19722015
  • 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:
    • 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:
    • 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:
    • 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:
    • Harrison, H.
    • Jackson, D.
  • Source: Journal of Economic Entomology
  • Volume: 101
  • Issue: 6
  • Year: 2008
  • Summary: Sweetpotatoes, Ipomoea batatas (L.) Lam. (Convolvulaceae), are typically grown on bare soil where weeds and erosion can be serious problems. Conservation tillage systems using cover crop residues as mulch can help reduce these problems, but little is known about how conservation tillage affects yield and quality of sweetpotato or how these systems impact populations of beneficial and pest insects. Therefore, field experiments were conducted at the U.S. Vegetable Laboratory, Charleston, SC, in 2002-2004 to evaluate production of sweetpotatoes in conventional tillage versus a conservation tillage system by using an oat ( Avena sativa L.) (Poaceae)-crimson clover ( Trifolium incarnatum L.) (Fabaceae) killed-cover crop (KCC) mulch. The four main treatments were (1) conventional tillage, hand-weeded; (2) KCC, hand-weeded; (3) conventional tillage, weedy; and (4) KCC, weedy. Each main plot was divided into three subplots, whose treatments were sweetpotato genotypes: 'Ruddy', which is resistant to soil insect pests; and 'SC1149-19' and 'Beauregard', which are susceptible to soil insect pests. For both the KCC and conventional tillage systems, sweetpotato yields were higher in plots that received hand weeding than in weedy plots. Orthogonal contrasts revealed a significant effect of tillage treatment (conventional tillage versus KCC) on yield in two of the 3 yr. Ruddy remained resistant to injury by soil insect pests in both cropping systems; and it consistently had significantly higher percentages of clean roots and less damage by wireworm- Diabrotica-Systena complex, sweetpotato flea beetles, grubs, and sweetpotato weevils than the two susceptible genotypes. In general, injury to sweetpotato roots by soil insect pests was not significantly higher in the KCC plots than in the conventionally tilled plots. Also, more fire ants, rove beetles, and carabid beetle were captured by pitfall traps in the KCC plots than in the conventional tillage plots during at least 1 yr of the study. This study suggests that a sweetpotatoes can be successfully grown under a killed-cover crop production system.
  • Authors:
    • Nason, R.
    • Entz, M.
    • Froese, J.
    • Ranjan, R.
    • Kahimba, F.
  • Source: Applied Engineering in Agriculture
  • Volume: 24
  • Issue: 3
  • Year: 2008
  • Summary: Excess root zone soil moisture resulting from annual precipitation in excess of crop water requirements negatively affects crop yields. A field study was conducted in the 2005 and 2006 seasons on sandy loam soils to investigate the influence of berseem clover ( Trifolium alexandrium L.) cover crop in oats ( Avena sativa L.) on soil temperature, infiltration, and soil moisture redistribution within the growing season and during the fall to spring seasons. A 4-year crop rotation experiment to investigate farming with fewer chemicals was used to grow oats in a no-till cultivation system with and without the cover crop. The total and unfrozen water contents were measured in the field using neutron moisture meter and time domain reflectometry, respectively, at 0.2-m intervals from the surface to 1.8-m deep, plus a 0.1-m measurement depth. The cover crop significantly reduced soil moisture during the growing season resulting in significantly lower biomass yields (6146 kg ha -1 combined biomass for oats and berseem clover, vs. 7327 kg ha -1 for oats alone). By mid-August 2005, the cover crop treatment had 34.6% lower water content (0.17 vs. 0.26 m 3 m -3) within the 0.0- to 0.7-m root zone depth compared to the non-cover crop. During the fall, the soil profile in the cover crop treatment was 3°C warmer, thus delaying soil freezing and leading to a shallower depth of the frozen soil layer (0.4 vs. 0.6 m) in March 2006. During the spring, the cover crop treatment warmed and thawed earlier enabling more snow melt infiltration and deep percolation. Areas experiencing excess soil moisture could use annual cover crops as a means for reducing excess soil moisture during the summer growing season and avoiding accumulation of soil moisture during the fall, winter and spring seasons.
  • Authors:
    • Konopinski, M.
  • Source: Vegetable Crops Research Bulletin
  • Volume: 68
  • Year: 2008
  • Summary: Field experiments were conducted in Poland, on a grey-brown podzolic soil, to assess the yields of scorzonera ( Scorzonera hispanica cv. Einjahrige Riesen) roots in different soil and plant cultivation systems, i.e. ridge and flat cultivation, reduced soil tillage prior to sowing (shallow tillage) and the application of cover crops ( Sinapis alba, Vicia sativa, Phacelia tanacetifolia and Avena sativa) in conservation tillage and no-tillage systems. Reduced spring tillage did not have a negative effect on the yields of scorzonera roots. Cultivation of plants on ridges had a positive effect on the total and marketable yields of roots compared to flat soil cultivation. Mulching with cover crops had a significant influence on the increase in the marketable yield of roots. No-tillage cultivation did not have a negative effect on the total and marketable yields of roots. Reduction in spring tillage prior to sowing, soil mulching and no-tillage cultivation had no negative effects on the inulin content of scorzonera roots. Among the investigated cover crops, Sinapis alba was the most beneficial plant for increasing the inulin content of roots. Cultivation of plants on ridges and flat soil and reduction in spring pre-sowing tillage did not have a significant effect on the protein content of roots. Irrespective of the soil cultivation methods, a significantly higher protein content was found in the roots harvested from the plots mulched with Vicia sativa. The various plant cultivation conditions exerted a considerable influence on nutrient uptake. Roots of the plants cultivated on ridges contained higher amounts of P, K and Ca. Soil mulching created better conditions for nutrient absorption. A significant effect of Sinapis alba in increasing the P and K content of roots was also observed.
  • 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:
    • Ojeda Trejo, E.
    • Martinez Menes, M.
    • Prat, C.
    • Bravo Espinosa, M.
    • Medina Orozco, L.
    • Serrato Barajas, B.
  • Source: Agricultura Tecnica en Mexico
  • Volume: 34
  • Issue: 2
  • Year: 2008
  • Summary: In the upper part of Cuitzeo Lake watershed, Michoacan, Mexico, farmers use a traditional short-fallow production system. With this system, land is sown one year, and left without cultivation from one to three years for grazing. Tins system is used mainly on Andisols and Acrisols, and it is supposed to be associated with soil degradation due to low nutrient recycling level and to excessive tillage during the cultivation year. The objective of this study was to measure soil, nutrient and runoff losses under the traditional short-fallow system (AV), and under two alternatives systems: organic (O), and improved traditional (TM) systems. Research was carried out on an Acrisol in the Cointzio subwatershed, during three years under rainfed conditions on 1 000 m 2 runoff plots without replications. Results showed that soil losses under all systems were permissible (