• Authors:
    • Beznosikov, V. A.
  • Source: Agrokhimiya
  • Issue: 5
  • Year: 2001
  • Summary: Studies have been made since 1985 on ways of improving the effectiveness of N fertilizers on non-gleyed and weakly gleyed podzolic soils, either undrained or with tile drains, in the Komi Republic (NE part of the Russian continental plateau). On this basis recommendations are made on land improvement by drainage, and on the optimum doses, application times and ways of covering the N fertilizers. These measures will improve crop productivity for annual ryegrass, potatoes, and mixtures (peas/oats, ryegrass/peas, ryegrass/barley, ryegrass/rape).
  • Authors:
    • Mielniczuk, J.
    • Martin-Neto, L.
    • Bayer, C.
    • Ceretta, C. A.
  • Source: Soil & Tillage Research
  • Volume: 53
  • Issue: 2
  • Year: 2000
  • Summary: In weathered tropical and subtropical soils organic matter is crucial for soil productivity and its quantity depends heavily on soil management systems. This study evaluated the effect of no-till cropping systems on organic matter content and quality in a sandy clay loam Acrisol soil (Paleudult in US taxonomy) from Southern Brazil. Ten cropping systems with varying additions of C and N were conducted for 12 years (from 1983 to 1994), The addition of crop residues increased total organic carbon (TOC) and total nitrogen (TN) in the soil at 0-17.5 cm depth, and this increase was directly related with C and N added or recycled by the systems. The crop residues added to the soil were associated with reduced semiquinone free radical concentration, detected by electron spin resonance (ESR), in the organo-mineral aggregates <53 mu m and humic acid (HA) samples, in the soil at 0-2.5 cm depth. This showed that stable organic matter originating from crop residues was less humidified than the original soil organic matter. Results obtained from organo-mineral aggregates showed a higher amplitude (highest and lowest values were 5.47 and 2.09 x 10(17) spins g(-1) of TOC, respectively) of semiquinone free radical concentration than HA samples (highest and lowest values were 2.68 and 1.77 x 10(17) spins g(-1) of HA, respectively). These data showed that alterations due to tillage in soil organic matter characteristics, e.g,, humification degree can be better identified through a combination of soil physical fractionation and spectroscopic analysis. Semiquinone content in the HA samples, detected by ESR, related significantly to aromaticity, as measured by nuclear magnetic resonance (NMR) of C-13. Management systems including no-till and cropping systems with high C and N additions to the soil improved its quality in Southern Brazil. (C) 2000 Elsevier Science B,V. All rights reserved.
  • Authors:
    • Fernandes, S. V.
    • Martin-Neto, L.
    • Amado, T. J. C.
    • Mielniczuk, J.
    • Bayer, C.
  • Source: Soil & Tillage Research
  • Volume: 54
  • Issue: 1-2
  • Year: 2000
  • Summary: Soil organic matter decline and associated degradation of soil and environmental conditions under conventional tillage in tropical and subtropical regions underline the need to develop sustainable soil management systems. This study aimed first to evaluate the long-term effect (9 years) of two soil-tillage systems (conventional tillage: CT, and no-tillage: NT) and two cropping systems (oat (Avena strigosa Schreb)/maize (Zea mays L.): O/M; and oat+common vetch (Vicia sativa L.)/ maize+cowpea (Vigna unguiculata (L.) Walp): O+V/M+C without N fertilization on total organic carbon (TOC) and total nitrogen (TN) concentrations in a sandy clay loam Acrisol in southern Brazil. The second objective was to assess soil potential for acting as an atmospheric CO2 sink. Under NT an increase of soil TOC and TN concentrations occurred, in both cropping systems, when compared with CT. However, this increase was restricted to soil surface layers and it was higher for O+V/M+C than for O/M, The O+V/M+C under NT, which probably results in the lowest soil organic matter losses (due to erosion and oxidation) and highest addition of crop residues, had 12 Mg ha(-1) more TOC and 0.9 Mg ha(-1) more TN in the 0-30.0 cm depth soil layer, compared with O/M under CT which exhibits highest soil organic matter losses and lowest crop residue additions to the soil. These increments represent TOC and TN accumulation rates of 1.33 and 0.10 Mg ha(-1) per year, respectively. Compared with CT and O/M, this TOC increase under NT and O+V/M+C means a net carbon dioxide removal of about 44 Mg ha(-1) from the atmosphere in 9 years. NT can therefore be considered, as it is in temperate climates, an important management strategy for increasing soil organic matter. In the tropicals and subtropicals, where climatic conditions cause intense biological activity, in order to maintain or increase soil organic matter, improve soil quality and contribute to mitigation of CO2 emissions, NT should be associated with cropping systems resulting in high annual crop residue additions to soil surface. (C) 2000 Elsevier Science B.V. All rights reserved.
  • Authors:
    • Tonkin, C. J.
    • Dellow, J. J.
    • Mullen, C. L.
  • Source: Weed control in winter crops 2000 Weed control in winter crops 2000.
