CERES :: Browsing by Author "Rickson, R. Jane"

Browsing by Author "Rickson, R. Jane"

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Open Access
Analysis of surface roughness in relation to soil loss and runoff at high rainfall intensities.
(John Wiley & Sons, Ltd, 2002-08-30T00:00:00Z) Idowu, O. J.; Rickson, R. Jane; Godwin, R. J.
The decay of roughness is an important factor governing surface processes such as infiltration and soil erosion. Thus the decay of surface roughness under different surface conditions was investigated and related to quantitative amounts of soil loss, runoff and sediment concentration in a laboratory experiment. Rainfall with an intensity of 128 mm/h was applied to a bare or mulched surfaces of a sandy loam soil with known surface roughness at specified time intervals. The decay of roughness as expressed by roughness ratio, in this experiment, was better predicted when related to an exponential function of the square root of cumulative kinetic energy of rainfall rather than with the cumulative rainfall. The roughness decay equations in literature did not predict breakdown under mulched surfaces accurately. Thus the exponent parameters of the roughness decay equations were adjusted to reflect the reduced decay occurring under mulched surfaces. In a bare soil, regression equations expressing the dependent variables as a function of initial roughness index were significant, but with low coefficients of determination, being 0.39 for soil loss, 0.12 for runoff and 0.36 for sediment concentration. In addition to initial roughness index, cumulative kinetic energy of rainfall was further included in the regressions. This led to an increase in coefficients of determination, which was 0.81 for soil loss, 0.74 for runoff and 0.49 for sediment concentration. The coefficients of determination (0.87 for soil loss, 0.85 for runoff and 0.51 for sediment concentration) were further increased when the final roughness index was included in addition to initial roughness index and cumulative kinetic energy in the regressions. This work shows that soil loss and runoff could be predicted from bare soil surface provided the initial roughness and the energy of rainfall is known. However, field verifications of these relationships are needed under different tillage tools and under natural rainfall. Copyright (C) 2002 John Wiley Sons, Ltd.
Open Access
Application of organic amendments to restore soil health and productivity of a degraded soil.
(2017-04) Unagwu, Benedict Onyebuchi; Simmons, Robert W.; Rickson, R. Jane;
Organic amendments (OAs) have the capacity to enhance physical, chemical, biological soil quality indicators (SQIs) and to improve soil productivity. This study investigated the effects of different OAs (Mushroom Compost, MC; PAS-100 compost, PAS; Anaerobic Digestate Solid Waste, AD_SW; and Poultry Manure, PM), applied at 10 t ha⁻¹ and 30 t ha⁻¹ with or without inorganic fertilizer (applied at 50% of the RB209 recommended rates for maize) on key SQIs, soil health and plant performance on a degraded sandy loam soil. The treatments were laid out in a greenhouse using a completely randomized design and replicated four times. The soil and OAs were thoroughly mixed and incubated for two weeks. Thereafter, composite 3-point soil samples were taken from each treatment replicate for post-incubation (POI) soil analysis. Maize (Zea mays, Severus variety), was used to assess the impact of the OAs on plant performance. Plant height, number of plant leaves and stem diameter were measured weekly. Post-harvest (POH) composite 3-point soil samples were again taken for soil analysis. The data generated from POI and POH laboratory analyses and plant measurements were subjected to analysis of variance (ANOVA) followed by post-hoc Fisher LSD analysis at 5% probability level. At POI, the OAs had 22-44.5% higher water holding capacity [WHC], increased porosity and reduced bulk density [BD] as compared with the un-amended control treatment (CNF). The results indicate that 1% increase in soil organic matter (SOM) increased the Available Water Content (AWC) by 5.31 g g⁻¹ while reducing the BD by 1 g cm⁻¹ and increasing the soil Water Content at Field Capacity (WCFC) by 36.5 g g⁻¹ . The Olsen-P, Available-K, Available-Mg, Total-N, and microbial biomass C [MBC] associated with the OA treatments were significantly higher as compared with CNF treatment. At POH, across application rates, OA treatments with or without inorganic fertilizer addition had >15% higher (p <0.05) WHC [WCFC], 40% higher porosity and 55% lower BD as compared with CNF treatment. For both POI and POH, higher rates (30 t ha⁻¹ ) of OAs with or without inorganic fertilizer addition had higher (p <0.05) effects on the water release characteristics [WCFC, EAW, AWC] than lower (10 t ha⁻¹ ) rates of OAs. At POH, across application rates, the OA treatments increased the Olsen-P, SOM, Total-C, and TOC by over 37, 23, 75 and 81%, respectively, relative to CNF. Across application rates with or without inorganic fertilizer addition, the OA treatments did not significantly affect the CEC as compared with CNF. The OAs increased the P, K and Mg indices relative to the CNF which increased with increase in OA application rates. Further, the OA treatments increased the MBC by 72-95% (p <0.05) and reduced microbial stress by over 30% relative to CNF. Without inorganic fertilizer addition, the OA treatments increased the above ground and below ground plant biomass (AGDB and BGDB) by 24-65% and 38-88% respectively, compared with the CNF treatment except for the PAS treatments. The OAs had 100% increases in cob yield as compared with CNF, except for PAS1NF/2NF and AD_SW1NF treatments. Inorganic fertilizer addition had marked effects on plant performance, particularly when combined with the PAS OA. The study concludes that application of OAs has the potential to improve soil health and productivity of a degraded sandy loam soil. Long term effects of these OAs merit further detailed exploration.
