• Authors:
    • Burrows, V.
  • Source: Oats: chemistry and technology
  • Issue: Ed.2
  • Year: 2011
  • Summary: This chapter emphasizes 2 points. First, no identified intrinsically new technological or functional characteristics distinguish a hulless from a covered-seeded oat. Second, as the agronomic deficiencies of the old hulless oat cultivars and genetic stocks are overcome through breeding, the opportunity arises for a whole new roster of small-scale enterpreneurs to expand the markets for and uses of oats. Breeding, commercial production and uses in food and animal feeds and non-food uses of hulless oats are discussed.
  • Authors:
    • Radicetti, E.
    • Mancinelli, R.
    • Campiglia, E.
    • Marinari, S.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 89
  • Issue: 3
  • Year: 2011
  • Summary: There is not sufficient knowledge concerning the risks involved in NO 3-N leaching in relation to the use of cover crops and mulches. A 2 year field experiment was carried out in a pepper ( Capsicum annuum L.) crop transplanted into different soil management treatments which involved the addition of mulch of three different types of winter cover crops (CC) [hairy vetch ( Vicia villosa Roth.), subclover ( Trifolium subterraneum L.), and a mixture of hairy vetch/oat ( Avena sativa L.)], and an un-mulched plot. At the time of CC conversion into mulch, the hairy vetch/oat mixture accumulated the highest aboveground biomass (5.30 t ha -1 of DM), while hairy vetch in pure stand accumulated the highest quantity of N (177 kg ha -1) and showed the lowest C/N ratio (12). The marketable pepper yield was higher in mulched than in conventional (on average 33.5, 28.9, 27.7 and 22.2 t ha -1 of FM for hairy vetch, subclover, hairy vetch/oat mixture, and conventional, respectively). Generally, the NO 3-N content of the soil was minimum at CC sowing, slightly higher at pepper transplanting and maximum at pepper harvesting (on average 15.2, 16.8, and 23.3 mg NO 3-N kg -1 of dry soil, respectively). The cumulative leachate was higher during the CC period (from October to April) than the pepper crop period (from April to September), on average 102.1 vs 66.1 mm over the years, respectively. The cumulative NO 3-N leached greatly depended on the type of mulch and it was 102.3, 95.3, 94.7, and 48.2 kg ha -1 in hairy vetch, subclover, hairy vetch/oat mixture, and conventional, respectively. A positive linear correlation was found between the N accumulated in the CC aboveground biomass and the NO 3-N leached during pepper cultivation ( R2=0.87). This research shows that winter legume cover crops, especially hairy vetch in pure stand, converted into dead mulch in spring could be used successfully for adding N to the soil and increasing the yield of the following pepper crop although the risks of N losses via leaching could be increased compared to an un-mulched soil. Therefore when leguminous mulches are used in the cultivation of a summer crop, appropriate management practices of the system, such as a better control of the amount of irrigation water and the cultivation of a graminaceous or a cruciferous catch crop after the harvesting of the summer crop, should be adopted in order to avoid an increase in NO 3-N leaching.
  • Authors:
    • Carson, M.
