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  • 1
    Electronic Resource
    Electronic Resource
    Fertilizer and temperature effects on urea hydrolysis in undisturbed soil (1993)
    Springer
    Biology and fertility of soils 16 (1993), S. 63-65 
    Details
    ISSN: 1432-0789
    Keywords: Activation energy ; Continuous fertilizer application ; Temperature ; Undisturbed soils ; Urea hydrolysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Few published studies have examined the effects of a continuous fertilizer application on urea hydrolysis. In the present study we investigated the effects of 9 years of continuous application of urea and P fertilizers on urea hydrolysis in undisturbed soil samples as affected by temperature (5–45°C). Undisturbed soil samples of surface horizons (0–7 cm) were obtained with cutting rings (50 cm3) from different fertilizer-treatment plots and inserted in polyethylene bottles (with cutting rings). Each soil sample (in the cutting ring) was treated with 10 ml urea solution (0.5 mmol urea N g-1 soil) and then broght to 90% field capacity. The samples were left to equilibrate for 30 min at a temperature of 4°C, then placed in an incubator at 37°C for 6 h. The results indicated that 9 years of continuous application of urea but not P had a significant effect on urea hydrolysis in soil. There was a good correlation between temperature and urea hydrolysis in soil. Q 10 was between 1.97 and 2.08 in the temperature range 5–45°C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00336517
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    A comparison of minirhizotron, core and monolith methods for quantifying barley (Hordeum vulgare L.) and fababean (Vicia faba L.) root distribution (1993)
    Springer
    Plant and soil 148 (1993), S. 29-41 
    Details
    ISSN: 1573-5036
    Keywords: barley ; core ; fababean ; minirhizotron ; monolith ; root density ; root distribution ; Typic Cryoboroll
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Root research has been hampered by a lack of good methods and by the amount of time involved in making measurements. The use of the minirhizotron as a quantitative tool requires comparison with conventional destructive methods. This study was conducted in the greenhouse to compare the minirhizotron technique with core and monolith methods in quantifying barley (Hordeum vulgare L.) and fababean (Vicia faba L.) root distribution. Plants were grown in boxes (80 cm long × 80 cm wide × 75 cm deep) in a hexagonal arrangement to minimize the effects of rooting anistrophy. Minirhizotron observations and destructive sampling to a depth of 70 cm using core and monolith methods were performed at the ripening growth stage. Total root length for the entire depth interval was generally higher in barley (159–309 m) than fababean (110–226 m). Significant correlation coefficients between monolith and core methods for root length density (RLD, cm cm−3) was observed in both crops (p ≤ 0.01). A method and depth interaction showed no significant differences in fababean RLD distribution measured by core and monolith methods. However, the RLD was different for the uppermost 40 cm depth in barley. The relationship for RLD between minirhizotron and core methods was significant only in barley (r=0.77*). For both crops, estimates of RLD in the top 10-cm layer by the minirhizotron technique were lower than those by core and monolith techniques. In contrast, estimates of RLD were higher in fababean at a depth 〉30 cm. Destructive sampling still remains the method to quantify root growth in the 0–10 cm soil layer. ei]B E Clothier
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02185382
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    A color composite technique for detecting root dynamics of barley (Hordeum vulgare L.) from minirhizotron images (1993)
    Springer
    Plant and soil 157 (1993), S. 275-287 
    Details
    ISSN: 1573-5036
    Keywords: barley ; change detection ; color composite ; digital image analysis ; Hordeum vulgare ; minirhizotron ; root dynamics ; technique ; Typic Cryoboroll
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Quantification of root dynamics by destructive methods is confounded by high coefficients of variation and loss of fine roots. The minirhizotron technique is non-destructive and allows for sequential root observations to be made at the same depth in situ. Observations can be stored on video tape which facilitates data handling and computer-aided image processing. A color composite technique using digital image analyses was adapted in this study to detect barley root dynamics from sequential minirhizotron images. Plants were grown in the greenhouse in boxes (80 × 80 × 75 cm) containing soil from a surface horizon of a Typic Cryoboroll. A minirhizotron was installed at a 45°C angle in each box. Roots intersecting the minirhizotron were observed and video-recorded at tillering, stem extension, heading, dough and ripening growth stages. The images from a particular depth were digitized from the analog video then registered to each other. Discrimination of roots from the soil matrix gave quantitative estimates of root appearance and disappearance. Changes in root appearance and disappearance were detected by assigning a separate primary color (red, green, blue) to selected growth stages, then overlaying the images to create red-green and red-green-blue color composites. The resulting composites allowed for a visual interpretation and quantification of barley root dynamics in situ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00011056
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    Paper (German National Licenses)
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