• Authors:
    • Tan, C. S.
    • Reynolds, W. D.
    • Yang, X. M.
    • Drury, C. F.
  • Source: Soil & Tillage Research
  • Volume: 79
  • Issue: 1
  • Year: 2004
  • Summary: The influence of soil and crop management practices on soil aggregation is well documented; however very little information is available on the impact of aggregation on biological processes such as greenhouse gas emissions. Soils (Ap horizon of a Brookston clay loam) were sampled in the spring of 2002 from two treatments in a long-term study (established in 1959). The treatments included continuous corn (Zea mays L.) and the corn phase of a 4-year crop rotation which included corn-oats (Avena sativa L.)-alfalfa (Medicago sativa L.)-alfalfa. The continuous corn (CC) treatment was plowed every fall whereas the rotation corn (RC) treatment was plowed 2 out of the 4 years (in the fall following second year alfalfa and following corn). The objectives were to determine the impact of crop rotation and continuous corn on aggregate size distribution, and the influence of aggregate size on CO2 and N2O production through denitrification. The soil samples were separated into six aggregate size fractions (<0.25, 0.25-0.50, 0.50-1.0, 1.0-2.0, 2.0-4.0, and 4.0-8.0mm diameter) using a dry sieving procedure. Each aggregate size fraction was separated into two subsamples with one subsample left intact and the other ground to <0.15mm (100-mesh sieve). The intact and ground aggregates from each size fraction were incubated anaerobically using the acetylene inhibition technique and carbon dioxide (CO2) and nitrous oxide (N2O) production (denitrification) were determined. Nitrate was added and thus not limiting in the incubations. In both cropping treatments, the 2–4mm aggregate size was the dominant size fraction (~35-45% of the soil by weight) followed by the 1-2mm size fraction (~20-25% of the soil by weight). Crop rotation increased both CO2 and N2O production (denitrification) and the proportion of <2mm diameter aggregates compared to continuous corn. For intact aggregates, CO2 production decreased with increasing aggregate size, while N2O production (denitrification) increased with increasing aggregate size. When the aggregates were ground, CO2 production was independent of the original aggregate size, while N2O production (denitrification) decreased as the size of the original aggregates increased. This study demonstrates that both the size distribution of natural soil aggregates and soil grinding can have substantial impacts on the CO2 and N2O production through denitrification.
  • Authors:
    • Carmo, C.
    • Lhamby, J.
    • Ambrosi, I.
    • Santos, H.
  • Source: Ciencia Rural
  • Volume: 34
  • Issue: 1
  • Year: 2004
  • Summary: Soil tillage and crop rotation and succession systems were assessed in Passo Fundo, Rio Grande do Sul, Brazil, from 1994/95 to 1997/98. Four soil tillage systems, i.e. no-tillage, minimum tillage, conventional tillage using a disc plough, and conventional tillage using a mouldboard plough, and three crop rotation and succession systems, i.e. system I (wheat/soyabean), system II (wheat/soyabean and common vetch [ Vicia sativa]/sorghum or maize) and system III (wheat/soyabean, common vetch/sorghum or maize, and white oats/soyabean), were compared. An experimental design of randomized blocks with split-plots and three replications was used. The main plot was formed by the soil tillage systems, while the split-plots consisted of the crop rotation and succession systems. Two types of analysis were applied to the net return of soil tillage and crop rotation and succession systems: mean-variance and risk analysis. By the mean-variance analysis, no-tillage and minimum tillage, which presented higher net returns, were the best alternatives to be offered to the farmer. By the stochastic dominance analysis, no-tillage and crop rotation with two winters without wheat showed the highest profit and the lowest risk.
  • 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:
    • 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:
    • 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:
    • 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.
  • Authors:
    • Zakharenko, V. A.
  • Source: Zashchita i Karantin Rastenii
  • Issue: 12
  • Year: 2004
  • Summary: Wild oat (Avena fatua) is widely spread in cereals, particularly wheat, barley and oat, in many regions of Russia, causing up to 40% losses of crops, and a decrease of quality of seed material, and food and feed grains. Investigations carried out in the Orlov region, European Russia, revealed significant infestations of agricultural crops, particularly winter and spring wheat, and pea, with wild oat. Data are tabulated on herbicides effective against Poaceae weeds including A. fatua in sugarbeet, sunflower, soyabean, rape, potato and vegetable crops. Strategies for prevention and control of A. fatua are discussed. Data are also tabulated on herbicides showing activity against Poaceae and dicotyledonous weeds, as well as A. sativa in maize, sugarbeet, sunflower, soyabean, rape, potato and vegetable crops.
  • Authors:
    • McRae, F. J.
    • Francis, R. J.
    • Dellow, J. J.
  • Source: Weed control in winter crops 2004
  • Year: 2004
  • Summary: This publication is a guide to chemical weed control in fallows, wheat, barley, oats, cereal rye, triticale, rape, safflower, lentil, linseed, lupin, chickpea, faba bean and field pea in New South Wales, Australia.
  • Authors:
    • Grzebisz, W.
  • Source: Journal of Elementology
  • Volume: 9
  • Issue: 4(Supplement)
  • Year: 2004
  • Summary: Natural availability of potassium in Polish soils and its uptake by various crops are examined on a regional basis. Potassium requirements of the main agricultural crops (wheat, rye, barley, oats, triticale, maize, potato, sugar beet, oilseed rape and grass for haymaking) are considered in view of the element's content both in farmyard manure and in chemical fertilisers; their use and the overall balance of potassium available for plant uptake in individual regions are shown in maps.