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  • 1
    Electronic Resource
    Electronic Resource
    Root:shoot ratios of old and modern, tall and semi-dwarf wheats in a mediterranean environment (1990)
    Springer
    Plant and soil 122 (1990), S. 89-98 
    Details
    ISSN: 1573-5036
    Keywords: harvest index ; old and modern wheats ; root:shoot ratio ; Rht genes ; root dry matter ; root length ; water use efficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A field study tested the hypothesis that modern wheat varieties invest a lesser proportion of the total dry matter (root plus shoot) in the root system compared to old varieties. The study was carried out on a duplex soil (sand over clay) at Merredin, Western Australia in a Mediterranean type environment. We also compared the root:shoot dry matter ratios of near-isogenic lines forRht dwarfing genes. Root:shoot ratios decreased with crop growth stage and were closely related to the developmental pattern of a variety. All varieties appeared to accumulate more dry matter into shoots after the terminal spikelet stage. For the modern variety Kulin this occurred as early as 55 days after sowing (DAS), but did not occur until 90 DAS in the old variety Purple Straw. For all varieties, root dry matter reached its maximum at anthesis, while shoot dry matter continued to increase till maturity. At anthesis there were no significant differences in shoot dry matter between varieties, but from Purple Straw to Kulin root dry matter and thus root:shoot ratio decreased. The tall and dwarf isogenic lines had similar developmental and root:shoot dry matter accumulation patterns. At anthesis, the old variety Purple Straw had significantly higher root dry matter and root length density in the top 40-cm of the profile than modern variety Kulin. There were no varietal differences in rooting depth, water extraction or water use. At maturity about 30% of the total dry matter was invested in the roots among wheat varieties. Grain yield, harvest index (HI) and water use efficiency of grain (WUEgr) increased from old to modern varieties. The reduced investment of dry matter in the root system and thus the lower root:shoot ratio from early in the growing season may partly explain the increased HI and WUEgr of modern compared to old varieties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02444108
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  • 2
    Electronic Resource
    Electronic Resource
    Effects of waterlogging and drought on winter wheat and winter barley grown on a clay and a sandy loam soil (1984)
    Springer
    Plant and soil 80 (1984), S. 53-66 
    Details
    ISSN: 1573-5036
    Keywords: Clay ; Drought ; Sandy loam ; Waterlogging ; Winter barley ; Winter wheat ; Yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The effects of winter waterlogging and a subsequent drought on the growth of winter barley and winter wheat have been examined. We used lysimeters containing soil monoliths with facilities to control the water table and a mobile shelter to control rainfall. Winter wheat was grown on a clay and on a sandy loam, but winter barley only on the clay soil. Lysimeters were either freely-drained during the winter or waterlogged with the water table 10 cm below the soil surface from 2 December until 31 March (that could occur by rainfall with a return period of 2 to 3 years). The lysimeters then were either irrigated so that the soil moisture deficit did not exceed 84 mm, or subjected to drought by limiting rainfall (equivalent to a 1 in 10 dry year in the driest area of England) so that the deficits reached maximum values of 150 mm in the clay and 159 mm in the sandy loam by harvest. Winter waterlogging restricted tillering and restricted the number of ears for all crops; grain yield of the winter barley was decreased by 219 g/m2 (30%), and that of winter wheat by 170 g/m2 (24%) and 153 g/m2 (21% on the clay and sandy loam respectively. The drought treatment reduced the straw weight of winter barley by 75 g/m2 (12%) but did not significantly depress the grain yield. For winter wheat on the clay, where the soil was freely-drained during the winter, drought depressed total shoot weight by 344 g/m2 (17%) and grain weight by 137 g/m2 (17%), but after winter waterlogging, drought did not further depress total or grain weight. In contrast, the winter wheat on the sandy loam was not significantly affected by drought. From these results, which are discussed in relation to other experiments in the United Kingdom, it seems that winter waterlogging is likely to cause more variation in the yield of winter barley and winter wheat than drought.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02232939
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  • 3
    Electronic Resource
    Electronic Resource
    Crop uptake and leaching losses of15N labelled fertilizer nitrogen in relation to waterlogging of clay and sandy loam soils (1986)
    Springer
    Plant and soil 92 (1986), S. 89-101 
    Details
    ISSN: 1573-5036
    Keywords: Arable crops ; Clay ; Denitrification ; Drainage ; Leaching ; Lysimeter ; 15N nitrogen ; Sandy loam ; Waterlogging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Ammonium nitrate fertilizer, labelled with15N, was applied in spring to winter wheat growing in undisturbed monoliths of clay and sandy loam soil in lysimeters; the rates of application were respectively 95 and 102 kg N ha−1 in the spring of 1976 and 1975. Crops of winter wheat, oilseed rape, peas and barley grown in the following 5 or 6 years were treated with unlabelled nitrogen fertilizer at rates recommended for maximum yields. During each year of the experiments the lysimeters were divided into treatments which were either freelydrained or subjected to periods of waterlogging. Another labelled nitrogen application was made in 1980 to a separate group of lysimeters with a clay soil and a winter wheat crop to study further the uptake of nitrogen fertilizer in relation to waterlogging. In the first growing season, shoots of the winter wheat at harvest contained 46 and 58% of the fertilizer nitrogen applied to the clay and sandy loam soils respectively. In the following year the crops contained a further 1–2% of the labelled fertilizer, and after 5 and 6 years the total recoveries of labelled fertilizer in the crops were 49 and 62% on the clay and sandy loam soils respectively. In the first winter after the labelled fertilizer was applied, less than 1% of the fertilizer was lost in the drainage water, and only about 2% of the total nitrogen (mainly nitrate) in the drainage water from both soils was derived from the fertilizer. Maximum annual loss occurred the following year but the proportion of tracer nitrogen in drainage was nevertheless smaller. Leaching losses over the 5 and 6 years from the clay and sandy loam soil were respectively 1.3 and 3.9% of the original application. On both soils the percentage of labelled nitrogen to the total crop nitrogen content was greater after a period of winter waterlogging than for freely-drained treatments. This was most marked on the clay soil; evidence points to winter waterlogging promoting denitrification and the consequent loss of soil nitrogen making the crop more dependent on spring fertilizer applications.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02372270
