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Desempenho de um trator em fun??o do tipo de pneu, da lastragem e da velocidade de trabalho
Lopes, Afonso;Lan?as, Kléber Pereira;Silva, Rouverson Pereira da;Furlani, Carlos Eduardo Angeli;Nagaoka, Alberto Kazushi;Reis, Gustavo Naves dos;
Ciência Rural , 2005, DOI: 10.1590/S0103-84782005000200018
Abstract: the objective of this study was to compare the performance of the fwd agricultural tractor, equipped with three types of tires (bias ply, radial and low pressure), with and without tire water ballasting, operating in four forward speed. the research was carried out at unesp, sp, brazil, with the tractor pulling a chisel plow. a tractor with 89kw (121cv) engine power equipped with fwd, was used in the experiment, and the tires used had the following characteristics: radial (front: 14.9r26 and rear: 620/75r30), bias ply (front: 14.9-26 and rear: 23.1-30) and low pressure (front: 500/60-26.5 and rear: 700/55-34). the experiment was conducted in a completely randomized block, design (3x2x4), with 24 treatments and three replications. the results evidenced advantages for the tractor equipped with radial tires.
Indicadores da qualidade física de um Latossolo Vermelho distrófico típico sob plantio direto escarificado
Klein, Vilson Antonio;Baseggio, Matheus;Madalosso, Tiago;
Ciência Rural , 2009, DOI: 10.1590/S0103-84782009005000225
Abstract: the assessment of the physical quality of agricultural soils has taken on added importance, especially in areas under no tillage, as important changes to soil structure occur as a result of this type of management. soil resistance to penetration (rp), the least limit water range (llwr) and relative density (rd) have been used as evaluation parameters. the aim of this study was to assess and model rp as a function of soil moisture and density and to determine the llwr as a function of rd under two management systems. samples of soils under no tillage (nt) and chiseled no tillage (cnt) for six months and whose structure had been preserved were collected at a depth of 0 to 5cm. in the laboratory, rp was assessed using an electronic penetrometer and each management system was statistically adjusted to busscher's equation. in cnt soils, rp was lower for the same density and moisture, and lower than the pd, whereas the difference in rp was larger between the two management systems when soil moisture in the field was lower. the llwr was higher under cnt up to an rd of 0.9. results allow us to conclude that rp is a sensitive parameter for determining the physical quality of the soil and that cnt significantly reduced rp and increased the llwr, providing favorable conditions for root growth for a longer time period.
Produtividade, qualidade dos frutos e distribui??o do sistema radicular da melancia em diferentes sistemas de cultivo
Rocha, Marta Rodrigues da;Eltz, Flávio Luiz Foletto;Santos, Michele Silva dos;Rocha, Pedro Vanti da;Goulart, Rafael Ziani;
Revista Brasileira de Ciência do Solo , 2011, DOI: 10.1590/S0100-06832011000400032
Abstract: the watermelon is cultivated mainly by small producers, in sandy soils under conventional tillage, with occurrence of high erosion taxes, since the crop doesn't form canopy capable to cover the soil entirely. watermelon (citrullus lanatus l.) was evaluated under different cultivation systems on an ultisol in the central depression of rs, brazil, in an experiment in the 2008/2009 growing season. on 48 m2 plots in a randomized block design with four repetitions, the following cultivation systems were tested: conventional tillage (ct), no-tillage (nt), nt chiseled with one chisel shank (nt1s), nt chiseled with two shanks (nt2s), nt chiseled with three shanks (nt3s), nt chiseled with four shanks (nt4s), nt chiseled with five shanks (nt5s); the distance between chisel shanks was 0.35 m. data were analyzed by the duncan test (p < 5 %). watermelon was sown in november 2008, in a spacing of 2.20 x 0.75 m, on black oat straw (avena strigosa). apart from the watermelon yield of marketable fruits (> 6 kg), the root surface area and root system distribution in the soil profile perpendicular to the sowing line were determined 30 and 60 d after sowing. besides, some soil physical properties (soil density and resistance to penetration) were determined after the watermelon cycle. the yield was highest under ct (126 t ha-1), differing statistically from the other treatments. the total root area increased with intensity and area of soil mobilization, except in the nt4s treatment. in the ct treatment, no difference in depth was observed, but in the other treatments the 0-5 cm layer differed from the deeper layers. resistance to penetration in the 0-10 cm layer was lower, which may be related to the higher root concentration in that layer.
