Arsenic (As) contamination of rice remains a major human health issue in Asia. Most research has been on irrigated rice. However much of the projected increase in global rice demand over coming decades must be met by rainfed lowland systems, for which As relations are poorly understood. We present the most comprehensive survey to date of As in rice in farmers' fields across Bangladesh, covering both irrigated and rainfed systems. We collected rice grain and soil at 943 sites in the three rice growing seasons: irrigated Boro, rainfed Aus, and longer-duration rainfed Aman. Grain As concentrations increased in the order Aman ≪ Boro < Aus with 2, 25 and 41 % of the sites exceeding permitted thresholds, respectively. The greater concentration in Aus than Boro challenges the accepted wisdom that contaminated irrigation water is the main source of As. The main growth and grain filling periods, when most As is taken up, coincide in Aus with the peak of the monsoon rains, suggesting a link between rainfall and high grain As. We suggest this is due to stronger soil reducing conditions and hence As solubility during peak rainfall. We discuss implications for rainfed lowland rice across Asia and mitigation options.

Only 5%–10% of irrigated lands in least developed countries (LDCs) are currently drained. Although drainage simulation models (DSMs) are used to evaluate alternative designs, it is unclear which drainage model is suitable for LDCs' arid and semi‐arid regions. This study evaluates selected DSMs (ADAPT, RZWQM2, DRAINMOD, EPIC, HYDRUS‐1D, WaSim and SWAP) and critically assesses their applicability to arid and semi‐arid areas. Also, establish and apply selection criteria based on the availability of data in LDCs with Libya as a case study, and identify the most suitable model for application in Libya. DRAINMOD had the highest overall score, and alternative methods to predict missing input parameters for DRAINMOD are discussed. Evaluating the feasibility of using predicted input parameters for DSMs to design drainage systems in LDCs would help farmers, planners and decision‐makers to reduce the overall cost of drainage system and, also, make DRAINMOD a more accessible tool to evaluate different drainage designs.

The use of superabsorbent polymers (SAPs) in dryland agricultural areas utilizing brackish irrigation water is a strategy to increase plant available water (AW). However, water retention by SAPs may be adversely affected under salinity. SAP containing calcium carbonate (Ca-SAP) is considered to be more resistant and provide more plant AW under saline conditions compared to conventional SAP (C-SAP) and to control. This research investigated two replicated lettuce trials to evaluate three treatments (Ca-SAP, C-SAP and control) subjected to irrigation water with electrical conductivities of 0.0, 0.5, 1.0, 2.0 and 4.0 dS m(-1). Both SAP treatments increased AW by an average of 0.16 m(3) m(-3) as compared to the control. Decrease in AW with salinity was lower in Ca-SAP (0.07 m(3) m(-3)) as compared with C-SAP (0.13 m(3) m(-3)). Lettuce fresh weight (g plant(-1)) was higher for Ca-SAP (22.9) as compared to C-SAP (16.4), however, did not differ from control (20.6). As water salinity increased, lettuce fresh biomass was higher in Ca-SAP as compared to C-SAP up to 2 dS m(-1) with no significant differences from control. The Ca-SAP is less affected by salts than the C-SAP, although its use did not benefit lettuce growth under saline conditions as expected.

There are significant gaps in our understanding of how to sustainably manage agricultural soils to preserve soil biodiversity. Here we evaluate and quantify the effects of agricultural management and location on soil microbiology using nine field trials that have consistently applied different soil management practices in the United Kingdom using DNA barcode sequence data. We tested the basic hypothesis that various agricultural management interventions have a significant and greater effect on soil bacterial and fungal diversity than geographic location. The analyses of soil microbial DNA sequence data to date has lacked standardisation which prevents meaningful comparisons across sites and studies. Therefore, to analyse these data and crucially compare and quantify the size of any effects on soil bacterial and fungal biodiversity between sites, we developed and employed a post-sequencing DNA-barcode biodiversity standard analysis method (DNA-BSAM). The DNA-BSAM comprises a series of standardised bioinformatic steps for processing sequences but more importantly defines a standardised set of ecological indices and statistical tests. Use of the DNA-BSAM reveals the hypothesis was not strongly supported, and this was primarily because: 1) there was a large variance in the effects of various management interventions at different sites, and 2) location had an equivalent or greater effect size than most management interventions for most metrics. Some dispersed sites imposed the same organic amendments interventions but showed different responses, and this combined with observations of strong differences in soil microbiomes by location tentatively suggests that any effect of management may be contingent on location. This means it could be unreliable to more widely extrapolate the findings from trials performed only at one location. The widespread use of a standard approach will allow meaningful cross-comparisons between soil microbiome studies and thus a substantial evidence-base of the effects of land-use on soil microbiology to accumulate and inform soil management decisions.

