• Authors:
    • Rosa, D. M.
    • Mauli, M. M.
    • Nobrega, L. H. P.
    • Piccolo, G.
    • Smanhotto, A.
  • Source: Central theme, technology for all: sharing the knowledge for development
  • Year: 2008
  • Summary: It was analyzed a possible allelopathic action of black oat ( Avena strigosa Schreb) (BO) in a consortium (CO) with BO, forage turnip ( Raphanus sativus L.) (FT) and vetch ( Vicia sativa L.) (V) in relation to seedling emergency (SE), emergency speed (ES), seedling emergency speed (SES) plants heights and soybean productivity, in interval between covering desiccation with Glyphosate 480 (3 L ha -1) and the cultivar BRS 232 sowing (IDS). Plots of 5*2.5 m were randomly prepared with 1 m of border, four treatments of BO and CO and two control treatments, with five replications of 0.15 among rows. At bloom term, the plots were desiccated in an IDS, of one, ten, twenty and thirty days. The soybean was sown in November 2006, with 0.45 m among rows, thirteen sowing lines and 14 seeds by linear m -1. The harvest was manual and productivity was adjusted to 13% of water content. The experimental design was completely randomized, subdivided in plots. The data were submitted to normality, while averages were compared by Scott and Knott test at 5% of significance. There was a possible effect of BO and CO on SES, with higher SES to CO. The coverings did not influence on the other parameters however, IDS interfered in all of them. Thus, it is recommended CO use with IDS from ten days.
  • Authors:
    • Souza Filho, A. P. da S.
    • Nobrega, L. H. P.
    • Piccolo, G.
    • Fortes, A. M. T.
    • Uribe-Opazo, M.
  • Source: Central theme, technology for all: sharing the knowledge for development
  • Year: 2008
  • Summary: It was analyzed the possible allelopathic action of vegetal remains of black oat ( Avena strigosa Schreb) (BO) and a consortium (CO) of BO with forage turnip ( Raphanus sativus L.) and vetch ( Vicia sativa L.) in relation to the incidence of weed plants on soybean culture; in intervals (IDS) between covering desiccation with Glyphosate 480 (3 L ha -1) and the cultivar BRS 232 sowing; 5*2.5 m parcels with 1 m of border; four treatments of BO and CO and two control treatments, with five randomized replications, in August, 2006, with 0.15 m among rows. At bloom term, the plots were desiccated in an IDS, of one, ten, twenty and thirty days. The soybean was sown in November 2006, with 0.45 m among rows, thirteen sowing lines and 14 seeds by linear m -1. The incidence of weed plants was evaluated with a 0.5*0.5 m metal frame. The plants were counted and classified by narrow leaf (NL) and large leaf (LL). The soybean harvest was manual and its productivity was adjusted to 13% of water content. The experimental design was completely randomized, in split plot. The data were submitted to normality, while averages were compared by Scott and Knott test at 5% of significance. There was a possible suppressor allelopathic effect of BO and CO coverings on weed plants. The interval between desiccation and sowing interfered on weed population.
  • Authors:
    • Simic, D.
  • Source: Poljoprivreda / Agricultur
  • Volume: 14
  • Issue: 1(Supplement)
  • Year: 2008
  • Summary: This publication contain 26 abstracts of papers that cover topics on: food vs. fuel (a turning point for bioethanol); Dow Agrosciences today and new revolutionary solutions; using maize as a sugar crop; remarks to the current discussion on bioenergy (for the public and/or for the agricultural or rural areas only); the production of biofuels and its impact on agriculture in Croatia; fuels in tobacco production; the role of MATH/BTB proteins in egg cell and at the onset of wheat embryogenesis; transgenic plants resistant to insects; microsatellite diversity of M3sS maize population under recurrent selection; long-term selection experiments or transgenics for composition traits of maize grain; genetic diversity of wheat cultivars estimated by SSR markers; genomic approaches for improvement of drought adaptation in wheat; application of molecular methods in soyabean breeding programme at the Agricultural Institute Osijek (Croatia); implementation of DNA markers to improve breeding of forage legumes; biotechnology in fruit growing; changes in levels of activity of serine proteinase accompany the exposure of common bean to water deficit; tilling in the service of plant improvement; marker assisted selection for development of barley and wheat lines with requested traits; oat seed as a multifunctional subject for biotechnology; mechanism and regulation of nonsense-mediated mRNA decay as an essential quality control system of plants; biotechnology as a useful tool for nutritional improvement of cereal-based materials enriched with polyunsaturated fatty acids and pigments; grapevine habituation (understanding of factors that contribute to somaclonal variation and neoplastic transformation); Agrobacterium-mediated transformation of wheat; nutritional enhancement of lucerne through genetic engineering; genes behind smoke action; cycloxydim-tolerant maize from a breeder's standpoint.
