186 resultados para Base saturation
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A greenhouse investigation was carried out to study the effects of liming on the dry matter (DM) production of the grasses Brachiaria brizantha (Hoscht.) Stapf. cv. Marandu, Andropogon gayanus Kunth cv. Planaltina and Panicum maximum Jacq cv. Aruana, cultivated on a Dark-Red Latosol, medium texture. The liming levels were obtained through the addition of carbonates in a Ca:Mg ratio of 4:1, necessary to increase the degree of base saturation (V%) to the following values; 4% (control), 20%, 36%, 52%, 68% and 84%. During the experimental period (180 days), four cuts were done to determine the DM production. The results indicated that the DM production was increased (P<0,05) with the liming-levels increased to the three grasses. Panicum maximum cv. Aruana yielded the lower DM quantity, but it presented a better response to liming. The inverse was observed in relation to A. gayanus. The data allowed to conclude that the DM production increased by liming and when the V% level was lower than 50%, it will be increased to 70% for establishment.
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This work aimed to evaluate root growth, shoot development and nutrient absorption efficiency by rice cultivars Caiapo and Maravilha as affected by lime application. The experiment was carried out in a greenhouse, with treatments set up by Caiapo and Maravilha cultivars in combination with the base saturation (V%) of 10%, 40% and 70%. The experiment was in a randomized complete block design, with four replications. The number of tillers, root length, root dry matter, leaves and stems, leaf content and macronutrients absorption efficiency were evaluated. Comparing cultivars, Maravilha cultivar presented higher root dry weight, root length, number of stems, dry matter of stems and shoot than Caiapo cultivar, as well as accumulated more nutrients in the shoots. on the other hand, nutrient contents were higher in the cultivar Caiapo compared to Maravilha. Maravilha cultivar shows greater root and shoot growth while Caiapo shows higher nutrient absorption efficiency from the soil. The base saturation of 40% is the most effective for both cultivars.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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In this work the distribution was evaluated "in situ" of phosphorus (P), organic matter (MO), potassium (K), calcium (Ca), magnesium (Mg), cation exchange capacity (CEC), aluminum (Al), sum of bases (S), base saturation (V) and pH of a soil cultivated with soybean and irrigated with swine wastewater in the 0, 25, 50 and 75% levels. The factorial scheme was constituted by the 20, 40 and 60 cm soil depths and four wastewater levels with five repetitions. The results showed that significant difference occurred only for P, K and CEC in the soil profile. However, in all parameters, the 60 cm soil depth showed that the concentrations levels are similar to before the aplication of treatments.
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The aim of this work was evaluate the physiological indicators of association between water deficiency and soil acidity, by determining the nitrate reductase activity, the levels of free proline and initial growth of the root system of seedlings of sugarcane cv. IAC91-5155. After 30 days, the seedlings were transferred to plastic pots with 12 dm3 of dystrophic alic Red Latosol (Oxisol) and submitted to association of three treatments of water availability: no stress (70%), moderate stress (55%) and severe stress (40%), in according with field capacity and three acidity treatments: no stress (55%), moderate stress (33%) and severe stress (23%), considering the base saturation. The experimental design was that of random blocks under factorial scheme of 3x3, with four replicates. After 60 days under the stress association, the levels of free proline, the nitrate reductase activity and the growth of the sugarcane roots system were evaluated in seedlings of sugarcane. The nitrate reductase enzyme activity can be considered a physiological indicator of the effect of the association of acid and water stress in moderate conditions in soil, while the free proline can be considered physiological indicator to both stress in severe conditions. Water deficiency increasing reduced growth of sugarcane roots.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Caracteristicas gerais e classificacao de solos basalticos da regiao Central do Estado de Sao Paulo.
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Giving a special emphasis on soil classification relative to their positions in the landscape, five soil profiles in the Barra Bonita-Jau area were characterized through morphological, granulometric and chemical routine soil analysis. It was observed that the soil structure gradually changes from strong blocks with cutans (lowlands and smooth parts - Jau). In this direction, the silt/clay ratio and the base saturation is reduced, and the aluminium saturation increases. -from English summary
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An experiment was conducted to study the effects of liming and drying method on Ca nutrition, fungus infection and aflatoxin production potential on peanut (Arachis hypogea) grains. Peanut cv. Botutatu was grown in the absence or presence of liming to raise the base saturation of the soil from 20 to 56%. Calcium contents of the soil were increased from 5.5 to 14.6 mmol((c))kg-1 and pH from 4.2 to 4.9. After harvest, plants and pods were dried in (1) shade, (2) field down to 100 g water kg-1 (3) field down to 250 g water kg-1 and transferred to a forced-air oven at 30°C, (4) field down to 360 g water kg-1 and transferred to a forced-air oven at 30°C. Calcium contents were analyzed in the grains, pericarps and seed coats. The incidence of Aspergillus spp., Penicillium spp., Rhizopus spp. and potential aflatoxin production in vitro were evaluated, as well as the seed coat thickness. The seed coat was thicker when peanut was grown in the presence of lime, leading to a decrease in seed infection by Aspergillus spp. and Penicillium spp. When plants were dried in shade, the growth of aflatoxinogenic fungi was independent of liming. However, in plants dried in the field or field + oven, the development of these fungi was decreased and even suppressed when the Ca content of the seed coat was increased from 2.2 to 5.5 g kg-1.
