Carlos Ricardo Trein

Demanda de tração em haste sulcadora na integração lavoura-pecuária com diferentes pressões de pastejo e sua relação com o estado de compactação do solo

An experiment was carried out with crop and cattle rotation in an Oxisoil, in Tupancireta - RS, which aimed to evaluate the draft effort in fertilizer direct drillings used in direct seeding, working at different depths and intensities of fields under different grazing pressures. Grazing pressure effects on soil compactness were also assessed. The main treatments were grazing maintaining 0.10, 0.20, 0.30, 0.40 m pasture (Lolium multiflorum + Avena strigosa) without grazing, height (adjusting the number of cows on the plots) and two working depths of fertilizer shanks: 0.12 m and 0.15 m. Root dry matter in the superficial layer (0.0 - 0.12 m) was increased when higher grazing pressures were used. Soil resistance to a penetrometer showed increased values at higher grazing pressures; it was detected until 0.12 m depth. Draft requirement of fertilizer shanks increased from 1,900 to 4,300 N (120%) when the working depth changed from 0.12 m to 0.15 m condition. Draft demand by fertilizer shanks was higher on soils under higher pressures as well, but the absolute values showed that only treatments with remaining heights of 0.10 and 0.20 m were different from those found without grazing systems. Soil resistance to penetrometer and power demand by fertilizer shanks was closely related.

Força de tração e volume de solo mobilizado por haste sulcadora em semeadura direta sobre campo nativo, em função do teor de água no solo, profundidade e velocidade de operação

Direct drilling or no tillage systems are among the most successful agricultural alternatives regarding soil and water conservation, energy economy and operational capacity of machinery. Some areas where cattle raising and grain production share the same grounds, or where soils are trafficked in moist conditions they may show compaction of the upper layers. Compacted soil areas may not need to be chiseled or plowed, if seed germination and good growing standards are reached by the initial soil conditioning solely by planters coulters. The specific aims of the present work are to determine the knowledge of coulter draft requirements and the amount of displaced soil and tractor slippage on a Paleudult soil at different soil moisture condition, in direct planting on natural pastures chemically killed. Draft requirements increased with an increase in working depth. The increase of the ground speed had no effect on draft when soil was dry or moist; it increased however, on friable soil. Soil displacement was always higher with dry soil and at 12 cm working depth. When soil was friable or dry, the front wheels traction was needed to keep tractor slippage within acceptable levels.

Força de tração e mobilização do solo por hastes sulcadoras de semadoras-adubadoras

No tillage implies keeping the soil surface covered with crops or crop residues, which might influence planter performance. Using fixed shanks as furrow openers to place fertiliser is an alternative to minimize compaction, as it mobilizes the soil in the sowing line. The aim of this research was to evaluate the effect of different amounts of winter cover crop residues evenly distributed on the soil, the effect of the shanks working depth and quantity of planter lines on power demand, cross sectional furrow area and total volume of soil mobilized in the lines and corresponding wheel slippage in distrophic red Argisol. During winter, black oats and black oats plus turnip were used as cover crops before maize and beans, respectively. Increasing the working depth showed an increase in power demand, as measured directly at the shanks (three lines for maize and five for beans). There was also an effect of residue, increasing power demand on the shanks, but only measurable with the planter operating with three lines in maize sowing. Soil mobilization in the sowing lines was influenced by the amount of residues, the working depths of shank and the quantity of planter lines. Wheel slippage was higher with larger amounts of soil cover residues and when power demand was higher.

Produtividade de soja e milho após coberturas de inverno e descompactação mecânica do solo

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.

Capacidade de suporte e compressibilidade de um argissolo, influenciadas pelo tráfego e por plantas de cobertura de inverno

One of the most effective practices in preventing soil compaction is to apply stresses below the bearing capacity of the soil, often estimated by the pre-compression stress (σp). To evaluate the effects of cover crops and tractor traffic on σp and compression index (CI), a field experiment was initiated in 2002 on sandy clay loam Paleudult, in Southern Brazil (Rio Grande do Sul State). Treatments under no-tillage involved winter fallow and two winter cover crops (black oats and black oats + vetch, which was substituted in 2006 by oilseed radish - Raphanus sativus L.) in the plots and two traffic conditions (with and without wheel-tractor traffic) in the subplots. Undisturbed soil cores were sampled in June and November 2006 to determine soil physical properties as well as σp and CI by uniaxial compression tests in an oedometer. Before oedometer tests, soil cores were equilibrated at different water tensions. Regardless of time and traffic conditions, winter fallow showed the highest σp value and the lowest CI value at 0.03-0.06 m. As the soil became drier, differences in σp between winter fallow and cover crops were reduced. In five years, seven wheel-tractor passages increased σp only in the surface layer (0.03-0.06 m), without altering CI. The use of cover crops and absence of traffic reduced the soil bearing capacity and increased soil susceptibility to compaction due to the reduction in soil bulk density and increase of macropores.

