Brereton, Jeremy Charles
The sensitivity of barley, field beans and sugar beet to soil compaction.
PhD thesis, University of Nottingham.
The sensitivity of spring barley (Hordeum vulgare, cv. Carnival), field beans (Vicia faba, ev. Maris Bead) and sugar beet (Beta vulgaris,cv. Monoire) to topsoil compaction induced by tractor wheelings, post sowing, on a coarse gravelly loam of the Arrow series was investigated in 1983 and 1984.
The study revealed that in both years topsoil compaction increased the dry bulk density, vane shear strength and cone resistance of the soil. Although compaction reduced only the plant population of sugar beet in 1983 (by 35%) in 1984 it both delayed emergence and decreased the field bean, spring barley and sugar beet populations by 41%, 50% and 64% respectively.
In 1983 the order of sensitivity of crop yield to soil compaction was spring barley < field beans <sugar beet and the following year a similar trend was apparent with spring barley ≈ field beans < sugar beet. Compaction reduced the total dry matter production of field beans and sugar beet in 1983 and of all the three crops examined a year later. No clear trend could be established on the influence of soil compaction on plant nutrient uptake.
The total length and distribution of roots in the soil profile was reduced in field beans (28%), spring barley (27%) and sugar beet (49%) by topsoil compaction in 1983. However, the reduced root length of spring barley was an order of magnitude greater than that of the other crops. In 1984 there was a trend for compaction to restrict the total root length of all crops throughout most of the growing season. Compaction did not restrict the maximum depth of rooting but it reduced the amount of deep roots in all crops. In 1983 and 1984, compaction restricted lateral proliferation of roots and the order of sensitivity of root distribution to soil compaction was similar to that for the sensitivity of yield: spring barley <field beans <sugar beet.
The maximum effective rooting depth, as measured by neutron probe, was consistently less for field bean and sugar beet compact treatments, while the evaporation was only reduced in compact sugar beet crops. Thermocouple psychrometer data indicated that compaction had generally delayed soil drying and reduced the extent of water use in all crops in 1984. The principal effect of soil compaction on crop growth and dry matter production was to reduce the leaf area index, by an initial restriction to individual leaf size and by a reduction in plant numbers such that the fraction of light intercepted by the leaf canopy was reduced. The efficiency of conversion of photosynthetically active radiation absorbed to dry matter was not affected by soil compaction.
Diurnal and seasonal plant water status was not detrimentally changed by soil compaction. It is suggested that plants adapt to adverse soil physical conditions by a reduction of leaf area expansion rather than by lowered leaf water potential.
The severity of the response of crops to topsoil compaction was strongly influenced by the environment, in particular the distribution of rainfall which appeared to determine the effect of compaction on crop emergence and the ability of that crop to compensate for a low plant population.
The results of this study are discussed in relation to the use of plant breeding, irrigation and management techniques in overcoming the detrimental effects of soil compaction on crop growth and development.
Thesis (University of Nottingham only)
||S Agriculture > S Agriculture (General)
S Agriculture > SB Plant culture
||UK Campuses > Faculty of Science > School of Biosciences
||21 Jan 2014 09:17
||14 Sep 2016 07:32
Actions (Archive Staff Only)