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A greenhouse experiment was conducted in the Soil Science Department of the Botucatu College of Agricultural Sciences (UNESP), Brazil, using a Dark Red Latosol in 25 L pots. The soil was limed to 50 and 70% of base saturation; and doses 0, 10, 20, 30 and 40 t ha-1 of chicken manure were applied, in December of 1999. The experimental design was completely randomized blocks with a factorial arrangement 5x2, 10 treatments and three replications. This work was carried to evaluate leaf number, height plants, fresh and dry weight by aerial part of sweet fennel, and macronutrients and micronutrients removal. The organic fertilization affected the accumulation of N, P, K, S, B and Mn; liming affected the nutrient uptake, except for the Ca, Mg, S and Fe; the interaction of factors affected K, Mg and Mn.
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The spatial variability of physical and chemical properties of soil were evaluated to provide subsidies for management of the agricultural input. The chemical variables: P, organic matter (OM), K, Ca, Mg, pH, CEC and base saturation (BS); and physical variables: sand and clay were analysed. Soil samples were collected at two depths (0-0.2 and 0.6-0.8 m) located at irregular mesh of sampling in the region of Monte Alto, in a Yellow-Red Podzol (Alfissolo) (PVA), under different managements, resulting in 88 points in 1465 ha of total area; and at the region of Jaboticabal in a Red Latosol (LV) cultivated with sugarcane, resulting in 128 points in 2597 ha of total area. The chemical and physical soil properties studied showed spatial dependence, except CEC in 0.6-0.8 m layer for LV; Ca and clay at 0-0.2 m layer and P, OM, K, Mg, sand and clay in 0.6-0.8 m layer for PVA. The chemical and physical variables studied were adjusted to spherical and exponential models and some of them showed semivariogram without defined structure. The PVA showed low spatial continuity of chemical and physical properties, mainly in 0.6-0.8 m layer, which suffers less antropic influence. The LV soil showed more homogenous zones of fertility and granulometric composition.
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This work studied alterations of physical properties of a distroferric red nitosol due to millet (Pennisetum americanum) covering, with or without liming, in a no-tillage system during the agricultural years of 1999/2000 and 2000/2001, using soybean and corn as culture succession. 6m×10m plots, with and without millet as vegetal covering, received only one initial superficial application of limestone, 3.1 t ha-1 in the first half of each plot in order to obtain 70% base saturation (V), after the desiccation of the millet. Some physical properties as soil density, aggregate stability, > 2 mm aggregate proportion, macro and micro porosity were analyzed whereas the chemical analysis determined Ca and Mg macro nutrients, organic matter, soil pH and H+Al. Millet vegetal residues and surface liming did not alter soil density nor the average weight diameter (AWD), > 2 mm aggregate, soil macro porosity and organic matter content, twenty-four months after the no-tillage system implantation for studied experimental conditions. Soil micro porosity was significantly affected in layers deeper than 0.20 m, in treatment with millet and limestone. Calcium, magnesium and H + Al contents and the soil pH values suffered significant alterations in superficial layer, between 0-0.05 m.
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The balance of liming and fertilization practice with nitrogen and zinc could affect the production of the pasture. Thus, the present work has as objective to evaluate the residual effect of the application of calcareous rock, nitrogen, and zinc on the dry matter production of Brachiaria decumbens, during three cuts. For this, an experiment was installed in Selvíria, Brazil, on a distrofic red Latosol, from october 1997 to may 1998. The experimental design was randomized blocks, in a factorial project 3×3×2, with four repetitions. The treatments were three doses of nitrogen: 0, 50, and 100 kg/ha, three doses of lime: 0, 267, and 556 kg/ha, corresponding to 41, 50, and 60% of the levels of base saturation, respectively, and two doses of zinc 0 and 5 kg/ha, applied in the first year and reapplied in the second year, except for the limestone. Four cuts were done in the grass at 10 cm of height, with intervals of 49 days, to obtain the dry matter production. The limestone application in the first year did not provide to residual effect on the production of Brachiaria decumbens. However, the nitrogen fertilization increased the dry matter production of the grass. The application of zinc in the first year and the reapplication in the second year did not result in a productive response of B. decumbens. © 2009 Instituto Nacional de Investigaciones Agricolas INIA.
