• Authors:
    • Ma, B.
    • Zhao, G.
  • Source: Multifunctional grasslands in a changing world, Volume II: XXI International Grassland Congress and VIII International Rangeland Congress, Hohhot, China, 29 June-5 July 2008
  • Year: 2008
  • Authors:
    • Zieminska-Smyk,M.
  • Source: Annales Universitatis Mariae Curie-Skodowska. Sectio E, Agricultura
  • Volume: 63
  • Issue: 3
  • Year: 2008
  • Summary: The characteristics of weeding in cereals were based on 68 phytosociological releves taken from ploughlands of traditional management. The main crops there were: rye, winter wheat, spring wheat, mixture of oat and barley, oat and triticale. Most of the records were taken from winter wheat (30). Cereal was the main crop of the area in Skierbieszowki Landscape Park. 26 samples were taken from spring cereals and 42 samples from winter cereal. Segetal weeds communities of the winter cereals were richer than spring cereals when the number of species is considered, which is shown with an average number of weed species in one single sample: 20.3 species in winter cereals and 17.7 species in spring cereals. Weed coverage varied from 20% to 70% but only occasionally reached 70%. Cereals fields were not very weeded because of good fertilization and crop protection chemicals. Most of the weeds in spring and winter cereals were short-lived rather than perennial, which can be a result of progress rhythm in arable crops. Spring cereals were less weeded than winter cereals. It can be noticed by covering coefficient which were 7.500 in spring cereals and 9.600 in winter cereals.
  • Authors:
    • Fabian, E.
    • Pegoraro, R.
    • Bertol, I.
    • Zoldan Junior, W.
    • Zavaschi, E.
    • Vazquez, E.
  • Source: REVISTA BRASILEIRA DE CIENCIA DO SOLO
  • Volume: 32
  • Issue: 1
  • Year: 2008
  • Summary: Surface soil roughness is affected by many factors, such as the residual effect of the soil management, tillage and rainfall erosivity and, together with the soil cover of crop residues, influences water erosion. The objective of this study was to determine the effects of a chiselling operation, together with rainfall erosivity, on soil surface roughness, from June 2005 to March 2006, in an aluminic Typical Hapludox, under the following soil management systems: bare soil under conventional tillage (BCT), cultivated soil under conventional tillage (CCT), no-tillage in a never-tilled soil with burnt plant residues (BNT), and traditional no-tillage (TNT). The crop sequence in the treatments CCT, BNT and TNT was black oat, soyabean, common vetch, maize, black oat, common bean, fodder radish, soyabean, common vetch, maize and black oat. Five simulated rain tests were applied, with a constant intensity of 64 mm h -1 and durations of 20, 30, 40, 50, and 60 min each. Natural rains during the experimental period accounted for 57 mm, between the 2nd and 3rd rainfall test; 21 mm, between the 3rd and 4th test; and, 30 mm, between the 4th and 5th test. The surface roughness was determined immediately before and immediately after the chiseling tillage, and immediately after each test of rain simulation. The original and linear soil surface roughness was not influenced by the management, unlike random roughness, at the end of a six-month fallow period. The original, linear and random roughness in different soil management systems was affected by a six-month fallow period, when the soil was subjected to chiselling. Random roughness was less influenced by soil slope than by tillage marks, which decreased with the increasing rainfall erosivity. The coefficient of decay of this kind of soil roughness was similar in the studied soil management systems under no tillage and conventional tillage.
  • Authors:
    • Pedersen, J. B.
  • Source: Oversigt over Landsfors<o>gene. Fors<o>g og unders<o>gelser i de land<o>konomiske foreninger, 2008
  • Year: 2008
  • Summary: Following a general account of the weather, land use, application of fertilizers and pest and disease control products, and an overview of the crops grown and their yields, most of the review is devoted to reports on individual crops. These were winter barley, winter rye, triticale, winter wheat, spring barley, oats, spring wheat, peas, grasses, spinach, rape, potatoes, sugarbeet and maize. Other sections cover alternative crops (for bioenergy production), manuring and fertilizers, cultural methods, organic methods, advisory work on plant breeding, tables of approved species and varieties of crop plants, lists of relevant organizations, a list of authors of the sections, and a comprehensive subject index.
  • Authors:
    • Basnyat, P.
    • Huber, D.
    • Fernandez, M. R.
    • Zentner, R. P.
