• Authors:
    • Bergonci, J. I.
    • Bergamaschi, H.
    • Rosa, L. M. G.
    • Mielniczuk, J.
    • Franca, S.
  • Source: REVISTA BRASILEIRA DE ENGENHARIA AGRICOLA E AMBIENTAL
  • Volume: 15
  • Issue: 11
  • Year: 2011
  • Summary: This work aimed to quantify the available nitrogen (N) to a maize crop and evaluate its effects on leaf area index (LAI), shoot dry matter (SDM) production, N absorption by the above ground biomass, and grain yield. The evaluations were performed in a soil management experiment run since 1985, with three cropping systems (oat- Avena strigosa/maize, oat+vetch- Vicia sativa/maize and oat+vetch/maize+cowpea- Vigna unguiculata) and two rates of nitrogen (0 and 180 kg ha -1) applied to maize. In the 2000/2001 cropping year, four nitrogen rates were applied (0, 60, 120 and 180 kg ha -1). The estimated available N to the maize calculated from the contribution from the soil, cover crops and N fertilizer varied from 27 to 192 kg ha -1. All evaluated variables presented high dependence on available N, and reached its maximum level near to the highest level of available N (192 kg ha -1). With this level of availability, at the stage of pollination, the largest values of LAI (4.41) and the highest leaf N concentration were observed, however, the highest N accumulation in the above ground biomass was observed at the milk grain stage and the shoot dry matter accumulation at the dent stage. The maximum grain yield obtained was 8,920 kg ha -1, corresponding to 112 kg ha -1 of exported N by the grain.
  • Authors:
    • Schuh, R.
    • Loffaguen, J.
    • Epping, J.
    • Costa, M.
    • Kunze, A.
    • Lovato, P.
  • Source: REVISTA BRASILEIRA DE CIENCIA DO SOLO
  • Volume: 35
  • Issue: 3
  • Year: 2011
  • Summary: Cover crops may difffer in the way they affect rhizosphere microbiota nutrient dynamics. The purpose of this study was to evaluate the effect of mycorrhizal and non-mycorrhizal cover crops on soil phosphatase activity and its persistence in subsequent crops. A three-year experiment was carried out with a Typic Quartzipsamment. Treatments were winter species, either mycorrhizal black oat ( Avena strigosa Schreb) or the non-mycorrhizal species oilseed radish ( Raphanus sativus L. var. oleiferus Metzg) and corn spurry ( Spergula arvensis L.). The control treatment consisted of resident vegetation (fallow in the winter season). In the summer, a mixture of pearl millet ( Pennisetum americanum L.) with sunnhemp ( Crotalaria juncea L.) or with soybean ( Glycine max L.) was sown in all plots. Soil cores (0-10 cm) and root samples were collected in six growing seasons (winter and summer of each year). Microbial biomass P was determined by the fumigation-extraction method and phosphatase activity using p-nitrophenyl-phosphate as enzyme substrate. During the flowering stage of the winter cover crops, acid phosphatase activity was 30-35% higher in soils with the non-mycorrhizal species oilseed radish, than in the control plots, regardless of the amount of P immobilized in microbial biomass. The values of enzyme activity were intermediate in the plots with corn spurry and black oat. Alkaline phosphatase activity was 10-fold lower and less sensitive to the treatments, despite the significant relationship between the two phosphatase activities. The effect of plant species on the soil enzyme profile continued in the subsequent periods, during the growth of mycorrhizal summer crops, after completion of the life cycle of the cover crops.
  • Authors:
    • Carvalho, P. C. de F.
    • Sulc, R. M.
    • Moraes, A. de
    • Pelissari, A.
    • Lang, C. R.
    • Lopes, E. C. P.
  • Source: Scientia Agraria
  • Volume: 12
  • Issue: 1
  • Year: 2011
  • Summary: Producers seeking higher corn ( Zea mays) production efficiency have pursued more sustainable, integrated systems. The objective of this investigation was to determine the effect of nitrogen fertilization on corn yield and yield components in an integrated crop-livestock production system. The experiment was conducted on the experimental farm Fazenda Capao da Onca of the Universidade Estadual de Ponta Grossa, Brazil during the 2002/2003 harvest. Treatments were replicated four times in a split-plot randomization of a randomized complete block design. Whole plot treatments were two N rates (0, 150 kg ha -1) with and without grazing applied to a winter cover crop of black oat and Italian ryegrass established in April 2002 and desiccated prior to planting the corn in October 2002. Sequentially, treatments were four N rates (0, 75, 150, 225 kg ha -1) applied to the corn. The corn presented an increasing yield in relation to increasing N rates in plots without neither grazing nor N fertilization during winter; however, grazing allows for higher corn yields with lower N rates.
