• Authors:
    • Barth, G.
    • Garbuio, F.
    • Caires, E.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 39
  • Issue: 13/14
  • Year: 2008
  • Summary: Crop residues that are left on the soil surface to serve as mulch can diminish the soybean response to surface application of lime under no-till management by ameliorating soil chemical and physical attributes and the plant nutrition. A field experiment was performed in the period from 2000 through 2003 in Parana State, Brazil, on a clayey-sandy Rhodic Hapludox. Soil chemical attributes and soybean [ Glycine max (L.) Merrill] nutrition, grain yield, and quality were evaluated after surface application of lime and covering with crop residues of black oat ( Avena strigosa Schreb) and corn ( Zea mays L.) under a no-till system. Dolomitic lime was surface applied at the rates of 0, 2.5, 5.0, and 7.5 t ha -1 on the main plots, and three treatments with vegetable covering were applied on the subplots: (i) without covering, (ii) with covering of corn straw, and (iii) with covering of corn straw and black oat residue (oat-corn-oat). After 30 months, surface-applied lime increased soil pH and the exchangeable calcium (Ca 2+) and magnesium (Mg 2+) levels down to a 10-cm depth, independent of the vegetable covering treatments. The black oat and corn residues on the soil surface increased the soil exchangeable K + level at the 5- to 10-cm depth. Liming increased leaf potassium (K) content and phosphorus (P) content in the soybean grain and reduced leaf zinc (Zn) content and manganese (Mn) content in the soybean leaf and grain. There was no effect of liming on soybean grain, oil, or protein yields, independent of the vegetable residues kept on the soil surface. The treatment with black oat covering and corn straw increased leaf N content, P content in the leaf and grain, and the contents of K, Mg, copper (Cu), and Zn in the soybean grain. It also increased soybean grain and protein yields. The corn straw left at the surface after harvesting was very important to the performance of the no-till soybean.
  • Authors:
    • Zardo Filho, R.
    • Pereira Filho, P.
    • Caires, E.
    • Feldhaus, I.
  • Source: Soil Use and Management
  • Volume: 24
  • Issue: 3
  • Year: 2008
  • Summary: A 3-year field trial examined in a long-term no-till system the effects of surface-applied lime and cover black oat ( Avena strigosa Schreb) residues on soil chemical attributes, root growth and grain yield of corn ( Zea mays L.) and soybean ( Glycine max L. Merrill) on a loamy, kaolinitic, thermic Typic Hapludox in Parana State, Brazil. The treatments consisted of dolomitic lime broadcast on the soil surface at 0 or 12 t/ha, with and without cover of black oat residues. Corn and soybeans were grown without rainfall limitation. Applying lime on the surface improved soil acidity and decreased aluminium (Al) toxicity to a 10-cm depth 1 year after application. Surface liming increased pH and the content of exchangeable Ca 2+ to a 20-cm depth, and decreased Al toxicity to a 40- to 60-cm depth, 3 years after application, indicating that the surface-applied lime moved deeper. Cover black oat residues did not favour the mobility of surface-applied lime to alleviate subsoil acidity and an increase in the Al 3+ saturation level at the soil surface was found in unlimed plots with black oat residues. Root growth and grain yields of corn and soybean were not influenced by surface liming with or without cover black oat residue. Despite the soil acidity level, root length of corn and soybean ranged from 55 to 60% at 0- to 10-cm depth. The results suggest that Al toxicity is low in no-till systems during cropping seasons with adequate and well-distributed rainfall, but this effect is not related to the presence of cover oat residues.
  • Authors:
    • Mbuya, O.
    • Chase, C.
  • Source: Weed Technology
  • Volume: 22
  • Issue: 2
  • Year: 2008
  • Summary: Twelve winter cover crops were planted in Citra and Live Oak, FL, in 2004, to evaluate their potential for use as living mulches in organic vegetable production: black oat, rye, annual ryegrass, hard fescue, two cultivars of white clover, berseem clover, crimson clover, subterranean clover, arrowleaf clover, barrel medic, and a hybrid disc * strand medic cultivar. The best canopy development and weed suppression occurred with black oat, rye, and annual ryegrass. In 2005, black oat, two rye cultivars, and annual ryegrass were evaluated as living mulches in broccoli at Citra and Live Oak, using organic production methods. 'Florida 401' (FL 401) rye was tallest, black oat was intermediate, and 'Wrens Abruzzi' (WA) rye and 'Gulf' ryegrass were of similar height and were the shortest living mulches. Biomass harvested at 12 and 13 wk after planting at Citra and Live Oak, respectively, was greatest with FL 401 rye. At Live Oak, the three other mulches had similar amounts of biomass; however, at Citra, black oat biomass was greater than that of WA rye, and biomass of ryegrass was lowest. The greatest weed infestation occurred with the weedy control. Weed biomass was highest with the weedy control, intermediate with ryegrass, and lowest with rye and black oat. However, the biomass of the weedy control was lower than that of the living mulches plus any associated weeds. Marketable broccoli yield was highest with the weed-free control. Yields with black oat, WA rye, and ryegrass were similar to that of the weedy control, whereas yield with the FL 401 rye was lower than with the weedy control. Suppression of living mulches by mowing at 3 and 7 wk after planting had no effect on broccoli growth or yield.
