• Authors:
    • Gunter, C. C.
  • Source: ISHS Acta Horticulturae IV International Symposium on Ecologically Sound Fertilization Strategies for Field Vegetable Production
  • Issue: 852
  • Year: 2010
  • Summary: Efforts are being made to reduce the negative impacts that high intensity vegetable production can have on the soil. Soil nutrient removal and soil compaction due to heavy equipment can lead to long lasting problems in future production cycles. Producers are beginning to look at the beneficial effects that cover crops can have on soil tilth and fertility. Three rotational cover crop areas were established on the Southwest Purdue Agriculture Center in Vincennes, Indiana and each area was divided into four cover crop plots, no-till wheat, clover, oilseed radish and a bare ground control. Processing tomatoes, sweetcorn and snap beans were planted across the four cover crop plots within each rotational area. Two varieties of each type of vegetable were grown in each cover crop. Processing tomatoes had significantly less yield in the no-till wheat cover crop compared to the other three cover crops. There were also a higher proportion of green and turning fruit in that treatment. Snap beans showed significantly higher yields when grown in the oilseed radish and clover cover crops. Sweetcorn had significantly shorter ear length when grown in the no-till wheat cover crop. Varietal differences exist with cover crops, suggesting that some varieties perform better than others when using a specific cover crop.
  • Authors:
    • Melander, B.
    • Munkholm, L. J.
    • Hansen, E. M.
    • Olesen, J. E.
  • Source: Soil & Tillage Research
  • Volume: 109
  • Issue: 1
  • Year: 2010
  • Summary: Finding ways of reducing nitrate leaching in Northern Europe has become an extremely important task, especially under the projected climate changes that are expected to exacerbate the problem. To this end, two field experiments were established under temperate coastal climate conditions to evaluate the effect of tillage, straw retainment and cropping sequences, including cover crops, on nitrate leaching. The experiments were established in autumn 2002 on a loamy sand with 92 g clay kg(-1) and a sandy loam with 147 g clay kg(-1). The tillage treatments were stubble cultivation to 8-10 cm or 3-4 cm, direct drilling, or ploughing to 20 cm. The hypothesis was that (i) decreasing soil tillage intensity would decrease leaching compared to ploughing, (ii) leaving straw in the field would decrease leaching compared to removing straw, and (iii) a spring/winter crop rotation with catch crops would be more efficient in reducing nitrate leaching than a winter crop rotation. Overall, we were not able to confirm the three hypotheses. The effect of soil tillage on leaching might be blurred because the studied crop rotations had a high proportion of winter crops and because catch crops were grown whenever the alternative would have been bare soil in autumn and winter. The spring/winter crop rotation with catch crops was not found to be more efficient in reducing nitrate leaching than the winter crop rotation. In contrast, in a single year the winter crop rotation showed significantly lower leaching than the spring/winter crop rotations, probably due to the spring/winter crop rotation including peas, which may be considered a high-risk crop. Our study highlights that management practices that improve biomass production throughout the year are crucial in order to tighten the nitrogen cycle and thereby reduce nitrate leaching. (C) 2010 Elsevier B.V. All rights reserved.
  • Authors:
    • Frederick, J. R.
    • Fortnum, B. A.
    • Bauer, P. J.