Open Access
Changes in soil surface properties under simulated rainfall and the effect of surface roughness on runoff, infiltration and soil loss
(Elsevier, 2023-02-03) Bahddou, Sophia; Otten, Wilfred; Whalley, W. Richard; Shin, Ho-Chul; El Gharous, Mohamed; Rickson, R. Jane
Soil erosion by water is a result of detachment of particles or small aggregates from the soil surface followed by transport of the detached material. One of the elements that affects surface runoff and soil erosion is the soil surface roughness (SSR). Prior research reports that increasing SSR reduces generation of runoff and soil loss. In addition to that, it is widely reported that across-slope oriented roughness is better at controlling soil and water losses. However, to date there have been few studies into the effect of both magnitude and orientation of SSR on runoff, infiltration and soil erosion at the sub process level (i.e. by raindrop splash and overland flow), occurring simultaneously. In this study, the effects of up-down-slope oriented SSR (Treatment A), across-slope oriented SSR (Treatment B) and random SSR (Treatment C) were compared, along with a smooth surface (Treatment D). A moderate slope gradient of 10 %, a simulated rainfall intensity of 90 mm hr−1 and storm durations of 15 or 30 min were considered. The SSR was measured using the chain method, before and after the rainfall event. Images of the soil surface were taken using a hand-held laser scanner to monitor the effect of rainfall on the surface morphology. The outcome of this study shows that rainfall erosivity increases the SSR of the initially smooth surface, but decreases that of the initially rough surface, particularly in the random SSR treatment, where the decrease in SSR was 64 % of the pre-rainfall condition. This was due to the effects of raindrop impacts and overland flow. The random SSR treatment generated significantly more runoff and soil loss, and less infiltration than all other treatments (p < 0.001), but for raindrop splash erosion, there was no significant difference between random SSR and the other treatments. Contrary to expectations, the across-slope oriented SSR did not always reduce runoff and soil erosion compared to the up-down-slope orientation. This can be explained by degradation of surface microtopography by rainfall and runoff, as confirmed by the post-rainfall SSR measurements.
Open Access
Controlling soil erosion in a changing climate: evaluating suitable plant species in grassed waterway design.
(2022-04) Lees, Corina; Simmons, Robert W.; Rickson, R. Jane
Soil erosion is a global problem which needs mitigating due to the on-site and off- site impacts it causes. Soil erosion is set to become an even greater problem due to climate change. Climate change is likely to increase the intensity, frequency and duration of precipitation events. This change in precipitation will increase flow erosivity and thus increase the chance of soil detachment. Grass-based erosion mitigation features will have to be able to withstand a higher volume of water as runoff volumes will increase due to climate change. An increased surface runoff rate will increase sediment transport capacity leading to more soil erosion when coupled with an increased detachment rate therefore solutions for the future need to be researched. Grass-based erosion mitigation features such as swales, buffer strips and grassed water ways (GWWs) have been shown to be effective. In this study, Festulolium Bx511 (F2), Festulolium cv Prior (F1) and a mixture of Festuca rubra and Lolium perenne (C) were used in mixtures and monocultures to investigate their efficacy in mitigating erosion. Experiment 1 used growth rooms under different climatic conditions, a summer scenario (22°C) and an autumn scenario (15°C). There were also different rainfall scenarios, drought (No rainfall), normal (100 % rainfall based on average rainfall (1981 – 2010) average rainfall (1981 – 2010) data from the Met Office) and excess (200 % of average rainfall (1981 – 2010) based on data from the Met Office) to see how they would affect the plant traits needed for erosion control. For summer establishment conditions the normal rainfall value was 49.2 mm, and the excess rainfall was 98.4 mm. For autumn establishment conditions the normal rainfall was 81.9 mm, and the excess value was 163.8 mm. A plant trait ranking system was devised, the species which showed promise were taken forward and used within hydraulic flume experiments to assess actual soil erosion mitigation potential. Plant traits linked to erosion control include both above ground (% cover, plant height, number of stems, number of tillers, stem diameter (mm), stem area density (mm² mm-²), above ground biomass (g) and below ground traits (root total length (cm), root total surface area (cm² ), root diameter (mm) and total root length (cm) of ≤0.25 mm diameter. Climate change is likely to change how grass plant traits are manifest due to the differing climatic conditions. Therefore, any solutions currently promoted that utilise grass monocultures and mixtures for erosion mitigation features such as GWWs may need to be revised to mitigate for climate change. Conclusions from Experiment 1 include that species selection for soil erosion control features such as GWWs must consider potential rainfall and temperature conditions during the grass establishment for optimal erosion control. There were, however, two species combinations which could be considered as year-round candidates, Fest_1+Fest_2+C and C. Experiment 2 was a hydraulic flume experiment where the inflow rates used were 0.2 – 1.4 l s¯¹. Significant differences in the following plant traits; number of stems, number of tillers, stem diameter (mm), stem area density (mm² mm-²), total root length (≤0.25 mm ⌀), total root surface area (cm ² ), and root diameter (mm) were observed between different treatments. Conv had a significantly higher number of stems as compared to all other experimental treatments. Fest_1 had a significantly higher number of tillers, stem diameter and stem area density as compared to all other treatments. Fest_1+Fest_2+C had a significantly higher total root length (≤0.25 mm ⌀) as compared to Conv. Fest_1+2 had a significantly higher total root surface area than the Fest_1 and Fest_1+Fest_2+C experimental treatments. Fest_1+Fest_2 had a significantly higher root diameter as compared to the Fest_1+Fest_2+C experimental treatment. However, significant differences did not manifest in sediment concentration. In conclusion, it did not matter if grass species monocultures or mixtures were used as there were no significant differences in sediment concentration between the experimental grass treatments. Experiment 3 was also a hydraulic flume experiment where the inflow rates used were 0.2 – 2.6 l s¯¹. In this experiment there was a lowered seeding rate (L) and a recommended seeding rate used (N). There were significant differences in plant traits and also in sediment concentration. The critical thresholds for the Environment Agency (EA) major event classification of 1000 mg l¯¹ to be reached were determined for Experiment 3. There were several experimental grass treatments which did not breach the limit set out by the EA (Conv N, Fest_1+2 L, Fest_1 N and Conv L). In conclusion the Conv L, Fest_1 N and Fest_1+2 L species treatments should be recommended for farmers for use in soil erosion mitigation features such as grassed waterways. This thesis was made possible thanks to the soils training and research studentship centre for doctoral training (STARS CDT). It was funded by Biotechnology and Biological Sciences Research Council (BBSRC) and Natural Environment Research Council (NERC), Grant/Award Number: NE-R010218-1.
Open Access
Do temperature and moisture conditions impact soil microbiology and aggregate stability?