  • Authors:
    • Lang, C.
    • Rios, E.
    • Moraes, A.
    • Carvalho, P.
    • Medrado, R.
    • Lopes, E.
  • Source: Scientia Agraria
  • Volume: 12
  • Issue: 2
  • Year: 2011
  • Summary: This study aimed to evaluate the decomposition of the residual dry mass and the initial release of nitrogen from different coverages winter for the subsequent cultivation of maize. The work was conducted in Major Vieira, SC, on a family property. The experimental design was a randomized block, with five treatments (alternative soil cover) and three replications. The treatments: (a) consortium of oat ( Avena strigosa)+ryegrass ( Lolium multiflorum)+vetch ( Vicia spp.)+vesiculoso clover ( Trifolium vesiculosum), with grazing and nitrogen fertilization (100 kg of N); (b) Grassland of black oat+ryegrass+vetch+clover vesiculoso, with grazing and without nitrogen fertilization; (c) coverage (oat+ryegrass+vetch+vesiculoso clover), without grazing and without nitrogen fertilization; (d) forage turnip ( Raphanus sativus), without grazing and without nitrogen fertilization, and (e) fallow (control). The rate of decay was measured through pockets of decomposition (litter bags), collected in seven seasons during the corn crop. The turnip forage was the treatment that was more difficult to decompose according to their chemical characteristics. This limited the supply of nitrogen for the corn crop. Treatment coverage consortium made rapid initial release of N and thus was considered the most appropriate for use in succession with the corn crop. The grazing influenced the release of nitrogen, mainly by the lower amount of total dry mass produced. The grain yield of maize was not influenced by soil cover.
  • Authors:
    • Dias, T.
    • Correa, M.
    • Alves, P.
    • Pereira, R.
  • Source: Revista Brasileira de Ciências Agrárias
  • Volume: 6
  • Issue: 1
  • Year: 2011
  • Summary: The success in weed control by using straw depends on the management time, straw quality and quantity. The objective of this research was to evaluate the suppressor effect of black-oats and millet straw cover on the incidence of weeds and on the productivity of the soybean crop. The experiment was carried out during the years 2006 and 2007, in an area from the Farm of Education, Research and Produtcion of FCAV-UNESP, Jaboticabal Campus, in a completely randomized block design, with four replications. Treatments consisted of different types of black oats and pearl millet straw management before soybean seeding (without management, obtained by machine cut, desiccated using glyphosate desiccation and with paraquat) and different periods of straw deposition (0, 15, 30 e 60 days before soybean seeding). The weed population and the characteristics of soybean growth and production were evaluated. The deposition of black oats and pearl millet straw provided reductions in weed density and dry mass, and this effect was more effective when the deposition occurred until 15 days prior to soybean seeding. The suppressor effect of black oats straw was more pronounced than that of pearl millet straw, regardless of the drying method, although the millet had a greater dry matter production. No significant differences were found between the drying methods and the straw effectiveness.
  • Authors:
    • Zwirtes, A. L.
    • Baronio, C. A.
    • Rigon, J. P. G.
    • Capuani, S.
  • Source: Revista Verde de Agroecologia e Desenvolvimento Sustentavel
  • Volume: 6
  • Issue: 4
  • Year: 2011
  • Summary: The objective of this study was to evaluate the influences of different plants covering on the agronomic characteristics of beans. The experiment was conducted on Red Latossol alumino-ferric, using randomized block design with four repetitions, being the data submitted to the Tukey test and compared by orthogonal contrasts. Treatments consisted of covering plants, carrying its growth in single system, as well as some consortia, across species: Flaxseed ( Linum usitatissimum); Ryegrass ( Lollium multiflorum), Black and White Oats ( Avena stringosa and A. sativa), vetch ( Vicia sativa), wild radish ( Raphanus sativus) and Triticale ( Triticum secale). The agronomic attributes evaluated of bean were: the 1000 seeds per pod, length and number of pods per plant and plot, plant population and yield. Direct and different influence was verified on the components yield of beans, vegetables and the number of the larger relationship with productivity beans. Among the plants used predecessor, the Vetch and Turnip provided larger productive increment, differently of Ryegrass, as well as flaxseed, which resulted in lower yields beans.
  • Authors:
    • Goulart, R. Z.
    • Rocha, P. V. da
    • Santos, M. S. dos
    • Eltz, F. L. F.
    • Rocha, M. R. da
  • Source: REVISTA BRASILEIRA DE CIENCIA DO SOLO
  • Volume: 35
  • Issue: 4
  • Year: 2011
  • Summary: 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 m 2 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 (p6 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.