  • Authors:
    • Mamo, M.
    • Drijber, R.
    • Quincke, J.
    • Wortmann, C.
    • Franti, T.
  • Source: Agronomy Journal
  • Volume: 100
  • Issue: 6
  • Year: 2008
  • Summary: Continuous no-till (NT) results in soil improvements, primarily in the surface 5 cm of soil. One-time tillage may improve NT systems by inverting surface soil with less improved deeper soil. Research was conducted to determine the change in abundance of soil microbial groups after a one-time tillage of NT and their recovery dynamics. Experiments were conducted under rainfed corn ( Zea mays L.) or sorghum [ Sorghum bicolor (L.) Moench] rotated with soybean [ Glycine max (L.) Merr.] in eastern Nebraska with one-time moldboard plow (MP) and mini-moldboard plow (mini-MP) tillage compared with continuous NT. Fatty acid methyl ester (FAME) profiles were used as biomarkers of soil microbial groups. The biomass of microbial groups within the soil profile was affected by tillage treatment, soil depth, and time after one-time tillage. Soil microbial biomass under NT was greatest at the 0- to 5-cm depth with 50% less in the 5- to 20-cm depth, and least in the 20- to 30-cm depth. Microbial group biomass was decreased by one-time MP tillage, and generally by mini-MP tillage, compared with NT. On an equivalent soil mass basis, the quantity of the arbuscular mycorrhizal (AM) biomarker C16:1(c11) in the second year after tillage was 22% less for tilled treatments compared with NT. In contrast, the fungal biomarker C18:2(c9,12) was 6% more in the second year after tillage for tilled compared with NT. Tillage affected biomass and recovery of microbial groups differently, with all except AM returning to the NT microbial biomass levels within 1 to 3 yr.
  • Authors:
    • Hilbert, J.
    • Huerga, I.
    • Donato, L.
  • 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 - ILES V
  • Year: 2008
  • Summary: The present study is focus on the final energy balance of bioenergy production in Argentina using soybean, sunflower, rapeseed, corn and sorghum as feedstocks. The balance considers the difference between the energy contained per unit and the amount used for its generation in all the different steps from sowing to final destination. For direct energy consumption costomaq software was employed using local fuel consumption forecast for each field labor. Particular attention is paid to the energy consumption in the agricultural steps considering the distinctive no till system spread out in Argentina that has a very low energy input. Direct and indirect energy were considered in the different steps of bioethanol and biodiesel generation. Industrial conversion consumption was based on international literature data. Comparisons were made between tilled and no till practices and considering or not the energy contained in co products. Results indicate a balance ranging from 0.96 to 1.54 not considering the co products. If co products were introduced the balances ranged between 1.09 and 4.67.
  • Authors:
    • Kay, B. D.
    • Wander, M. M.
    • Drury, C. F.
    • Yang, X. M.
  • Source: Pedosphere
  • Volume: 18
  • Issue: 4
  • Year: 2008
  • Summary: Three long-term field trials in humid regions of Canada and the USA were used to evaluate the influence of soil depth and sample numbers on soil organic carbon (SOC) sequestration in no-tillage (NT) and moldboard plow (MP) corn (Zea mays L.) and soybean (Glycine max L.) production systems. The first trial was conducted on a Maryhill silt loam (Typic Hapludalf) at Elora, Ontario, Canada, the second on a Brookston clay loam (Typic Argiaquoll) at Woodslee, Ontario, Canada, and the third on a Thorp silt loam (Argiaquic Argialboll) at Urbana, Illinois, USA. No-tillage led to significantly higher SOC concentrations in the top 5 cm compared to MP at all 3 sites. However, NT resulted in significantly lower SOC in sub-surface soils as compared to MP at Woodslee (10-20 cm, P = 0.01) and Urbana (20-30 cm, P < 0.10). No-tillage had significantly more SOC storage than MP at the Elora site (3.3 Mg C ha(-1)) and at the Woodslee site (6.2 Mg C ha(-1)) on an equivalent mass basis (1350 Mg ha(-1) soil equivalent mass). Similarly, NT had greater SOC storage than NIP at the Urbana site (2.7 Mg C ha(-1)) on an equivalent mass basis of 675 Mg ha-1 soil. However, these differences disappeared when the entire plow layer was evaluated for both the Woodslee and Urbana sites as a result of the higher SOC concentrations in NIP than in NT at depth. Using the minimum detectable difference technique, we observed that up to 1500 soil sample per tillage treatment comparison will have to be collected and analyzed for the Elora and Woodslee sites and over 40 soil samples per tillage treatment comparison for the Urbana to statistically separate significant differences in the SOC contents of sub-plow depth soils. Therefore, it is impracticable, and at the least prohibitively expensive, to detect tillage-induced differences in soil C beyond the plow layer in various soils.
