The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Tino Colombi - One of the best experts on this subject based on the ideXlab platform.
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feedbacks between soil Penetration Resistance root architecture and water uptake limit water accessibility and crop growth a vicious circle
Science of The Total Environment, 2018Co-Authors: Tino Colombi, Lorena Chagas Torres, Achim Walter, Thomas KellerAbstract:Abstract Water is the most limiting resource for global crop production. The projected increase of dry spells due to climate change will further increase the problem of water limited crop yields. Besides low water abundance and availability, water limitations also occur due to restricted water accessibility. Soil Penetration Resistance, which is largely influenced by soil moisture, is the major soil property regulating root elongation and water accessibility. Until now the interactions between soil Penetration Resistance, root system properties, water uptake and crop productivity are rarely investigated. In the current study we quantified how interactive effects between soil Penetration Resistance, root architecture and water uptake affect water accessibility and crop productivity in the field. Maize was grown on compacted and uncompacted soil that was either tilled or remained untilled after compaction, which resulted in four treatments with different topsoil Penetration Resistance. Higher topsoil Penetration Resistance caused root systems to be shallower. This resulted in increased water uptake from the topsoil and hence topsoil drying, which further increased the Penetration Resistance in the uppermost soil layer. As a consequence of this feedback, root growth into deeper soil layers, where water would have been available, was reduced and plant growth decreased. Our results demonstrate that soil Penetration Resistance, root architecture and water uptake are closely interrelated and thereby determine the potential of plants to access soil water pools. Hence, these interactions and their feedbacks on water accessibility and crop productivity have to be accounted for when developing strategies to alleviate water limitations in cropping systems.
A. Glyn Bengough - One of the best experts on this subject based on the ideXlab platform.
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Root cap removal increases root Penetration Resistance in maize (Zea mays L.)
Journal of experimental botany, 2003Co-Authors: Morio Iijima, Toshifumi Higuchi, Peter W. Barlow, A. Glyn BengoughAbstract:The root cap assists the passage of the root through soil by means of its slimy mucilage secretion and by the sloughing of its outer cells. The root Penetration Resistance of decapped primary roots of maize (Zea mays L. cv. Mephisto) was compared with that of intact roots in loose (dry bulk density 1.0 g cm ‐3 ; Penetration Resistance 0.06 MPa) and compact soil (1.4 g cm ‐3 ; Penetration Resistance 1.0 MPa), to evaluate the contribution of the cap to decreasing the impedance to root growth. Root elongation rate and diameter were the same for decapped and intact roots when the plants were grown in loose soil. In compacted soil, however, the elongation rate of decapped roots was only about half that of intact roots, whilst the diameter was 30% larger. Root Penetration Resistances of intact and decapped seminal axis were 0.31 and 0.52 MPa, respectively, when the roots were grown in compacted soil. These results indicated that the presence of a root cap alleviates much of the mechanical impedance to root Penetration, and enables roots to grow faster in compacted soils.
A. Hatjiioannidou - One of the best experts on this subject based on the ideXlab platform.
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Compaction and Penetration Resistance of an Alfisol and Entisol and their influence on root growth of maize seedlings
Soil & Tillage Research, 1994Co-Authors: K.p. Panayiotopoulos, C.p. Papadopoulou, A. HatjiioannidouAbstract:Traffic and tillage induced compaction affect soil physical, chemical and biological properties and processes directly and influences plant root growth indirectly. In a pot experiment with an Entisol and an Alfisol, the effect of 0, 50, 100 and 200 kPa of compactive stress on bulk density, Penetration Resistance, and on root growth of maize seedlings, at the early stages of development, was studied. Compaction resulted in a progressive increase in bulk density and Penetration Resistance for both soils. The Entisol reached a greater bulk density and Penetration Resistance than the Alfisol. Bulk density or Penetration Resistance were closely correlated with compactive stress. The correlation between bulk density and Penetration Resistance was not so close. Increased bulk density and Penetration Resistance resulted in a reduction of all the root growth parameters such as number of roots, mean and total root length, rateof root elongation and fresh and dry root mass. Significant linear or curvilinear relationships were found between bulk density or Penetration Resistance and most of the root growth parameters studied. However, the relationships were improved when relative values (expressed as fractions of the controls) of bulk density or Penetration Resistance and of any one of the root growth parameters were considered. Roots grown in more compact soil had a smaller ratio of fresh to dry mass.
Thomas Keller - One of the best experts on this subject based on the ideXlab platform.
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feedbacks between soil Penetration Resistance root architecture and water uptake limit water accessibility and crop growth a vicious circle
Science of The Total Environment, 2018Co-Authors: Tino Colombi, Lorena Chagas Torres, Achim Walter, Thomas KellerAbstract:Abstract Water is the most limiting resource for global crop production. The projected increase of dry spells due to climate change will further increase the problem of water limited crop yields. Besides low water abundance and availability, water limitations also occur due to restricted water accessibility. Soil Penetration Resistance, which is largely influenced by soil moisture, is the major soil property regulating root elongation and water accessibility. Until now the interactions between soil Penetration Resistance, root system properties, water uptake and crop productivity are rarely investigated. In the current study we quantified how interactive effects between soil Penetration Resistance, root architecture and water uptake affect water accessibility and crop productivity in the field. Maize was grown on compacted and uncompacted soil that was either tilled or remained untilled after compaction, which resulted in four treatments with different topsoil Penetration Resistance. Higher topsoil Penetration Resistance caused root systems to be shallower. This resulted in increased water uptake from the topsoil and hence topsoil drying, which further increased the Penetration Resistance in the uppermost soil layer. As a consequence of this feedback, root growth into deeper soil layers, where water would have been available, was reduced and plant growth decreased. Our results demonstrate that soil Penetration Resistance, root architecture and water uptake are closely interrelated and thereby determine the potential of plants to access soil water pools. Hence, these interactions and their feedbacks on water accessibility and crop productivity have to be accounted for when developing strategies to alleviate water limitations in cropping systems.
K.b. Laryea - One of the best experts on this subject based on the ideXlab platform.
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Spatial variability in Penetration Resistance of a hardsetting tropical alfisol
Soil and Tillage Research, 1994Co-Authors: G.j. Ley, K.b. LaryeaAbstract:Geostatistical techniques were used to analyse the spatial variation of Penetration Resistance on an experimental plot intended for root studies. Penetration Resistance was measured at two soil water conditions. Penetration Resistance exhibited spatial structure but the models describing the semivariograms were different for the two soil water conditions. An isotropic linear model provided the best fit for Penetration Resistance in the dry soil while an isotropic spherical model was used for Penetration in the wet soil. A complementary study of the spatial structure of water content also showed a similar trend. Cross-semivariograms were constructed to determine the spatial relationship between Penetration Resistance and water content. Penetration Resistance in the dry soil was negatively correlated with water content. The nugget variances as the percentage of the sill in the wet soil data set suggest that the topsoil was slightly more variable than the subsoil. The spatial scale of variation in Penetration Resistance of the wet soil was 33 m at 7.5 cm depth and 20–27 m at 15–30 cm depth. Punctual kriging was used to estimate the Penetration Resistance and water content values. The estimated values are presented as contour maps. The pattern of variation and the underlying possible processes for the variation are discussed. The results suggest that the likely influence of spatial variation of soil properties on crop growth may have to be considered in modelling in order to simulate the real field situation.