The agricultural sector faces multiple challenges linked to increased climate uncertainty, causing severe shocks including increased frequency of extreme weather events, new pest and disease risks, soil degradation, and pre and postharvest food losses. This situation is further exacerbated by geopolitical instability and volatility in energy prices impacting on fertiliser supplies and production costs. Net zero strategies are vital to achieve both food security and address negative environmental impacts. This perspective paper reviews and assesses the most viable options (actions) to achieve net zero with a focus on the arable/livestock and protected cropping sectors in the UK. The methodology was based on a synthesis of relevant literature, coupled with expert opinions using the holistic PESTLE (Political, Environmental, Social, Technological, Legal and Environmental) approach to categorise actions, leading to formulation of a roadmap to achieve net zero. The PESTLE analysis indicated that there are technically and economically viable actions available which need to be prioritised depending on the ease of their implementation within the two crop sectors investigated. These actions include (i) policy changes that are better aligned to net zero; (ii) circular economy approaches; (iii) connectivity and accessibility of information; (iv) increased resilience to shocks; (v) changing diets, nutrition and lifestyles; (vi) target setting and attainment; and (vii) farm economics and livelihoods. The outputs can be used by stakeholders and decision makers to inform policy and drive meaningful changes in global food and environmental security.

Yield physiology of asparagus (Asparagus officinalis L.) is strongly influenced by biotic factors such as crown and root rot caused by Fusarium spp. and by abiotic conditions such as precipitation or temperatures, duration of each harvest, and field management practices. Asparagus yields are linked to the availability of soluble carbohydrates (CHO) in the storage root system which is considered a key factor in asparagus productivity. The aim of this study was to quantify the impacts of the long-term application of a range of potential Best Management Practices (BMPs) on yield and storage root carbohydrate content in green asparagus in a long-term field trial. The trial was established in 2016 with the asparagus 'Gijnlim' variety. Commercial yields were collected in 2018, 2019 and 2020. Root carbohydrate content was determined in 2019 and 2020. BMPs included (1) companion crops - Rye (Secale cereale L.), Mustard (Sinapis alba L.), (2) interrow surface mulch applications of either straw mulch or PAS 100 compost (Publicly available specification) in combination with shallow soil disturbance (SSD), (3) the conventional practice and modifications of the conventional tillage practice by applying SSD or not applying SSD and (4) a zero-tillage option. Annual re-ridging (R) and not ridging (NR) were applied to BMP options 1-3. SSD had no significant impact on asparagus yields while annual re-ridging negatively affected total yields of treatments with bare soil interrows, which were managed without SSD. Conventional practice was associated with a 22% yield reduction and similar to is an element of 4250 ha(-1) annual loss in potential revenue as compared to the Zero-tillage treatment. Companion cropping with mustard did not have a significant impact on asparagus yields. Rye without annual re-ridging was however associated with yield reductions of > 20% as compared to the Conventional practice. PAS 100 Compost applied in asparagus interrows (at 25 t ha(-1) per year) in combination with SSD without annual re-ridging resulted in improvements to yields of 20%, 10% and 34% in 2018, 2019 and 2020, respectively, as compared to the Conventional practice. No correlation was observed between storage root soluble carbohydrate content and asparagus yields. The results of this study confirmed that asparagus yield, and thus total farm income can be significantly improved through implementation of several of the BMPs investigated.