(Springer, 2023-08-29) Dowdeswell-Downey, Emily; Grabowski, Robert C.; Rickson, R. Jane
Purpose: Studies predicting the impacts of climate change on erosion have considered numerous variables, such as rainfall erosivity and vegetation cover, but have not considered potential changes in soil erodibility. Erodibility is an intrinsic property of the soil, strongly correlated with the stability of soil aggregates. It is influenced by soil physico-chemical attributes, including the microbiological community. The study aim was to determine how shifts in temperature and moisture conditions, which other studies have shown affect microbiological communities, might affect aggregate stability. Methods: Using an experimental approach with laboratory microcosms, aggregates from a sandy loam soil and a clay soil were incubated at three temperatures and three moisture conditions in a factorial experimental design. Aggregate stability was quantified using rainfall simulation. Microbiological indicator metrics were measured to evaluate treatment microbiological impacts, including community composition (PLFA), biomass carbon, and respiration. Results: Temperature and moisture content affected aggregate stability significantly, but differently for the two soil types tested. For the sandy loam soil, aggregate stability decreased significantly with increasing moisture content. For the clay soil, aggregate stability increased significantly with increasing temperature. For both soil textures, temperature and moisture content affected microbiological community composition and respiration. Regression analysis indicated that microbiological properties were significant predictors of aggregate stability. Conclusion: Our results emphasise the dynamic nature of soil aggregate stability. Changes in microbiological metrics suggest possible biological mechanisms for aggregate stability changes, which should be investigated further to better understand the potential impacts of climate change on soil erodibility and erosion.
Open Access
Effect of clay and organic matter amendments on water and nutrient retention of sandy soils: column leaching experiment
(I I A R D Publication Company, 2021-04-30) Esther, Ogunniyi Jumoke; Olowookere, Bolanle T.; Burns, Ian G.; Lillywhite, Robert; Rickson, R. Jane
Two types of clay and an organic matter was used to investigate the potential of combined application of clay and organic matter (OM) to improve water and nutrient retention of sandy soils. Sandy soils are generally known to be problematic because of poor water and nutrient retention resulting in economic losses and environmental pollution. A laboratory column leaching experiment was conducted using a pure sand (PS) and a sandy loam (SL). Soils were amended with Kaolin (K) and bentonite (B) at 0, 2.5 and 5% (w/w) and peat (Pt) at 0, 10, 20, and 30% (v/v). Water and nutrient retention was simulated using ammonium nitrate at 150 kg N /ha in RO water. Water retention increased with the rate of each amendment applied, except for the SL amended with 2.5%K. Pt-clay combinations were more effective than either Pt or clay alone at the same rate. Combined application retained more water than the additive effect of Pt and clay for corresponding treatment except for 2.5%B in PS soil. For nutrient retention, all the clay amendments reduced nitrate and ammonium nitrogen losses in PS. Application of Pt, 2.5%K with or without Pt and 5%B with >20%Pt reduced nitrate leaching in SL. The results demonstrate that amending sandy soils with both clay and organic matter has potential to improve their water and nutrient retention
Open Access
Effects of conservation tillage drills on soil quality indicators in a wheat‐oilseed rape rotation: organic carbon, earthworms and water stable aggregates
(Wiley, 2019-07-18) Giannitsopoulos, Michail; Burgess, Paul; Rickson, R. Jane
The effects of five conservation tillage drills with crop residue levels covering between 17% and 79% of the soil, and tillage depths ranging from 25 mm to 200 mm, were examined over three years. The tillage systems ranged from a relatively disruptive Farm System to a Low Disruption system, with three intermediate treatments labelled Sumo DTS, Claydon, and Mzuri. The study involved field sites on a clay or clay loam soil, where winter wheat and oilseed rape were grown in rotation. In the clay field, the Mzuri and Low Disruption treatments, which produced the highest residue coverage, showed the greatest increase in surface total soil organic carbon (1.1 and 0.48 Mg C ha−1 respectively) between year 1 and 3. The least disruptive tillage system also resulted in the highest density of earthworms (181‐228 m−2), and the most disruptive system produced the lowest densities (75‐98 m−2). In the third year, the least disruptive system also showed a higher proportion of water stable aggregates (29.8%) than the other treatments (22.7‐25.3%). Linear regressions showed positive relationships of both soil organic carbon and earthworm density with surface residue cover, and of the proportion of water stable aggregates with soil organic carbon.
Open Access
Efficacy of mulch and tillage options to reduce runoff and soil loss from asparagus interrows
(Elsevier, 2020-04-01) Niziolomski, Joanna C.; Simmons, Robert W.; Rickson, R. Jane; Hann, Michael J.
