• Authors:
    • Lollato, R. P.
    • Lollato, M. A.
    • Edwards, J. T.
  • Source: Journal of Soil and Water Conservation
  • Volume: 67
  • Issue: 3
  • Year: 2012
  • Authors:
    • Martins, M. dos R.
    • Angers, D. A.
    • Cora, J. E.
  • Source: Soil Science Society of America Journal
  • Volume: 76
  • Issue: 2
  • Year: 2012
  • Summary: In no-till systems, plants play a substantial role in soil physical conditioning because physical management is otherwise confined to sowing operations. We performed a study to determine the effect of 28 different crop sequences on soil water-stable aggregation, soil organic C (SOC), and the neutral carbohydrate composition of the surface layer (0-5-cm depth) of an Oxisol under no-till. Summer crop sequences with corn ( Zea mays L.) on a continuous basis or in rotation with soybean [ Glycine max (L.) Merr.] showed a higher mean weight diameter (MWD) of water-stable aggregates than those with a rice ( Oryza sativa L.)-bean ( Phaseolus vulgaris L.)-cotton ( Gossypium hirsutum L.) rotation. Among winter crops, pearl millet [ Pennisetum americanum (L.) Leeke] or grain sorghum [ Sorghum bicolor (L.) Moench] were associated with a higher MWD than oilseed radish ( Raphanus sativus L. var. oleiformis Pers.). Plant tissues of Poaceae species (corn, pearl millet, and sorghum) were enriched in pentoses relative to other plant species. A principal component analysis showed a close positive relationship of the soil aggregate MWD with the soil xylose content, but not with other soil monosaccharide and SOC contents, and a positive relationship with the amount of pentose input to the soil, notably from aboveground plant materials. A possible explanation is that pentosans are used as an energy source by filamentous microorganisms, which play a well-known role in stabilizing soil aggregates. Our results suggest that plant-derived carbohydrates mediate crop species effects on soil structure under no-till conditions, and this effect appears to be independent of changes in total SOC.
  • Authors:
    • Silva, A.
    • Colleta, Q.
    • Matoso, S.
    • Maia, E.
    • Fiorelli-Pereira, E.
  • Source: Acta Amazonica
  • Volume: 42
  • Issue: 2
  • Year: 2012
  • Summary: The aim of this study was to assess quality indicators of a dystrophic Red Yellow Latosol (Oxisol) soil under native forest, pasture ( Brachiaria brizantha cv. marandu), conventional tillage, minimum tillage system and no till system. It was determined the soil carbon and soil nitrogen in the microbial biomass, organic carbon and total nitrogen, ratios for microbial carbon and nitrogen and relationships between organic carbon and total nitrogen (C/N tot) and between carbon and soil nitrogen in the microbial biomass (C/N mic). The soil samples were collected in the Municipality of Cerejeiras/RO, at two depths (0-10 and 10-20 cm) in five treatments with five replications. The statistical analysis consisted of outliers analysis by Chauvenet method, and assumptions of variances by Bartlett's test and Shapiro-Wilk, followed by Kruskal-Wallis, between treatments, and comparison the variables between the depths, by Mann-Whitney' test, and the group analysis using Ward's method, all at 5% probability. The results show that different uses influence the variables, except for ration C/N tot, and the microbiology variables showed themselves more sensitive to changes in land use and management than other. The conventional tillage is the treatment that has greater homogeneity among the depths. The group analysis shows that the soil under no till system, minimum tillage system and conventional tillage have similarities among well as the soil under native forest and pasture are similar.
  • Authors:
    • Penha, L.
    • Khatounian, C.
    • Fonseca, I.
  • Source: Planta Daninha
  • Volume: 30
  • Issue: 1
  • Year: 2012
  • Summary: Weed control has always been an important issue in agriculture. With the advent of no-till systems, soil erosion was reduced but herbicide use was increased. Organic no-till systems try to adjust reduced erosion to the no use of herbicides. Nevertheless, this adjustment is limited by the cost of mechanical weed control. This cost may be reduced by improved cultural weed control with cover crops mulches. In this paper we report a study on the application of compost manure on an oats winter cover crop, preceding soybean, instead of on the soybean summer crop. Treatments comprised a control without compost manure, and compost manure doses of 4 and 8 Mg ha -1 applied either on oats in winter or soybean in summer, organized in a randomized block design, with five replications. In summer, plots were split into weed-controlled or not controlled subplots. The timing of application and the manure doses did not affect the oats biomass or the soybean performance. However, in summer, without water stress, the application of manure at 8 Mg ha -1 directly on soybean has reduced weed biomass in this crop.
