• Authors:
    • Carvalho, P. C. de F.
    • Sulc, R. M.
    • Moraes, A. de
    • Pelissari, A.
    • Lang, C. R.
    • Lopes, E. C. P.
  • Source: Scientia Agraria
  • Volume: 12
  • Issue: 1
  • Year: 2011
  • Summary: Producers seeking higher corn ( Zea mays) production efficiency have pursued more sustainable, integrated systems. The objective of this investigation was to determine the effect of nitrogen fertilization on corn yield and yield components in an integrated crop-livestock production system. The experiment was conducted on the experimental farm Fazenda Capao da Onca of the Universidade Estadual de Ponta Grossa, Brazil during the 2002/2003 harvest. Treatments were replicated four times in a split-plot randomization of a randomized complete block design. Whole plot treatments were two N rates (0, 150 kg ha -1) with and without grazing applied to a winter cover crop of black oat and Italian ryegrass established in April 2002 and desiccated prior to planting the corn in October 2002. Sequentially, treatments were four N rates (0, 75, 150, 225 kg ha -1) applied to the corn. The corn presented an increasing yield in relation to increasing N rates in plots without neither grazing nor N fertilization during winter; however, grazing allows for higher corn yields with lower N rates.
  • Authors:
    • Foster, A.
    • Malhi, S.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 42
  • Issue: 19
  • Year: 2011
  • Summary: Annual cover crops compete with underseeded perennial forages for light, moisture, and nutrients and may suppress their establishment and growth. Field experiments were established in 2000 and 2001 at Nipawin and in 2002 and 2003 at Melfort in northeastern Saskatchewan to determine the effects of seeding rates of cover crops of oat (19, 38, and 112 kg ha -1) and barley (31, 62, and 124 kg ha -1) on forage dry-matter yield (DMY) of the cover crop cut as greenfeed in the seeding year, DMY of the underseeded meadow bromegrass-alfalfa mixture in the following 1 or 2 years after establishment, and forage quality [concentration of crude protein (CP), acid detergent fiber (ADF) and neutral detergent fiber (NDF)]. In the first establishment year, the no cover crop treatment produced considerably less DMY than the treatments with cover crops. Oat seeded at 112 kg ha -1 produced greater DMY than when it was seeded at 19 or 38 kg ha -1 in all four site-years, but DMY differences between the 19 or 38 kg ha -1 seeding rates were not significant in any site-year. For barley, there was no significant difference in DMY among the three seeding rates in 2000, 2001, and 2002. In 2003, barley seeded at 62 or 124 kg ha -1 produced greater DMY than when it was seeded at 31 kg ha -1, but DMYs were not significantly different between the 62 and 124 kg ha -1 seeding rates. The use of a cover crop did reduce DMY in 2003 of bromegrass-alfalfa mixture underseeded in 2002, but the type of cover crop and its seeding rate did not appear to affect DMY in any site-year. Forage quality in the seeding year was consistently superior in no cover crop treatment compared to that in treatments with cover crops, especially related to CP concentration. There was no consistent trend of forage quality in the cover crop treatments, indicating cover crops and their seeding rates had little effect on forage quality. In conclusion, oat appeared to be more sensitive to seeding rate than barley for forage DMY in the establishment year, but in the subsequent 1 or 2 years after establishment there was little effect of cover crop type and its seeding rate on DMY of bromegrass-alfalfa mixture, although DMY was considerably greater in the no cover treatment than that in treatments with cover crops in 1 site-year.
  • Authors:
    • Leap, J.
    • Klonsky, K. M.
    • Shennan, C.
    • Smith, R. F.
    • Muramoto, J.
    • Ruiz, M. S.
    • Gliessman, S. R.
  • Source: HortScience
  • Volume: 46
  • Issue: 8
  • Year: 2011
  • Summary: Legume/cereal mixed winter cover crops are commonly used by organic growers on the central coast of California, but they are unable to provide sufficient nitrogen (N) for a high N-demanding vegetable crop such as broccoli and supplemental fertilizer application may be necessary. The goals of this project were to evaluate the contribution of N from a mixed legume/cereal cover crop (CC) and feather meal and blood meal as organic fertilizers (OF) to an organic broccoli crop and to evaluate economic benefits of CC and OF to the subsequent organic broccoli crop. Trials were conducted at two sites (A and B) with different management histories. Cover crops were grown over the winter and incorporated into the soil in the spring and subsequently broccoli [ Brassica oleracea L. (Italica group)] was grown in 2006 at both sites and in 2007 at B only. Cover crop and no CC treatments were grown with supplemental organic fertilizers at four fertility levels (0, 84, 168, and 252 kg N/ha of OF) with four replicates. Generally broccoli head yields at A (14.9 to 26.3 Mg.ha -1) were higher than at B (0.7 to 17.4 Mg.ha -1 in 2006 and 5.5 to 17.9 Mg.ha -1 in 2007). Yield and aboveground biomass N were significantly increased by OF at rates up to 168 kg N/ha at A and to 252 kg N/ha at B and by CC in 2006 at both sites but not in 2007 at B. Although N content of the CC was similarly low at A (2006) and at B (2007), immobilization of soil mineral N occurred only at B. This suggests that the addition of a low N content CC was offset by high N mineralization from the soil at A with a long organic management history (greater than 33 years). Supplemental fertilizer applications may be necessary to achieve optimal yields, but the amount needed can be reduced by cover cropping in fields with a long history of cover crop-based organic management (A) or when cover crop N content is sufficiently high to prevent immobilization (B, 2006). Soil NO 3-N patterns suggest a pre-side dress nitrate test may also be useful for N management in organic broccoli. Use of cover crops increased net return above harvest and fertility costs when the yield reduction by N immobilization did not take place. However, the net return increase by the use of cover crops tended to diminish as the rate of OF application increased.