  • Source: Agronomy Journal
  • Volume: 102
  • Issue: 4
  • Year: 2010
  • Summary: Longer rain-free periods are predicted to occur more often in the southeastern United States as a result of global climate change. This nonirrigated field study was conducted from 1997 through 2002, which coincided with the 1998-2002 drought that affected most of the United States. The objective was to determine the effect of rotation and tillage on cotton (Gossypium hirsutum L.) productivity. Treatments in the study were rotation [cotton rotated with corn (Zea mays L.), cotton planted after a rye (Secale cereale L.) winter cover crop, and continuous cotton with no cover crop] and tillage system (conventional tillage and conservation tillage). Two levels of aldicarb [2-methyl-2-(methylthio)propanal O-{(methylamino)carbonyl}oxime] (0 and 1.18 kg a.i. ha(-1)) were also included because of known soil management effects on thrips (Frankliniella sp.) and root-knot nematodes (Meloidigyne incognita). The predominant soil types were Bonneau loamy sand (loamy, siliceous, subactive, thermic Arenic Paleudult) and Norfolk loamy sand (fine-loamy, kaolinitic, thermic Typic Kandiudult). Rotation did not affect cotton yield in any year. Tillage did not affect cotton yield in 1997. Conservation tillage resulted in an average 25% yield increase in cotton lint yield over conventional tillage during the 5-yr drought. Tillage and aldicarb affected both thrips and root-knot nematodes, but lack of interaction among these factors for lint yield suggested that management of these pests was not the predominant cause for the cotton yield increase with conservation tillage. Conservation tillage for cotton production could be an important method to help mitigate the effects of climate change in the region if change occurs as predicted.
  • Authors:
    • Benoit, P.
  • Source: FOURRAGES
  • Issue: 202
  • Year: 2010
  • Summary: There are many studies proving the favourable effects of grass covers on the workings of the soil and on the polluting potential of the pesticides. They are described here, but uncertainties still remain. A synthesis of the studies in progress shows that grass covers (either in the crop rotation or as particular strips) first decreases the amounts of pesticides to be used per hectare, and moreover reduces the transfer of substances to places outside the farmed area by delaying the start of run-offs and by improving the infiltration and retention of the contaminating substances. The risk of pollution of the underground waters may also be diminished, according to the efficiency of the retention and bio-degradation processes, which occur mainly in the upper horizons. The questions regarding the fate of the stabilized residues, the evolution of the degradation processes, and the possible uptake of the pesticides by the grass vegetation are as yet but little studied.
  • Authors:
    • Hansson, M.
    • Adler, A.
    • Bergkvist, G.
    • Weih, M.
  • Source: Weed Research
  • Volume: 50
  • Issue: 5
  • Year: 2010
  • Summary: P>Elytrigia repens (syn. Elymus repens) is a perennial grass weed that is controlled by herbicides or by tillage. Both methods are expensive and may have negative effects on the environment. Therefore, alternative methods of weed control, such as using competition from under-sown perennial forage crops, are of interest. Red fescue can be sown together with winter wheat as a non-flowering understorey crop that has its main growth during late summer and autumn. This study quantified the effect of red fescue and E. repens on wheat biomass and tested the hypothesis that under-sown red fescue reduces the amount of E. repens rhizomes and thus the need for herbicides or tillage. Two field experiments in which winter wheat, red fescue and E. repens were grown in all possible combinations were conducted between 2003 and 2005. Elytrigia repens reduced wheat biomass by 8%, while red fescue had no significant effect on wheat biomass. Red fescue reduced late autumn biomass of E. repens rhizomes by 40%. The results suggest that red fescue sown with winter wheat can reduce propagation of E. repens during summer and autumn, without a significant reduction in wheat biomass.
  • Authors:
    • McSorley, R.
    • Bhan, M.
    • Chase, C. A.
  • Source: Nematropica
  • Volume: 40
  • Issue: 1
  • Year: 2010
  • Summary: Two field experiments were initiated in summer 2006 in north-central Florida to compare the effects of integrating cover crops, living mulches, and intercropping on plant-parasitic nematode populations, as well as the effect of fall and spring vegetables on the multiplication rate of root-knot nematodes. Treatments consisted of seven organic cropping systems that included a summer cover crop followed by fall and spring vegetables. The summer cover crop included: pearl millet (Pennisetum glaucum), sorghum sudangrass (Sorghum bicolor x S. bicolor var. sudanense), sunn hemp (Crotalaria juncea), velvetbean (Mucuna pruriens var. pruriens), weedy fallow, mixture of pearl millet-sunn hemp, and mixture of sorghum sudangrass-velvet bean. One experiment utilized fall yellow squash (Cucurbita pepo) and spring bell pepper (Capsicum annuum) as vegetable crops, and fall broccoli (Brassica oleracea) and spring sweet corn (Zea mays) were used in the other experiment. Nematode populations were monitored at the end of the cover crop and vegetable seasons. Summer cover crops of sorghum-sudangrass or pearl millet increased root-knot nematode (Meloidogyne incognita) population levels in some instances while sunn hemp suppressed it in the broccoli-sweet corn experiment. The multiplication rate of root-knot nematodes was lowest when broccoli was planted in the cropping system. Systems with sorghum-sudangrass (alone or in mixture) increased population densities of ring (Mesocriconema spp.) and lesion (Pratylenchus spp.) nematodes, and occasionally increased stubby-root nematodes (Paratrichodorus spp.). Cover crops that increased nematode numbers when planted alone usually gave the same result when planted in mixtures with another cover crop. Other cropping systems failed to suppress plant-parasitic nematodes but maintained low densities similar to weedy fallow.