In the UK, conventional asparagus cultivation practices on sloping land, erodible soils and increased frequency of extreme rainfall events combine to promote runoff generation and soil loss, particularly from interrows. This instrumented field study investigated the interactive effect of mulch and shallow soil disturbance (working depth of 0.175 m) on reducing runoff and soil loss. Ten treatments were installed in a commercial asparagus field near Ross-on-Wye (England, UK) during May 1st–July 17th, 2012. Straw and compost were applied to the interrows at high and low application rates (straw = 5 t ha−1 and 3 t ha−1 and compost = 18 t ha−1 and 8 t ha−1, respectively), both with or without shallow soil disturbance (SSD and Non-SSD) as compared with a bare soil, unamended Control. Across five sampling periods, Non-SSD straw mulch applied at 5 t ha−1 and 3 t ha−1; Non-SSD compost mulch at 18 t ha−1; and straw mulch applied at 5 t ha−1 with SSD all significantly reduced cumulative total soil loss by 53–72% as compared with the Control. Further, mulch treatments with SSD were in general less effective at reducing total soil loss as compared to non-SSD mulch treatments. Compost application was less effective than straw, due to sub-optimal compost blanket depths as dictated by N restrictions for Nitrate Vulnerable Zones, in which the study took place. Despite an overall reduction in total soil loss of 72% (associated with Non-SSD straw mulch applied at 5 t ha−1), soil erosion rates exceeded 1.4 t ha−1 yr−1, considered to be a tolerable erosion rate in the EU. In addition, measured sediment concentrations in the runoff consistently exceeded the EU water quality guideline value of 25 mg l−1. The results indicate that the efficacy of the treatments tested was not adequate to reduce soil erosion in commercial asparagus fields in the UK to tolerable rates. This may in large part be due to daily foot trafficking events that occur during the asparagus harvesting period (April–June) which disturbs and degrades the treatments applied reduing their efficacy. This study demonstrates that additional research is required in order to identify effective erosion control measures to ensure the sustainability of commercial asparagus production systems in the UK
Open Access
Efficacy of selected phosphorous sorbing materials (PSMs) to enhance the orthophosphate sorption capacity of filter socks
(Wiley, 2020-11-18) Cooke, A. L.; Simmons, Robert W.; Rickson, R. Jane; Sakrabani, Ruben
Agricultural phosphate (PO43‐) is a major cause of water quality compliance failures. Filter socks (FS) are a sediment‐control method proven to be effective at removing sediment and sediment bound‐P. Within the water and wastewater treatment industries phosphorous sorbing materials (PSMs) are widely used to remove reactive PO43‐. Combining PSMs with FS provides an opportunity to concomitantly remove sediment, sediment bound‐P and PO43‐ from agricultural runoff. A column experiment was undertaken to evaluate the efficacy of selected PSMs to remove PO43‐ across a range of PO43‐ concentrations (0.08, 0.26 and 1.3 mg/l) and contrasting FS fill media (PAS 100 Compost and Woodchip). The results indicate that Ca‐enriched ferrihydrite removed up to 99% of PO43‐, and was the only PSM to reduce PO43‐ to below the target value of <0.05 mg/l. An initial cost benefit analysis indicates that PSM‐enhanced FS are a viable option to remove PO43‐ from agricultural runoff.
Open Access
Evaluation of pedotransfer functions to estimate some of soil hydraulic characteristics in North Africa: a case study from Morocco
(Frontiers, 2023-02-08) Beniaich, Adnane; Otten, Wilfred; Shin, Ho-Chul; Cooper, Hannah; Rickson, R. Jane; Soulaimani, Azia; El Gharous, Mohamed
Soil hydraulic properties are an important factor to optimize and adapt water management for a given crop. Pedotransfer functions (PTFs) present a solution to predict soil variables such as hydraulic properties, using fundamental soil properties. In this research, we compared two sources of soil information: iSDAsoil data and field data, in four regions in Morocco. We then used this data to evaluate published data and developed new PTFs using soil information to estimate soil gravimetric moisture content at saturation (w0), field capacity (w330) and permanent wilting point (w15000). A total of 331 samples were collected from four regions: Doukkala, Gharb-Loukous, Moulouya and Tadla. The data was divided into calibration and validation datasets. For development of different PTFs, we used simple linear regression, multiple linear regression, regression tree, Cubist algorithm, and random forest approaches. PTFs developed by Dijkerman (Geoderma, 1988, 42, 29–49) presented the best performance, showing lower RMSE, Bias and MAE compared to other PTFs. Using multiple linear regression to develop PTFs, models based on clay, silt and soil organic matter as input variables showed the best performance after calibration (R2 of 0.590, 0.785, 0.786 for w0, w330, and w15000, respectively). Regarding the techniques based on machine learning, random forest showed the best performance after calibration compared with other algorithms (R2 of 0.930, 0.955, 0.954 for w0, w330, and w15000, respectively). PTFs represent a low cost and easy technique to estimate soil hydraulic properties, to improve water management efficiency for the farmers.
Open Access
Filter socks to mitigate sediment, sediment-bound phosphate and orthophosphate losses, from arable lands under extreme rainfall events.
(2018-02) Cooke, Alexandra; Simmons, Robert W.; Rickson, R. Jane; Sakrabani, Ruben
Agricultural diffuse pollution is a major environmental issue within the UK. Within England alone, sediment and phosphates in agricultural runoff account for 2967 rivers failing their Water Framework Directive (WFD) water quality targets. Effective end-of-pipe solution sediment control measures include silt fences, buffer strips and berms. However, with the exception of buffer strips, these are not widely used in agricultural lands. Furthermore in terms of extreme rainfall events, their long-term efficacy is limited or unproven, as well as their ability to also remove orthophosphate. Filter socks (FS) are widely used as construction site sediment control within the USA, and could provide another mitigation option; however there has been limited testing for a UK environment, and their current fill media does not aid orthophosphate removal. Phosphorus sorbing materials (PSMs) are widely used within the wastewater treatment industry to remove orthophosphate. This research evaluated the efficacy of PSM amended FS to concurrently remove sediment, sediment-bound phosphate, and orthophosphate. In Phase 1, FS were evaluated in terms of their sediment removal ability, with and without a proprietary PSM, under UK agricultural field conditions. Runoff and eroded sediment was collected from erosion plots under a maize cropping regime. The 9-month replicated field trial results indicated variable results. The fill media produced an initial release of fines and orthophosphate after installation, although this declined over time. This flush event significantly increased the amount of sediment and orthophosphate found within the runoff of the FS compared to the runoff from the control, in sampling period 1. By the last sampling period, irrespective of fill-media (Woodchip or PAS 100 Compost), FS reduced runoff sediment load compared to the non-FS control. Orthophosphate removal was not increased by the addition of the proprietary PSM. Consequently a range of alternative PSMs were evaluated in Phase 2. Alternative PSMs were identified from a literature review. Their ability to remove orthophosphate was established through a fully replicated column experiment over a range of orthophosphate concentrations (0.08 – 1.30 mg P l⁻¹). The results indicate that ferrihydrite and goethite ochres were significantly more effective than all other treatments, with orthophosphate removal efficiencies ranging from 51 – 99 % and 32 –94 %, respectively. Furthermore the ferrihydrite ochre was the only PSM to reduce the orthophosphate concentration to below that of the water quality target for the Lugg river catchment (0.05 mg P l⁻¹). As the most effective PSMs, these were taken forward to Phase 3 where PSM amended FS were assessed for concurrent sediment, sediment-bound phosphate and orthophosphate removal under simulated laboratory experiments. Efficacy and performance was established across a series of replicated laboratory experiments using a rainfall-runoff simulator. These incorporated extreme rainfall events (80 mm hr⁻¹ intensity, 5 - 25 min duration), representing return periods of 5, 18,41, 74 and 126 yr for the Lugg catchment, Herefordshire. These used an erodible sandy loam soil that represented the dominant erodible soil type of the Lugg catchment, and a 17o slope representing the 80th Percentile slope for these erodible soils within the Lugg catchment. There were no significant differences in sediment removal efficiency between the treatments, irrespective of fill media (Woodchip or PAS 100 Compost), PSM (ferrihydrite ochre, goethite ochre, proprietary product), or rainfall event. Sediment removal efficiencies ranged from 66 – 97%. Treatments consistently removed up to 88% and 82% of eroded clay and silt sized particles, which is significant for the effective removal of sediment-bound phosphate. Ferrihydrite was the most effective PSM for orthophosphate removal with removal efficiencies of up to 34%. The 3 year trial indicated that more research is required to establish the wider validity of FS as a mitigation measure. This needs to encompass extensive field trials, incorporating their efficacy in other cropping situations with different soil types, slopes and climate conditions (e.g. annual rainfall). The research showed that PSM-amended FS are efficient at concurrently removing sediment, sediment-bound phosphate, and orthophosphate from runoff in laboratory studies, and are efficient under a range of laboratory based rainfall events. However this needs to be verified in field conditions to ensure that they remain a viable mitigation option for the future. Furthermore, research needs to be undertaken into the longevity of the materials for sediment and orthophosphate control in field conditions.
