Gilberto Omar Tomm

Efeitos de sistemas de produção de grãos envolvendo pastagens sob plantio direto nos atributos físicos de solo e na produtividade

Ley forming modifier soil structure, which, in turn, effects soil physical characteristics in the upper layer. The objective of this study was to evaluate soil physical attributes and grain yield in a typical dystrophic Red Latosol (Typic Haplorthox) located in Passo Fundo county (RS), Brazil, after eight years of mixed production cultivation (1993 to 2000). The effects of production systems integrating grain production with winter annual and perennial pastures under no-tillage were assessed. Four mixed production systems were evaluated: system I (wheat/soybean, white oat/soybean, and common vetch/corn); system II (wheat/soybean, white oat/soybean, and grazed black oat + grazed common vetch/corn); system III [perennial cool season pastures (fescue + white clover + red clover + birdsfoot trefoil)]; and system IV [perennial warm season pastures (bahiagrass + black oat + rye grass + white clover + red clover + birdsfoot trefoil)]. System V (alfalfa as hay crop) was established in an adjacent area in 1994. The areas under systems III, IV, and V returned to system I after the 1996 summer. The treatments were arranged in a randomized complete block design, with four replicates. As a control, physical soil parameter were evaluated in samples of a subtropical forest fragment adjacent to the experiment. Soil bulk density values were lower in the top layer (0-5 cm) than in the deeper layer (10-15 cm), while the reverse was observed for the total porosity and macroporosity. Systems I, II, III, and IV showed higher bulk density values and lower total porosity and macroporosity values in the surface layer (0-5 cm). System V and subtropical forest presented low bulk density and high total porosity and macroporosity values compared to the other treatments. It was observed no differences between physical attributes of integrated and non-integrated crop and livestock systems. No significant correlation was verified between crop yields and physical soil attributes, with exception of the soil macroporosity under soybean in the 0-5 cm layer.

Disponibilidade de nutrientes e teor de matéria orgânica em funçäo de sistemas de cultivo e de manejo de solo

Cropping systems and soil managment can change soil chemical properties. Soil fertility characteriscs were assessed after eight years (1985 to 1993) on a typical dystrophic red latosol located in Passo Fundo, State of Rio Grande do Sul, Brazil. Four soil management systems - 1) no-tillage, 2) minimum tillage, 3) conventional tillage using a disk plow plus disk harrow, and 4) conventional tillage using a moldboard plow plus disk harrow - and three cropping systems [I (wheat/soybean), II (wheat/soybean and common vetch/corn), and III (wheat/soybean, common vetch/corn and white oat/soybean)] were evaluated. A randomized complete block design, with split-plots and three replicates, was used. The main field plots (4 x 90m) were formed by soil management systems, while the subplots (4 x 10m) consisted of crop systems. The pH and concentration of exchangeable Al, exchangeable Ca + Mg, soil organic matter, extractable P, and exchangeable K were affected by soil management and cropping systems. Higher contents of soil organic matter, extractable P, and exchangeable K were observed in the 0-5cm layer for the conservation tillage systems (minimum tillage and no-tillage), as compared to the conventional tillage systems (disk plow and moldboard plow). The values of soil organic matter, P, and K were higher in the 0-5 cm layer, when compared to the ones observed in the 15-20cm layer, in all soil management and cropping systems.

Efeito de pastagens de inverno e de verão em características físicas de solo sob plantio direto

Soil physical characteristics were evaluated, after seven years (1995 to 2001), on a typical Dystrophic Red Latosol located in Coxilha, State of Rio Grande do Sul, Brazil. Six systems integrating crop production with livestock and a subtropical forest were evaluated. Both winter and summer crops were seeded under no-tillage. Cropping systems and soil of different sampling depths were compared using the contrast procedure. In the I and II sistems and in the forest, the soil density and the resistance to penetration increased in the top layer (0-0,05m) concerning the deeper layer (0,10-0,15m). In the II system, total porosity and microporosity decreased in the surface. In the subtropical forest, the some was observed in relation to total porosity and microporosity. The forest showed decrease on soil density and resistance to penetration, compared to most crop systems studied, from 0-0,05m layer to 0,100,15m layer. Soil degradation in the systems could not be considered severe.

