• 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:
    • 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:
    • Bragagnolo, J.
    • Girardello, V.
    • Lanzanova, M.
    • Schneider, S.
    • Amado, T.
    • Nicoloso, R.
  • Source: REVISTA BRASILEIRA DE CIENCIA DO SOLO
  • Volume: 32
  • Issue: 4
  • Year: 2008
  • Summary: This study aimed to evaluate the efficiency of a mechanical (chisel plough) and biological (forage radish) soil decompaction method or the combination of both to improve the physical properties of a very clayey texture Oxisol and to increase soyabean grain yield under no-tillage. The treatments were: black oat on no-till (NT-O), consortium of forage radish and black oat on no-till (NT-R+O), black oat on chiselled soil (CH-O) and consortium of forage radish and black oat on chiselled soil (CH-R+O). The following properties were evaluated: soil bulk density, macroporosity, microporosity and total porosity in the layers 0-0.05, 0.05-0.10, 0.10-0.15 and 0.15-0.20 m, soil penetration resistance, soil moisture and soil water infiltration at soyabean flowering. The winter cover biomass production and soyabean yield were also measured. The treatments did not affect the soil bulk density significantly at any of the soil depths. However, the treatments NT-R+O and CH-R+O doubled the mean soil macroporosity values in the 0-0.20 m layer, with more pronounced effects in the upper soil layers. The treatments NT-R+O and CH-R+O reduced soil penetration resistance compared to NT+O, while treatment CH-O had intermediate results. The treatments NTR+O and CH-R+O increased the accumulated infiltrated water by 44.6 as compared to treatments NT-O and CH-O. The highest soyabean yields were observed in the treatment CH-R+O (3.73 tonnes/ha), which did not differ significantly from treatment NT-R+O (3.49 tonnes/ha). The effect of winter mechanical chiseling was temporary and nine months later no soil physical improvements were observed, apart from the increase of total porosity and macroporosity in the 0-0.05 m layer. Biological chiselling increased soil macroporosity, reduced soil penetration resistance and improved soil water infiltration. Mechanical chiselling was only efficient to improve the soil physical conditions when associated with biological chiselling, which prevented soil reconsolidation.
  • Authors:
    • Coelho, S.
    • Rosa, D.
    • Mauli, M.
    • Nobrega, L.
    • Piccolo, G.
  • 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: It was registered the allelopathic interference of remains of black oat (BO) in a consortium with BO, forage turnip and vetch (CO) in relation to seeds quality and soybean productivity, in interval of one, ten, twenty and thirty days between the covering desiccation with Glyphosate 480 (3 L ha -1) and the cultivar BRS 232 sowing (IDS). The coverings were prepared with plots of 5*2.5 m with 1 m of border, which were desiccated according to the IDS. So, there were four treatments and one control treatment for each covering, randomized with five replications. The soybean was sown with 0.45 m among rows, thirteen lines and 14 seeds by linear meter. The productivity was determined according to water content adjusted to 13%; germination percentage; mass of 100 seeds (m-100); water content and vigor (accelerated aging test). The experimental design was completely randomized, subdivided in parcels and averages were compared by Scott and Knott test at 5% of significance. The cropped soybean under BO presented the best answer for mass of 100 seeds, but when it was cropped under CO, it had the best vigor. Productivity did not differ between BO and CO. The IDS affected m-100 and productivity. IDS, at the first day, increased m-100, but did not reduce productivity. So, it does not recommend the soybean crop near the covering desiccation.
  • Authors:
    • Scapim, C. A.
    • Lucca e Braccini, A. de
    • Pinheiro Neto, R.
    • Bortolotto, V. C.
    • Pinheiro, A. C.
  • Source: Acta Scientiarum - Agronomy
  • Volume: 30
  • Issue: Suplemento Espec
  • Year: 2008
  • Summary: The objective of this work was to evaluate the performance of two seeders offered commercially for no-tillage. The assays were conducted at the Cazarotto Farm, located in the Iguatemi District, municipal district of Maringa, Parana State, in a HAPLOTOX Soil. Two experiments were set up: the first using a seeder with a horizontal plate distribution mechanism, and the second using a seeder with pneumatic-type mechanism. A split-plot design was used, with four replications. The main treatments were: soil covering conditions (spontaneous vegetation, desiccated black oat, and desiccated+rolled black oat); and the secondary treatments were the forward speeds (horizontal plate: 4.74, 5.41, 6.47 and 7.24 km h -1; and pneumatic: 5.56, 8.04 and 10.21 km h -1). With the increase in speed, the plant population and the percentage of acceptable spacings were reduced, and the recommended plant population was not reached by either seeder. The pneumatic mechanism obtained better results than the horizontal plate. The yield was larger where smaller populations were obtained, influenced by the water deficit.