  • Authors:
    • Maniutiu, D.
    • Indrea, D.
    • Muresan, A. O.
    • Sima, R.
  • Source: Journal of Horticulture, Forestry and Biotechnology
  • Volume: 15
  • Issue: 1
  • Year: 2011
  • Summary: In comparative stationary field experiments performed in Apahida, Cluj County, during four years (2005-2008), cabbage, sweet corn, carrot and garden bean crops have been followed on two different tillage systems: a conventional system - 5-6 tillage works including deep ploughing (25-28 cm deep) and 2-3 weeding, and the minimum tillage system: the strip-tillage cover crop system (spring fodder=oat+vetch) that was treated with Glyphosat herbicide (2 l/ha) and remained on the ground as mulch on which 10-15 cm wide sowing strips were split open. With the minimum tillage a 3-5 day delay in plant sprouting was noticed and vegetation was prolonged for few days in sweet corn, carrot and bean. Yield decreases by the minimum tillage vary between 7.7% and 16.7% in carrot and 5.0% and 10.9% in garden bean. In cabbage and sweet corn yield decrease was stated only during the first 2 years, while during the last 2 years the crop would balance on the two tillage methods. There was some product quality decrease with the minimum tillage, especially in carrots and beans.
  • Authors:
    • Muchaonyerwa, P.
    • Chiduza, C.
    • Murungu, F. S.
    • Mnkeni, P. N. S.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 89
  • Issue: 1
  • Year: 2011
  • Summary: Increasing land degradation has prompted interest in conservation agriculture which includes growing cover crops. Besides providing soil cover, decaying cover crops may release substantial amounts of nutrients. Decomposition, N and P release from winter cover crops [grazing vetch ( Vicia darsycarpa), forage peas ( Pisum sativum) and oats ( Avena sativa)] were assessed for suitability in a cropping system found in the smallholder irrigation sector of South Africa. Nitrogen and P contribution to maize growth by cover crop residues was also estimated. Decrease in mass of cover crop residues was highest in grazing vetch (7% remaining mass after 124 days) followed by forage peas (16%) and lastly oats (40%). Maximum net mineralized N and P were higher for grazing vetch (84.8 mg N/kg; 3.6 mg P/kg) than for forage peas (66.3 mg N/kg; 2.7 mg P/ha) and oats (13.7 mg N/kg; 2.8 mg P/kg). Grazing vetch and forage pea residues resulted in higher N contribution to maize stover than oat residues. Farmers may use grazing vetch for improvement of soil mineral N while oats may result in enhancement of soil organic matter and reduction land degradation because of their slow decomposition. Terminating legume cover crops a month before planting summer crops synchronizes nutrient release from winter-grown legume cover crops and uptake by summer crops.
  • Authors:
    • Muchaonyerwa, P.
    • Chiduza, C.
    • Murungu, F. S.
    • Mnkeni, P. N. S.
  • Source: Soil & Tillage Research
  • Volume: 112
  • Issue: 1
  • Year: 2011
  • Summary: Low soil fertility and weeds reduce maize yields on most smallholder (SH) irrigation schemes in South Africa (SA). While cover cropping can increase maize productivity, benefits from different types of mulch are not well understood, leading to challenges in selecting the most appropriate cover crop species to grow. Field experiments investigating the effects of oat ( Avena sativa), grazing vetch ( Vicia dasycarpa), faba bean ( Vicia faba), Lupin ( Lupinus angustifolius) and forage pea ( Pisum sativum) mulch on maize grown at two fertilizer levels (0 and 60 kg N/ha) were undertaken in the 2007/08 and 2008/09 seasons. Plots where maize was grown without mulch were included as controls. Treatments were arranged in a randomised complete block design with three replications. Grazing vetch and forage pea mulch significantly ( P
  • Authors:
    • Konopinski, M.
    • Patkowska, E.