  • Authors:
    • Pimentel, I.
    • Gabardo, J.
    • Brondani, G.
    • Dionisio, J.
    • Motta, A.
    • Roveda, L.
    • Cuquel, F.
  • Source: Revista Brasileira de Agrociencia
  • Volume: 17
  • Issue: 3
  • Year: 2011
  • Summary: The reuse of industrial waste with low potential contaminant in agriculture is an important option for final disposal. To evaluate the agronomic potential of waste liquid from the production of enzymes (WLPE), set up an experiment in a Cambissoil cultivated under no tillage. There were two treatments (with and without the addition of 50 m 3 of WLPE). It was evaluated in soil pH CaCl 2, (H+Al), P, K, Ca, Mg and V% in 4 depths and in three samples of soil. The effects of three successive crops on the yield and nutrient content in the tissue: black bean ( Phaseolus vulgaris), a consortium of oat ( Avena strigosa)+forage turnip ( Raphanus sativus) and maize ( Zea mays L.). Increases in soil available P were observed, there were no changes in pH, (H+Al), K, Ca, Mg and V% using RLPE, and this provided no change in productivity in beans and corn, but a large increase in productivity and cycling of nutrients in plant cover (oat+turnip forage) were observed. There was no change in the concentration of nutrients in plant tissue of beans and oats+turnip indicating changes in nutritional status. The RLPE presented as an alternative for the supply of P, growth and cycling of nutrients in oats+turnip.
  • Authors:
    • Spera, S.
    • Fontaneli, R.
    • Santos, H.
    • Maldaner, G.
  • Source: PESQUISA AGROPECUARIA BRASILEIRA
  • Volume: 46
  • Issue: 10
  • Year: 2011
  • Summary: The objective of this work was to assess energy conversion and balance of integrated crop-livestock production systems, under no-tillage. The experiment was carried out from 2001 to 2008. From 2001 to 2002, the following systems were evaluated: 1, wheat/soybean, and black oat pasture+common vetch/corn; 2, wheat/soybean, and black oat pasture+common vetch+ryegrass/corn; 3, wheat/soybean and black oat pasture+common vetch/millet pasture; 4, wheat/soybean and black oat pasture+common vetch+rygrass/millet pasture; 5, wheat/soybean, white oat/soybean, and black oat pasture+common vetch/millet pasture; 6, wheat/soybean, white oat/soybean, and black oat pasture+common vetch+rygrass/millet pasture. From 2003 to 2008, the following systems were evaluated: 1, wheat/soybean, and common vetch/corn; 2, wheat/soybean, and black oat pasture/corn; 3, wheat/soybean, and black oat pasture/soybean; 4, wheat/soybean, and field pea/corn; 5, wheat/soybean, common vetch/soybean, and double purpose triticale/soybean; and 6, wheat/soybean, double purpose white oat/soybean, and double purpose wheat/soybean. Corn showed highest returned energy in comparison to the other grain crops, and to winter and summer annual pastures. Of the winter cover crops and green manure species evaluated, field pea was the most efficient in energy conversion. Systems 1, 2, and 4, from 2003 to 2008, had the most efficient energy balance.
  • Authors:
    • Goncalves, M.
    • Vitorino, A.
    • Souza, L.
    • Silva, D.
  • Source: Bragantia
  • Volume: 70
  • Issue: 1
  • Year: 2011
  • Summary: Soil physical degradation, like compaction, reduces water movement and root development. Soil structure is considered one of most importance to agriculture and closely related to it are other fundamental properties in soil-plant relationship. The objective of this study was to evaluate the effect of crop sequences on physical attributes. The research was realized in 2004/05 and 2005/06 growing seasons, in a Typic Clayey Rhodic Hopludox, under eight years of no-tillage system, at Dourados (MS). The experiment was a randomized complete block design, with three replications. Treatments were constituted by cover crops: sunflower ( Helianthus annuus L.), sunnhemp ( Crotalaria juncea L.), hairy vetch ( Vicia villosa Roth), mixture of sunnhemp+black oat ( Avena strigosa Schreb), and mixture of black oat+hairy vetch+oilseed radish ( Raphanus sativus L. Var. oliferus Metzg). Differences were not observed in soil density, porosity and aggregation rate when it was cultivated with sunflower, hairy vetch, sunnhemp, or the mixtures. Differences were observed in soil physical properties between 0-5 cm layer and 5-10 cm-10-20 cm layers, but no differences between 5-10 cm and 10-20 cm layers. Soil carbon trend to higher contents in crops with high production of surface residues, although differences in carbon contents were insufficient to modify aggregation.