Open Access
Human cadaver burial depth affects soil microbial and nutrient status
(Equinox Publishing, 2019-05-16) Pawlett, Mark; Rickson, R. Jane; Niziolomski, Joanna; Churchill, Sophie; Kešner, Michal
this can enhance the natural recycling of nutrients to the soil through improved interactions between the corpse and the soil ecosystem. However, there is a paucity of knowledge describing the interactions between the human cadaver and soil microbiology at any depth. The effects of shallow were compared to standard burial depth on soil chemical (available nitrogen and phosphorus, and organic matter) and microbial (total biomass and activity, fungal biomass, and microbial community composition) characteristics in two soil types (sandy loam and clay). Measurements were taken six and eight weeks after the burial of fresh pork ribs (used as a substitute for the human cadaver). Quantities of plant available nitrogen, as both ammonium-N (clay soil) and nitrate-N (both soil types), were greater where the pork was shallow buried. In addition, there was a shift in the composition of the bacterial component of the soil microbial community where the pork was shallow buried compared to deep burial (sandy loam soil only). There were no differences between the two burial depths (both soil types) in soil organic matter, available phosphorus, total microbial biomass or activity, or the proportion of fungi within the microbial community. The differences in available nitrogen and the lack of differences in the bacterial community composition between the two depths for the clay soils is likely to be due to reduced pore space and hence reduced oxygen at depth, which would dominate any response of the microbial community to the decomposing meat.
Open Access
Indicators of soil quality - Physical properties (SP1611). Final report to Defra
(Defra, 2012-09-30) Rickson, R. Jane; Deeks, Lynda K.; Corstanje, Ronald; Newell-Price, Paul; Kibblewhite, Mark G.; Chambers, B.; Bellamy, Patricia; Holman, Ian P.; James, I. T.; Jones, Robert; Kechavarsi, C.; Mouazen, Abdul; Ritz, K.; Waine, Toby
The condition of soil determines its ability to carry out diverse and essential functions that support human health and wellbeing. These functions (or ecosystem goods and services) include producing food, storing water, carbon and nutrients, protecting our buried cultural heritage and providing a habitat for flora and fauna. Therefore, it is important to know the condition or quality of soil and how this changes over space and time in response to natural factors (such as changing weather patterns) or to land management practices. Meaningful soil quality indicators (SQIs), based on physical, biological or chemical soil properties are needed for the successful implementation of a soil monitoring programme in England and Wales. Soil monitoring can provide decision makers with important data to target, implement and evaluate policies aimed at safeguarding UK soil resources. Indeed, the absence of agreed and well-defined SQIs is likely to be a barrier to the development of soil protection policy and its subsequent implementation. This project assessed whether physical soil properties can be used to indicate the quality of soil in terms of its capacity to deliver ecosystem goods and services. The 22 direct (e.g. bulk density) and 4 indirect (e.g. catchment hydrograph) physical SQIs defined by Loveland and Thompson (2002) and subsequently evaluated by Merrington et al. (2006), were re-visited in the light of new scientific evidence, recent policy drivers and developments in sampling techniques and monitoring methodologies (Work Package 1). The culmination of these efforts resulted in 38 direct and 4 indirect soil physical properties being identified as potential SQIs. Based on the gathered evidence, a ‘logical sieve’ was used to assess the relative strengths, weaknesses and suitability of each potential physical SQI for national scale soil monitoring. Each soil physical property was scored in terms of: soil function – does the candidate SQI reflect all soil function(s)? land use - does the candidate SQI apply to all land uses found nationally? soil degradation - can the candidate SQI express soil degradation processes? does the candidate SQI meet the challenge criteria used by Merrington et al. (2006)?This approach enabled a consistent synthesis of available information and the semi-objective, semi-quantitative and transparent assessment of indicators against a series of scientific and technical criteria (Ritz et al., 2009; Black et al., 2008). The logical sieve was shown to be a flexible decision-support tool to assist a range of stakeholders with different agenda in formulating a prioritised list of potential physical SQIs. This was explored further by members of the soil science and soils policy community at a project workshop. By emphasising the current key policy-related soil functions (i.e. provisioning and regulating), the logical sieve was used to generate scores which were then ranked to identify the most qualified SQIs. The process selected 18 candidate physical SQIs. This list was further filtered to move from the ‘narrative’ to a more ‘numerical’ approach, in order to test the robustness of the candidate SQIs through statistical analysis and modelling (Work Package 2). The remaining 7 physical SQIs were: depth of soil; soil water retention characteristics; packing density; visual soil assessment / evaluation; rate of erosion; sealing; and aggregate stability. For these SQIs to be included in a robust national soil monitoring programme, we investigated the uncertainty in their measurement; the spatial and temporal variability in the indicator as given by observed distributions; and the expected rate of change in the indicator. Whilst a baseline is needed (i.e. the current state of soil), it is the rate of change in soil properties and the implications of that change in terms of soil processes and functioning that are key to effective soil monitoring. Where empirical evidence was available, power analysis was used to understand the variability of indicators as given by the observed distributions. This process determines the ability to detect a particular change in the SQI at a particular confidence level, given the ‘noise’ or variability in the data (i.e. a particular power to detect a change of ‘X’ at a confidence level of ‘Y%’ would require ‘N’ samples). However, the evidence base for analysing the candidate SQIs is poor: data are limited in spatial and temporal extent for England and Wales, in terms of a) the degree (magnitude) of change in the SQI which significantly affects soil processes and functions (i.e. ‘meaningful change’), and b) the change in the SQI that is detectable (i.e. what sample size is needed to detect the meaningful signal from the variability or noise in the signal). This constrains the design and implementation of a scientifically and statistically rigorous and reliable soil monitoring programme. Evidence that is available suggests that what constitutes meaningful change will depend on soil type, current soil state, land use and the soil function under consideration. However, when we tested this by analysing detectable changes in packing density and soil depth (because data were available for these SQIs) over different land covers and soil types, no relationships were found. Schipper and Sparling (2000) identify the challenge: “a standardised methodology may not be appropriate to apply