• Authors:
    • Ngouajio, M.
    • Kaya, E.
    • Isik, D.
    • Mennan, H.
  • Source: Crop Protection
  • Volume: 28
  • Issue: 4
  • Year: 2009
  • Summary: Weed control is a major constraint for organic production around the world. Field studies were conducted in pepper ( Capsicum annuum L.) from 2004 to 2006 at the Black Sea Agricultural Research Institute experimental field in Turkey to determine the weed suppressive effects of winter cover crops. Treatments consisted of ryegrass ( Lolium multiflorum L.), oat ( Avena sativa L.), rye ( Secale cereale L.), wheat ( Triticum aestivum L.), gelemen clover ( Trifolium meneghinianum Clem.), Egyptian clover ( Trifolium alexsandrinum L.), common vetch ( Vicia sativa L.), hairy vetch ( Vicia villosa Roth.) and a bare fallow with no cover crop. Weed density and total weed dry biomass were assessed at 14, 28, and 56 days after incorporation to quantify effects of cover crops during a subsequent pepper crop. Cover crop establishment was similar in both growing seasons and individual species produced in the range of 1800-3500 kg/ha biomass. Ryegrass produced the greatest biomass compared with other species. Weed dry biomass production just before cover crop incorporation varied with year and cover crop species. Hairy vetch, ryegrass, oat and common vetch were the most competitive cover crops based on total weed dry biomass. Hairy vetch was the most promising cover crop and reduced weed density by 73% and 70% at 28 and 56 DAI, respectively. Pepper yields were higher following all cover crops except Egyptian clover. The highest yield was obtained from hairy vetch plots in both years. This research indicates that cover crops such as hairy vetch, ryegrass, oat and common vetch could be used in integrated weed management programs to reduce weed infestation in organic pepper.
  • Authors:
    • Migliorini, P.
    • Mazzoncini, M.
    • Bigongiali, F.
    • Antichi, D.
    • Lenzi, A.
    • Tesi, R.
  • Source: Renewable Agriculture and Food Systems
  • Volume: 24
  • Issue: 2
  • Year: 2009
  • Summary: When animal husbandry is not included in organic farming systems, green manure may be crucial to preserve or increase soil organic matter content and to ensure an adequate N supply to crops. Different species, both legumes and nonlegumes, may be used as cover crops. The present research was carried out to investigate the effect of different green manure crops [oats and barley mixture ( Avena sativa L. and Hordeum vulgare L.), rye ( Secale cereale L.), brown mustard ( Brassica juncea L.), flax ( Linum usitatissimum L.), pigeon bean ( Vicia faba L. var. minor)] on the production of the following tomato crop. A field trial was conducted for two cropping seasons (2003-2004 and 2004-2005) in a commercial organic farm. The yield of tomato crop was positively affected by pigeon bean, although statistically significant differences in comparison with the other treatments were observed only in 2004-2005, when the experiment was conducted in a less fertile soil. This was probably due mainly to the effect of the pigeon bean cover crop on N availability. In fact, this species, in spite of a lower biomass production than the other cover crops considered in the study, provided the highest N supply and a more evident increase of soil N-NO 3. Also, cover crop efficiency, evaluated using the N recovery index, reached higher values in pigeon bean, especially in the second year. The quality of tomato fruits was little influenced by the preceding cover crops. Nevertheless, when tomato followed pigeon bean, fruits showed a lower firmness compared to other cover crops, and in the second year this was associated with a higher fruit N content.
  • Authors:
    • Logsdon, G.
  • Source: Small-scale grain raising
  • Issue: Ed.2
  • Year: 2009
  • Summary: This book (12 chapters) discusses the basics of the organic farming and processing of whole grains (specifically maize, wheat, sorghum, oats, dry beans, rye and barley, buckwheat and millet, rice, some uncommon grains, and legumes) for home gardeners and small-scale farmers. Topics covered include planting; pest, weed and disease management; harvesting; and processing, storing and using whole grains. Some recipes are also included.
