• Authors:
    • Arshad, M.
    • Soon, Y.
  • Source: Canadian Journal of Soil Science
  • Volume: 84
  • Issue: 4
  • Year: 2004
  • Summary: A field study was conducted to determine the effects and interactions of crop sequence, tillage and residue management on labile N pools and their availability because such information is sparse. Experimental treatments were no-till (NT) vs. conventional tillage (CT), and removal vs. retention of straw, imposed on a barley ( Hordeum vulgare L.)-canola ( Brassica rapa L.)-field pea ( Pisum sativum L.) rotation. 15N-labelling was used to quantify N uptake from straw, below-ground N (BGN), and fertilizer N. Straw retention increased soil microbial biomass N (MBN) in 2 of 3 yr at the four-leaf growth stage of barley, consistent with observed decreases in extractable soil inorganic N at seeding. However, crop yield and N uptake at maturity were not different between straw treatments. No tillage increased soil MBN, crop yield and N uptake compared to CT, but had no effect on extractable soil inorganic N. The greater availability of N under NT was probably related to soil moisture conservation. Tillage effects on soil and plant N were mostly independent of straw treatment. Straw and tillage treatments did not influence the uptake of N from its various sources. However, barley following pea (legume/non-legume sequence) derived a greater proportion of its N from BGN (13 to 23% or 9 to 23 kg N ha -1) than canola following barley (non-legumes) (6 to 16% or 3 to 9 kg N ha -1). Fertilizer N constituted 8 to 11% of barley N uptake and 23 to 32% of canola N uptake. Straw N contributed only 1 to 3% of plant N uptake. This study showed the dominant influence of tillage on N availability, and of the preceding crop or cropping sequence on N uptake partitioning among available N sources.
  • Authors:
    • Stachecki, S.
    • Jakubiak, S.
  • Source: Plant Toxicology
  • Volume: 25
  • Issue: 1
  • Year: 2004
  • Summary: The residual effects of clomazone, metazachlor and their mixtures on re-sown crops were studied in field experiments carried out during 1997-2000 on leached brown soil in Poland. Two-factor experiments were established in 4 replications for the following crops. The treatments consisted of herbicides and the method of pre-sowing soil tillage (pre-sowing ploughing or reduced soil tillage). In autumn, after sowing of winter oilseed rape, Command 480 EC (clomazone) was applied to soil at 0.2 litre/ha (96 g a.i./ha) alone and as a mixture with Butisan 400 SC (metazachlor) at 2.5 litre/ha (1000 g a.i./ha). Butisan 400 SC was applied twice at 1.5 litre/ha (600 g a.i./ha) at the cotyledon stage of weeds. The following crops were re-sown in spring: spring barley, spring wheat, oat, pea and sugarbeet. The frosty winter enhanced the residual effects of the herbicides on the re-sown crops, injuries were much more visible, and the yields of the re-sown crops were decreased. Generally, reduced tillage presown harrowing with disc harrowing did not affect the phytotoxicity of the herbicides. Oat was as susceptible to the herbicides as the other spring cereals.
  • Authors:
    • Andren, O.
    • Katterer, T.
    • Persson, J.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 70
  • Issue: 2
  • Year: 2004
  • Summary: Land use in general and particularly agricultural practices can significantly influence soil carbon storage. In this paper, we investigate the long-term effects of management changes on soil carbon stock dynamics on a Swedish farm where C concentrations were measured in 1956 at 124 points in a regular grid. The soil was re-sampled at 65 points in 1984 and at all grid points in 2001. Before 1956 most of the fodder for dairy cattle was produced on the farm and crop rotations were dominated by perennial grass leys and spring cereals with manure addition. In 1956 all animals were sold; crop rotations were thereafter dominated by wheat, barley and rapeseed. Spatial variation in topsoil C concentration decreased significantly between 1956 and 2001. C stocks declined in fields with initially large C stocks but did not change significantly in fields with moderate C stocks. In the latter fields, soil C concentrations declined from 1956 to 1984, but increased slightly thereafter according to both measurements and simulations. Thus, the decline in C input due to the altered management in 1956 was partly compensated for by increasing crop yields and management changes, resulting in increased C input during the last 20 years. A soil carbon balance model (ICBM) was used to describe carbon dynamics during 45 years. Yield records were transformed to soil carbon input using allometric functions. Topsoil C concentrations ranging between 1.8 and 2.4% (depending on individual field properties) seemed to be in dynamic equilibrium with C input under recent farming and climatic conditions. Subsoil C concentrations seemed to be unaffected by the management changes.