across contrasting soils and land uses. However, it is not practical to optimise sampling and analytical techniques for each soil and land use for extensive sampling on a national scale”. Despite the paucity in data, all seven SQIs have direct relevance to current and likely future soil and environmental policy, because they can be related (qualitatively) to soil processes, soil functions and delivery of ecosystem goods and services. Even so, meaningful and detectable changes in physical SQIs may be out of time with any soil policy change and it is not usually possible to link particular changes in SQIs to particular policy activities. This presents challenges in ascertaining trends that can feed into policy development or be used to gauge the effectiveness of soil protection policies (Work Package 3). Of the seven candidate physical SQIs identified, soil depth and surface sealing are regarded by many as indicators of soil quantity rather than quality. Visual soil evaluation is currently not suited to soil monitoring in the strictest sense, as its semi-qualitative basis cannot be analysed statistically. Also, few data exist on how visual evaluation scores relate to soil functions. However, some studies have begun to investigate how VSE might be moved to a more quantified scale and the method has some potential as a low cost field technique to assess soil condition. Packing density requires data on bulk density and clay content, both of which are highly variable, so compounding the error term associated with this physical SQI. More evidence is needed to show how ‘meaningful’ change in aggregate stability affects soil processes and thus soil functions (for example, using the limited data available, an equivocal relationship was found with water regulation / runoff generation). The analysis of available data has given promising results regarding the prediction of soil water retention characteristics and packing density from relatively easy to measure soil properties (bulk density, texture and organic C) using pedotransfer functions. Expanding the evidence base is possible with the development of rapid, cost-effective techniques such as NIR sensors to measure soil properties. Defra project SP1303 (Brazier et al., 2012) used power analyses to estimate the number of monitoring locations required to detect a statistically significant change in soil erosion rate on cultivated land. However, what constitutes a meaningful change in erosion rates still requires data on the impacts of erosion on soil functions. Priority cannot be given amongst the seven SQIs, because the evidence base for each varies in its robustness and extent. Lack of data (including uncertainty in measurement and variability in observed distributions) applies to individual SQIs; attempts at integrating more than one SQI (including physical, biological and chemical SQIs) to improve associations between soil properties and processes / functions are only likely to propagate errors. Whether existing monitoring programmes can be adapted to incorporate additional measurement of physical SQIs was explored. We considered options where one or more of the candidate physical SQIs might be implemented into soil monitoring programmes (e.g. as a new national monitoring scheme; as part of the Countryside Survey; and as part of the National Soil Inventory). The challenge is to decide whether carrying out soil monitoring that is not statistically robust is still valuable in answering questions regarding current and future soil quality. The relationship between physical (and other) SQIs, soil processes and soil functions is complex, as is how this influences ecosystem services’ delivery. Important gaps remain in even the realisation of a conceptual model for these inter-relationships, let alone their quantification. There is also a question of whether individual quantitative SQIs can be related to ecosystem services, given the number of variables.
Open Access
The microbiology of arable soil surfaces
(Cranfield University, 2007-10) Jeffery, Simon; Ritz, K.; Harris, Jim A.; Rickson, R. Jane
Whilst much is known about the physics and erosion of soil surfaces on a millimetre scale, little is known about the associated microbiology, particularly in temperate arable systems. The vast majority of research regarding microbial interactions at soil surfaces has concerned microbiotic crusts. However, such surface crusts take many years to form and then only in relatively undisturbed soil systems. Arable soil surfaces are subject to relatively extreme environmental conditions, potentially undergoing rapid changes in relation to temperature, water status and solar radiation compared to deeper soil zones. These extreme environmental parameters are likely to have a large impact on the biota found at the arable soil surface when compared to that which occurs in deeper soil zones. Phenotypic profiling using phospholipid fatty acid (PLFA) analysis, microbial biomass, and chlorophyll concentration were used to characterise soil microbial communities with the aim of quantifying differences within the surface layers of arable systems on a millimetre scale. This field work was supported with a series of microcosm-scale studies in which parameters such as length of time between disturbance events and the quality of light reaching the soil surface were controlled. Using microcosms subjected to simulated rainfall and imaged using X-ray computed tomography scanning, the effects of the soil surface microbiota on associated physical properties including structural integrity, porosity, erodibility and hydrological properties were investigated. This research showed that given sufficient time between disturbance events, environmental parameters such as temperature and wet:dry cycling were sufficient to drive the formation of a distinct soil surface phenotype, which appeared to be consistently confined to an order of depth of circa 1 mm. It was notable that the PLFA 16:0 was consistently associated with discrimination between phenotypes between soil surface layers. Calculation of the ratio of fungal to bacterial PLFA biomarkers showed a consistently higher ratio of fungi to bacteria present in the soil surface layer to a depth of circa 1 mm, providing evidence that fungi grow preferentially over the soil surface compared to through the soil matrix. Further investigation demonstrated that light, particularly at photosynthetically active wavelengths, was the main driving factor in the establishment of the distinct soil surface phenotypes. The inocula which drove the formation of such soil-surface community phenotypes, especially the photoautotrophic components, was demonstrated to derive predominantly from aerial sources. Functionally the nature of the soil surface community was found to affect run-off generation and shear strength at the surface. There was no significant impact of the soil surface microbiota on erodibility or water infiltration rates, although whilst distinct surface phenotypes had developed in this experimental circumstance, these were relatively deficient in photoautotrophs compared to other microcosm experiments and field circumstances, and hence extrapolation of this conclusion is not sound. This project has demonstrated that a soil surface ecological niche may exist in other unexplored soil surfaces and highlights the needs to explore this possibility and to examine any associated functional consequence should such niches be found to exist.