  • Authors:
    • Kaul, H. -P
    • Loiskandl, W.
    • Himmelbauer, M.
    • Bodner, G.
  • Source: Agronomy for Sustainable Development
  • Volume: 30
  • Issue: 2
  • Year: 2010
  • Summary: Cover crops are plants that are integrated in the crop rotation between two cash crops. The main objectives of cover cropping are organic matter input, mitigation of nitrate leaching and reduction of soil erosion. These benefits will only be achieved efficiently if the selected cover crop species are adapted to local environmental conditions and appropriate for the defined agro-ecological target. Therefore, a main limitation in cover cropping is the lack of a comprehensive species description. An improved cover crop characterization could be achieved with quantitative parameters derived from growth functions. Here, we show the use of this approach to assess plant traits relevant for erosion control by cover cropping. An experiment with four cover crop species (phacelia, vetch, rye and mustard) was performed over two years at a semi-arid site in Eastern Austria. Canopy cover was measured four times over the vegetation period. Root length density measurements were made to 40 cm soil depth before winter. Canopy dynamics were characterized by parameters from the asymptotic Gompertz function and from an extended logistic model that includes a parameter for decay after maximum coverage. Our results show that vetch had the lowest early vigor after dry conditions at sowing, with +45% longer time to attain maximum growth rate (parameter t(max)) than the other species. Drought during the later autumn growing period led to the highest reduction in maximum canopy cover (parameter y(max)) for phacelia (-41%). The rooting pattern was assessed by parameters from the exponential distribution function of Gerwitz and Page. The most intense rooting near the soil surface (parameter L(0)) was found for phacelia (9.7 cm cm(-3)). Vetch had the lowest L(0) (4.6 cm cm(-3)) but highest root allocation to deeper soil layers. Mustard combined high average values in y(max) (76%) and L(0) (6.3 cm cm(-3)) with a stable growth over both years. The potential strengths of phacelia and vetch were more dependent on the particular year. Rye showed a stably high L(0) (8.6 cm cm(-3)), but had only a low average value of y(max) (55.1%). The quantitative parameter sets we derived for plant traits required for erosion control improved cover crop comparison and analysis of their local adaptation. Based on this extended species description our approach allows a better evaluation of cover crops and can be used for the optimization of management and decision support.
  • Authors:
    • Catania, C. D.
    • Parera, C. A.
    • Monte, R. F. del
    • Uliarte, E. M.