  • Authors:
    • Frigo, E. P.
    • Marins, A. C. de
    • Santos, R. F.
    • Souza, S. N. M. de
    • Borsoi, A.
    • Secco, D.
  • Source: Journal of Food, Agriculture, and Environment
  • Volume: 10
  • Issue: 1; Part 2
  • Year: 2012
  • Summary: Soil organic matter is of fundamental importance to improve the structure and retention of water and nutrients. This assay aims at evaluating the dynamic of organic matter in a clayey oxisol under three tillage systems, five periods and in five depths. The experiment was conducted in the Experimental Center of Agricultural Engineering in the State University of Western Parana (UNIOESTE), in Cascavel city, Parana, Brazil, in a red latosol (usually known as oxisol) from clayey to very clayey texture (600 g kg -1 clay; 320 g kg -1 silt and 80 g kg -1 sand) basalt substrate and soft-wavy relief. The area is geographically set by the coordinates 24degrees48′ south latitude and 53degrees26′ west longitude, 760 m average height. The treatments were composed of three soil tillage systems: CT conventional tillage=disc plowing followed by harrowing to level; RT reduced tillage=scarification without a following harrowing to level; and NT no-till farming=implantation of crops on the stubble of the previous crop. The depths of soil sample extractions, for the determination of organic carbon content, in each tillage system, were as follows: 0.0-0.025; 0.025-0.05; 0.05-0.10; 0.10-0.20 and 0.20-0.30 m. Organic carbon content was determined in accordance with the Walkley-Black methodology, from years 2006 to 2010. The experimental design used was a 5*3*5 factorial (five periods, three tillage systems and five depths). Tukey's test was applied to compare the average of treatments, with the significance level at 5%. After five years, NT showed an increase of 3.5% and 4.8% in organic carbon contents, related to CT and to RT, respectively.
  • Authors:
    • Bortoluzzi, T.
    • Silva, C. A. T. da
    • Arieira, C. R. D.
    • Silva, T. R. B. da
  • Source: African Journal of Agricultural Research
  • Volume: 7
  • Issue: 2
  • Year: 2012
  • Summary: Poultry manure, applied like organic fertilizer on corn, has not been studied extensively; so, no one knows its effect on the genealogy of the soil. However, organic fertilizer does not cost much, it is easy to buy and it has less degree of environmental degradation as compared to chemical fertilizers. This study was conducted in the commercial fields of St. Helena/PR with corn, using the triple hybrid 2B688, established in 2008 with no-till farming for seven years in order to evaluate the effect of poultry manure on corn yield. The treatment used was chemical fertilizer having nitrogen in the formulation NPK with an addition of three doses of poultry manure (0, 3.5 and 7 t ha -1) and a witness; whereas the experimental design was randomized blocks with split plots and five replications. It was observed that the results were not significant for the number of rows per ear and grains per spike. Nevertheless, increased yield in corn was observed with 100% of poultry manure.
  • Authors:
    • Tessier, D.
    • Curmi, P.
    • Guimaraes, M.
    • Tavares Filho, J.
  • Source: REVISTA BRASILEIRA DE CIENCIA DO SOLO
  • Volume: 36
  • Issue: 1
  • Year: 2012
  • Summary: It is known that any kind of soil management causes changes in the soil physical characteristics and can affect agricultural yield. The purpose of this study was to evaluate soil properties of an Alfisol and soybean yield under different management systems for no-tillage annual crops, no-tillage with chiseling and no-tillage crop rotation. The 11-year experiment was initiated in the 1998/99 growing season, on 100*30 m plots (11% slope). Soil samples (5 per management system) were systematically collected (0-25 cm layer) in the summer growing season, to quantify soil organic matter, bulk density, macroporosity and flocculation, as well as soybean yield. The highest values for soil bulk density and organic matter content and the lowest for macroporosity were observed in the no-till system alone, whereas in the no-till system with quarterly chiseling the values for organic matter content were lowest, and no-tillage crop rotation resulted in the highest values for organic matter and macroporosity, and the lowest for soil bulk density. The average soybean yield was highest under no-till and trimestrial chiseling or crop rotation, and lowest for no-tillage annual crops no-tillage annual crops alone.
