitian ini menggunakan rancangan acak lengkap (RAL) yang terdiri dari 2 faktor, yaitu pemberian guano walet dengan pengurangan pupuk SP-36, pola faktorial 4 x 4 dengan 3 ulangan. Variabel yang diamati adalah jumlah daun, umur berbunga, bobot segar total tanaman, bobot segar bunga, dan diameter krop bunga. Hasil penelitian menunjukkan bahwa kombinasi pemberian guano walet 100% dengan pengurangan SP-36 0% pada tanah Spodosol memberikan hasil terbaik jumlah daun dengan nilai rata-rata sebesar 16,00 helai tanaman-1 pada umur 6 minggu setelah tanam dan bobot segar bunga 166,76 g tanaman-1. Pemberian guano walet pada tanah Spodosol dengan dosis 100% memberikan hasil terbaik terhadap jumlah daun sebesar 25,83 helai tanaman-1 pada umur 9 minggu setelah tanam, umur munculnya bunga pada hari ke- 79,33, bobot segar total tanaman sebesar 326,82 g tanaman-1dan pada variabel diameter krop bunga pemberian guano 50% dengan pengurangan pupuk SP-36 0% memberikan hasil sebesar 12,15 cm tanaman-1.Kata kunci: Guano walet, kubis bunga, pupuk SP-36, tanah spodoso

  • PENGARUH PEMOTONGAN UMBI TERHADAP PERTUMBUHAN DAN HASIL TANAMAN TIGA VARIETAS BAWANG MERAH (Allium ascalonicum L.) PADA TANAH Spodosol ( Effect of Buld Cutting on Growth and Yields of Three Varieties of Red Onions (Allium ascalonicum L) on Spodoso
    'Universitas Palangka Raya', 2019
    Co-Authors: Journal Admin
    Abstract:

    ABSTRAKPenelitian ini bertujuan untuk mengetahui pengaruh pemotongan umbi terhadap pertumbuhan dan hasil tanaman tiga varietas bawang merah pada tanah Spodosol. Rancangan yang digunakan dalam percobaan ini adalah Rancangan Acak Kelompok (RAK) Faktorial yang terdiri dari 2 faktor perlakuan. Faktor pertama adalah pemotongan umbi bibit bawang merah,yaitu : P0 = tanpa pemotongan, P1 = pemotongan setengah (1/2), P2 = pemotongan sepertiga (1/3) P3 = pemotongan seperempat (1/4). Faktor kedua adalah varietas bawang merah, yang terdiri 3 varietas, yaitu : V1 = varietas Bauji, V2= varietas Bima Brebes dan V3 = varietas Tajuk. Hasil penelitian menunjukkan bahwa interaksi pemotongan umbi dan varietas bawang merah berpengaruh terhadap jumlah daun dan bobot brangkasan segar. Kombinasi perlakuan pemotongan umbi 1/3 dan penggunaan varietas Tajuk mampu meningkatkan jumlah daun dan bobot brangkasan segar. Hasil bawang merah terbaik terdapat pada perlakuan pemotongan umbi 1/3 (sepertiga) dan varietas Tajuk dengan perolehan hasil bobot brangkasan segar 1126,67 g/petak atau setara dengan 23,47 ton.ha-1.Kata kunci : pemotong umbi, bawang merah, varietas, Spodosol.ABSTRACTThe purposed of this experiment the effect of bulbs cutting on growth and yield of three varieties of onion on Spodosol. This study used Randomized Block Design (RBD) of factorial pattern with two factors : The first factor was cutting the tuber ofonion of 4 levels, namely : P0 = no cutting, P1 = cutting ½, P2 = cutting 1/3, and P3 = cutting ¼. The second factor was the red onion varieties, consisting of 3 varieties, namely: V1 = Varietas Bauji, V2 = Varieties Bima Brebes and V3 = Varieties Tajuk. The results showed that interaction of the part cuttings and varieties of onion bulbs have an effect on the number of leaves and weight of fresh palnt biomassa. Combination treatment of cutting 1/3 bulbs and Tajuk varieties could be able to inrease the number of leaves and weight of fresh plant biomassa. The best results of onion per harvest swaths of the best there is on the treatment of cutting the tuber 1/3 and of the Tajuk varieties with the acquisition of weight fresh stover (1126.67 g)/plot harvest or the equivalent of 23.47. ton.ha-1.Keywords: cutting bulb, red onion, varieties, Spodosol