    • Monte, M. S. A. de del
  • Source: Bulletin de l'OIV
  • Volume: 82
  • Issue: 938/939/940
  • Year: 2009
  • Summary: The aim of this work was to assess the effects of a cover crop, on the vegetative growth and production of grapevine. Three permanent cover crops: Agropyron elongatum (Host) Beauv. (tall wheatgrass), Trifolium pratense L. (red clover), the association Secale cereale L. - Bromus catharticus Vahl (cereal rye-rescuegrass) and two annual species: Sorghum sudanense (Piper) Stapf (Sudangrass), X Triticosecale Wittmack (triticosecale) were compared, with respect to no till soil management by herbicides application. The study was developed in a cv. Malbec vineyard with surface irrigation and in a vertical shoot positioning trellis system, located in Mendoza, Argentina. Parameters related to vegetative expression, grape production and its oenological potential were determined. Permanent covers of red clover, tall wheatgrass and the mixture cereal rye-rescuegrass restricted grapevine vigour compared to open soil (control), diminishing shoot growth, size of leaves and pruning weight. A lower yield production was also observed, with smaller clusters and a reduction of clusters per vine; with greater amounts of total anthocyanins and polyphenols. Permanent cover crops decreased titratable acidity and free amino nitrogen in the must; which slightly delayed alcoholic fermentation, although without stuck fermentation. In the wine tasting evaluation, wines coming from the three treatments with permanent cover crops were preferred by tasters and they appear with greater varietals authenticity. The introduction of a permanent cover crop reduced vegetative growth and yields of the grapevine, modifying the balance vigour/production of the vineyard, and therefore the composition of grapes and wine, without the need to conduct specific cultural operations.
  • Authors:
    • Veiga, M.
    • Pelissari, A.
    • Moraes, A.
    • Balbinot Junior, A.
    • Dieckow, J.
    • Nesi, C.
  • Source: Revista de Ciencias Agroveterinarias
  • Volume: 8
  • Issue: 1
  • Year: 2009
  • Summary: Animal trampling is one of the major causes of soil compaction in areas subjected to integrated crop-livestock system. The objective of this work was to evaluate the effect of winter annual pasture grazing, in crop-livestock system, and other winter soil uses on soil compaction. The experiment was carried out from May 2006 to February 2007 at three sites of the North Plateau of Santa Catarina State, Brazil. Five winter treatments were investigated on each site: (1) intercropping with black oat+ryegrass+vetch+arrow leaf clover without grazing and nitrogen fertilization (multicropping cover); (2) the same intercropping, with grazing and 100 kg ha -1 of nitrogen, (grazing with N); (3) the same intercropping, with grazing and without nitrogen fertilization (grazing without N); (4) oil seed radish, without grazing and nitrogen fertilization (oil seed radish); and (5) natural vegetation, without grazing and nitrogen fertilization (fallow). Undisturbed cores were collected from the layers 2 to 7 cm and 10 to 15 cm, at three times: experiments implantation (May 2006), at maize sowing in succession of winter soil use (November 2006) and close to maize physiological maturity (February 2007). Soil total porosity, bulk density and soil resistance to penetration were evaluated in these samples. According to the environmental and management conditions, as well as the time of experimentation, the livestock presence in winter pastures, winter cover crops and fallow did not affect the variables related to soil compaction.
  • Authors:
    • Dieckow, J.
    • Pelissari, A.
    • Veiga, M.
    • Moraes, A.
    • Balbinot Junior, A.
    • Carvalho, P.
  • Source: Ciencia Rural
  • Volume: 39
  • Issue: 8
  • Year: 2009
  • Summary: Soil use and management during the winter can affect soil physical properties, reminiscent straw and performance of the crop cultivated in succession. The effect of winter soil use on these variables, cultivating black bean ( Phaseolus vulgaris) under no tillage system in summer, was investigated. Three experiments were carried out in the North Plateau of Santa Catarina State, Brazil, during 2007/08 crop season, with five strategies of soil use during the winter: (1) multicropping with black oat+ryegrass+commom vetch+arrow leaf clover ( Trifolium vesiculosum) without grazing and N application (multicropping cover); (2) the same multicropping, with grazing and 100 kg N ha -1 application (pasture with N); (3) the same multicropping, with grazing and without N application (pasture without N); (4) oil seed radish, without grazing and N application (oil seed radish); and (5) natural vegetation, without grazing and N application (fallow). The highest straw dry mass was verified in multicropping cover, but the strategies of winter soil use did not affect significantly the soil bulk density and macroporosity. The soil use with winter annual pasture in crop-livestock system, cover crops and fallow did not affect the black bean performance in succession, under no tillage system.