  • Authors:
    • Castagnara, D. D.
    • Fey, R.
    • Seidel, E. P.
    • Testa, J. V. P.
    • Steiner, F.
    • Zoz, T.
    • Zoz, A.
  • Source: SEMINA-CIENCIAS AGRARIAS
  • Volume: 33
  • Issue: 2
  • Year: 2012
  • Summary: The objective of this work was to evaluate the effect of foliar application of molybdenum on agronomic characteristics and yield of wheat in a no-till system. The experiment was carried out in a clayey Rhodic Hapludox, in Maripa, State of Parana, Brazil. The experimental design was randomized blocks with five replications. Treatments consisted of four doses of molybdenum (0, 13.8, 27.6 and 55.2 g ha -1 Mo), divided into two foliar applications, the first at tillering (18 days after plant emergence) and the second at the boot stage (65 days after emergence). The foliar application of Mo up to a dose of 35 g ha -1 increased the number of spikes per square meter and yield of wheat; however, it had no effect on the agronomic characteristics of the crop in a no-till system.
  • Authors:
    • Pacheco, C.
    • Martelli, I.
    • Schinor, E.
    • Rossetto, M.
    • Azevedo, F.
  • Source: REVISTA BRASILEIRA DE FRUTICULTURA
  • Volume: 34
  • Issue: 1
  • Year: 2012
  • Summary: The inter-row management of citrus orchards has undergone major changes in recent years. Thus, this study aimed to evaluate the effect of winter cover crops and rotary mower in sweet orange 'Pera' production. The experiment was conducted in two seasons (2007/2008 and 2008/2009), in a split plot design, where at the plots three species of winter cover crops (oat, lupine and radish) were sown in April and in sub-plots it was used two types of rotary mower (conventional and ecological). Natural vegetation (NV) and NV+herbicide ( glyphosate) in the total area were the standard treatments of the experiment. In July (2007 and 2008) it was measured the mass of fresh and dry mass of each treatment and also after mowing. To calculate the production in August (2007 and 2008) the fruit were harvested and weighted and later it was obtained the efficiency of production. The treatments with winter cover crops showed greater production of fresh and dry mass and the use of ecological rotary mower released amount of plant material significantly higher under the canopy of sweet orange 'Pera' plants. In two seasons, higher production and efficiency of fruit production occurred in plots using the ecological rotary mower. Only lupines increased the efficiency of production of sweet orange 'Pera' in 2009. Thus, it can be concluded that the use of ecological rotary mower increases the production of sweet orange 'Pera'.
  • Authors:
    • Valaci, F.
    • Andrade, L.
    • Fonseca, G.
    • Andrade, M.
    • Carvalho, G.
    • Carvalho, W.
    • Oliveira, D.
  • Source: Revista Brasileira de Biociencias
  • Volume: 10
  • Issue: 1
  • Year: 2012
  • Summary: This study aimed at evaluating the allelopathic effect of species used as cover crops in no-tillage system on common bean crop. It was conducted in the greenhouse and at the Seed Analysis Laboratory in the Agricultural Department of the Federal University of Lavras, Brazil. The cover crop species used in the experiment were sunn hemp, jack bean, pigeon pea, black oat, sorghum and millet, with and without intercropping, with their straws collected at the early grain filling stage. The aqueous extracts of 5% and 10% (w/v) obtained from those straws were placed in plastic boxes (Gerbox-type) containing common bean seeds. The straws were also laid on the substrate surface sown with common bean in plastic pots and installed in the greenhouse for chemical and physical effects evaluation of the cover crops. Considering most of the variables studied, it was not verified any damage by either using of mulch or by applying allelopathic extracts. When used as mulch or when applied as aqueous extracts, residues from the intercropping between sunn hemp and sorghum positively affected the common bean plant, benefiting its initial growth.