  • Source: Soil & Tillage Research
  • Volume: 100
  • Issue: 1-2
  • Year: 2008
  • Summary: Fusarium head blight (FHB) is an important disease which has been causing damage to wheat and barley crops in western Canada. Because crop residues are an important source of inoculum, it is important to know the ability of Fusarium spp. to colonize and survive in different residue types, and how their populations might be affected by agronomic practices. Sampling of residue types on producers' fields for quantification of Fusarium and other fungi was conducted in 2000-2001 in eastern Saskatchewan. Fusarium spp. were isolated from most fields, whereas their mean percentage isolation (MPI) was over 50% for cereal and pulse residues, and under 30% for oilseed residues. The most common Fusarium, F. avenaceum, had a higher MPI in pulse and flax (45-48%) than in cereal or canola (10-22%) residues. This was followed by F. equiseti, F. acuminatum, F. graminearum, F. culmorum and F. poae which were isolated from all, or most, residue types. Factors affecting Fusarium abundance in residues included the current crop, cropping history, and tillage system. In cereal residues, the MPI of F. avenaceum was higher when the current crop was another cereal (24%) versus a noncereal (4-8%). When the current crop was another cereal, the lowest MPI of F. avenaceum and F. culmorum occurred when the field had been in summerfallow (SF) two years previous (F. avenaceum: 17% for SF, 28% for a crop; F. culmorum: 1% for SF, 4% for a crop); in contrast, F. equiseti and Cochliobolus sativus were most common in residues of cereal crops preceded by SF (F. equiseti: 16% for SF, 10% for a crop; C. sativus: 22% for SF, 13% for a crop). The MPI of F graminearum was higher when the crop two years previous was an oilseed (7%) versus a cereal (4%). In regards to tillage effects, when the current crop was a cereal, the MPI of F. avenaceum was higher under minimum (MT) and zero tillage (ZT) (22-37%) than conventional tillage (CT) (15%), that of F. graminearum was lowest under ZT (3% for ZT, 7-11% for CT-MT), whereas that of C. sativus was highest under CT (27% for CT, 6-11% for MT-ZT). Under ZT, previous glyphosate applications were correlated positively with F. avenaceum and negatively with F. equiseti and C. sativus. These observations generally agreed with results from previous FHB and root rot studies of wheat and barley in the same region. Percentage isolation of F avenaceum from noncereal and of F. graminearum from cereal residues were positively correlated with FHB severity and percentage Fusarium-damaged kernels of barley and wheat caused by the same fungi. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.
  • Authors:
    • Brenzil, C. A.
    • Hall, L. M.
    • Thomas, A. G.
    • Leeson,J. Y.
    • Beckie, H. J.
  • Source: Weed Technology
  • Volume: 22
  • Issue: 4
  • Year: 2008
  • Summary: Agricultural practices, other than herbicide use, can affect the rate of evolution of herbicide resistance in weeds. This study examined associations of farm management practices with the occurrence of herbicide (acetyl-CoA carboxylase or acetolactate synthase inhibitor)-resistant weeds, based upon a multi-year (2001 to 2003) random Survey of 370 fields/growers from the Canadian Prairies. Herbicide-resistant weeds Occurred in one-quarter of the surveyed fields. The primary herbicide-resistant weed species was wild oat, with lesser occurrence of green foxtail, kochia, common chickweed, spiny sowthistle, and redroot pigweed. The risk of weed resistance was greatest in fields with cereal-based rotations and least in fields with forage crops, fallow, or where three or more crop types were grown. Weed resistance risk also was greatest in conservation-tillage systems and particularly low soil disturbance no-tillage, possibly due to greater herbicide use or weed seed bank turnover. Large farms (> 400 ha) had a greater risk of weed resistance than smaller farms, although the reason for this association Was unclear. The results of this study identify cropping system diversity as the foundation of proactive weed resistance management.
  • Authors:
    • Buschiazzo, D. E.
    • Alvarez, R.
    • Bono, A.
    • Cantet, R. J. C.
  • Source: Soil Science Society of America Journal
  • Volume: 72
  • Issue: 4
  • Year: 2008
  • Summary: Tillage systems may affect soil C sequestration, with a potential impact on crop productivity or organic matter mineralization. We evaluated crop yield, C inputs to the soil, and in situ CO 2-C fluxes under no-till and conventional tillage (disc tillage) during the 3- to 6-year period from the installation of an experiment in an Entic Haplustoll of the Semiarid Pampean Region of Argentina to elucidate the mechanisms responsible for possible management-induced soil organic matter changes. Yield and biomass production were greater under no-till than disc tillage for all the crops included in the rotation (oat + hairy vetch ( Vicia villosa ssp. villosa), maize, wheat and oat). This result was attributed to the higher soil water content under no-till. Carbon inputs to the soil averaged 4 Mg C ha -1 year -1 under no-till and 3 Mg C ha -1 year -1 under disc tillage. Soil temperature was similar between tillage systems and CO 2-C emission was approximately 4 Mg C ha -1 year -1, with significant but small differences between treatments (~0.2 Mg C ha -1 year -1). Carbon balance of the soil was nearly equilibrated under no-till; meanwhile, greater C losses as CO 2 than inputs in crop residues were measured under conventional tillage. Organic C in the soil was 5.4 Mg ha -1 higher under no-till than the disc tillage treatment 6 years after initiation of the experiment. Results showed that in our semiarid environment, C sequestration occurred under no-till but not conventional tillage. The sequestration process was attributed to the effect of the tillage system on crop productivity rather than on the mineralization intensity of soil organic pools.