  • Authors:
    • Brandsater, L. O.
    • Løes, A. K.
    • Riley, H.
  • Source: European weed research society. Proceedings of the 6th EWRS workshop on physical and cultural weed control, Lillehammer, Norway, 8-10 March, 2004
  • Year: 2004
  • Summary: Due to official regulations, Norwegian agriculture is divided into cereal cropping areas with very little animal husbandry, and areas with high livestock density in the coastal and mountain regions. Stockless organic farming requires a good management of green manure crops. This paper presents crop rotations designed for organic farming with low livestock density, combining weed control and nutrient supply. Rotation 1 consists of green manure, followed by barley with subcropped legume, oats and peas, green manure or winter rye, rye, ryegrass-clover, and late planted rapeseed. Rotation 1 is designed for a full-time farmer with good access to cultivated land, where 66% of the land is used for cereals and rapeseed, and 34% for green manure. Rotation 2 consists of cereal or lettuce, followed by 4-5 rotations of ley, then potatoes, green manure, cabbage with early mulch, and carrots with late mulch. Rotation 2 is designed for a part-time farmer with less farmland who wants to keep the land in shape and produce some cash crops, but cannot manage to cultivate all the farmland intensively. Forty-four percent of the land is then used for vegetables and herbs, and 56% to produce mulch or green manure crops. Green manure and mulch leys must be cut regularly to control perennial weeds.
  • Authors:
    • Riley, H.
    • Løes, A. K.
    • Brandsæter, L. O.
  • Source: European weed research society. Proceedings of the 6th EWRS workshop on physical and cultural weed control, Lillehammer, Norway, 8-10 March, 2004
  • Year: 2004
  • Summary: Due to official regulations, Norwegian agriculture is divided into cereal cropping areas with very little animal husbandry, and areas with high livestock density in the coastal and mountain regions. Stockless organic farming requires a good management of green manure crops. This paper presents crop rotations designed for organic farming with low livestock density, combining weed control and nutrient supply. Rotation 1 consists of green manure, followed by barley with subcropped legume, oats and peas, green manure or winter rye, rye, ryegrass-clover, and late planted rapeseed. Rotation 1 is designed for a full-time farmer with good access to cultivated land, where 66% of the land is used for cereals and rapeseed, and 34% for green manure. Rotation 2 consists of cereal or lettuce, followed by 4-5 rotations of ley, then potatoes, green manure, cabbage with early mulch, and carrots with late mulch. Rotation 2 is designed for a part-time farmer with less farmland who wants to keep the land in shape and produce some cash crops, but cannot manage to cultivate all the farmland intensively. Forty-four percent of the land is then used for vegetables and herbs, and 56% to produce mulch or green manure crops. Green manure and mulch leys must be cut regularly to control perennial weeds.
  • Authors:
    • Harker, K. N.
    • Newman, J. C.
    • O'Donovan, J. T.
    • Clayton, G. W.
  • Source: Weed Technology
  • Volume: 18
  • Issue: 3
  • Year: 2004
  • Summary: Glyphosate-resistant canola was seeded at Vegreville, Alberta, in 1997 and 1999 and barley in rotation with the canola in 1998 at three seeding rates. The effects, at each crop seeding rate, of variable glyphosate (canola) and tralkoxydim plus bromoxynil plus MCPA (barley) rates on crop yield, net economic return and seed production by wild oat, wild mustard, and wild buckwheat, and the amount of weed seed in the soil seed bank was determined. Crop seeding rate influenced the response of canola and barley yield and weed seed production to herbicide rate. At the lowest crop seeding rates, yield responses tended to be parabolic with yields increasing up to one-half and three-quarters of the recommended herbicide rates and trends toward reduced yields at the full rates. This response was not evident at the higher crop seeding rates, where, in most cases the yield reached a maximum between one-half and the full recommended rate. The effects of the herbicides on weed seed production, especially at the lowest rate, were often superior at the higher crop seeding rates. The results indicate that seeding canola and barley at relatively high rates may reduce risk associated with lower crop yields and increased weed seed production at lower than recommended herbicide rates. However, the current cost of herbicide-resistant canola seed may preclude the adoption of this integrated weed management practice by growers.
  • Authors:
    • Philip, H.
    • Woods, S.
    • Weiss, R. M.
    • Olfert, O.
    • Dosdall, L.
