361. Efficiency of mechanical and biological chiseling in the improvement of physical attributes of a heavy clay oxisol and the increment of soybean yield.; Eficiencia da escarificacao mecanica e biologica na melhoria dos atributos fisicos de um latossolo muito argiloso e no incremento do rendimento de soja.

• 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.

362. Pathogenicity of fungi colonising the soil after the cultivation of cover crops towards the seedlings of salsify Tragopogon porrifolius var. sativus (Gaterau) Br.

• Authors:
  • Konopinski, M.
  • Patkowska, E.
• Source: Folia Horticulturae
• Volume: 20
• Issue: 2
• Year: 2008
• Summary: The purpose of the present study was to conduct pathogenicity tests for salsify seedlings in a soil environment colonised by selected fungi species, after the cultivation of cover crops such as oats, common vetch and tancy phacelia. A growth chamber experiment used the seeds of 'Mamut' salsify and soil overgrown with Altenaria alternata, Fusarium culmorum, F. oxysporum, Pythium irregulare, Rhizoctonia solani and Sclerotinia sclerotiorum. The pathogenicity of these microorganisms towards salsify seedlings was established on the basis of the grown plants, their health and a disease index calculated on the basis of a five-degree scale. The examined isolates considerably weakened the emergence and health of salsify. Based on pathogenicity tests, such species as R. solani, S. sclerotiorum and P. irregulare were considered as the major cause of seedling necrosis and root rot of the plants of the Tragopogon porrifolius var. sativus. Among the studied soil-borne plant pathogens, the most pathogenic ones towards salsify seedlings proved to be the isolates of R. solani, S. sclerotiorum and P. irregulare, whereas the least harmful included A. alternata and F. culmorum.

363. Seeds quality and soybean productivity under non-tillage system and cover crops with black oat, forage turnip and vetch.

• 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.

364. Seedlings emergence, plants heights and yield of soybean seeded under cover crops with black oat, forage turnip and vetch.

• 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.

365. Incidence of weeds species and soybean productivy under vegetal covering crops.

• 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.

366. Performance of seed distribution mechanisms under different speeds and soil covering conditions.; Desempenho de mecanismos dosadores de sementes em diferentes velocidades e condicoes de cobertura do solo.

• 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.

367. Development and yield of birdsfoot trefoil sown under the cover of other crops in conditions of the Kirov region.

• 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.

368. Effect of cover crop extracts on cotton and radish radicle elongation.

• Authors:
  • Balkcom, K. S.
  • Arriaga, F. J.
  • Bergtold, J. S.
  • Stoll, M. E.
  • Price, A. J.
  • Kornecki, T. S.
  • Rap, R. L.
• Source: Communications in Biometry and Crop Science
• Volume: 3
• Issue: 1
• Year: 2008
• Summary: Research has shown that some cover crops are allelopathic and can inhibit weed germination and growth. Additionally, negative allelopathic effects have been documented in cash crops planted into cover crop residue. However, little literature exists comparing relative the allelopathic potential of cover crops producers utilize in conservation-agriculture systems. This study assessed the effects of twelve cover crop extracts on radish ( Raphanus sativus L.) and cotton ( Gossypium hirsutum L.) radicle elongation, in three trials, using an extract-agar bioassay. In Trial 1 the cover crops were black oat ( Avena strigosa Schreb) cv. SoilSaver, crimson clover ( Trifolium incarnatum L.) cv. AU Robin, white lupin ( Lupinus albus L.) cvs. AU Homer and AU Alpha, rye ( Secale cereale L.) cv. Elbon, wheat ( Triticum aestivum L.) cv. Vigoro Grazer, and triticale (* Triticosecale Wittmack) cv. Trical 2700. In Trial 2 the cover crops were forage rape ( Brassica napus L. var. napus) cv. Licapo, sunn hemp ( Crotalaria juncea L.), Austrian winter field pea ( Pisum sativum spp. arvense L. Poir), black medic ( Medicago lupilina L.), hairy vetch ( Vicia villosa Roth), black oat cv. SoilSaver, and crimson clover cv. AU Robin. Cotton was evaluated using the same bioassay and all of the cover crops mentioned above in a single trial (Trial 3). All cover crop extracts inhibited radicle elongation compared to water. Allelopathic potential was highly variable among cultivars within a cover crop species, and within a cultivar. Allelopathic differences among cover crops give an additional weed control tool in conservation systems. However, winter cover selection may impact on cash crop performance if producers plant their crop into green residue.

369. Bulk density critical limits for normal root growth of cover crops.; Limites criticos de densidade do solo para o crescimento de raizes de plantas de cobertura em argissolo vermelho.

• 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.

370. Growth of Pinus elliottii and Eucalyptus tereticornis associated with cover plants, in degraded soils by arenization.; Desenvolvimento do Pinus elliottii e do Eucalyptus tereticornis consorciado com plantas de cobertura, em solos degradados por arenizacao.

• Authors:
  • Eltz, F.
  • Rovedder, A.
• Source: Ciencia Rural
• Volume: 38
• Issue: 1
• Year: 2008
• Summary: This study investigated the growth of Pinus elliottii and Eucalyptus tereticornis from Rio Grande do Sul, Brazil, and tested their capacity for reducing the arenization process. The treatments consisted of planting two species on: (i) arenization-degraded soil (DS); (ii) native grassland (C); (iii) native grassfield associated with cover crops (C+PC); and (iv) degraded soil associated with cover crops (DS+PC). Black oat ( Avena nuda) and Lupinus albescens were used as cover crops. The survival rate, height, basal diameter and productivity factor of tree species were obtained 30 days, 6 months and 12 months after planting. In relation to initial survival, only pine showed significant differences, with lower percentage in the treatment C+PC. Eucalyptus benefited from the consortium with cover crops, while pine presented higher sensibility to interspecific competition.