Resistência mecânica do solo e força de tração em hastes sulcadoras de semeadoras-adubadoras em sistema de integração lavoura-pecuária

A integracao lavoura-pecuaria, realizada mediante a implantacao de pastagens no inverno e a semeadura de milho ou soja no verao, constitui-se numa alternativa para a diversificacao de atividades e ampliacao dos lucros. Animais em pastejo, principalmente em areas agricolas manejadas sob semeadura direta, podem resultar na compactacao adicional do solo, diagnosticada geralmente pelo aumento de resistencia do solo a penetracao (RP). Com o objetivo de avaliar a correlacao entre RP e forca de tracao (FT) medida em hastes sulcadoras de semeadoras-adubadoras, nos anos de 2004 e 2005, foi conduzido um experimento em Sao Miguel das Missoes - RS, em Latossolo Vermelho (0.540 kg kg-1 de argila). Os tratamentos consistiram em quatro intensidades de pastejo, que resultaram em alturas de pastagem de 10; 20; 30 e 40 cm, e de testemunha sem pastejo, organizados em DBC, com tres repeticoes. Avaliou-se a RP, no final do periodo de pastejo, e na semeadura da soja, obteve-se a FT exigida nas hastes sulcadoras de semeadoras-adubadoras. A RP e a FT aumentaram com o incremento na intensidade de pastejo. A correlacao entre essas variaveis foi significativa, comprovando que e possivel avaliar o estado de compactacao do solo por meio da medicao da FT requerida pelas hastes sulcadoras de semeadoras-adubadoras.

Demanda de tração, mobilização de solo na linha de semeadura e rendimento da soja, em plantio direto

The objective of this work was to evaluate the relationship between the draft power (FT) in the fertilizer furrow-opener and the volume of mobilized soil in the sowing line as affected by the amount of residues, tractor traffic and furrow‑opening working depth, and its influence on soybean agronomic performance. Treatments consisted of six residue dosages (DR), two fertilizer furrow‑opener working depths (PT) and two soil traffic conditions - with and without tractor traffic - carried out in a randomized block design, in a split‑split‑plot scheme. The treatments were applied with or without irrigation under no-tillage on a Rhodic Paleudult soil. The different PT and tractor traffic conditions influenced FT significantly. Regardless of the irrigation conditions, DR treatments did not affect soybean grain yield and shoot dry matter weight. In the absence of irrigation, soybean productivity increased by 180 kg ha -1 when PT was changed from 0,064 to 0,10 m, which indicates fertilizer furrow-opener at greater depths as a viable practice to decrease the effects of drought on crop.

Produtividade de soja em semeadura direta influenciada por profundidade do sulcador de adubo e doses de resíduo em sistema irrigado e não irrigado

harvesting oats, the straw was returned to plots in amounts of 0; 2; 3; 4; 5 and 6 Mg ha -1 ;t hese were the main treatments, which, were divided according to the furrow opening depth (0.06 m and 0.12 m) by the shanks of the drill. The experimental design followed a random design, with three repetitions. The area was divided in two, with and without irrigation. The volume of soil mobilized by the fertilizer furrow openers was 53% higher when the working depth reached 0.12 m compared to 0.06 m, but no difference due the amount of cover crop residues was attained. Grain yield, crop biomass and root mass to 0.15 cm depth did not differ with both soil working depth and crop residue cover. Irrigation increased in 11% grain yield and total biomass of soybeans. Even without irrigation, soybean productivity was higher than the Rio Grande do Sul State average, showing its suitability to be grown on native pastures under the no-till system.

Parâmetros solo-máquina em função de doses de resíduos vegetais e profundidades de deposição de adubo em semeadura direta

O trafego continuo e inadequado de maquinas em solos sob semeadura direta tem provocado alteracoes dos atributos fisicos e mecânicos dos solos, influenciando, dessa forma, na produtividade das culturas. O experimento foi conduzido na Estacao Experimental Agronomica da Universidade Federal do Rio Grande do Sul, no municipio de Eldorado do Sul - RS, num Argissolo Vermelho distrofico tipico, com o objetivo de quantificar a forca de tracao e obter informacoes sobre os atributos fisicos do solo, em semeadura direta sobre residuos de aveia-preta e ervilhaca parcialmente decomposta. O delineamento experimental utilizado foi em blocos casualizados, com parcelas subsubdivididas, sendo, nas parcelas principais, doses de residuos da cultura de inverno (0; 1,3; 2,6; 3,2; 3,8 e 5,1 Mg ha-1) de palha de aveia-preta consorciada com ervilhaca, nas subparcelas profundidades de atuacao da haste sulcadora de adubo (0,06 e 0,12 m) e nas subsubparcelas trafegos dos rodados do trator e colhedora. Os atributos fisicos do solo foram afetados pelo trafego dos rodados da maquina. A forca de tracao foi influenciada pela profundidade de atuacao das hastes sulcadoras e o trafego dos rodados.

Atributos físicos do solo sob intensidades de pastejo e métodos de pastoreio com cordeiros em integração lavoura‑pecuária

The objective of this work was to evaluate possible alterations in the soil bulk density and total porosity due to lamb trampling, under different grazing management after no-tillage summer crop. The experiment was carried out in the layers 0-2.5, 2.5-5 e 5-10 cm of an arenic Ultisol, in an annual ryegrass pasture with forage allowance of 2.5 and 5.0 of animal potential consumption, under continuous and rotational stocking. An ungrazed area was used as check. Grazing intensities and methods did not affect soil bulk density and total porosity. It is possible to use areas with this kind of soil texture, with cover crops for lamb grazing in the winter, without alterations on soil physical attributes, caused by animal trampling, reach harmful levels for subsequent crops.