  • Source: The Canadian Entomologist
  • Volume: 136
  • Issue: 2
  • Year: 2004
  • Summary: Cereal leaf beetle, Oulema melanopus L., is an invasive pest insect of small grain cereal crops, particularly oat, wheat, and barley. The first report of cereal leaf beetle populations in North America came from Michigan in 1962. Surveys indicate that populations have become established throughout eastern North America from Ontario to Alabama and in northwestern North America from Utah to southern British Columbia. The establishment of O. melanopus in western North America has raised concern that its presence is a potential risk to the Canadian cereal industry, especially in the prairie ecozone of western Canada, where up to 10 million hectares of cereal crops are grown annually. Field surveys to date have indicated that O. melanopus has not yet become established in this region. A CLIMEX(TM)model for O. melanopus in North America was developed, based on climate and ecological parameters, and validated with actual distribution records. The actual distribution of O. melanopus in eastern North America matched the predicted distribution well. The model predicts that, once introduced, O. melanopus would readily survive in the cereal-growing areas of western Canada and present a significant risk to cereal production. The potential for establishment of O. melanopus in the prairie ecozone of western Canada substantiates the efforts by regulatory agencies to prevent accidental introduction of this pest species.
  • Authors:
    • Shofman, L. I.
  • Source: Kormoproizvodstvo
  • Issue: 10
  • Year: 2004
  • Summary: Ways of increasing the productivity of 1 ha of arable land under fodder crops in the central zone of Belarus are discussed including the use of sequential cropping. Investigations were conducted to determine productivity and quality of various fodder mixtures at different harvest dates of cover crops, as well as compare the effectiveness of use of land under monoculture of fodder barley, sowing dates, soil cultivation methods, and nitrogen fertilizer doses used in oilseed radish and rape sown after barley harvest. Field trials were conducted with Pukhovchanka winter rye, Belotserkovskaya spring vetch, Lutch annual ryegrass, Erbgraf oat, Nemiga spring triticale, Syabra barley, Prygazhunya oiseed radish and Smak spring rape. Data are tabulated on dry matter content and protein yield obtained from various fodder mixtures used for oversowing in winter rye during 1995-98. Data are included on productivity of crop mixtures used for oversowing during 1996-98. The importance of choosing the optimal sowing date for increase of fodder yield using oilseed rape as an additional fodder crop after harvesting the main crop, i.e. barley, and the optimal soil cultivation method for growing of rape after barley is outlined. Data are tabulated on the effect of sowing dates, soil cultivation method and nitrogen doses on yield of oilseed radish and rape grown after barley. Data are included on qualitative parameters of green fodders produced in the multiple cropping systems. Data are tabulated on efficiency of energy use in intensive cropping systems in fodder crop monocultures.
  • Authors:
    • Clayton, G. W.
    • Harker, K. N.
    • Soon, Y. K.
  • Source: Soil Science Society of America Journal
  • Volume: 68
  • Issue: 2
  • Year: 2004
  • Summary: We evaluated weed competition effects on the N economy of field pea (Pisum sativum L.) and the subsequent crop to address the paucity of such information. Plots were seeded to pea, canola (Brassica napus L.) and barley (Hordeum vulgare L.) in 1997 and 1998. Weeds, augmented by cross-seeding experimental plots with oat (Avena sativa L.), were removed with herbicides one and four weeks after crop emergence (WAE). The subsequent barley crop received 0 or 6 g N m(-2). Mean percentage of N derived from the atmosphere (%Ndfa) for the 2 yr, estimated by N-15 isotopic dilution, was 81% for the 4-WAE treatment and 51% for the 1-WAE treatment, indicating that a pea plant subjected to greater weed competition derived more of its N from symbiotic fixation. Total N fixed by pea was not affected by the time of weed removal, however, and total N uptake and seed yield were greater with early weed removal due to less competition for soil N. Early weed removal resulted in net N export in pea seeds (because of higher production) while later weed removal resulted in gains of 1.1 to 1.3 g N m(-2). However, time of weed removal during pea cultivation had no effect on the yield or N uptake of the subsequent barley crop. Higher barley yield and N uptake following pea than following barley were mostly the result of greater N availability. Nitrogen fertilization benefited the subsequent barley regardless of preceding crop type.
  • Authors:
    • UK, HGCA
  • Source: HGCA recommended list 2004/05 for cereals and oilseeds
  • Year: 2004
  • Summary: Descriptions are provided for cultivars of cereals (winter, late autumn and spring wheat, winter and spring barley, winter rye, winter triticale, and winter and spring oat) and oilseeds (winter and spring oilseed rape and spring linseed) recommended for cultivation in the UK in 2004/05.