  • Source: ACTA SCIENTIARUM POLONORUM-HORTORUM CULTUS
  • Volume: 10
  • Issue: 2
  • Year: 2011
  • Summary: Salsify has a remarkable taste and nutritious values. It is a rich source of inulin - a glycoside which has a positive effect on human and animal organisms. The paper presents studies on the species composition of soil-borne fungi infecting the roots of Tragopogon porrifolius var. sativus cultivated with the use of oats, tansy phacelia and spring vetch as cover crops. In a field experiment the cover crops formed abundant green mass before winter and it constituted a natural mulch on the surface of the plough land. It was managed in two ways: (1) mixed with the soil as a result of spring ploughing, or (2) mixed with the soil as a result of pre-winter ploughing. The conventional cultivation of salsify, i.e. without cover crops, constituted the control. The studies established the number and health status of four-week-old salsify seedlings and roots with necrotic signs. A laboratory mycological analysis made it possible to determine the quantitative and qualitative composition of fungi infecting the underground parts of Tragopogon porrifolius var. sativus. The emergences and the proportion of infected salsify seedlings varied and depended on the species of the mulching plant. The smallest number of infected seedlings was obtained after the mulch with oats, slightly more after the application of spring vetch or tansy phacelia as cover crops, and the most in the control. Regardless of the species of the mulching plant, the following were frequently isolated from the diseased seedlings and roots of salsify: Alternaria alternata, Fusarium culmorum, Fusarium oxysporum, Penicillium spp., Rhizoctonia solani and Sclerotinia sclerotiorum. Rhizoctonia solani and Sclerotinia sclerotiorum proved to be the most harmful towards the roots of salsify. The system of cultivation, i.e. performing spring or pre-winter ploughing, had no significant effect on the total population of fungi.
  • Authors:
    • Dias, T.
    • Correa, M.
    • Alves, P.
    • Pereira, R.
  • Source: Revista Brasileira de Ciências Agrárias
  • Volume: 6
  • Issue: 1
  • Year: 2011
  • Summary: The success in weed control by using straw depends on the management time, straw quality and quantity. The objective of this research was to evaluate the suppressor effect of black-oats and millet straw cover on the incidence of weeds and on the productivity of the soybean crop. The experiment was carried out during the years 2006 and 2007, in an area from the Farm of Education, Research and Produtcion of FCAV-UNESP, Jaboticabal Campus, in a completely randomized block design, with four replications. Treatments consisted of different types of black oats and pearl millet straw management before soybean seeding (without management, obtained by machine cut, desiccated using glyphosate desiccation and with paraquat) and different periods of straw deposition (0, 15, 30 e 60 days before soybean seeding). The weed population and the characteristics of soybean growth and production were evaluated. The deposition of black oats and pearl millet straw provided reductions in weed density and dry mass, and this effect was more effective when the deposition occurred until 15 days prior to soybean seeding. The suppressor effect of black oats straw was more pronounced than that of pearl millet straw, regardless of the drying method, although the millet had a greater dry matter production. No significant differences were found between the drying methods and the straw effectiveness.
  • Authors:
    • Robles, A. B.
    • Garcia, P. A.
    • Altieri, M. A.
    • Ramos, M. E.
  • Source: Journal of Sustainable Agriculture
  • Volume: 35
  • Issue: 7
  • Year: 2011
  • Summary: We evaluate the forage yield and quality, species composition, and carrying capacity of oats and oat-vetch as fodder-cover crops, grown in almond orchards, under mineral or organic fertilizer and three harvesting regimes ("grazing," "hay," and "grain plus straw"). Also, we show preliminary results of almond yield. Differences in yield due to mineral and organic fertilization were only 9%. The carrying capacity was similar for all treatments. The almond yield was greater when the cover crop was removed early as "grazing." Therefore, oats and oat-vetch could be used as cover crops in almond orchards if removed early by livestock grazing.
  • Authors:
    • Zwirtes, A. L.
    • Baronio, C. A.
    • Rigon, J. P. G.
    • Capuani, S.
  • Source: Revista Verde de Agroecologia e Desenvolvimento Sustentavel
  • Volume: 6
  • Issue: 4
  • Year: 2011
  • Summary: The objective of this study was to evaluate the influences of different plants covering on the agronomic characteristics of beans. The experiment was conducted on Red Latossol alumino-ferric, using randomized block design with four repetitions, being the data submitted to the Tukey test and compared by orthogonal contrasts. Treatments consisted of covering plants, carrying its growth in single system, as well as some consortia, across species: Flaxseed ( Linum usitatissimum); Ryegrass ( Lollium multiflorum), Black and White Oats ( Avena stringosa and A. sativa), vetch ( Vicia sativa), wild radish ( Raphanus sativus) and Triticale ( Triticum secale). The agronomic attributes evaluated of bean were: the 1000 seeds per pod, length and number of pods per plant and plot, plant population and yield. Direct and different influence was verified on the components yield of beans, vegetables and the number of the larger relationship with productivity beans. Among the plants used predecessor, the Vetch and Turnip provided larger productive increment, differently of Ryegrass, as well as flaxseed, which resulted in lower yields beans.