Compressibilidade de um Argissolo Vermelho-Amarelo trafegado e escarificado
Vogelmann, Eduardo Saldanha;Mentges, Marcelo Ivan;Reichert, José Miguel;Rosa, David Peres da;Barros, Cláudia Alessandra Peixoto de;Reinert, Dalvan José;
Ciência Rural , 2012, DOI: 10.1590/S0103-84782012005000004
Abstract: farm machinery wheeling is considered a major source of soil compaction. the use of chisel plow can minimize such effects, but the chisel can cause subsurface compaction. the aim of this study was to evaluate the effect of traffic and is present below the compaction layer thought compressive parameters of soil. the treatments investigated were: no-tillage, no-tillage with additional traffic (traffic intensity of 24.67mg km ha-1), no-tillage chiseling recent implanted, no-tillage with additional traffic and chiseling recent implanted. for the density, void ratio, preconsolidation pressure and coefficient of compressibility determination in the layers 0.0-0.10m, 0.10-0.20m, 0.20-0.30m and 0.30 to 0.40m samples were collected. the treatment no-tillage showed the lowest load support capacity and greater susceptibility to compaction. the traffic intensity of 24.67mg km ha-1 increased bulk density and decreased void ratio until 0.30m depth. the chisel plow did not affect the preconsolidation pressure and coefficient of compressibility of soil layer below the line of action of the chisel tip.
Porosidade de aera??o de um Latossolo Vermelho e rendimento de trigo em plantio direto escarificado
Klein, Vilson Antonio;Vieira, Márcio Luis;Durigon, Fabio Fernando;Massing, Jo?o Paulo;Fávero, Fernando;
Ciência Rural , 2008, DOI: 10.1590/S0103-84782008000200011
Abstract: the soil management should be aimed at providing optimal conditions for plant growth and development. no-tillage is a quintessential conservative system; however, it has caused compaction, thus affecting crop development and yield. sporadic soil chiseling in these areas has been used as an alternative to minimize the negative effects of an increase in bulk density. the soil bulk density, total porosity, air-filled porosity, maximum density, relative density, and wheat grain yield of an oxisol were assessed in two areas: under no-tillage for 6 years and under no tillage chiseled. soil water potential was monitored throughout the wheat crop cycle by using electronic sensors and a datalogger. results show that sporadic chiseling of the soil under no-tillage reduced soil density and relative density by 5%, increased total porosity and changed the soil water dynamics, resulting in a higher volume of water-free pores (7.6%) throughout the wheat crop cycle, remarkably increasing grain yield (682kg ha-1).
Produtividade de soja e milho após coberturas de inverno e descompacta??o mecanica do solo
Debiasi, Henrique;Levien, Renato;Trein, Carlos Ricardo;Conte, Osmar;Kamimura, Karina Marie;
Pesquisa Agropecuária Brasileira , 2010, DOI: 10.1590/S0100-204X2010000600010
Abstract: the objective of this work was to evaluate the effect of soil winter covers and soil mechanical loosening on soybean and corn yield, in no-tillage system. two experiments were carried oud in rio grande do sul state, brazil, in a compacted argissolo vermelho (haplic acrisol), in the 2005/2006 and 2006/2007 crop seasons. the first experiment was carried out in a complete block design, with a split plot arrangement. the treatments were two theoretical working depths of a driller chisel-type furrow opener (0.06 and 0.12 m, split plot), and three soil winter covers (main plot): fallow, black oat (avena strigosa), and black oat+common vetch (vicia sativa). in 2006, the soil cover black oat+common vetch was replaced by oilseed radish (raphanus sativus). in the second experiment, in a complete block design, the soil was chiseled and treatments consisted of black oat or oilseed radish as winter cover crops. cover crops reduced soil superficial (0-0,06 m) compaction compared to fallow and, in the 2005/2006-crop season, under low water availability, provided higher soybean and corn yields. in the 2006/2007-crop season, when water availability was higher, the same did not happen. increasing working depths of the chisel-type furrow opener did not affect soybean or corn yields. soil chiseling reduced soybean and corn yields in comparison to the continuous no-tillage system.
Varia??o temporal de propriedades físicas do solo e crescimento radicular de feijoeiro em quatro sistemas de manejo
Reichert, José Miguel;Kaiser, Douglas Rodrigo;Reinert, Dalvan José;Riquelme, Ursino Federico Barreto;
Pesquisa Agropecuária Brasileira , 2009, DOI: 10.1590/S0100-204X2009000300013
Abstract: the objectives of this work were to determine the temporal variation in soil porosity, bulk density and penetration resistance, in four soil management systems, and study their effects on the root growth of black beans (phaseolus vulgaris). the experiment was conducted in a hapludalf using three replicates. the treatments consisted of: long-term (10 years) no-tillage, conventional tillage, chiseling of the long-term no-tillage (chi. recent), and no-tillage in area after one year since chiseling (chi. 1 year) of the long-term no-tillage area. chiseling reduced soil bulk density and increased total porosity during the bean growing cycle. the greatest bulk densities were observed at 0.10 to 0.15 m in the no-tillage and in chi. 1 year. soil resistance was the best property to differentiate the effects of the soil management systems, the restricted layers, and time of sampling. howerver, soil resitance did not affect the root growth of black beans. the effects of the soil chiseling on bulk density and soil resistance disappeared after one year, which indicated soil consolidation.