  • Authors:
    • Isk, D.
    • Ngouajio, M.
    • Mennan, H.
    • Kaya, E.
  • Source: PHYTOPARASITICA
  • Volume: 37
  • Issue: 4
  • Year: 2009
  • Summary: Weed control is a major concern for organic farmers around the world and non-chemical weed control methods are now the subject of many investigations. Field studies were conducted in tomato ( Solanum lycopersicum L.) from 2004 to 2006 at the Black Sea Agricultural Research Institute experiment field to determine the weed suppressive effects of winter cover crops. Treatments consisted of ryegrass ( Lolium multiflorum L.), oat ( Avena sativa L.), rye ( Secale cereale L.), wheat ( Triticum aestivum L.), gelemen clover ( Trifolium meneghinianum Clem.), Egyptian clover ( Trifolium alexandrinum L.), common vetch ( Vicia sativa L.), hairy vetch ( Vicia villosa Roth.) and a control with no cover crop. Treatments were arranged in a randomized complete block design with four replications. To determine the weed suppressive effects of the cover crops, weed density and total weed dry biomass were assessed at 14, 28, and 56 days after termination (DAT) of the cover crops from all plots using a 50*50 cm quadrat placed randomly in each plot. After cover crop kill and incorporation into soil, tomato seedlings variety 'H2274' were transplanted. Broadleaved weed species were the most prominent species in both years. Total weed biomass measured just prior to cover crop incorporation into the soil was significantly lower in S. cereale plots than in the others. The number of weed species was lowest at 14 DAT and later increased at 28 and 56 DAT, and subsequently remained constant during harvest. This research indicates that cover crops such as L. multiflorum, S. cereale, V. sativa and V. villosa could be used in integrated weed management programs to manage some weeds in the early growth stages of organic tomato.
  • Authors:
    • Vargas, L.
    • Nohatto, M.
    • Amarante, C.
    • Mafra, A.
    • Pelizza, T.
  • Source: REVISTA BRASILEIRA DE FRUTICULTURA
  • Volume: 31
  • Issue: 3
  • Year: 2009
  • Summary: Soil cover is one of the options for weed management in the orchard but this might affect fruit trees development. The objective of this work was to evaluate apple trees growth during the orchard establishment stage by using different materials and soil cover plants. The experimental apple orchard was planted in 2003, in Vacaria, RS, Southern of Brazil, with the cv. Galaxy managed under organic system. The experiment followed the randomized block design, with three replications. The treatments were applied in the tree rows, as follows: control (without weed management), manual weeding, black plastic film, black net, pinus sawdust, pinus needle mulch, Andropogon sp. mulch, annual ryegrass ( Lolium multiflorum), black oat ( Avena strigosa), black oat+common vetch ( Vicia sativa), black oat+fodder radish ( Raphanus sativus), annual ryegrass+white clover ( Trifolium repens)+spontaneous plant cover, weed mowing. The soil covered by weeds was monthly measured, during the spring/summer season, over the second and third years of the orchard establishment, and this was related to the apple trees growth. The treatments with manual weeding, black plastic film, pinus needle and Andropogon mulch maintained the soil cover by weeds below 20%. The apple tree height and diameter decreased with the increase of soil cover by weeds, reflecting weeds competition with apple trees.
  • Authors:
    • Komecki, T. S.
    • Balkcom, K. S.
    • Raper, R. L.
    • Arriaga, F. J.
    • Price, A. J.
    • Reeves, D. W.