Due to their high-water retention capacity, hydrogels are considered promising soil conditioners to improve soil plant available water content in semi-arid environments; however, little is known about how soil temperature affects the functionality of hydrogels. In this study, the effect of soil temperature on physical attributes of soil amended with a Acrylamide-co-Potassium Acrylate hydrogel was evaluated. A laboratory experiment was installed in a scheme (4 x 4) x 4 - four soil temperatures (30, 45, 65 and 105 degrees C), four exposure times (40, 70, 100, and 130 days) with four repetitions. The test soil was a Leptsol with sandy loam texture and of the hydrogel was applied at a dose of 0.1% w w(-1). Soil moisture at field capacity (theta(FC)) and permanent wilting point (theta(WP)), plant available water (AW), bulk density (BD), and soil porosity were evaluated. The resulting data was subjected to two-way analysis of variance. The hydrogel increased the theta(FC) of the soil, from 0.14 to 0.19 m(3) m(-3) at 45 degrees C and 56 days. At 40 days, a minimum theta(WP) (0.05 m(3) m(-3)) was observed at 92 degrees C. In general, theta(FC) increased, while the theta(WP) decreased, providing improved soil water storage. Plant available water was up to three times higher in soil with hydrogel across a temperature range of 30-105 degrees C. In all treatments irrespective of temperature and exposure time, the soil BD and porosity were improved in comparison to the un-amended control. This constitutes an advantage in the use of the hydrogel as a soil conditioner. Even with the interaction of abiotic factors acting on the hydrogel, there are beneficial effects on the water storage capacity, soil BD, and soil porosity.

Study region: The study data draws on the drainage design for Hammam agricultural project (HAP) and Eshkeda agricultural project (EAP), located in the south of Libya, north of the Sahara Desert. The results of this study are applicable to other arid areas. Study focus: This study aims to improve the prediction of saturated hydraulic conductivity (Ksat) to enhance the efficacy of drainage system design in data-poor areas. Artificial Neural Networks (ANNs) were developed to estimate Ksat and compared with empirical regression-type Pedotransfer Function (PTF) equations. Subsequently, the ANNs and PTFs estimated Ksat values were used in EnDrain software to design subsurface drainage systems which were evaluated against designs using measured Ksat values. New hydrological insights: Results showed that ANNs more accurately predicted Ksat than PTFs. Drainage design based on PTFs predictions (1) result in a deeper water-level and (2) higher drainage density, increasing costs. Drainage designs based on ANNs predictions gave drain spacing and water table depth equivalent to those predicted using measured data. The results of this study indicate that ANNs can be developed using existing and under-utilised data sets and applied successfully to data-poor areas. As Ksat is time-consuming to measure, basing drainage designs on ANN predictions generated from alternative datasets will reduce the overall cost of drainage designs making them more accessible to farmers, planners, and decision-makers in least developed countries.

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.

This research tested the hypothesis that the interaction between time and salinity reduces the water absorption potential of a hydrogel - Poly (Acrylamide-co-Potassium Acrylate) and influence the degradation of residual acrylamide monomer. The experimental design was completely randomized split-plot with four replications. The treatments were time periods (30, 60, 90 and 120 days) and levels of salinity of the hydrating solution (distilled water = 0.003, 0.5; 1.5; 3.0 and 6.0 dS m-1). Swelling, hydrogel composition, and residual acrylamide monomer concentration were evaluated. The hydrogel showed lowest water absorption potential (8.1 g g-1) in a saline solution of 4.20 dS m-1 after 120 days. The C/N ratio of the hydrogel increased by up to 47% in a hydrating solution with an EC of 4.4 dS m-1 at 120 days. Additionally, there was an observed shift in the wavelength of methylene, amide, and acrylate bands, that indicates degradation. Residual acrylamide monomer concentration was <0.5 mg g-1 (safe for agricultural use). After 120 days up to 85% of the residual acrylamide monomer was degraded. About the water absorption potential, the results suggest that under semi-arid conditions hydrogel durability for forestry and crops applications may be impaired by the salinity of the hydrating solution.