Open Access
National-scale geodata describe widespread accelerated soil erosion
(Elsevier, 2020-04-20) Benaud, Pia; Anderson, Karen; Evans, Martin; Farrow, Luke; Glendell, Miriam; James, Michael R.; Quine, Timothy Andrew; Quinton, John Norman; Rawlins, Barry G.; Rickson, R. Jane; Brazier, Richard E.
Accelerated soil erosion can result in substantial declines in soil fertility and has devastating environmental impacts. Consequently, understanding if rates of soil erosion are acceptable is of local and global importance. Herein we use empirical soil erosion observations collated into an open access geodatabase to identify the extent to which existing data and methodological approaches can be used to develop an empirically-derived understanding of soil erosion in the UK (by way of an example). The findings indicate that whilst mean erosion rates in the UK are low, relative to the rest of Europe for example, 16% of observations on arable land were greater than the supposedly tolerable rate of 1 t ha−1 yr−1 and maximum erosion rates were as high as 91.7 t ha−1 yr−1. However, the analysis highlights a skew in existing studies towards locations with a known erosion likelihood and methods that are biased towards single erosion pathways, rather than an all-inclusive study of erosion rates and processes. Accordingly, we suggest that future soil erosion research and policy must address these issues if an accurate assessment of soil erosion rates at the national-scale are to be established. The interactive geodatabase published alongside this paper offers a platform for the simultaneous development of soil erosion research, formulation of effective policy and better protection of soil resources
Open Access
Optimising conservation tillage systems for wheat and oilseed rape production.
(2017-02) Giannitsopoulos, Michail; Burgess, Paul J.; Rickson, R. Jane; Littlemore, James
The aims of the thesis are to determine the effect of different conservation tillage systems on the agronomic, environmental and economic performance of a wheat and oilseed rape rotation, and to understand the processes involved so that the systems can be improved. The field research examined five systems over three seasons (September 2013 to August 2016) in two fields (one clay and one clay loam) in Northamptonshire. The most disruptive tillage treatment was the Farm system comprising the use of a Sumo Trio when establishing oilseed rape, and the Sumo Trio and a Kuhn seed drill when establishing wheat. The least disruptive system was a Väderstad Seed Hawk or Rapid. The other three treatments were all one pass conservation tillage systems comprising a Claydon Hybrid Drill, a Mzuri Pro til 3, and a Sumo Deep Tillage Seeder (DTS). To understand the effect on draught and soil disturbance, specific components of the systems were tested under controlled conditions at Cranfield University’s soil bin facility. The shallow working Väderstad required the lowest draught and disturbed less soil than deep working treatments. A low aspect ratio (working depth/implement width) and rake angle reduced the draught. In the field immediately after tillage, the Farm system showed the greatest reduction in bulk density and penetration resistance at 0-50 mm and 150-200 mm, but this effect was not maintained during the season. The level of surface residue was lowest (15%) with the Farm system and greatest (75%) with the Väderstad. The shallow Väderstad led to the highest earthworm abundance in all years and both fields, proportions of water stable aggregates and microbial biomass carbon in third and first year respectively. In the clay field, blackgrass infestation doubled from 8.2% in 2013-14 to 16.0% in 2015-16; it was not a major problem in the clay loam field. Due to high variability, there was no significant effect (p>0.05) of tillage treatments on the yield of wheat and oilseed rape over the 3-year trial period in either field, except when delayed drilling of oilseed rape with the Sumo DTS in September 2015 which led to reduced yields. At a reduced significance level of p=0.15, higher yields observed for Väderstad and Mzuri in the clay soil were associated with higher levels of organic matter. The relative profitability of the five systems was primarily determined by the assumed yields and secondly by the cost of the systems. The predicted annual net margin for the five systems varied from £545 to £659 ha¯¹. The calculated cost of the five tillage systems (assuming working areas ranging from 370 to 1,100 ha) ranged from £11 to £31 ha¯¹ a¯¹, with the lowest cost achieved by the 6 m Claydon system. Assuming blackgrass weeds are not an issue, shallow low disturbance systems can result in low costs, improved soil biology and carbon storage, and sustainable high yields.
Open Access
Optimising soil disturbance and mulch attenuation for erosion and runoff control in asparagus crops
(Cranfield University, 2014-12) Niziolomski, Joanna; Simmons, Robert W.; Rickson, R. Jane
Exposure of bare soil for long periods and onsite compaction create soil and water problems in asparagus production. This project aims to develop a cost effective and practical runoff and soil erosion management system. Two field trials (Phase 1 running from April - July 2012 and Phase 2 running from May - November 2013) tested different combinations of shallow soil disturbance (SSD) and mulch (straw and compost) application for soil erosion control. Cranfield University’s soil bin was used to test the effect of different tine configurations on soil disturbance. The results of this research corroborated observations that asparagus production can result in levels of unsustainable soil loss that will contribute to the degradation of the existing soil resource. The field trials demonstrated that a straw mulch applied at 6 t ha- 1 significantly improved key performance indicators (KPIs, i.e. runoff initiation, volume and rate; total soil loss; sediment concentration; total oxides of nitrogen; orthophosphate-P; and sediment-bound P) as compared with the Non-SSD Control. In general, SSD (irrespective of tine configuration) was ineffective at improving key performance indicators as compared with the Non-SSD Control. In the soil bin work, different tine configurations generated varying degrees and extent of SSD, with the modified para-plough giving the greatest soil disturbance for the least draught force. However, the differences in SSD observed in the soil bin had no effect on the KPI’s tested in the Phase 2 field trial. The effective treatments observed in the field trials only yielded cost savings to the farmer/grower when a high level of soil loss occurred. This research highlights the need to develop erosion control measures in asparagus fields, with wider implications to other row crops. However caution is needed, given the observed variation in effectiveness and reliability of in-field mitigation measures, especially during ‘extreme’ rainfall events.