  • Source: Journal of Cotton Science
  • Volume: 13
  • Issue: 4
  • Year: 2009
  • Summary: An integral component of conservation agriculture systems in cotton ( Gossypium hirsutum L.) is the use of a high-residue winter cover crop; however, terminating cover crops is an additional expense and planting into high-residue can be a challenge. An experiment was conducted using black oat ( Avena strigosa Schreb.), rye ( Secale cereale L.), and wheat ( Triticum aestivum L.) cover crops established in early November at three locations. In mid-April each year all winter cover crops were flattened with a straight-blade mechanical roller-crimper alone or followed by three rates of glyphosate (0.84, 0.42, 0.21 kg ae/ha). Additionally, glyphosate alone at each rate and a non-treated check were included to complete the factorial treatment arrangement. Cotton was then planted 3 weeks after treatments were administered following in-row sub-soiling at E.V. Smith and direct seeding at Tennessee Valley and Robertsdale. Results showed that rolling followed by reduced glyphosate rates as low as 0.42 kg ae/ha can effectively and reliably terminate mature cereal winter cover crops; thus maintaining cotton population and protecting growth. Additionally, reduced glyphosate rates applied as low as 0.84 kg ae/ha alone can effectively terminate immature cereal covers while conserving soil moisture. Rolling mature winter cereal cover crops will likely conserve more soil moisture compared to standing covers; however, rolling immature cereal cover crops provides no benefit. In 2005 at E.V. Smith and at Tennessee Valley in 2006, increasing glyphosate rate increased cotton yield likely due to less mature cereal covers at time of treatment application. However, the inclusion of glyphosate did not increase cotton yield for any other comparison.
  • Authors:
    • Miquelluti, D. J.
    • Oliveira, O. L. P. de
    • Ferreira, E. Z.
    • Nohatto, M. A.
    • Mafra, A. L.
    • Rosa, J. D.
    • Cassol, P. C.
    • Medeiros, J. C.
  • Source: REVISTA BRASILEIRA DE CIENCIA DO SOLO
  • Volume: 33
  • Issue: 1
  • Year: 2009
  • Summary: This study was conducted to evaluate the effect of phytomass management forms of different cover crop species on soil chemical properties related to organic matter, nutrient availability, and on grapevine yields. The experiment was carried out in Embrapa Uva e Vinho, in Bento Goncalves, Rio Grande do Sul, in Southern Brazil, on a Haplic Cambisol, in a vineyard established in 1989, using White and Rose Niagara grape in a horizontal overhead trelling system. The treatments established in 2002 were three cover crops: spontaneous native species, black oat ( Avena nuda), and a mixture of white clover ( Trifolium repens) + red clover ( Trifolium pratense) + annual ryegrass ( Lolium multiflorum); and two management systems: desiccation by herbicide spraying and mechanical mowing, performed each autumn prior to cover crop resowing. The experiment had a completely randomized block design, with three replications. Soil acidity and nutrient contents were little influenced by the plant cover. In comparison with the mowed management, herbicide application increased exchangeable Ca and Mg, extracted P, and organic C levels in the soil. The grape yield in the seasons 2004 and 2006 was low in view to the cultivar potential, probably affect by climatic limitations, but was higher when black oat was used as plant cover instead of the mixture of plant covers.
  • Authors:
    • Cao, E.
    • Andrigueti, M.
    • Carvalho, P.
    • Anghinoni, I.
    • Costa, S.
    • Souza, E.
  • Source: REVISTA BRASILEIRA DE CIENCIA DO SOLO
  • Volume: 33
  • Issue: 6
  • Year: 2009
  • Summary: The potential for adopting crop-livestock systems in southern Brazil is high, especially in untilled soybean areas with cover crops in the winter season. The long-term use of this system at different grazing intensities will result in different carbon and nitrogen stocks in the soil due to the different plant and animal residues. This research was conducted to evaluate alterations in total carbon and nitrogen pools and in organic matter fractions in a soil under different grazing intensities under no-tillage. The experiment on a Rhodic Hapludult (Oxisol) was initiated in 2001, after soybean harvest. The treatments were different cattle grazing (black oat+ryegrass) pressures (10, 20 and 40 cm sward height) and an ungrazed treatment in the winter and soybean in the summer, in a randomized block design. Soil samples were taken at the beginning of the experiment (May, 2001), after three years (May, 2004) and after six years (May, 2007) to evaluate the content and stocks of organic carbon and nitrogen. Moderate grazing intensities (20 and 40 cm plant height) resulted in an increase of total carbon and nitrogen and in the organic matter particulate fraction, similarly to the ungrazed area. However, at the most intensive grazing pressure (10 cm plant height) there were losses in the stocks of these elements and reduction in soil organic matter quality.
