• Authors:
    • Brennan, E. B.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 5
  • Year: 2011
  • Summary: Winter cover crops can add soil organic matter, improve nutrient cycling, and suppress weeds in organic vegetable systems. A 2-yr study was conducted on organic farms in Salinas and Hollister, CA, to evaluate the effect of seeding rate (SR) and planting arrangement on cover crop density, ground cover, and cover crop and weed dry matter (DM) with a mixed cover crop. The mix contained legumes (35% Vicia faba L., bell bean; 15% Vicia dasycarpa Ten., woolypod vetch; 15% Vicia benghalensis L., purple vetch; and 25% Pisum sativum L., pea) and 10% oat (Avena sativa L.) by seed weight. Three SRs (112, 224, and 336 kg ha(-1)) and two planting arrangements (one-way versus grid pattern) were evaluated. Planting arrangement had no effect on the variables measured. When weeds were abundant, weed DM declined linearly with increasing SR from approximately 300 kg ha(-1) at the low SR to <100 kg ha(-1) at the high SR. Increasing SR increased oat and legume DM early in the season, but did not affect final cover crop DM that ranged from 7 to 12 Mg ha(-1). Year affected final cover crop DM production at both sites. The legume DM portion of the total cover crop declined through the season but varied between sites and year, probably due to soil and climatic differences. Higher SRs may be cost effective because weed control is expensive and cover crop seed is a relatively small component of cover cropping costs in this region.
  • Authors:
    • Montfort, F.
    • Faloya, V.
    • Schlaunich, E.
    • Aubree, N.
    • Breton, D.
  • Source: 4eme Conference Internationale sur les Methodes Alternatives en Protection des Cultures.
  • Year: 2011
  • Summary: To study the interest and the limits of the insertion of various cover crop with biofumigation potential in a crop succession, three trials, one in Aquitaine (40), one in Normandy (50) and one in Rheu (35) were performed on two important soilborne diseases of carrot: cavity-spot due to Pythium sulcatum or the brown rot disease due to Rhizoctonia solani. Intercrop plants were cultivated then crushed and incorporated in the soil one month before carrot crop. In the three trials, the effect of the mustard Brassica juncea on the incidence and the severity of the diseases is studied and compared with bare soil. In the Normandy trial, two other cover crops are also studied: oat and rye crop. In Le Rheu trial, regular observations allow to compare the development of cavity-spot over time after insertion then incorporation of a mustard crop or after a bare soil. The results are presented; the technical feasibility and the impact of method on disease development 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:
    • 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:
    • 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:
    • 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.
  • Authors:
    • Cavariani, C.
    • Gazola, E.
  • Source: BIOSCIENCE JOURNAL
  • Volume: 27
  • Issue: 5
  • Year: 2011
  • Summary: The objective of this research was to evaluate crop yield and some characteristics and yield components of transgenic soybean cultivars sown after different winter cover crops in the first year under no tillage system. The experimental design was the completely randomized block with split plots and four replications. The main plots consisted of five winter cover crops, white oat ( Avena sativa L.), forage turnip ( Raphanus sativus L.), barley ( Hordeum vulgare L.), wheat ( Triticum aestivum L.) and ground pea ( Pisum sativum L.) and an area under fallow (spontaneous vegetation). The subplots consisted of six soybean cultivars (BRS 243 RR, BRS 245 RR, BRS 247 RR, BRS 255 RR, BRS 256 RR and BRS 244 RR). Variance analysis for agronomic characteristics showed that soybean yield components were influenced by the interaction between winter crop and soybean cultivar. Thus, final population, number of nodes and pods per plant, nodes dry matter per plant, number of grains per pod and grain yield were affected significantly. When soybean nodulation was evaluated, the treatment with the area under fallow showed lower values. There was difference among winter crops for BRS 243 RR grain yield, white oat showed the highest values.
  • Authors:
    • Hoare, T.