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The high rate of mineralization of organic matter on savannah soils, which is reached fi ve times faster than in temperate regions, leads us to the challenge of electing the best system of management that maintains and/or increase it in soil, guaranteeing its quality and sustainability. In this sense the present research aimed to study the effects of green, organic and mineral manure on the chemical properties on the chemical properties of an Oxisol, on Savannah area, cultivated with cotton (Gossypium hirsutum) under conventional tillage and no-tillage in the pasture fi eld (Brachiaria decumbens) for 20 years. The experimental design was a randomized block design with split plots. The main plots consisted of two treatments: conventional tillage and no-tillage, and the subplots of six treatments: control (no fertilizer), mineral fertilizer recommended for the crop, according to the soil chemical analysis, organic fertilizer (cattle manure - 20 t ha-1), organic fertilizer (cattle manure - 20 t ha-1) + 1/2mineral fertilization recommended according to the analysis of soil, green manure-1 (Crotalaria juncea) and green manure-2 (Pennisetum americanum). There were studied the following soil chemical properties: P, OM, pH, K, Ca, Mg, Al, Al + H, S, exchange capacity cations and base saturation. The soil samples for the analysis were performed on layers of 0,00-0,05 m, 0,05-0,10 and 0,10-0,20 m. Then it came the following conclusions: the fertilization interfere in soil chemical properties and the preparation did not interfere, the cattle manure and its association with the mineral fertilizer caused increasing level elements in the soil, Crotalaria juncea and Pennisetum americanum did not infl uence on soil chemical properties.
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This study was carried out to evaluate the effects of surface application of lime rates on soil chemical attributes and soybean yield in a no-tillage system. It was installed a field experiment in a factorial 2×4, and the factors were: two types of lime (calcitic and dolomitic); four rates (0.0 - 0.5 - 1.0 and 1.5 t ha-1 of CaCO3), in a completely randomized blocks experimental design, with four replications. The experiment was located in Matupá, Mato Grosso State, Brazil, being the work developed between November 2006 and May 2007. The evaluations were chemical attributes in the soil layers (0,0-2,5 cm, 2,5-5,0 cm and 5,0-10,0 cm), and the productive characteristics of soybean. Application of lime increased the soil pH (CaCl 2), the exchangeable Ca and Mg, the effective CEC and the base saturation only in the soil surface layer. The two limes were different only for Ca and Mg values in the first layer of soil, and only for the Mg values in the layer of 2,5-5,0 cm. The surface liming in no-tillage system did not change soybean yield.
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This work aimed to evaluate the effect of cattle manure levels in the phase of implementation Corymbia citriodora (Hook.) K. D. Hill & L. A. S. Johnson (Eucalyptus citriodora) seedlings in field, produced from seeds collected from four mother trees. The experiment was carried out in green house, in pots filled with 5 dm 3 of Oxisol. Five cattle manure levels were applied 0, 10, 20, 30, and 40 t ha -1 (0, 25, 50, 75, and 100 g pot -1). All treatments received lime levels which were calculated to increase the base saturation degree to 50%. The soil fertility was evaluated after 30 days of soil incubation with manure and lime. The seeds were collected from mother trees called 2, 8, 20 and 29. Sowing was performed directly in rigid plastic containers of 50 cm 3 and seedlings were transplanted when they were around 17 cm height. The experimental design was entirely randomized, in a factorial 5 × 4 (five doses of cattle manure and seeds of four mother trees) scheme and four repetitions. Each parcel was a pot with two plants. At 90 days the height, foliar area, stalk diameter, shoot and root dry matter. The plants responded positively to application of manure, but differently for each evaluated growth characteristic linearly or quadratically. The manure levels had linear effects on growth characteristics and dry matter production of the plants from mother trees 2 and 20 moreover these plants require more cattle manure levels than ones from mother trees 8 and 29. The cattle manure promoted the best development of plants from mother trees 8 and 29, in relationship with dry matter production of shoot components was approximately 27 t ha-1, equivalent to 67.5 g pot.