  • Source: Plant Disease
  • Volume: 95
  • Issue: 12
  • Year: 2011
  • Summary: The use of race-specific seedling genes for resistance is the primary means of controlling crown rust of oat ( Puccinia coronata f. sp. avenae) in the United States. To better utilize those resistance genes, knowledge of the occurrence and frequency of corresponding virulence in the population of P. coronata f. sp. avenae in the United States is essential. In total, 571 single-pustule isolates of oat crown rust were collected from cultivated and wild oat ( Avena sativa and A. fatua, respectively) in the major oat production areas of the United States from 2006 through 2009. They were tested for virulence on seedlings of 31 differential oat lines in the greenhouse. In all, 201 races were found among the 357 isolates from the spring oat region of the north-central United States, and 140 races were found among 214 isolates from the southern winter oat region. The crown rust populations from the winter and spring oat regions were clearly differentiated from one another, differing in the frequency of virulence for 24 of the 31 differentials. Some virulence associations previously reported in the U.S. oat crown rust population were also found in both regions in this survey, even when the dataset was clone corrected. Associations between virulence to the Pc genes were predominately positive in both regions but both positive and negative associations occurred more frequently in the winter oat region, where sexual reproduction does not occur. Some of the virulence diversity in the oat crown rust population in the United States can be related to the deployment of resistance genes in commercial oat cultivars and virulence associations existing in the oat crown rust population. When data from a previous report covering 2001 through 2005 is combined with data reported in this article, the mean virulence of the U.S. populations of crown rust continued to increase from 2001 to 2009. Virulence to Pc38, Pc39, Pc45, Pc48, Pc52, Pc55, Pc56, Pc57, Pc59, Pc62, Pc63, Pc64, Pc68, and Pc96 significantly increased in one or both regions during this time period. No significant declines in virulence frequency were found in either region. Genes for crown rust resistance derived from A. sterilis appear to be as rapidly defeated as has happened to Pc genes from A. sativa. There is an urgent need to find additional sources of effective resistance to P. coronata f. sp. avenae and introgress it into adapted oat cultivars.
  • Authors:
    • Arbugeri, F.
    • Kaminski, J.
    • Casali, C.
    • Piccin, R.
    • Doneda, A.
  • Source: Informacoes Agronomicas
  • Volume: 21-24
  • Issue: 135
  • Year: 2011
  • Summary: This study evaluated the forms of phosphorus accumulated in plant tissue cover crops and their release from the mineralization of their residues. The field work was conducted in the agricultural year 2008/2009, in the town of Mantiqueira, in the municipality of Touch-Me-Not, RS, Brazil. The treatments were: black oats ( Avena nuda), rye ( Secale cereale), pea ( Pisum sativum subsp. arvense) and radish ( Raphanus sativus var. oleferus). Observations showed that the chemical fractionation of P in plant tissue used in this study is a reliable method that aids in understanding the dynamics of the release of P. The cover crops accumulate different forms of P in plant tissue, which interferes with the dynamics of release of this element. It was also observed that rye is a plant that releases the P tissue with greater speed to the ground, while the pea tissue P releases more slowly.
  • Authors:
    • Crusciol, C.
    • Calonego, J.
    • Castro, G.
  • Source: PESQUISA AGROPECUARIA BRASILEIRA
  • Volume: 46
  • Issue: 12
  • Year: 2011
  • Summary: The objective of this work was to evaluate the effects of crop rotation systems and liming materials on soil physical properties. The experiment was carried out from October 2006 to July 2008, in Botucatu, SP, Brazil, in a completely randomized block design in a split-plot arrangement with eight replicates. Main plots consisted of four crop rotation systems: soybean/fallow/maize/fallow, soybean/white-oat/maize/bean, soybean/millet/maize/pigeon pea and soybean/signal grass/maize/signal grass. Subplots consisted of the control treatment, without soil correction, and of the application of 3.8 Mg ha -1 of dolomitic lime (ECC=90%) or 4.1 Mg ha -1 of calcium-magnesium silicate (ECC=80%), on the surface of a clayed Rhodic Ferralsol. Aggregate stability, soil bulk density, total porosity, macro and microporosity, soil penetration resistance and moisture content were evaluated. Superficial application of the lime materials does not reduce soil aggregation and increases macroporosity down to 0.20 m, with calcium-magnesium silicate application, and to 0.10 m, when lime is applied. Soil under fallow in off-season decreases aggregate stability and increases soil penetration resistance in upper layers. The cultivation of Congo signal grass, between summer crops, increases aggregate stability down to 0.10-m depth.
  • Authors:
    • Orr, W.
    • Cooper, J.
    • Chataway, R.
    • Cowan, R.
