Browsing by Author "Morris, N."
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Item Open Access Long-term impacts of repeated cover cropping and cultivation approaches on subsoil physical properties(Elsevier, 2023-06-02) Martlew, J.; Wilfred, Otten; Morris, N.; De Baets, S.; Deeks, Lynda K.The intensification of arable agriculture has resulted in an increase in vehicle wheel load and the intensity of field operations, which has increased the risk and incidence of degradation in physical properties of the uncultivated subsoil layer. Biopores generated by the long-term, repeated use of specific cover crops within an arable rotation has been suggested as an approach to improve subsoil physical properties. Therefore, this paper aimed to determine the impact of long-term repeated cover cropping and the interaction of rotation treatments with different cultivation approaches on subsoil physical properties. Data was collected at the NIAB ‘Sustainable Trial for Arable Rotations’ long-term, rotation and cultivation field experiment established in 2006. Rotation treatments comprised a brassica cover crop alternated annually with winter wheat (ALTCC) compared to continuous winter wheat (CWW). Cultivation treatments comprised PLOUGH (250 mm depth), and non-inversion cultivation at 250 mm (DEEP) and 100 mm (SHALLOW) depths. Penetration resistance and volumetric soil moisture were collected at bi-monthly intervals during the 2018/19 growing season. Undisturbed soil cores were collected for laboratory analyses of soil water retention, water stable aggregates, root morphology digital scanning and biomass, and X-ray computed tomography (CT). Results showed that treatment ALTCC combined with SHALLOW, resulted in lower penetration resistance and increased moisture in the subsoil. This increased subsoil moisture persisted later into the season compared to the control. SHALLOW increased subsoil water retention, improved subsoil root morphology and increased subsoil porosity. Benefits from treatment ALTCC were not observed where combined with higher intensity, deeper cultivation. Overall, the combination of treatments ALTCC with SHALLOW, produced significant benefits to subsoil physical properties.Item Open Access Quantifying and alleviating subsoil compaction in arable soils.(Cranfield University, 2021-09) Martlew, Joseph Philip; Deeks, Lynda K.; Otten, Wilfred; Morris, N.Modern agricultural machinery and the intensity of arable field operations has increased the risk and incidence of subsoil compaction. There is potential to improve the management of subsoil compaction through addressing the current spatial and temporal limitations of characterisation methods and determining the potential of alternative alleviation approaches. Therefore, the aim of this thesis was to determine the suitability of alternative methods to quantify and alleviate subsoil compaction in arable soils. A combination of literature, field and laboratory studies were used to consider the appropriateness of different methods. The long-term, repeated use of a cover crop in rotation with winter wheat improved subsoil physical properties compared to a control. Cultivation treatments had a significant interaction with this, where reducing the intensity and depth of cultivation resulted in the greatest subsoil benefits. Combining alternate season cover cropping and non-inversion, shallow depth cultivation produced the largest advantage to subsoil properties. High subsoil compaction had a significant negative effect on arable crop performance under controlled conditions. Although both brassica and graminaceous cover crops increased root proliferation in compacted subsoil compared to a control, neither significantly improved arable crop performance after two consecutive seasons. Electromagnetic conductivity soil scanning presented significant spatial and temporal advantages for use at a large spatial scale. However, data interpretation requires further development for application to subsoil compaction. Visual soil evaluation using the SubVESS approach provided the greatest detail on the position of compact subsoil layers and the underlying cause but was limited by the time-consuming methodology. A combination of characterisation methods was most applicable to provide the highest level of detail for subsoil management. Overall, the work presented in this thesis indicated that the characterisation and alleviation of subsoil compaction may be improved through the adoption and further investigation of the alternative approaches presented.