• Authors:
    • Dimitrova, T.
  • Source: Herbologia
  • Volume: 9
  • Issue: 1
  • Year: 2008
  • Summary: With the purpose of studying the weed suppressive capacity of some cover crops as an alternative for weed control in lucerne ( Medicago sativa) and the effect on its productivity, a study was carried out under field non-irrigated conditions on slightly leached medium-deep chernozem. During the 2005-2007 period, a trial was carried out with the following variants: V 1 - Lucerne ( Medicago sativa), pure stand (PS) - check, zero; V 2 - Lucerne, PS - check, weeded; V 3 - Lucerne, PS - with chemical control; V 4 - Lucerne+cover oat ( Avena sativa); V 5 - Lucerne+cover spring barley ( Hordeum sativum); V 6 - Lucerne+cover rye ( Secale cereale). As a result of the study the following conclusions were drawn: In the systems of environmentally friendly agriculture, the use of some cover cereal crops (spring barley, oat and rye) in the year of establishment of lucerne stands, under favourable agro-meteorological conditions, could be an alternative to conventional technology. The cover crops had a weed suppressive capacity and as a result they decreased weed infestation degree, though to a smaller extent, as compared to chemical control. The cover crops allowed more efficient area use in the first year of lucerne cultivation, when it had a slow rate of growth and development. In spite of lower seed yields from the lucerne stands with cover crops, as compared to the pure stands by conventional technology, they are of interest in ecological aspect. Under the conditions of the concrete study, the cover crops were in the following ascending order according to aggressiveness: spring barley, oat and rye.
  • Authors:
    • Hamaker, B.
  • Source: Technology of functional cereal products
  • Year: 2008
  • Summary: This book reviews technologies for producing a wide range of cereal products with different health-promoting properties and more acceptable sensory quality. Part I discusses the health effects of cereals, with chapters on topics such as whole grain foods, cereal micronutrients and resistant starch. Consumer perception of health-promoting cereal products and regulatory and labelling issues are also described. Part II focuses on technologies to improve the quality of functional cereal products, reviewing issues such as grain improvement, novel cereal-derived ingredients and formulation of low Gl products. Chapters dedicated to a wide range of product types are also included, covering cereal foods made from oats, rye, barley and speciality grains and breads fortified with vitamins and minerals, soy and omega-3 lipids among others.
  • Authors:
    • Pimenov, K. I.
    • Kutuzov, G. P.
  • Source: Kormoproizvodstvo
  • Issue: 9
  • Year: 2008
  • Summary: In a 3-year experiment carried out on a common chernozem in central Russia, woad ( Isatis costata) was grown as an intercrop in fodder crop rotations. The effect of early spring cover crops (barley or an oats + peas mixture) on woad cold resistance, the optimal sowing rate (1, 2 or 3 million seeds/ha), the effect of spring nitrogen fertilizer on yield, and the productivity and effectiveness of rotations were examined. Results showed that the cover crop - woad - Sudan grass rotations gave 3 harvests within 2 years. By including woad as an undersown intercrop (at 1 million seeds/ha), the yield of the rotation involving oats + peas as cover crop increased to 12.6 thousand fodder units/ha compared to 6.5 thousand/ha in a woad-Sudan grass control.
  • Authors:
    • Blecharczyk, A.
    • Maecka, I.
  • Source: Agronomy Research
  • Volume: 6
  • Issue: 2
  • Year: 2008
  • Summary: Yield, N uptake, weeds and diseases of spring barley were examined under five mulching practices (white mustard, phacelia, oat-pea mixture, straw mulch, and no mulch), three tillage systems (conventional, reduced and no-tillage) and three doses of nitrogen fertilization (0, 50 and 100 kg N ha -1). In general the grain yield of spring barley for cover crops was 10-31% higher compared with the no-mulch treatment. A mulch of straw provided a smaller barley grain yield than the no-mulch treatment. Compared to conventional tillage, grain yield under reduced tillage and no-tillage were 7 and 12% less, respectively. Spring barley sowing after a mixture of oat-pea led to decreased a negative response of reduced and no-tillage. Grain yield after treatment with legume cover crops and without N fertilization was similar compared as the rates 50 kg N ha -1 after white mustard or phacelia and as the rate 100 kg N ha -1 without mulches. There was no evidence of tillage * N fertilization interaction on grain yield, dry matter production and plant-N uptake. Cover crops and straw mulch significantly decreased total weed populations compared with the treatment without mulch. Total weed density increased from 108 plants per m 2 in the no-tillage to 322 plants per m 2 for reduced tillage, and to 416 plants per m 2 for the conventional tillage over mulch. Higher infestation of spring barley with stem base and root diseases was observed in reduced and no-tillage in comparison with the conventional soil tillage and after straw mulch and no-mulch than after cover crops.
  • Authors:
    • Starkova, D. L.
    • Platunov, A. A.
  • Source: Kormoproizvodstvo
  • Issue: 8
  • Year: 2008
  • Summary: The effect of soil moisture level on development of perennial leguminous grasses in conditions of the Kirov region, Russia, is considered. The results of previous field trials revealed that the soil moisture content was higher under winter rye compared with spring crops or the absence of crops. Growing of a vetch-oat mixture for green fodder resulted in the driest soil conditions compared with oat, barley and wheat. Advantages of growing birdsfoot trefoil under the cover of cereal crops are discussed as a way of weed control, also resulting in better soil water conditions. However, birdsfoot trefoil had more light and soil moisture content and showed more intensive above-ground growth in the absence of a crop cover. Field trials were conducted to study the complex relationship between the growth and yield of spring and winter crops, availability of water and light, and weed control and production of high yield of green fodder. Data are tabulated on development and green fodder yield of birdsfoot trefoil during the 1st and 2nd years of growth without plant cover compared with growth under the cover of winter rye, barley, wheat, oat and vetch + oat in 2005 and 2006. Overall results confirmed advantages of growing birdsfoot trefoil under spring crops, especially oat, a vetch-oat mixture and wheat for higher yield of green fodder.