  • Authors:
    • Kang, J.
    • Osmond, D. L.
  • Year: 2008
  • Authors:
    • Parkin, T. B.
  • Source: Journal of Environmental Quality
  • Volume: 37
  • Issue: 4
  • Year: 2008
  • Summary: It is generally recognized that soil N2O emissions can exhibit pronounced day-to-day variations; however, measurements of soil N2O flux with soil chambers typically are done only at discrete points in time. This study evaluated the impact of sampling frequency on the precision of cumulative N2O flux estimates calculated from field measurements. Automated chambers were deployed in a corn/soybean field and used to measure soil N2O fluxes every 6 h from 25 Feb. 2006 through 11 Oct. 2006. The chambers were located in two positions relative to the fertilizer bands--directly over a band or between fertilizer bands. Sampling frequency effects on cumulative N2O-N flux estimation were assessed using a jackknife technique where populations of N2O fluxes were constructed from the average daily fluxes measured in each chamber. These test populations were generated by selecting measured flux values at regular time intervals ranging from 1 to 21 d. It was observed that as sampling interval increased from 7 to 21 d, variances associated with cumulative flux estimates increased. At relatively frequent sampling intensities (i.e., once every 3 d) N2O-N flux estimates were within {+/-}10% of the expected value at both sampling positions. As the time interval between sampling was increased, the deviation in estimated cumulative N2O flux increased, such that sampling once every 21 d yielded estimates within +60% and -40% of the actual cumulative N2O flux. The variance of potential fluxes associated with the between-band positions was less than the over-band position, indicating that the underlying temporal variability impacts the efficacy of a given sampling protocol.
  • Authors:
    • Tyedmers, P.
    • Arsenault, N.
    • Pelletier, N.
  • Source: Environmental Management
  • Volume: 42
  • Issue: 6
  • Year: 2008
  • Summary: We used Life Cycle Assessment to scenario model the potential reductions in cumulative energy demand (both fossil and renewable) and global warming, acidifying, and ozone-depleting emissions associated with a hypothetical national transition from conventional to organic production of four major field crops [canola (Brassica rapa), corn (Zea mays), soy (Glycine max), and wheat (Triticum aestivum)] in Canada.
  • Authors:
    • Desjardins, R. L.
    • Wagner-Riddle, C.
    • Pennock, D. J.
    • McConkey, B. G.
    • Lemke, R. L.
    • Worth, D. E.
    • Rochette, P.
  • Source: Canadian Journal of Soil Science
  • Volume: 88
  • Issue: 5
  • Year: 2008
  • Summary: International initiatives such as the United Nations Framework Convention on Climate Change and the Kyoto Protocol require that countries calculate national inventories of their greenhouse gas emissions. The objective of the present study was to develop a country-specific (Tier II) methodology to calculate the inventory of N2O emissions from agricultural soils in Canada. Regional fertilizer-induced emission factors (EFreg) were first determined using available field experimental data. Values for EFreg were 0.0016 kg N2O-N kg-1 N in the semi-arid Brown and 0.008 kg N2O-N kg N-1 in the sub-humid Black soil zones of the Prairie region, and 0.017 kg N2O-N kg-1 N in the humid provinces of Quebec and Ontario. A function relating EFreg to the "precipitation to potential evapotranspiration" ratio was determined to estimate annual emission factors (EFeco) at the ecodistrict scale in all agricultural regions of Canada. Country-specific coefficients were also developed to account for the effect of several additional factors on soil N2O emissions. Emissions from fine-textured soils were estimated as being 50% greater than from coarse- and medium-textured soils in eastern Canada; emissions during winter and spring thaw corresponded to 40% of emissions during the snow-free season in eastern Canada; increased emissions from lower (wetter) sections of the landscape and irrigated areas were accounted for; emissions from no-till soils were 10% greater in eastern, but 20% lower in western Canada than from those under conventional tillage practices; emissions under summerfallow were estimated as being equal to those from soils under annual cropping. This country-specific methodology therefore accounts for regional climatic and land use impacts on N2O emission factors, and includes several sources/offsets that are not included in the Intergovernmental Panel on Climate Change (IPCC) default approach.