Cover crops can be utilized to lower soil nitrate leaching. However, depending on the species grown and cover crop termination management, this may lead to nitrogen (N) immobilization and/or depletion of soil moisture available to the following cash crop, potentially impacting on crop yields. Cover crop management is also dependent on using herbicides to terminate growth prior to planting the next crop. We used an alternative method for cover crop termination by capitalizing on plant senescence by frost in a multi‐species cover crop established over winter between wheat and maize. The cover crops accumulated greater quantities of N than the control. However, upon cover crop senescence due to cold temperatures, the partially terminated cover crop significantly increased topsoil available N from December to late February. This available N in the topsoil could be susceptible to leaching although this was not observed in our study. Cover crops did not have a significant prolonged effect on soil moisture over winter and late spring. The following maize yields were not significantly different between the control and cover crop treatment. Frost‐sensitive cover crop species could not be reliably terminated under a temperate climate, but provided a continuous supply of soil available N as the plants senesced. Depending on the soil moisture and weather conditions in the spring, there could be a N leaching risk although this could be mitigated by establishing early spring crops.

Grassed waterways are used to mitigate the offsite transport of sediment generated by soil erosion. This study used a novel trait-based ranking approach as a method to screen potential candidate grass monocultures and mixes based on their theoretical performance in reducing (a) detachment via rainsplash, (b) detachment via scouring due to concentrated flow and (c) sediment transport and deposition processes. Selected grass species were grown under simulated UK summer and autumn establishment conditions under three different replicated rainfall scenarios: drought, normal rainfall and excess rainfall. The grass species used were the novel hybrid species Festulolium cv Prior (Fest_1) and Festulolium Bx511 (Fest_2) and a conventional mixture of Lolium perenne and Festuca rubra (Conv). Monocultures and mixtures of these species were studied. Plant traits pertinent to control of soil erosion by water were measured. Aboveground traits included plant height, percentage ground cover, aboveground biomass, stem diameter, stem area density and number of tillers. Belowground traits included total root length, root total surface area, belowground biomass, root diameter and % fine roots <= 0.25 mm. For summer conditions, the species treatments that had the highest overall soil erosion mitigation potential were Conv, Fest_1 + 2 + Conv and Fest_2. For autumn conditions, the best treatments were Fest_1 + 2, Fest_1 + 2 + Conv and Conv. The Fest 1 + 2 + Conv had more desirable traits for erosion control than mono Festulolium treatments for the autumn conditions. The conventional mixture had more desirable traits for erosion control than mono Festulolium treatments in both climate scenarios. The results indicate that the trait-based ranking approach utilized in this study can be used to inform rapid screening of candidate grass species for soil erosion control. Highlights How to select the most suitable grass species for soil erosion control under changing climate conditions? A novel scoring system based on plant traits associated with soil erosion mitigation was developed. Fest_1 + 2 and Conv treatments expressed traits strongly associated with maximum soil erosion mitigation. Species selection for grassed waterways should consider the establishment growing season and expected rainfall.

Hydrogels are a promising management option to increase the efficiency of water use in agriculture in arid and semi-arid regions. However, abiotic factors may affect hydrogel efficacy. The effect of abiotic stress on the swelling and residual acrylamide in hydrogels was evaluated. The treatments were three hydrogels (A, B and C), four temperatures (20, 30, 40 and 65 degrees C) and two salinities (0.003 and 3.0 dS m(-1)). The swelling degree and the residual acrylamide concentration of the hydrogels were measured. Data were analyzed with univariate and multivariate statistics. The swelling order of hydrogels under low salinity was A>C>B; at high salinity was B>A>C. All hydrogels presented swelling reduction at high salinity, with swelling reductions in A and C of 97% and 85%, respectively, while B presented a swelling reduction of 37% at 20 degrees C and greater than 89% at higher temperatures. Hydrogel B achieved good swelling under saline conditions, but only at 20 degrees C. Thus, the temperature tolerance of this hydrogel should be improved so it can be used to improve water use efficiency in regions with high temperatures and salinity levels. Residual acrylamide levels of hydrogels decreased by 95% over 30 days, being safe for agricultural applications.