Efeito de sistemas de produção de grãos e de pastagens sob plantio direto sobre o nível de fertilidade do solo após cinco anos

Soil fertility characteristics were evaluated on a typical dystrophic Red Latosol located in Passo Fundo, Rio Grande do Sul, Brazil, after five years of combined production systems (1993 to 1997). The effects of integrated grain production systems and with winter annual and perennial pastures under no-tillage were assessed. Four production systems were evaluated: system I (wheat/soybean, white oat/soybean, and common vetch/corn); system II (wheat/soybean, white oat/soybean, and grazed black oat + grazed common vetch/corn); system III [perennial cool season pastures (fescue + white clover + birdsfoot trefoil)]; and system IV [perennial warm season pastures (bahiagrass + black oat + rye grass + red clover + birdsfoot trefoil)]; and system V (alfalfa for forage), which was established in an adjacent area in 1994. The treatments were arranged in a randomized complete block design, with four replications under no-tillage. The production systems increased the contents of organic matter, extractable P, and exchangeable K, mainly at 0-5 cm depth. There was an increase in the pH value and exchangeable Ca + Mg contents in the first four production systems from the soil surface (0-5 cm) to deeper layers (15-20 cm). The reverse occurred with values of exchangeable Al. The systems with grazed perennial pastures showed higher organic matter content at soil surface, as compared to systems with annual pastures.

Produtividade de grãos e componentes de produção da canola de acordo com fontes e doses de nitrogênio

The objective of this work was to evaluate the response of canola to nitrogen sources and rates applied at sowing. The experiment was carried out on a dystroferric Red Ferralsol, with a very clayey texture. A randomized complete block design was used, in a 7x2 factorial arrangement, with seven N rates applied on soil surface at sowing (0, 20, 40, 60, 80, 100, and 120 kg ha-1), two N sources (ammonium sulfate and urea), and four replicates. The experiment was carried out with the Hyola 61 hybrid for two years, and the following variables were evaluated: plant height, number of plants per square meter, shoot dry matter mass, pod mass per plant, weight of a thousand grains, grain yield, and protein and oil contents in seeds. The variables were not affected by the N sources. The highest grain yield is obtained with 88 kg ha-1 N. Increasing N rates increase protein contents and reduce oil contents in canola seeds.

Rotação de culturas para trigo, após quatro anos: efeitos na fertilidade do solo em plantio direto

Soil fertility parameters were evaluated after four years (1990 to 1994) on a alic dusky latosol located in Guarapuava, Parana, Brazil, under four wheat crop rotation systems as follows: system I (wheat/soybean); system II (wheat/soybean and white oats/soybean); system III (wheat/soybean, common vetch/corn, and white oats/soybean); and system IV (wheat/soybean, white oats/soybean, barley/soybean and common vetch/cor). Both winter and summer crops were seeded under no tillage. A randomized complete block design, with four replications, was used. Crop systems and soil samples at different depths were compared using the contrast procedure. All crop rotation systems, in the 0 to 5cm soil layer, higher values were observed for pH in water and Ca+Mg and lower contents for Al (except system III), as compared to the 15 to 20cm layer. Raising in Ca+Mg, K, and P levels occurred in the soil layer with the greatest root concentration (0 to 10cm). The soil organic matter contents decreased with depth from 0-5cm to 15-20cm.

Efeito de práticas culturais na conversão e no balanço energéticos

Desenvolveu-se de 1997 a 2003, em Passo Fundo (RS), um experimento constituido de quatro sistemas de manejo de solo (plantio direto, cultivo minimo, preparo convencional de solo com arado de discos e preparo convencional de solo com arado de aivecas) e de tres sistemas de rotacao de culturas: sistema I (trigo/soja); sistema II (trigo/soja e ervilhaca/milho ou sorgo) e sistema III (trigo/soja, ervilhaca/milho ou sorgo e aveia branca/soja). O delineamento experimental foi o de blocos ao acaso, com parcelas subdivididas e tres repeticoes. A parcela principal foi constituida pelos sistemas de manejo de solo, e as subparcelas, pelos sistemas de rotacao de culturas. Neste trabalho, apresentam-se a conversao energetica (energia disponivel/energia consumida) e o balanco energetico (energia disponivel - energia consumida) no periodo de 7 anos. No sistema plantio direto houve conversao e balanco energeticos (72,44 e 190.766 MJ ha-1) superiores ao cultivo minimo (64,06 e 167.349 MJ ha-1), aos preparos convencionais de solo com arado de discos (54,35 e 134.982 MJ ha-1) e com arado de aivecas (52,02 e 128.159 MJ ha-1) respectivamente. O trigo em rotacao de culturas foi mais eficiente energeticamente do que a monocultura desse cereal. Na cultura de milho foi observada maior eficiencia energetica.