  • Authors:
    • Aita, C.
    • Reichert, J. M.
    • Albuquerque, J. A.
    • Reinert, D. J.
    • Andrada, M. M. C.
  • Source: REVISTA BRASILEIRA DE CIENCIA DO SOLO
  • Volume: 32
  • Issue: 5
  • Year: 2008
  • Summary: The physical quality of a Typic Hapludalf in a no-tillage system was evaluated after the use of cover crops, and the critical limit of bulk density was measured. In autumn/winter of 1999/00 and 2000/01, the site was cultivated with black oats ( Avena strigosa) [ Avena nuda] with vetch ( Vicia sativa) and in 2001/02, with forage turnip ( Raphanus sativus). Corn ( Zea mays) was sown in summer and at the end of the cycle, four summer cover crops ( Crotalaria juncea, Cajanus cajan, Stilozobium cinereum and Canavalia ensiformis) were sown compared to fallow soil. Soil bulk density and penetration resistance were measured. The rooting system was evaluated by a root profile method during the cycle of forage turnip, corn and summer cover crops. The soil bulk density was increased by no-tillage to levels considered critical for plant growth. The root growth of all crops used in the rotations suffered some degree of restriction. There was no difference among the species in their root growth potential in the compacted soil. The root growth of the cover crop was normal up to a bulk density of 1.75 Mg/m 3, while values between 1.75 and 1.85 Mg/m 3 were restrictive, with visible deformation of the root morphology. These deformations were more pronounced when bulk density was greater than 1.85 Mg/m 3, with increased root thickening, deviations in the vertical root growth direction and concentration of roots in the topmost soil layer. The evaluated species can be used in compacted soils, but at soil bulk density >1.85 Mg/m 3, soil mobilization through mechanical methods may be necessary to alleviate the effects on root and plant growth.
  • Authors:
    • Fabian, A.
    • Pereira, M.
    • Torres, J.
  • Source: PESQUISA AGROPECUARIA BRASILEIRA
  • Volume: 43
  • Issue: 3
  • Year: 2008
  • Summary: This study investigated dry biomass production, decomposition rate and macronutrients release (N, P, Ca, Mg and S) of cover crops cultural residues, in a no-till savanna soil in Minas Gerais, Brazil. The cover crops tested were: pearl millet ( Pennisetum americanum syn. typhoides), brachiaria grass ( Brachiaria brizantha [Urochloa brizantha] cv. Marandu), sorghum ( Sorghum bicolor), pigeon pea ( Cajanus cajan), sunn hemp ( Crotalaria juncea) and black oat ( Avena nuda), compared to a fallow plot (control). The experiment was carried out in an Oxisol, medium texture. A randomized block design, in a split-plot array in time, with four replications, was used. Dry biomass production was evaluated 110 days after sowing. Decomposition rate was evaluated by litter bags containing cultural residues. Millet and sunn hemp were the cover crops (grass and legume) with the highest dry biomass production and N accumulation, in the two evaluation periods. The highest decomposition rate and nutrient release occurred at 42 days after desiccation. The highest values of half life were observed in dry period.
  • Authors:
    • Castoldi, G.
    • Gobbi, F.
    • Pivetta, L.
    • Costa, L.
    • Steiner, F.
    • Costa, M.
    • Tremea, A.
  • 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 objective of this work was to evaluate the effect of two soil tillage systems (rotation and succession crops) and three fertilizations (mineral, organic and organomineral) in the wheat yield, under no-tillage system. The assay was conducted in the Experimental Station Prof. Dr. Antonio Carlos dos Santos Pessoa, located at the Nucleo of Experimental Station belonging to West Parana State University - Marechal Candido Rondon. In the winter of the 2006 was cropping the wheat in the plots in succession crops and black oat+radish+hairy vetch in the plots in rotation crops. The wheat received the mineral, organic and organomineral fertilization, while the cover crops weren't fertilized. In the summer was cropping corn in all the plots, receiving the three kind of fertilization. In the winter of the 2007 was cropping wheat in all the plots, receiving again the three kind of fertilization. The plant high and the weight of 100 grains weren't affected by the management systems and fertilizations. The succession system (wheat/corn/wheat) showed superior yield than the rotation system (green manure/corn/wheat). The organic manure showed superior hectoliter weight than mineral fertilization.