  • Source: Animal Production Science
  • Volume: 51
  • Issue: 10
  • Year: 2011
  • Summary: Dairy farms located in the subtropical cereal belt of Australia rely on winter and summer cereal crops, rather than pastures, for their forage base. Crops are mostly established in tilled seedbeds and the system is vulnerable to fertility decline and water erosion, particularly over summer fallows. Field studies were conducted over 5 years on contrasting soil types, a Vertosol and Sodosol, in the 650-mm annual-rainfall zone to evaluate the benefits of a modified cropping program on forage productivity and the soil-resource base. Growing forage sorghum as a double-crop with oats increased total mean annual production over that of winter sole-crop systems by 40% and 100% on the Vertosol and Sodosol sites respectively. However, mean annual winter crop yield was halved and overall forage quality was lower. Ninety per cent of the variation in winter crop yield was attributable to fallow and in-crop rainfall. Replacing forage sorghum with the annual legume lablab reduced fertiliser nitrogen (N) requirements and increased forage N concentration, but reduced overall annual yield. Compared with sole-cropped oats, double-cropping reduced the risk of erosion by extending the duration of soil water deficits and increasing the time ground was under plant cover. When grown as a sole-crop, well fertilised forage sorghum achieved a mean annual cumulative yield of 9.64 and 6.05 t DM/ha on the Vertosol and Sodosol, respectively, being about twice that of sole-cropped oats. Forage sorghum established using zero-tillage practices and fertilised at 175 kg N/ha.crop achieved a significantly higher yield and forage N concentration than did the industry-standard forage sorghum (conventional tillage and 55 kg N/ha.crop) on the Vertosol but not on the Sodosol. On the Vertosol, mean annual yield increased from 5.65 to 9.64 t DM/ha (33 kg DM/kg N fertiliser applied above the base rate); the difference in the response between the two sites was attributed to soil type and fertiliser history. Changing both tillage practices and N-fertiliser rate had no affect on fallow water-storage efficiency but did improve fallow ground cover. When forage sorghum, grown as a sole crop, was replaced with lablab in 3 of the 5 years, overall forage N concentration increased significantly, and on the Vertosol, yield and soil nitrate-N reserves also increased significantly relative to industry-standard sorghum. All forage systems maintained or increased the concentration of soil nitrate-N (0-1.2-m soil layer) over the course of the study. Relative to sole-crop oats, alternative forage systems were generally beneficial to the concentration of surface-soil (0-0.1 m) organic carbon and systems that included sorghum showed most promise for increasing soil organic carbon concentration. We conclude that an emphasis on double- or summer sole-cropping rather than winter sole-cropping will advantage both farm productivity and the soil-resource base.
  • Authors:
    • Ferraz, S.
    • Lopes, E. A.
    • Freitas, L. G.
    • Dallemole-Giaretta, R.
    • Podesta, G. S. de
    • Agnes, E. L.
  • Source: NEMATOLOGY
  • Volume: 13
  • Issue: 8
  • Year: 2011
  • Summary: The objective of this research was to evaluate the effect of the combination of Pochonia chlamydosporia var. chlamydosporia with summer and winter cover plants on the control of Meloidogyne javanica on tomato plants under glasshouse conditions. Treatment combinations were with four soil covers (pearl millet and Surinam grass in Experiment 1, oil radish and black oat in Experiment 2; plus tomato and fallow controls) and two P. chlamydosporia treatments (with or without the fungus). The antagonist was applied to nematode-infested soil when the cover crops or tomato were planted. Tomato plants were removed and the above-ground parts of the cover crops were cut, dried, and placed on the pots 60 days after planting. One tomato seedling was transplanted in each pot in a no-tillage system and cultivated for 60 days. Surinam grass, pearl millet and black oat reduced galls and eggs of M. javanica by more than 90%, without application of the fungus. However, P. chlamydosporia+Surinam grass significantly reduced by 72% the number of galls compared with cultivation of the grass in soil without the fungus. Pochonia chlamydosporia became established in soil and could be re-isolated at the end of both experiments. Colony forming units (CFU) (g soil) -1 varied from 1.0*10 5 (fallow) to 2.6*10 5 (pearl millet) and from 1.1*10 5 (fallow) to 2.3*10 5 (oil radish) for the experiments with summer soil cover crops and winter soil cover crops, respectively. The cultivation of Surinam grass, pearl millet and black oat reduced M. javanica populations, and the combination with P. chlamydosporia may favour the establishment of the fungus in the soil and enhance the control of the nematode.