Efeito de sistemas de manejo de solo e de rotação de culturas na fertilidade do solo, após vinte anos

ABSTRACT SOIL TILLAGE AND CROP ROTATION SYSTEMS ON SOIL FERTILITYATTRIBUTES AFTER TWENTY YEARS Long term field studies on crop rotation and soil tillage systems under Brazilian conditions are scarce. Soilfertility characteristics were assessed after twenty years (1985 to 2005) on a typical dystrophic Red Latosol locatedin Passo Fundo, in Rio Grande do Sul, the southernmost state of Brazil. Four soil tillage systems (STS) – 1) no-tillage, 2) minimum tillage, 3) conventional tillage using disk plow followed by disk harrow, and 4) conventionaltillage using moldboard plow followed by disk harrow – and three crop rotation systems (CRS): I (wheat/soybean),II (wheat/soybean and common vetch/corn), and III (wheat/soybean, common vetch/corn, and white oat/soybean)were evaluated, including as check a fragment of subtropical forest (FST). A randomized complete block design,with split-plots and three replicates, was used. The main field plots (4 x 90 m) in a total of 12, were the soil tillagesystems, whereas the subplots (4 x 10 m), in a total of 72 comprised the crop rotation systems. Values of soil pH,soil organic carbon, extractable P, and exchangeable K were affected by soil tillage systems (STSs). Higher levelsof soil organic matter and contents of soil carbon, extractable P, and exchangeable K were observed in the 0-0,05m layer for the no-tillage system. No statistical differences were found in soil organic matter levels between no-tillage and tropical forest, in any soil layer. Values of soil organic matter, P, and K were higher in the 0-0,05 mlayer, when compared to the ones observed in the 0,15-0,20 m layer, in no-tillage and II and III CRSs. Values ofpH, Ca, P, and K observed in all STSs and CRSs were higher than in the tropical forest area.

Desempenho agronômico de canola em diferentes espaçamentos entre linhas e densidades de plantas

The objective of this work was to evaluate the agronomic performance of canola at different row spacing and plant densities. A randomized complete block design was used with four replicates in a split-plot arrangement. The plots consisted of row spacing (17, 34, 51 and 68 cm), and subplots consisted of plant densities (15, 30, 45 and 60 plants per square meter). The experiments were carried out in 2011 and 2012. Evaluations were done for: number of secondary, tertiary, and quaternary branches; number of pods on primary, secondary, tertiary, and quaternary branches; number of pods per plant; number of grains per plant; thousand grain weight; grain yield; apparent biological yield per plant; straw and grain yield per plant; and harvest index. The largest numbers of branches, pods per plant, and grains per plant, as well as the highest total mass of plants were obtained when using plant density of 15 plants per square meter. The highest grain yield per area is obtained when using 17 cm row spacing and plant density of 45 plants per square meter.

Temperatura base inferior e ciclo de híbridos de canola

The aim of this study was to determine the lower base temperature (Tb) of two canola hybrids during the subperiods emergency-beginning of flowering (EM-IF), early-flowering-late flowering (FI-FF) and late-flowering physiological maturity (FF-MF), and the number of days in each subperiod. The experiment was carried out with nine seeding times with the hybrids Hyola 61 and Hyola 433 in Santa Maria, being utilized two methods to estimate: least deviation and relative development. There was a negative linear relationship between air temperature and cycle length in days. The Tb values of canola genotypes ranged from -0.6 to 9.1°C for relative development method, and -1 to 11°C for the least deviation method. The average duration for the subperiods EM-IF, IF-FF and FF-MF were respectively 65, 47 and 24 days for hybrid Hyola 61 and, 68, 48 and 23 days for hybrid Hyola 433. The cycle duration of two hybrids decreased with delayed sowing, which reduced from 162 to 100 days in Hyola 433 and 162 to 104 days in Hyola 61.