  • Source: Wine and Viticulture Journal
  • Volume: 26
  • Issue: 3
  • Year: 2011
  • Summary: This paper describes the suitability of rolled cover crops (including oats, triticale and faba beans), white alyssum ( Lobularia maritima), saltbush ( Atriplex semibaccata and Enchylaena tomentosa) and chicory for cultivation with grape under the mid-row crop management system (MCS). The characteristics of vineyards suitable for MCS, and the beneficial effects of the aforementioned crops on vineyard profitability and productivity are covered.
  • Authors:
    • Tomer, M.
    • Cambardella, C.
    • Singer, J.
    • Moorman, T.
    • Kovar, J.
  • Source: Journal of Environmental Quality
  • Volume: 40
  • Issue: 2
  • Year: 2011
  • Summary: Injection of liquid swine manure disturbs surface soil so that runoff from treated lands can transport sediment and nutrients to surface waters. We determined the effect of two manure application methods on P fate in a corn ( Zea mays L.)-soybean [ Glycine max (L.) Merr.] production system, with and without a winter rye ( Secale cereale L.)-oat ( Avena sativa L.) cover crop. Treatments included: (i) no manure; (ii) knife injection; and (iii) low-disturbance injection, each with and without the cover crop. Simulated rainfall runoff was analyzed for dissolved reactive P (DRP) and total P (TP). Rainfall was applied 8 d after manure application (early November) and again in May after emergence of the corn crop. Manure application increased soil bioavailable P in the 20- to 30-cm layer following knife injection and in the 5- to 20-cm layer following low-disturbance injection. The low-disturbance system caused less damage to the cover crop, so that P uptake was more than threefold greater. Losses of DRP were greater in both fall and spring following low-disturbance injection; however, application method had no effect on TP loads in runoff in either season. The cover crop reduced fall TP losses from plots with manure applied by either method. In spring, DRP losses were significantly higher from plots with the recently killed cover crop, but TP losses were not affected. Low-disturbance injection of swine manure into a standing cover crop can minimize plant damage and P losses in surface runoff while providing optimum P availability to a subsequent agronomic crop.
  • Authors:
    • Schuh, R.
    • Loffaguen, J.
    • Epping, J.
    • Costa, M.
    • Kunze, A.
    • Lovato, P.
  • Source: REVISTA BRASILEIRA DE CIENCIA DO SOLO
  • Volume: 35
  • Issue: 3
  • Year: 2011
  • Summary: Cover crops may difffer in the way they affect rhizosphere microbiota nutrient dynamics. The purpose of this study was to evaluate the effect of mycorrhizal and non-mycorrhizal cover crops on soil phosphatase activity and its persistence in subsequent crops. A three-year experiment was carried out with a Typic Quartzipsamment. Treatments were winter species, either mycorrhizal black oat ( Avena strigosa Schreb) or the non-mycorrhizal species oilseed radish ( Raphanus sativus L. var. oleiferus Metzg) and corn spurry ( Spergula arvensis L.). The control treatment consisted of resident vegetation (fallow in the winter season). In the summer, a mixture of pearl millet ( Pennisetum americanum L.) with sunnhemp ( Crotalaria juncea L.) or with soybean ( Glycine max L.) was sown in all plots. Soil cores (0-10 cm) and root samples were collected in six growing seasons (winter and summer of each year). Microbial biomass P was determined by the fumigation-extraction method and phosphatase activity using p-nitrophenyl-phosphate as enzyme substrate. During the flowering stage of the winter cover crops, acid phosphatase activity was 30-35% higher in soils with the non-mycorrhizal species oilseed radish, than in the control plots, regardless of the amount of P immobilized in microbial biomass. The values of enzyme activity were intermediate in the plots with corn spurry and black oat. Alkaline phosphatase activity was 10-fold lower and less sensitive to the treatments, despite the significant relationship between the two phosphatase activities. The effect of plant species on the soil enzyme profile continued in the subsequent periods, during the growth of mycorrhizal summer crops, after completion of the life cycle of the cover crops.