  • Authors:
    • Pridham, J. C.
    • Entz, M. H.
  • Source: Agronomy Journal
  • Volume: 100
  • Issue: 5
  • Year: 2008
  • Summary: The success of organic wheat ( Triticum aestivum L.) production can be severely inhibited by weed and disease pressures. This study sought to determine the effectiveness of wheat intercrop mixtures in suppressing weeds and diseases and increasing grain yield and net return. Field experiments were conducted on organically managed land in 2004 and 2005 and three representative intercrop systems were tested: wheat with other cereals [oats ( Avena sativa L.), barley ( Hordeum vulgare L.), and spring rye ( Secale cereale L.)]; wheat and noncereal seed crops (flax [ Linum usitatissimum L.], field pea [ Pisum sativum L.], oriental mustard [ Brassica juncea L.]); and wheat and cover crops (red clover [ Trifolium pratense L.], hairy vetch [ Vicia villosa L.], annual ryegrass [ Lolium multiflorum Lam.]). The cereal intercrop systems provided no consistent yield benefit over wheat monocultures. Results from noncereal-wheat intercrops were variable. Wheat-flax reduced the wheat crop to unacceptable levels but was capable of reducing wheat flag leaf disease levels. Wheat-field pea resulted in the lowest disease levels, yet had inconsistent yields, and more weeds than wheat monoculture. Wheat-mustard did not reduce weeds or diseases, but it was capable of high grain yields and net returns, though usually hampered by flea beetle ( Phyllotreta cruciferae) attack. The effect of cover crops on wheat was affected by environment. Wheat-red clover and wheat-hairy vetch did demonstrate the ability to maintain high wheat grain yield in certain site-years. In conclusion, wheat intercrop mixtures provided little short-term benefit over monoculture wheat in this study.
  • Authors:
    • Lopez, M. V.
    • Cantero-Martinez, C.
    • Arrue, J. L.
    • Alvaro-Fuentes, J.
  • Source: Soil Science Society of America Journal
  • Volume: 72
  • Issue: 2
  • Year: 2008
  • Summary: Under semiarid conditions, soil quality and productivity can be improved by enhancing soil organic matter content by means of alternative management practices. In this study, we evaluated the feasibility of no-till (NT) and cropping intensification as alternative soil practices to increase soil organic C (SOC). At the same time, we studied the influence of these management practices on two SOC fractions (particulate organic matter C, POM-C, and the mineral-associated C, Min-C), in semiarid agroecosystems of the Ebro River valley. Soil samples were collected from five soil layers (0–5-, 5–10-, 10–20-, 20–30-, 30–40-cm depth) during July 2005 at three long-term tillage experiments located at different sites in the Ebro River valley (northeast Spain). Soil bulk density, SOC concentration and content, SOC stratification ratio, POM-C, and Min-C were measured. Higher soil bulk density was observed under NT than under reduced tillage (RT), subsoil tillage (ST), or conventional tillage (CT). At the soil surface (0–5-cm depth), the highest total SOC concentration, POM-C, and Min-C were measured under NT, followed by RT, ST, and CT, respectively. In the whole soil profile (0–40 cm), similarly, slightly greater SOC content was measured under NT than under CT with the exception of the Selvanera site, where deep subsoil tillage combined with moldboard plowing accumulated more SOC than NT. In semiarid Mediterranean agroecosystems where CT consists in moldboard plowing, NT is a viable management practice to increase SOC.
  • Authors:
    • Kang, J.
    • Osmond, D. L.
  • Year: 2008
  • Authors:
    • Bertrand, N.
    • Chantigny, M. H.
    • Angers, D. A.
    • Rochette, P.
  • Source: Soil Science Society of America Journal
  • Volume: 72
  • Issue: 5
  • Year: 2008
  • Summary: The anticipated benefits of increased soil C stocks on net soil-surface greenhouse gas (GHG) emissions after adoption of soil conservation practices can be offset by increases in soil N2O emissions. The objective of this study was to assess the short-term impacts of no-till (NT) on soil N2O emissions. The study was conducted in eastern Canada in the 3rd, 4th, and 5th yr after initiation of NT and fall moldboard plowing (MP) on heavy clay and gravelly loam soils. Annual emissions of N2O were exceptionally high in the heavy clay soil, varying from 12 to 45 kg N2O-N ha-1 during the 3 yr of the study. Such high emissions were probably not associated with fertilizer N inputs but rather with denitrification sustained by the decomposition of large soil organic matter stocks (192 Mg C ha-1 in the top 0.5 m). On average, NT more than doubled N2O emissions compared with MP in the heavy clay soil. The influence of plowing on N2O flux in the heavy clay soil was probably the result of increased soil porosity that maintained soil aeration and water content at levels restricting denitrification and N2O production in the top 0.20 m. In the loam soil, average emissions during the 3 yr were similar in the NT and MP plots. The results of this study indicate that the potential of NT for decreasing net GHG emissions may be limited in fine-textured soils rich in organic matter that are prone to high water content and reduced aeration.
  • 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.