Open Access
Physical soil quality indicators for monitoring British soils
(Copernicus Publications, 2016-11-18) Corstanje, Ronald; Mercer, Theresa G.; Rickson, R. Jane; Deeks, Lynda K.; Newell-Price, Paul; Holman, Ian P.; Kechavarzi, Cédric; Waine, Toby W.
The condition or quality of soils determines its ability to deliver a range of functions that support ecosystem services, human health and wellbeing. The increasing policy imperative to implement successful soil monitoring programmes has resulted in the demand for reliable soil quality indicators (SQIs) for physical, biological and chemical soil properties. The selection of these indicators needs to ensure that they are sensitive and responsive to pressure and change e.g. they change across space and time in relation to natural perturbations and land management practices. Using a logical sieve approach based on key policy-related soil functions, this research assessed whether physical soil properties can be used to indicate the quality of British soils in terms of its capacity to deliver ecosystem goods and services. The resultant prioritised list of physical SQIs were tested for robustness, spatial and temporal variability and expected rate of change using statistical analysis and modelling. Six SQIs were prioritised; packing density, soil water retention characteristics, aggregate stability, rate of erosion, depth of soil and soil sealing. These all have direct relevance to current and likely future soil and environmental policy and are appropriate for implementation in soil monitoring programs.
Open Access
Polymer-based treatments to control runoff, leachate and erosion from engineered slopes at Simfer Mine, Guinea, Africa
(Cranfield University, 2013-05) Campbell, Stephanie; Simmons, Robert W.; Rickson, R. Jane
It is necessary to understand the erodibility and hydrological response of mine-site slope forming materials (SFMs), because of increasing awareness of the environmental impacts of mining. Steep engineered slopes in high intensity rainfall environments present a serious erosion risk. Temporary surface stabilisers, such as polyacrylamides (PAMs) and polyvinylacrylic latex (PVALs) are potentially cost effective erosion control solutions. In this study PAM and PVAL efficacy to reduce runoff, leachate and erosion was assessed at two application rates, with and without gypsum on SFMs from an iron ore mine in Guinea (West Africa). NSPASS (near-surface photogrammetry assessment of slope forming materials’ surface roughness) is a novel method that integrates digital image capture and GIS. It is shown to detect and quantify surface micro-relief changes of 2-3 mm, not visible to the naked eye. As expected, soil and non-soil SFMs were significantly different in terms of their physical and chemical properties. Phase I of the study investigated the erodibility of ten SFMs, including soil, ore and waste-rock. The results indicate that the hydrological response to rainfall of most SFMs is to generate leachate. Weathered phyllite (PHY-WEA) is the most erodible SFM by both runoff and leachate. Multiple regression analysis demonstrated that magnetic susceptibility, mineralogy and dry aggregate distribution; parameters not commonly assessed in erosion studies, are important in explaining SFM erodibility and hydrological response. Phase II evaluated critically the effectiveness of three commercially available polymer solutions (two PAMs and one PVAL) at reducing runoff, leachate and erosion from four of the most erodible SFMs identified in Phase I. The results indicate that some PAM and PVAL treatments significantly reduce runoff, leachate and erosion. Polymer efficacy is highly dependent on the physical and chemical properties of the SFM, as well as the mechanism of polymer to SFM adsorption. Increasing the application rate of select treatments lowered leachate volumes, runoff and leachate total sediment loads. Contrary to previous studies, gypsum amendments did not significantly improve polymer efficiency. This research has added to our understanding of the erodibility and hydrological response of soil and non-soil SFMs. This is the first study to evaluate critically the efficacy of PVALs in controlling erosion from mine-site SFMs. Future studies should continue to optimise NSPASS performance in monitoring changes in surface micro-relief.
Open Access
Practical soil protection and stabilization in Mediterranean viticulture
(Cranfield University, Cranfield University at Silsoe, 2006-11-01T11:57:43Z) Llewellyn, C. A.,; Rickson, R. Jane
The accelerated erosion of soil by water from Mediterranean hill-slopes under viticulture is a major problem. It is largely a result of the land management techniques employed and their influence on soil protection, structure and stability. Within this study, the relationships between viticulture practices, soil physical characteristics and erosion processes have been explored in detail, and a soil conservation strategy, which incorporates the use of herbicide managed cover, has been developed. The strategy was applied and tested in two established vineyards in southern France over a three year period (October 2001 to December 2004). Sediment and runoff losses were monitored at the plot scale from the date of treatment installation and comparisons were made with the losses from plots under conventional soil management. Cultivation, to produce a fine seedbed for cover establishment, encouraged soil to become hydrophobic and impeded drainage at depth. This aggravated soil losses under saturated conditions and impeded cover establishment. However, total sediment losses were reduced by the presence of a cover at both sites within the monitoring period. The results of a ‘Visual Soil Assessment’ showed that there was a measurable improvement in the physical condition of the soil of the vegetated plot three and a half years after the cover was sown. Controlled laboratory studies were conducted to identify the most suitable herbicide product and dose rate for inducing dormancy in a grass cover, whilst retaining its protective and stabilizing properties. Two products were tested: Paraquat and Glyphosate. At 21 days after treatment application, the treatment effects on plant and soil physical characteristics were assessed. Herbicide product and dose were found to indirectly influence a soil’s potential to erode but more detailed studies are required. Initial results suggest that Paraquat is the more suitable of the two products tested. The study concluded that herbicide managed permanent cover is a practical option for soil conservation in Mediterranean viticulture.