Rendimento da soja e intervalo hídrico ótimo em latossolo vermelho sob plantio direto escarificado
Klein, Vilson Antonio;Camara, Rodrigo Kurylo;
Revista Brasileira de Ciência do Solo , 2007, DOI: 10.1590/S0100-06832007000200004
Abstract: the least limiting water range (llwr) was used to determine several factors that influence plant growth. the llwr is defined as the water content range in which aeration (afp) and soil resistance to root penetration (rp) are not restrictive, within the field capacity (fc) and permanent wilting point (pwp). the aim of the present study was to determine the llwr and soybean grain yield in an oxisol under non-tillage (nt) and chiseled no-tillage (cnt) systems. the soil density, llwr, soil water content range throughout the soybean crop cycle and grain yield were assessed. soil density was lower in the cnt system, which resulted in a wider llwr. critical density (llwr=0) was similar in the nt and cnt systems. the soil water content decreased to values outside the llwr at different periods during the crop cycle when a limiting rp of 2 mpa was considered. it was concluded that an rp of 2 mpa is not limiting for soybean because there were no significant differences in grain yield between the two tillage systems.
Altera??es nos atributos físicos de um latossolo vermelho sob plantio direto induzidas por diferentes tipos de escarificadores e o rendimento da soja
Girardello, Vitor Cauduro;Amado, Telmo Jorge Carneiro;Nicoloso, Rodrigo da Silveira;H?rbe, Tiago de Andrade Neves;Ferreira, Ademir de Oliveira;Tabaldi, Fabiano Mauricio;Lanzanova, Mastrangello Enívar;
Revista Brasileira de Ciência do Solo , 2011, DOI: 10.1590/S0100-06832011000600026
Abstract: soil compaction at high intensity degrees is a hardly reversible process in the no-till system (nt), mainly in clayey soils. generally, its occurrence in croplands is often irregular and restricted to areas with a previous history of pressures associated to intensive traffic of agricultural machineries. the purpose of this study was to investigate changes in soil physical properties of a red oxisol with clayey texture (450 g kg-1) and soybean yield, caused by two site-specific chisels and conventional (random) chisel tillage. for this work, a 50.6 ha cropland area under long-term no-till and site-specific farming was selected in the municipality of victor graeff, located in the plateau region of rio grande do sul. the climate is a subtropical cfa with annual rainfall ranging from 1500 to 1750 mm, average temperature of 20 °c, at 490 m asl. based on three crop yield maps, the field was subdivided in three management zones with distinct yield potential where the soil physical properties were investigated. the following treatments were established in the low yield zone (lz): (a) conventional chiseling at fixed soil depth (0.30 m) (cc); (b) site-specific chiseling with fox? equipment at fixed soil depth (0.30 m) (sscf); (c) site-specific chiseling with fox? equipment at variable soil depth (0.10 to 0.30 m) based on maximum soil penetration resistance maps (sscv); and (d) control without chiseling (cwc). the high yield zone (hz) was used as a reference to evaluate treatment effects on soybean grain yield. treatments were arranged in parallel strips of 100 x 20 m, in a randomized block design. in three evaluations, the soil water infiltration and bulk density, macro and microporosity and total porosity were evaluated in the layers 0.0-0.05, 0.05-0.10, 0.10-0.15 and 0.15-0.20 m. the results of the initial soil characterization showed higher bulk density and lower soil porosity in the 0.15-0.20 m layer, in the lz in relation to hz. treatments showed an immediate increase of
Quantifica??o da resistência tênsil e da friabilidade de um latossolo vermelho distroférrico sob plantio direto
Tormena, Cássio Antonio;Araújo, Marcelo Alessandro;Fidalski, Jonez;Imhoff, Silvia;Silva, álvaro Pires da;
Revista Brasileira de Ciência do Solo , 2008, DOI: 10.1590/S0100-06832008000300004
Abstract: the soil structural quality is important for plant emergence as well as for crop growth, development and yield. a wide range of soil tensile strength values indicates that soil structure conditions meet these requirements. the objective of this study was to evaluate the tensile strength and friability of an oxisol (acrudox) under no-tillage with crop rotation and crop succession. the soil management treatments consisted of: crop succession with wheat and soybean (sds); crop rotation with corn-oats-soybean-oats-soybean-wheat (sdr) and sdr plus periodic soil chiseling (sde). ten soil blocks (0.15 x 0.20 x 0.10 m) were randomly collected from the 0-0.20 m layer for each treatment, on two sampling dates (october 2003 and april 2004). the soil tensile strength and soil friability was estimated in 450 soil aggregates from each treatment and sampling date. the soil organic carbon content of the aggregates was also measured. there was no effect of soil organic carbon on soil tensile strength and friability. results showed lower tensile strength in sde soil collected in 2003. crop succession (sds) temporarily changed the friability classification from very friable to friable. crop rotation (sdr) was effective in maintaining the soil structure at the very friable class, resulting in a better structure and soil physical quality. the parameters tensile strength and friability proved sensitive enough to evaluate soil structural quality under the crop management systems studied.
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