  • Authors:
    • Robertson, G. P.
    • Kravchenko, A. N.
    • Basso, B.
    • Senthilkumar, S.
  • Source: Soil Science Society of America Journal
  • Volume: 73
  • Issue: 6
  • Year: 2009
  • Summary: Temporal changes in soil C content vary as a result of complex interactions among different factors including climate, baseline soil C levels, soil texture, and agricultural management practices. The study objectives were: to estimate the changes in soil total C contents that occurred in the past 18 to 21 yr in soils under agricultural management and in never-tilled grassland in southwest Michigan; to explore the relationships between these changes and soil properties, such as baseline C levels and soil texture; and to simulate C changes using a system approach model (SALUS). The data were collected from two long-term experiments established in 1986 and 1988. Georeferenced samples were collected from both experiments before establishment and then were resampled in 2006 and 2007. The studied agricultural treatments included the conventional chisel-plow and no-till management systems with and without N fertilization and the organic chisel-plow management with cover crops. Total C was either lost in the conventional chisel-plowed systems or was only maintained at the 1980s levels by the conservation management systems. The largest loss in the agricultural treatments was 4.5 Mg ha(-1) total C observed in the chisel-plow system without N fertilization. A loss of 17.3 Mg ha(-1) occurred in the virgin grassland sod. Changes in C content tended to be negatively related to baseline C levels. Under no-till, changes in C were positively related to silt + clay contents. The SALUS predictions of soil C changes were in excellent agreement with the observed data for most of the agricultural treatments and for the virgin soil.
  • Authors:
    • Jones, R.
    • Hatfield, J. L.
    • Kerr, B. J.
    • Singer, J. W.
    • Moorman, T. B.
    • Kaspar, T. C.
    • Chan, A. S. K.
    • Parkin, T. B.
    • Jarecki, M. K.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 134
  • Issue: 1-2
  • Year: 2009
  • Summary: Agriculture contributes 40-60% of the total annual N2O emissions to the atmosphere. Development of management practices to reduce these emissions would have a significant impact on greenhouse gas levels. Non-leguminous cover crops are efficient scavengers of residual soil NO3, thereby reducing leaching losses. However, the effect of a grass cover crop on N2O emissions from soil receiving liquid swine manure has not been evaluated. This study investigated: (i) the temporal patterns of N2O emissions following addition of swine manure slurry in a laboratory setting under fluctuating soil moisture regimes; (ii) assessed the potential of a rye (Secale cereale L.) cover crop to decrease N2O emissions under these conditions: and (iii) quantified field N2O emissions in response to either spring applied urea ammonium nitrate (UAN) or different rates of fall-applied liquid swine manure, in the presence or absence of a rye/oat winter cover crop. Laboratory experiments investigating cover crop effects N2O emissions were performed in a controlled environment chamber programmed fora 14 h light period, 18 degrees C day temperature, and 15 degrees C night temperature. Treatments with or without a living rye cover crop were treated with either: (i) no manure: (ii) a phosphorus-based manure application rate (low manure): or (iii) a nitrogen-based manure application rate (high manure). We observed a significant reduction in N2O emissions in the presence of the rye cover crop. Field experiments were performed on a fine-loamy soil in Central Iowa from October 12, 2005 to October 2, 2006. We observed no significant effect of the cover crop on cumulative N2O emissions in the field. The primary factor influencing N2O emission was N application rate, regardless of form or timing. The response of N2O emission to N additions was non-linear, with progressively more N2O emitted with increasing N application. These results indicate that while cover crops have the potential to reduce N2O emissions, N application rate may be the overriding factor.