TY - JOUR
T1 - Soil compaction-N interactions in barley
T2 - root growth and tissue composition
AU - Bingham, Ian J.
AU - Bengough, A. Glyn
AU - Rees, Robert M.
PY - 2010/1
Y1 - 2010/1
N2 - A controlled environment study investigated the interactions between soil compaction and N availability on the growth and root tissue composition of young barley plants. Plants were grown for 14 days in a mixture of sand and calcined clay (fired clay granules) at two levels of compaction (low and high: dry bulk densities of 0.94 and 1.08 g cm(-3) respectively) and two levels of N supply (high, resulting in N sufficient plants and low giving plants deficient in N). High compaction reduced total root length by 23%, leaf area by 21% and altered biomass partitioning (reduced leaf area ratio and increased root weight ratio), but had no effect on total biomass production over the time-course of the experiment. By contrast low N Supply, reduced root biomass by 42% and shoot biomass by 47%, but had less effect on shoot morphology than compaction. There was no significant interaction between compaction and N supply on growth and biomass partitioning, although towards the end of the experiment, the rate of N uptake per unit root dry weight was reduced by about 50% by high compaction when N supplies were low, but not when they were high. Compaction altered the concentration of some root tissue components independently of N supply. For example, high compaction reduced the concentration of cellulose plus hemi-cellulose by 30% and increased the mineral content by 38%, whilst N supply had no effect. The concentration of several other components was altered by compaction and N supply in the same direction. Both high compaction and low N supply increased the lignin concentration whilst reducing the concentration Of Organic N Compounds and nitrate, thereby increasing the C:N and lignin:N ratios. Compaction and low N supply increased C:N by a factor of 1.3 and 1.8 respectively, whilst the lignin:N ratio was increased by 1.7 and 2.1 respectively. Thus, both compaction and low N availability altered root tissue composition in a way that might reduce the rate of root degradation by soil microbes. The implications of these findings for modelling nutrient cycling are briefly discussed. (C) 2009 Elsevier B.V. All rights reserved.
AB - A controlled environment study investigated the interactions between soil compaction and N availability on the growth and root tissue composition of young barley plants. Plants were grown for 14 days in a mixture of sand and calcined clay (fired clay granules) at two levels of compaction (low and high: dry bulk densities of 0.94 and 1.08 g cm(-3) respectively) and two levels of N supply (high, resulting in N sufficient plants and low giving plants deficient in N). High compaction reduced total root length by 23%, leaf area by 21% and altered biomass partitioning (reduced leaf area ratio and increased root weight ratio), but had no effect on total biomass production over the time-course of the experiment. By contrast low N Supply, reduced root biomass by 42% and shoot biomass by 47%, but had less effect on shoot morphology than compaction. There was no significant interaction between compaction and N supply on growth and biomass partitioning, although towards the end of the experiment, the rate of N uptake per unit root dry weight was reduced by about 50% by high compaction when N supplies were low, but not when they were high. Compaction altered the concentration of some root tissue components independently of N supply. For example, high compaction reduced the concentration of cellulose plus hemi-cellulose by 30% and increased the mineral content by 38%, whilst N supply had no effect. The concentration of several other components was altered by compaction and N supply in the same direction. Both high compaction and low N supply increased the lignin concentration whilst reducing the concentration Of Organic N Compounds and nitrate, thereby increasing the C:N and lignin:N ratios. Compaction and low N supply increased C:N by a factor of 1.3 and 1.8 respectively, whilst the lignin:N ratio was increased by 1.7 and 2.1 respectively. Thus, both compaction and low N availability altered root tissue composition in a way that might reduce the rate of root degradation by soil microbes. The implications of these findings for modelling nutrient cycling are briefly discussed. (C) 2009 Elsevier B.V. All rights reserved.
U2 - 10.1016/j.still.2009.10.008
DO - 10.1016/j.still.2009.10.008
M3 - Article
SN - 0167-1987
VL - 106
SP - 241
EP - 246
JO - Soil & Tillage Research
JF - Soil & Tillage Research
IS - 2
ER -