  • Year: 2000
  • Summary: This guide provides information on chemical weed control in New South Wales, Australia, for the following winter crops: wheat; barley; oats; rye; triticale; canola [rape]; safflower; lentils; linseed; lupins; chickpeas; faba beans; field pea; and fallows.
  • Authors:
    • Powell, C.
  • Source: New South Wales Department of Agriculture
  • Year: 2000
  • Summary: This report presents tabulated yield data from variety trials held in New South Wales, Australia, for barley, rape, faba beans, field peas, lentils, lupins, mixed cereals (barley, oats, triticale and wheat), oats, triticale, wheat.
  • Authors:
    • Powell, C.
  • Source: New South Wales Department of Agriculture
  • Year: 2000
  • Summary: Tabulated data on yield are presented from variety trials conducted in New South Wales, Australia, during 1999 for barley, rape, chickpeas, faba beans, field peas, lentils, lupins, mixed cereal (barley, oats, rye, triticale and wheat), oats, triticale and wheat.
  • Authors:
    • Soderstrom, M.
    • Rydberg, A.
  • Source: Proceedings of the 5th International Conference on Precision Agriculture, Bloomington, Minnesota, USA, 16-19 July, 2000
  • Year: 2000
  • Summary: This study investigates the potential of using SPOT multispectral images of agricultural fields to distinguish spatial variation in crop-growth patterns that can be used for site-specific agricultural management. Four years of SPOT data from 1995 to 1997 and 1999 are used in this study over south-western Sweden where satellite derived yield maps are compared to data from commercial yield mapping systems. The crops included rape, wheat, barley, meadow fescue [Festuca pratensis], oats, peas and rye. Our concept of crop growth maps is intended for use in areas where yield mapping, soil sampling and ground spectral measurements are not available. Maps of crop growth variability produced by clustering processes applied to images of the Normalized Difference Vegetation Index are compared to clustering of yield maps from the same years. Qualitative yield estimation is derived by dividing each field into several thematic classes, going from lowest to highest potential yield within a particular field. Qualitative comparisons are made within each field. For one year, the satellite data are also compared to three traditional yield maps derived from the same set of yield data. For a few fields where the time of image acquisition coincides with stages of optimum grain fill, high correlations were obtained between yield and NDVI. This study illustrates that satellite images can be a useful tool in precision agriculture management. The clusters created from the NDVI images show similar patterns as clusters created from the yield maps.
  • Authors:
    • Stenberg, B.
    • Stenberg, M.
    • Rydberg, T.
  • Source: Applied Soil Ecology
  • Volume: 14
  • Issue: 2
  • Year: 2000
  • Summary: The effects of reduced tillage and lime on crop yield and soil physical and microbial properties were studied in a weakly-structured silty clay loam soil at a site in Sweden. Two autumn primary tillage practices were compared, mouldboard ploughing to 20-25 cm and cultivation to 12 cm. Seedbed preparation was carried out by several harrowing operations in the mouldboard ploughed treatment, and with a harrow in the same operation as sowing in the shallow cultivation treatment. The tillage treatments were applied alone or were combined with liming aimed at soil structural improvement. Lime was added as 6.5 t CaO ha -1 before the start of the experiment and mixed into the top 12 cm of soil with a disc cultivator. A 4-year crop rotation was used: spring barley, spring oilseed rape, spring/winter wheat and oats, and all crops were compared each year. Crop residues were retained in the experiment and incorporated at cultivation. Aggregate stability was improved by the shallower tillage depth, probably as an effect of an increase in soil organic matter and a more active microbial biomass. Liming had little effect on soil structure variables but increased microbial activity to some extent. This was reflected in higher crop yields, especially when the shallow tillage depth was combined with liming. Penetration resistance in the seedbed subsoil was highest when mouldboard ploughing was carried out in plots without liming. Data were examined with principal component analyses, and the structures in the data were presented as scores and loading plots, which showed groupings between samples and relationships between variables, respectively.
  • Authors:
    • Clark, K.
  • Source: Regional on-farm experiments 1999: Deniliquin, Finley, Hillston, Leeton & Beckom agronomy districts
  • Year: 2000
  • Summary: Tabulated yield data are presented from variety trials conducted throughout New South Wales, Australia, for barley, rape, lentils, lupins, oats, peas, wheat and narbon ( Vicia narbonensis).
  • Authors:
    • Gurin, A. G.
  • Source: Sadovodstvo i Vinogradarstvo
  • Issue: 1
  • Year: 2000
  • Summary: In Russia, strips of shelter plants are sometimes grown between the rows of strawberries, so that at the end of the growing season the first frosts will kill off the tops of these plants which then fall and cover the strawberry plants like a mulch, and help to retain a protective snow cover through the winter. An account is given of the performance of oats, barley, rape, and mustard sown as shelter plants between the rows of Redgauntlet strawberries, with details of the snow accumulation and of the strawberry yields. The shelter plants did depress the growth of the strawberry plants somewhat, but had little or no effect on fruit yields, and also significantly reduced weed growth.