caa a22 4500 477109608 CHVBK 20180405111604.0 cr unu---uuuuu 170330e19960301xx s 000 0 eng 10.1007/BF02257571 doi (NATIONALLICENCE)springer-10.1007/BF02257571 Soil structure and plant growth: Impact of bulk density and biopores [Elektronische Daten] [R. Stirzaker, J. Passioura, Y. Wilms] Compacted soils are not uniformly hard; they usually contain structural cracks and biopores, the continuous large pores that are formed by soil fauna and by roots of previous crops. Roots growing in compacted soils can traverse otherwise impenetrable soil by using biopores and cracks and thus gain access to a larger reservoir of water and nutrients. Experiments were conducted in a growth chamber to determine the plant response to a range of uniform soil densities, and the effect of artificial and naturally-formed biopores. Barley plants grew best at an intermediate bulk density, which presumably represented a compromise between soil which was soft enough to allow good root development but sufficiently compact to give good root-soil contact. Artificial 3.2 mm diameter biopores made in hard soil gave roots access to the full depth of the pot and were occupied by roots more frequently than expected by chance alone. This resulted in increased plant growth in experiments where the soil was allowed to dry. Our experiments suggest that large biopores were not a favourable environment for roots in wet soil; barley plants grew better in pots containing a network of narrow biopores made by lucerne and ryegrass roots, responded positively to biopores being filled with peat, and some pea radicles died in biopores. A theoretical analysis of water uptake gave little support to the hypothesis that water supply to the leaves was limiting in either very hard or very soft soil. The net effect of biopores to the plant would be the benefits of securing extra water and nutrients from depth, offset by problems related to poor root-soil contact in the biopore and impeded laterals in the compacted biopore walls. Kluwer Academic Publishers, 1996 biopores nationallicence compaction nationallicence root growth nationallicence root-soil contact nationallicence root signals nationallicence Stirzaker R. CSIRO Division of Plant Industry, P.O. Box 1600, 2601, ACT, Australia aut Passioura J. CSIRO Division of Plant Industry, P.O. Box 1600, 2601, ACT, Australia aut Wilms Y. Larenstein, P.O. Box 9001, 6880, GB Velp, The Netherlands aut Plant and Soil Kluwer Academic Publishers 185/1(1996-03-01), 151-162 0032-079X 185:1<151 1996 185 11104 https://doi.org/10.1007/BF02257571 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02257571 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Stirzaker R. CSIRO Division of Plant Industry, P.O. Box 1600, 2601, ACT, Australia aut NATIONALLICENCE 700 1- Passioura J. CSIRO Division of Plant Industry, P.O. Box 1600, 2601, ACT, Australia aut NATIONALLICENCE 700 1- Wilms Y. Larenstein, P.O. Box 9001, 6880, GB Velp, The Netherlands aut NATIONALLICENCE 773 0- Plant and Soil Kluwer Academic Publishers 185/1(1996-03-01), 151-162 0032-079X 185:1<151 1996 185 11104 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer