Fig 1.
Representative 3D renderings of root systems grown in repacked soil columns.
(A) tillage radish after 20 days growth; (B) tillage radish after 58 days growth; (C) vetch after 20 days growth; (D) vetch after 58 days growth; (E) black oat after 20 days growth; (F) black oat after 58 days growth. Red arrows indicate location of change in dry bulk density of soil profile from 1.2 to 1.4 g cm-3.
Fig 2.
Location maps of roots in 2D cross-section representative slices of segmented root systems shown in Fig 1.
(A-D) Tillage radish: (A-B)) Day 20; (C-D) Day 58; (E-H) Vetch: (E-F) Day 20; (G-H) Day 58; (I-L) Black oat: (I-J) Day 20; (K-L) Day 58. Orange circles denote position of root within column and do not relate to root diameter (actual sizes would be indiscernible in many cases at this scale of imaging; diameter of core, here black circles, is 75 mm). For all species 3 cm depth falls within the uncompacted zone and 10 cm depth is within the uncompacted zone.
Fig 3.
Average surface area of root (cm2) and root volume as% of full soil column.
(A) Surface area of root (cm2) within full soil column for tillage radish, vetch and black oat root systems, derived from X-ray CT data. Bars denote means, whiskers pooled SE. (B) Volume of root as a percentage of the uncompacted and compacted soil zones for tillage radish, vetch and black oat root systems, derived from X-ray CT data. Due to the disproportionately large increase in total root volume for tillage radish the data was not subject to ANOVA. Bars denote means, whiskers individual standard deviation.
Fig 4.
Visual representation of convex hull volumes for representative root systems, red arrows indicate change in dry bulk density of soil profile.
(A) Tillage radish after 20 days growth. (B) Vetch after 20 days growth. (C) Black oat after 20 days growth. (D) Tillage radish after 58 days growth. (E) Vetch after 58 days growth. (F) Black oat after 58 days growth.
Fig 5.
Average root systems convex hull (cm3) and solidity value of full soil column.
(A) Convex hull (cm3) of tillage radish, vetch and black oat root systems. Data represents full root systems, derived from X-ray CT. Bars denote means, whiskers pooled SE. (B) Solidity values of tillage radish, vetch and black oat root systems. Data represents full root systems, derived from X-ray CT data. Due to extreme range of values, tillage radish the data was not subject to ANOVA. Bars denote means, whiskers standard error.
Fig 6.
Average surface area (cm2), volume of root (%), number of laterals and lateral angle (°) of tillage radish root systems.
(A) Average surface area of tillage radish root (cm2). (B) Average volume of tillage radish root as a percentage of the soil volumes. Due to extreme range of data values data was not subject to ANOVA. (C) Average number of lateral roots observed protruding from the taproot. (D) Average angle of lateral roots protruding from taproot. For all graphs data is presented for both the compacted and uncompacted zones over two time periods. Bars denote means, whiskers pooled (A, C, D) or individual (B) s.e.
Fig 7.
Average surface area (cm2), volume of root (%), number of laterals and lateral angle (°) of vetch root systems.
(A) Average surface area of vetch root (cm2) (B) Average volume of vetch root as a percentage of the soil volumes, (C) Average number of lateral roots observed protruding from the taproot into the soil volumes. (D) Average angle of lateral roots protruding from taproot into the soil volumes. For all graphs data is presented for both the compacted and uncompacted zones over two time periods Bars denote means, whiskers pooled SE.
Fig 8.
Average surface area (cm2), volume of root (%) of black oat root systems.
(A) Average surface area of black oat root (cm2). (B) Average volume of black oat root as a percentage of the soil volume. For all graphs data is presented for both the compacted and uncompacted zones over two time periods. Bars denote means, whiskers s.e.
Fig 9.
Soil porosity of uncompacted and compacted layers with tillage radish, vetch and black oat roots systems growing at three time points.
Average percentage of pore space from representative samples within both the uncompacted and compacted soil volumes, bars denote means, whiskers pooled s.e.