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  • Polymer and Materials Science  (2)
  • hedgerow intercropping  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Agroforestry systems 13 (1991), S. 143-158 
    ISSN: 1572-9680
    Keywords: Tree-crop interface ; row orientation ; hedgerow intercropping ; alley cropping ; Leucaena ; sorghum ; sunflower ; experimental design ; semi-arid tropics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The paper describes a tree/crop interface (TCI) experiment designed to investigate the effects of row orientation using Leucaena leucocephala Lam. Each TCI plot consisted of a regularly pruned Leucaena hedge in the middle and 12 crop rows on either side. Eight such plots were arranged at 45° around a sole Leucaena plot with rows oriented in four compass directions viz., North-South, East-West, Northeast-Southwest and Northwest-Southeast. Results of four years from 1984 to 1987 did not show any effect of row orientation, and similarly, no effect was seen on crop rows due to their location on the windward or leeward side of the hedge. The TCI effect was positive on the first crop row in the first year because Leucaena grew slowly, but depressed the yield of the first 4 to 6 crop rows(1.8 to 2.7 m from hedge) in subsequent years. The negative effect of Leucaena was noted more on sunflower in a relatively dry year than on sorghum in other years. Results from the TCI plots were used to estimate the yield of five hedgerow intercropping (HI) systems with varying alley widths (2.7 to 9.9 m). Comparison with sole stands of Leucaena and crops indicated that HI was more productive particularly at close alley widths. For example, hedges spaced at 2.7 m and 3.6 m averaged 37% and 25% higher productivity than the respective sole stands; but this advantage may be an overestimation of the real potential. The relevance of TCI experiments for studying agroforestry systems, their merits and limitations, especially of the design employed in this study are discussed.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1572-9680
    Keywords: perennials ; agroforestry ; alley cropping ; hedgerow intercropping ; Leucaena ; pearl millet ; pigeonpea ; castor ; semi-arid tropics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract An experiment was conducted at ICRISAT Center, Patancheru, India from June 1984 to April 1988 on a shallow Alfisol to determine whether the productivity of annual crop systems can be improved by adding perennial species such as Leucaena leucocephala managed as hedgerows. Except in the first year, crop yields were suppressed by Leucaena due to competition for moisture. The severity of competition was high in years of low rainfall and on long-duration crops such as castor and pigeonpea. Based on total biomass, sole Leucaena was most productive; even on the basis of land productivity requiring both Leucaena fodder and annual crops, alley cropping had little or no advantage over block planting of both components. Application of hedge prunings as green manure or mulch on top of 60 kg N and 30 kg P 2 O 5ha−1 to annual crops did not show any benefit during the experimental period, characterized by below average rainfall. Indications are that (i) alley cropping was beneficial in terms of soil and water conservation with less runoff and soil loss with 3 m alleys than with 5.4 m alleys, and (ii) root pruning or deep ploughing might be effective in reducing moisture competition.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 9 (1965), S. 561-568 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The dynamic behavior at low frequencies of Penton (chlorinated polyether) which displays nonlinear response is described in terms of a free energy function and a dissipated energy function. The variation of the energy functions with frequency and magnitude of stress is determined experimentally from hysteresis tests. The dynamic properties of the material are expressed in terms of storage and loss modulus functions. In addition the dynamic behavior of the material at low frequencies is predicted from uniaxial static creep properties, using a modified superposition principle.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A: General Papers 1 (1963), S. 3079-3089 
    ISSN: 0449-2951
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Stress relaxation tests on Penton polymer were conducted at various initial strain rates and initial strains. The data indicates that Penton is a nonlinearly viscoelastic material for the range of values of stresses and strains considered. It is found that the course of the relaxation depends considerably on the initial strains rates employed to attain a particular initial strain in a relaxation test. For the range of initial strain rates considered, the relaxation function can be represented as a function of the time φ(t) and by a power function of the strain rate ε0 of the type Ψ(t,ε0) = φ(t)(ε0)n. From the relaxation tests conducted at the same initial strain rate and for various initial strains, the relaxation stress σ for Penton can be expressed by the relation: σ = σ0 (1 - k log t), where σ0 is the stress at 1 min., t is the time, and k is a material constant.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
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