  • Authors:
    • Souza, J.
    • Finger, J.
    • Gobbi, F.
    • Vanin, J.
    • Fey, E.
    • Conti, C.
  • Source: Central theme, technology for all: sharing the knowledge for development. Proceedings of the International Conference of Agricultural Engineering, XXXVII Brazilian Congress of Agricultural Engineering, International Livestock Environment Symposium
  • Year: 2008
  • Summary: The cassava has great ability to adapt and better develop in deep soils without compaction and aeration well. To achieve these characteristics, this work was carried out by subjecting the culture to eight formats furrows and three separate roofs of soil under the tillage system. The work was conducted in a farm located in the district of Pearl Independent municipality of Maripa - Parana - Brazil, which has Latosol red eutrophic. The experiment went installed in randomized blocks with split plot, in the plots main the different furrow in the subplots the coverages. Effectuate up assessments of moisture, penetrometro of impact, breakup of soil in the furrow, depth of maniva and groove, population of plants, stalks per plant and percentage of plants fallings. The coverages of forage turnip and oats had higher humidity and lower resistance to penetration in the layer of up to 8.75 cm. For sulcadores are obtained different breakup of soil, influencing the depth of furrow and maniva. The coverage of oats presented grooves and manivas most deeper, lower breakup soil, providing conditions for less plants fallings.
  • Authors:
    • Zanatta, J. A.
    • Bayer, C.
    • Costa, F. de S.
    • Mielniczuk, J.
  • Source: Revista Brasileira de Ciencia do Solo
  • Volume: 32
  • Issue: 1
  • Year: 2008
  • Summary: Carbon (C) addition through crop residues (residue-C), C dioxide emission (CO 2-C) and the soil C stock (soil-C) are components of the C cycle in the soil-plant-atmosphere system. This 18-year study was conducted to identify agricultural practices that could potentially increase C retention in the soil and lessen global warming trends. The three C pools (residue-C, CO 2-C and soil-C) under different tillage systems (CT-conventional tillage and NT-no tillage) and cropping systems (O/M-oat ( Avena strigosa [ Avena nuda])/maize ( Zea mays) and V/M-vetch ( Vicia sativa)/maize) were evaluated and the CO 2-C/[residue-C+soil-C] quotient was proposed as C retention index (CRI), where low values indicate a high capacity of the management system to keep C in the soil. The CO 2-C emissions were measured for 17 months (between November 2002 and March 2004), sampling of aboveground residues of cover crops and harvest indexes of maize were used to quantify C addition by cropping systems, and soil-C stocks (0-0.2 m) were evaluated in 2003. The soil temperature (0.05 m) and gravimetric water content (0-0.05, 0.05-0.1 and 0.1-0.2 m) were also monitored from May 2003 onwards. In comparison to 1985, the C balance was negative in the soil under CT (-0.31 t ha -1 year -1 for O/M and -0.10 t ha -1 year -1 for V/M). On the other hand, the C balance was positive in NT soil, but only under V/M (+0.15 t ha -1 year -1) due to the greater C addition by crop residues. The CO 2-C emission was related to the soil temperature (r>0.85). The total CO 2-C emission varied from 3.6 to 4.0 t ha -1 and was not affected by the soil management systems. However, the CRI allowed a clear discrimination of the soil management systems to keep C in the soil. The C retention potential increased in the following order: CT O/M
  • Authors:
    • Lima, E. do V.
    • Moro, E.
    • Crusciol, C. A. C.
    • Andreotti, M.
  • Source: Bragantia
  • Volume: 67
  • Issue: 2
  • Year: 2008
  • Summary: The objective of this research work was to evaluate black oat decomposition and release of nutrients. The experiment was carried out during the 1998 cropping season in an experimental area located in Marechal Candido Rondon, Parana State, Brazil. A randomized block design with four replications was used. The cover crop was rolled over thirty days after emergence. The persistence and release of nutrients were evaluated at 0, 13, 35 and, 53 days after rolling and desiccation. The decomposition rate of oat residue was constant during this period (remaining 34% of the initial amount) and inversely proportional to the C:N ratio that showed an initial value of 34 and a final value of 50. Most K was released soon after oat management, remaining only 2% of the initial content in the last sampling time. N, P, Ca and S were gradually released, and in the last evaluation the remaining amount of these nutrients was 55, 42, 48, and 47% of the total accumulated amount, respectively. Compared to other plant nutrients, K followed by N were the nutrients available in higher amount in the soil, reaching maximum release speed between 10 and 20 days after rolling and dessication of black oat.
  • Authors:
    • Conte, O.
    • Trein, C. R.
    • Levien, R.
    • Debiasi, H.
    • Mazurana, M.