Field operations associated with UK asparagus production (re-ridging and intensive foot and vehicular trafficking of the wheelings) can result in severe deep-seated compaction in interrows, impacting on crop health and productivity. In this project, we investigate the long-term efficacy of a range of Best Management Practices (BMPs) targeted at preventing or remediating soil compaction in asparagus (Asparagus officinalis L.) interrows as compared to Conventional practice. BMPs included (1) companion crops - Rye (Sereale cecale L.), Mustard (Sinapis alba L.), (2) interrow surface mulch applications (straw mulch and PAS 100 compost in combination with shallow soil disturbance (SSD)), (3) modifications of the conventional tillage practice (re-ridging (R) or not ridging (NR) and applying SSD or not applying SSD) and (4) a zero-tillage option. In general, companion cropping had no effect on soil compaction or water infiltration rates as compared to the Conventional practice. Application and incorporation of straw mulch or PAS 100 compost however significantly reduced soil compaction of the interrows to >0.45 m beyond the working depth of the subsoiler (0.25 m). Composts and mulches in combination with SSD significantly reduce deep-seated compaction of the interrows within 3 years of annual application. Further, Conventional practice equivalent treatment (Bare soil No-SSD R) was associated with significantly higher PR values as compared to the zero-tillage (Bare soil No-SSD NR). These findings show that the extremely high levels of deep-seated compaction in interrows, associated with re-ridging, foot and vehicular traffic can be alleviated using surface mulches in combination with SSD.

Grassed waterways reduce water runoff, prevent scouring and encourage sediment deposition from erosion prone land. The aim of this study was to assess the efficacy of conventional and novel grass species (as monocultures and mixtures) to control erosion, at an early establishment stage (6 weeks), within grassed waterways. The experimental treatments included bare soil (B), a conventional mix of Lolium perenne and Festuca rubra (C), Festulolium cv prior (F1), Festulolium cv prior and Festulolium bx511 (F1+F2), and all grass species combined (F1+F2+C). F1 is adapted to flooded conditions, whilst F2 is adapted to drought conditions. With climate change in the UK likely to result in drier summers and wetter winters these Festulolium species will be adapted to future climatic conditions. However, little is known about their efficacy within grassed waterways. The grasses were established in 1.2 x 1 x 0.5m macrocosms in a sandy clay loam soil during June-Aug, 2019. A sub sample of each experimental treatment was taken (0.3 x 0.1 x 0.1m) from the macrocosms within a stainless steel box. Tests were replicated in quadruplicate. The following above ground trait (Stem area density) and the following below ground traits (Total root length of fine roots <0.25mm, root diameter and root surface area) were determined for each experimental replicate. Prior to testing, the grass was cut to circa 3.0 cm height to represent a mowed grass sward before being placed into a fully instrumented hydraulic flume. The hydraulic flume simulated a concentrated flow event and treatment performance was assessed in terms of turbidity, sediment concentration, soil loss and flow velocity. The effects of roots+shoots and of roots only on performance indicators were determined to quantify the relative contribution of above ground vs below ground traits in controlling erosion. One set of replicates was tested only with roots whilst another set of replicates was tested with roots+shoots and then with roots only. This was done to isolate the effect of below ground and above ground traits. All replicates were subjected to a concentrated flow event with increasing incremental flow velocities from 0.2-0.6l s-1 for bare soil, 0.2-0.8l s-1 for roots+shoots treatments and 0.2-1.4l s-1 for roots only treatments. Each flow rate velocity was run for 60 seconds. For each flow rate, duplicate water samples were taken downslope of the treatment and water depth was measured, upstream of the treatment, in the centre of the treatment and downstream of the treatment. The water samples were used to determine sediment concentrations. The water depth measurements were used to determine runoff velocity. Furthermore, a turbidity meter continuously measured turbidity during the concentrated flow event. Soil detachment and transport rates were significantly reduced for all experimental treatments as compared to the bare soil (p<0.05). Final treatment efficacy will be assessed based on a ranking of the key performance indicators. The knowledge gained from this research can be used and applied to other grassed soil erosion mitigation features such as in field and riparian buffer strips, swales as well as grassed waterways.