  • Authors:
    • Kumari, S. G.
    • Ekzayez, A. M.
    • Ismail, I.
  • Source: Plant Disease
  • Volume: 95
  • Issue: 1
  • Year: 2011
  • Summary: A field survey covering the major cereal-production areas of Syria was conducted during May 2009. A total of 938 wheat and 971 barley samples with typical symptoms of viral infection were collected from 45 wheat and 58 barley fields. Serological tests showed that Wheat dwarf virus (WDV) was detected in 16 wheat (cv. Cham 8) and 5 barley (cv. Arabic abiad) samples collected from Al-Hasskah governorate (eastern region of Syria) and showing dwarfing, yellowing, and reduced heading. The identity of WDV was confirmed by PCR assay. Leafhopper transmission tests indicated that only Psammotettix provincialis was able to transmit Syrian barley WDW isolates from infected barley plants to healthy barley (48 plants became infected of 50 plants inoculated) and oats (45 of 50) under greenhouse conditions. WDV has been reported to infect cereals in other countries in West Asia and North Africa (Turkey, Tunisia and Morocco) and causes economic losses on wheat in many countries in Europe (e.g. Sweden). WDV has been reported to be transmitted in a persistent manner only by leafhoppers ( Psammotettix alienus) to a wide range of cereal and wild grasses. Two strains of WDV are known, one that primarily infects wheat and another that infects barley. This is thought to be the first report of WDV (both strains) infecting wheat and barley crops in Syria and the first report of P. provincialis as a WDV vector worldwide.
  • Authors:
    • Emeran, A. A.
    • Shtaya, M. J. Y.
    • Fernandez-Aparicio, M.
    • Allagui, M. B.
    • Kharrat, M.
    • Rubiales, D.
  • Source: Crop Protection
  • Volume: 30
  • Issue: 8
  • Year: 2011
  • Summary: Chocolate spot incited by Botrytis fabae is a serious faba bean disease of worldwide distribution. The increasing interest in sustainable tools for disease control, together with the lack of sufficient levels of genetic resistance triggered our interest in the use of intercropping as a tool for the management of this disease. The effect of intercropping on chocolate spot severity was studied in field experiments performed in Egypt, the Palestinian Territories, Spain and Tunisia, in which a susceptible faba bean cultivar was grown as a monocrop or with two mixed species intercrops of either barley, oat, triticale, wheat, pea or common vetch, or with three mixed species intercrops of wheat and berseem clover. Chocolate spot was significantly reduced when faba bean was intercropped with cereals, but not when intercropped with legumes. Suppressive effects can be ascribed to a combination of host biomass reduction, altered microclimate and physical barriers to spore dispersal.
  • Authors:
    • Ferrari, J. V.
    • Furlani Junior, E.
    • Ferrari, S.
    • Pereira, G. A.
  • Source: SEMINA-CIENCIAS AGRARIAS
  • Volume: 32
  • Issue: 4
  • Year: 2011
  • Summary: Nitrogen application on the cover and the maintenance of straw, conducted by direct seeding, should meet the needs of agriculture and promote soil conservation. This study evaluates the effect of pre-sowing nitrogen application in cotton crops and cover crops by direct seeding, on the development and yield of cotton. It was conducted in the municipality of Selviria-MS during the agricultural years 2005/06, 2006/07 and 2007/08. The experimental design used was a randomized block design consisting of three cover crops (forage turnip, black oat and white oat) and four nitrogen doses (0, 30, 60 and 90 kg of N ha -1) in pre-sowing of cotton. In April 2006, April 2007 and April 2008, the assessments of plant development and also harvesting of the experimental plots of cotton cultivars were conducted. The results showed that after planting the cover crops, the yield and development and the heights of cotton plants increased with the use of pre-sowing N of 90 kg ha -1, also showing that the forage turnip is a coverage plant that provides increased cotton.