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  • 4
    Electronic Resource
    Electronic Resource
    A model (WHTROOT) which synchronizes root growth and development with shoot development for winter wheat (1986)
    Springer
    Plant and soil 92 (1986), S. 133-145 
    Details
    ISSN: 1573-5036
    Keywords: Development ; Model ; Root ; Shoot ; Thermal time ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A model has been developed of root growth in winter wheat based on cumulative thermal time with description of the extension and branching of individual age classes of seminal and crown root axes. The model requires, as input, the sowing date and average monthly mean air temperatures and gives, as output, the maximum depth of penetration of each age class of root and the root length density or root weight in any 10 cm layer of soil contributed by main axes, first-order and second-order laterals on any calendar date. The impact of soil temperature on root length density distributions with time was assessed by comparing a warm site (Perth, Australia) with a cool site (Rothamsted Experimental Station, England). Simulated values of root length density for plants with six leaves were consistently high when soil temperature was held constant at 10°C, but variable soil temperatures at each site resulted in rooting profiles characteristic for the two sites, although root length densities were larger than commonly observed at either location. The model simulates well described sequences of root production and permits calculation of maximal root development rates for unstressed plants growing in moist soil with no mechanical impedance to growth. It allows the co-development of root and shoot to be modelled and since it uses only about 5 K bytes of computer memory could be easily used for the assessment of management practices in the field.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02372274
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Root:shoot ratios of old and modern, tall and semi-dwarf wheats in a mediterranean environment (1990)
    Springer
    Plant and soil 121 (1990), S. 89-98 
    Details
    ISSN: 1573-5036
    Keywords: harvest index ; old and modern wheats ; root:shoot ratio ; Rht genes ; root dry matter ; root length ; water use efficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A field study tested the hypothesis that modern wheat varieties invest a lesser proportion of the total dry matter (root plus shoot) in the root system compared to old varieties. The study was carried out on a duplex soil (sand over clay) at Merredin, Western Australia in a Mediterranean type environment. We also compared the root:shoot dry matter ratios of near-isogenic lines for Rht dwarfing genes. Root:shoot ratios decreased with crop growth stage and were closely related to the developmental pattern of a variety. All varieties appeared to accumulate more dry matter into shoots after the terminal spikelet stage. For the modern variety Kulin this occurred as early as 55 days after sowing (DAS), but did not occur until 90 DAS in the old variety Purple Straw. For all varieties, root dry matter reached its maximum at anthesis, while shoot dry matter continued to increase till maturity. At anthesis there were no significant differences in shoot dry matter between varieties, but from Purple Straw to Kulin root dry matter and thus root:shoot ratio decreased. The tall and dwarf isogenic lines had similar developmental and root:shoot dry matter accumulation patterns. At anthesis, the old variety Purple Straw had significantly higher root dry matter and root length density in the top 40-cm of the profile than modern variety Kulin. There were no varietal differences in rooting depth, water extraction or water use. At maturity about 30% of the total dry matter was invested in the roots among wheat varieties. Grain yield, harvest index (HI) and water use efficiency of grain (WUEgr) increased from old to modern varieties. The reduced investment of dry matter in the root system and thus the lower root:shoot ratio from early in the growing season may partly explain the increased HI and WUEgr of modern compared to old varieties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00013101
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Effects of waterlogging on soil aeration and on root and shoot growth and yield of winter oats (Avena sativa L.) (1985)
    Springer
    Plant and soil 85 (1985), S. 361-373 
    Details
    ISSN: 1573-5036
    Keywords: Oxygen flux density ; Root growth ; Sandy loam ; Waterlogging ; Winter oats ; Yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Winter oats were grown outdoors in lysimeters containing monoliths of a sandy loam soil. The soil was either freely-drained throughout the experiment or waterlogged to the soil surface from mid-January until mid-April. After the start of waterlogging the oxygen flux density decreased most rapidly nearer the soil surface and in the upper 50 cm declined to zero. At 80 cm depth the oxygen flux density at the end of the waterlogging still had not diminished to zero. While the soil was waterlogged root growth was negligible in the 20–50 cm zone of the soil profile, whereas below that depth root growth continued, reaching 95 cm by the end of the treatment. During the latter part of the waterlogging period root growth resumed in the upper 10 cm, and in the upper 2.5 cm was greater than in the freelydrained treatment. At the end of the waterlogging period, the total root length and shoot dry weights were 77 and 60% of those in the freely-drained treatment, tillering was restricted and leaf area index diminished. However, by anthesis, root length and shoot weights of the plants that had been waterlogged were only 10 and 12% less respectively than for the freely-drained plants. At harvest, total dry matter and grain yields were only 9% less, the latter largely through fewer grains per panicle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02220191
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    Paper (German National Licenses)
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