  • Authors:
    • Deng, L.
    • Ren, C. Z.
    • Ma, B. L.
    • Burrows, V.
    • Zhou, J.
    • Hu, Y. G.
    • Guo, L.
    • Wei ,L.
    • Sha, L.
  • Source: Field Crops Research
  • Volume: 103
  • Issue: 3
  • Year: 2007
  • Summary: Increased land degradation and shortage of forage resources for animal production over-winter have accentuated the need for alternative cropping systems in northeast China. While short frost-free period and cool temperatures are major limitations to cereal grain production in the northern regions of China (45degreesN, 122degreesE), crop varieties that are able to produce food and feed in short growing season and tolerant to low temperature may extend the total cropping period. Three hulless oat ( Avena sativa L.) lines, Baiyan 9015, Baiyan 9017 and Baiyan 9044, were bred and tested for 3 years (2004-2006) to determine their suitability for summer seeding in a double cropping system. The new lines were sown both in the spring and summer to provide growers with opportunities to harvest two grain-crops in a year. Averaged across 3 years, Baiyan 9044 produced 2.5 and 1.6 Mg ha -1 yr -1 grain yield when sown in spring and summer, respectively. The new lines seeded in 20th or 21st July and harvested in early October allowed utilization of an average of over 1500 growing degree days (GDDs). For grain yield alone, the net income for two oat crops a year was up to 1390 Chinese yuan (RMB) ha -1, more than that of growing a single oat crop in 3 years, or in most cases, equivalent to monocultured corn ( Zea mays L.) production, the dominant crop in the region. In addition, an average of 5 Mg ha -1 of oat straw was produced as valuable forage fodder for the livestock industry, which was in great demand for over-wintering animals. Furthermore, in the traditional single small grain cereal cropping system, bare ground after harvest leads to severe water and wind erosions. Our results indicate that the new oat lines could be a potential crop for summer seeding, particularly when spring-seeded crops fail due to abiotic (hail, drought, etc.) or biotic (e.g. insects) stresses. The double cropping system provides growers with a potential opportunity to facilitate the farming strategy of food, cash crops and control soil erosion in the region.
  • Authors:
    • Moraes, A.
    • Balbinot Junior, A.
    • Backes, R.
  • Source: PLANTA DANINHA
  • Volume: 25
  • Issue: 3
  • Year: 2007
  • Summary: Straw on the soil significantly reduces weed infestation under no-tillage system. The potential of winter cover crops and their management timing in reducing weed infestation in maize crop were studied in Canoinhas, Santa Catarina, Brazil, in 2003/04 and 2004/05. In the first experiment, 6 winter cover crops were investigated: oilseed radish, black oat [ Avena nuda], rye, ryegrass [ Lolium sp.], intercropped among black oat and common vetch [ Vicia sativa] and among oilseed radish, black oat, rye, ryegrass and common vetch. These cover crops were slashed down at three different times before maize sowing (1, 10 and 25 days). In the second experiment, the potential to reduce weed infestation was investigated in the 6 cover crops previously mentioned, plus the common vetch. The straw of ryegrass and from intercropping among the 5 species used had a high capacity to suppress weed emergence and dry matter production, while oilseed radish straw showed low weed suppression potential. The winter cover crops slashed down next to maize sowing decreased the weed infestation.
  • Authors:
    • Backes, R.
    • Moraes, A.
    • Balbinot Junior, A.
    • Souza, A.
  • Source: Scientia Agraria
  • Volume: 8
  • Issue: 2
  • Year: 2007
  • Summary: A study was undertaken in Canoinhas, Santa Catarina, Brazil, during 2004/05 season to evaluate the effect of cover crop desiccation time in relation to maize sowing on the weed infestation and maize yield. Ryegrass ( Lolium multiflorum) as a single crop and in an intercropping system (rye grass+black oat ( Avena strigosa [ A. nuda])+rye+common vetch ( Vicia sativa)+oilseed radish) were desiccated 5 times at 1, 10 20 and 30 days before maize sowing. Cover crop management near maize sowing decreased the density and mass accumulation of weeds and improved the maize grain yield.