  • Source: REVISTA BRASILEIRA DE CIENCIA DO SOLO
  • Volume: 32
  • Issue: special
  • Year: 2008
  • Summary: 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 (sigma p). To evaluate the effects of cover crops and tractor traffic on σ p 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 ( Avena strigosa) and black oats + vetch ( Vicia faba), which was substituted in 2006 by oilseed radish - Raphanus sativus) 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 sigma p 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 sigma p value and the lowest CI value at 0.03-0.06 m. As the soil became drier, differences in sigma p between winter fallow and cover crops were reduced. In five years, seven wheel-tractor passages increased sigma p 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.
  • Authors:
    • Gobbi, F. C.
    • Vanin, J. P.
    • Conti, C.
    • Dallmeyer, A. U.
    • Fey, E.
    • Pivetta, L. A.
  • Source: Central theme, technology for all: sharing the knowledge for development
  • Year: 2008
  • Summary: The soil preparation, characterized by intense lossening soil and low straw remaining in the soil surface, it is usually used for the cultivation of cassava and has worried producers, technicians, agronomists and researchers because of the environmental problems associated with this kind of preparation. Thus, this study aimed to evaluate the physical properties of soil proportionate by different tillage systems as well as the performance of a planter of cassava. The experiment was conducted in the municipality of Maripa - PR, in Latosol eutroferrico red. It was used the randomized blocks design with split plot disposition, where the main plots went consist of five tillage systems (tillage system with offset disk harrow, disk plow and chisel plow, conservation tillage with chisel plow in April and no-tillage) and two subplots (fallow and consortium of forage turnip+oats). It was evaluated the cone index, the soil moisture, porosity of air and water, total porosity, soil bulk density, the depth of the seed cuttings of cassava and, the population of plants. The soil tillage with disc plow and chisel plow provided better physical conditions in comparison to the no tillage system. The depth of deposition of the seed cuttings of cassava was lower in no-tillage system and in the coverage with forage turnip+oats. The plants population was not influenced by soil tillage systems and coverages.
  • Authors:
    • Foloni, J. S. S.
    • Rosolem, C. A.
  • Source: REVISTA BRASILEIRA DE CIENCIA DO SOLO
  • Volume: 32
  • Issue: 4
  • Year: 2008
  • Summary: An earlier application of potassium fertilizer, in the cultivation of cover crop species preceding the main summer crop in no-tillage system can be an advantageous in commercial farming. This study evaluated grain yield and K accumulation in soyabean due to an earlier application of potassium fertilizer to a pearl millet cover crop, and compared to K applied at sowing of the subsequent soyabean under no-tillage. The experiment was conducted in Sao Paulo, Brazil during the 2000/2001, 2001/2002 and 2002/2003 growing seasons, on a dystroferric red Latosol (sandy loam Oxisol), cultivated with soyabean (summer) in rotation with black oats (winter) under no-till for two years prior to the experiment. Pearl millet ( Pennisetum glaucum) was sown in September over the residues of black oat ( Avena strigosa [ Avena nuda]), and soyabean ( Glycine max) was planted in the first weeks of December, in the three growing seasons. The treatments consisted of 0, 30, 60, and 90 kg/ha K 2O doses applied to pearl millet, in combination with 0, 30, 60, and 90 kg/ha K 2O applied to soyabean. Soyabean plants were harvested 25, 50, 75, and 100 days after emergence, and the grains harvested at the end of the experiment in order to determine K accumulation and yield. The early application of 60 to 90 kg/ha K 2O at pearl millet sowing did not affect K accumulation in soyabean plants. Soyabean yields were higher with applications of 80 to 90 kg/ha K 2O, which can be totally applied at pearl millet sowing. The anticipation of the application of KCl at pearl millet sowing reduced K export in soyabean grains.
  • Authors:
    • Levien, R.
    • Gamero, C. A.
    • Furlani, C. E. A.
    • Silva, R. P. da
    • Cortez, J. W.
  • Source: REVISTA BRASILEIRA DE CIENCIA DO SOLO
  • Volume: 32
  • Issue: 1
  • Year: 2008
  • Summary: To evaluate the effect of soil tillage and management of winter cover crops (black oat+radish intercrop) on the soil temperature, an experiment was conducted in a Nitossol (Alfisol) in Botucatu, state of Sao Paulo, Brazil, in the 2000 autumn/winter season. A design in randomized blocks was used in a 3*3 factorial scheme (three tillage and three cover crop managements). Soil tillage consisted of: conventional tillage, conservation tillage with chiselling, and no-tillage. The cover crops managements included plant killing with post-emergence herbicide, rolling, or shredding. The soil temperature (thermocouples) was evaluated at a depth of 5 cm, every hour, 7, 14, 30, 45, and 60 days after plant emergence; the soil water content at a depth of 10 cm, at the same dates and, the soil surface coverage (dry mass and cover index) were measured immediately after treatment application. Lower soil temperatures were observed in the no-tillage system than under conventional tillage until the 14th day after plant emergence (DAE). From the 30th DAE, the temperature was no longer influenced by the treatments due to the soil cover and sufficient water availability in the soil. The cover managements with plant rolling, shredding, or herbicide had no influence on the soil temperature. The soil temperature did not affect the development of the cover crops.