Over 36% of the arable area in England is at moderate to very high risk of surface sealing/crusting and erosion, including much of the better-drained and more easily worked land, especially sandy soils (Evans, 1990).The intensive production of leafy greens consists of short growing cycles –between 21 and 28 days- and intensive seedbed preparation. From seeding to emergence, the bare soil is susceptible to rainfall and irrigation induced soil sealing. The direct consequence is an impeded seedling emergence, a delay in stand establishment and reduction in plant populations, with direct impacts on productivity. To avoid soil sealing, the grower is required to undertake additional field operations such as breaking the crust, applying supplementary low intensity irrigations or, in extreme cases, replanting crops, in a vicious cycle that spirals into soil structure degradation, loss of nutrients and further soil-sealing susceptibility.Polyacrylamides (PAMs) are long-chained carbon polymers featuring an amide functional group that allows them to form bonds with an array of soil surfaces. The efficacy of PAMs to stabilise soil aggregates and prevent soil splash, capping and erosion has been documented for >25 yrs. Further, it has been demonstrated that PAMs consistently outperform bio-polymers and other synthetic alternatives. However, a technological innovation is required to effectively spray PAM on to the soil surface as typically PAM’s become extremely viscous when mixed with water making conventional spray application un-viable. This research investigates the efficacy of a dual-fluid nozzle to apply PAM to the soil surface. Conventional applications to mitigate soil sealing are either in powder form or diluted within the sprinkle irrigation system and are effective at application rates ranging from between 10 and 20 kg ha-1[SR1] (Levy et al. 1992). However, the powdered form is extremely susceptible to wind drift, and the sprinkle irrigation alternative is severely limited by the amount of water required to deliver the same amount of product. Initial nozzle calibration results indicate that PAM can be applied at rates of 13-20 kg ha-1 using 110-150 litres of water ha-1 instead of 1000 m3 ha-1(Levy et al. 1992). Subsequently, the effect of three PAM formulations with contrasting molecular weight and charge density were tested on a crust susceptible soil. Soil microcosms were subjected to two consecutive simulated rainfall events, representing pre-emergence conditions of field grown leafy salads. Treatment performance was assessed in terms of degree of crust formation. This was quantified by assessing pre and post rainfall changes in Soil Surface Roughness (SSR) using a Creaform HEXAScan laser scanner at 0.20 mm resolution, in infiltration rate using a Decagon Devices minidisk infiltrometer, and in crust penetrative resistance with a 3 mm diameter probe using an Instron 5542 tension and compression testing machine.

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); NonSSD 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.

Annually, sand and gravel processing generates approximately 20 million tonnes of non-commercial by-product as fine silt particles (<63 μm) which constitutes approximately 20% of quarry production in the UK. This study is significant as it investigated the use of quarry silt as a sub-soil medium to partially substitute soil-forming materials whilst facilitating successful post-restoration crop establishment. In a glasshouse pot experiment, top-soil and sub-soil layering was simulated, generating an artificial sub-soil medium by mixing two quarry non-commercial by-products, i.e. silt and overburden. These were blended in three ratios (100:0, 70:30, 50:50). Pots were packed to two bulk densities (1.3 and 1.5 g cm-3) and sown with three cover crops used in the early restoration process namely winter rye (Secale cereale), white mustard (Sinapis alba) and a grassland seed mixture (Lolium perenne, Phleum pratense, Poa pratensis, Festuca rubra). Three weeks into growth, the first signs of nitrogen (N) deficiency were observed in mustard plants, with phosphorus (P) and potassium (K) deficiencies observed at 35 days. Rye exhibited minor N deficiency symptoms four weeks into growth, whilst the grassland mixture showed no deficiency symptoms. The 70:30 silt:overburden sub-soil blend resulted in significantly higher Root Mass Densities of grassland seed mixture and rye in the sub-soil layer as compared with the other blends. The innovation in this work is the detailed physical, chemical and biological characterisation of silt:overburden blends and effects on root development of plants commonly used in early restoration to bio-engineer soil structural improvements.

There is a growing trend in the use of cover crops in the United Kingdom, and whilst research shows there are many soil and environmental benefits, little is known about the farmer's perspective of cover cropping. A survey was designed and distributed to ask farmers about their use and management of cover crops. The online survey received 117 usable responses between January and March 2017, following distribution through social media in the United Kingdom. The survey highlighted that 66% of respondents used cover crops following harvest in 2016. Respondents observed benefits to soil structure, soil erosion control and water infiltration in addition to reductions in the use of chemical fertilisers, herbicide and fuel use. Of those not using cover crops, 90% would consider their use in the future if additional information on their use and benefits were known in a UK context. Changes to the 2016 Basic Payment Scheme guidelines for cover crops would have been welcomed by 71% of respondents using cover crops.