This paper reports the design and results of a study to consider the effects of deep, shallow and zero tillage with random conventional and low tyre inflation pressures and controlled traffic systems on the yield of winter wheat, winter barley (x2) and spring oats. The results show that crop yields for zero tillage were significantly less (P<0.001) than deep and shallow tillage for all crops with an overall reduction of 1.0 t/ha below the mean of the deep and shallow tillage practices. Controlled traffic farming with a 30% trafficked area produced significantly higher yields than random conventional pressure traffic for the winter wheat and spring oats. Controlled traffic farming, with trafficked areas of 30% and 15% showed overall benefits over random conventional inflation pressure traffic of 0.32 t ha-1 (£41 ($51) ha-1) and 0.61 t ha-1 (£77 ($96) ha-1) respectively, requiring breakeven areas of 312 ha and 168 ha to cover the costs of 3 vehicle guidance/auto-steering systems.

Biosolids were applied with urea to produce a granulated organo-mineral fertiliser (OMF) for application by farm fertiliser equipment to a range of agricultural crops. The recommended rates of nitrogen, phosphate and potash were calculated for the test crops using “The Fertiliser Manual”, which assesses the nutrient requirement based on previous cropping, rainfall and soil index. The OMF produced similar crop yields compared to ammonium nitrate fertiliser when applied as a top-dressing to winter wheat, forage maize and grass cut for silage in the cropping years 2010 to 2014. In 2012 the grain yield of spring barley top-dressed with OMF was significantly lower than the conventional fertiliser treatment, due to dry conditions following application. For this reason it is recommended that OMF is incorporated into the seedbed for spring sown crops and The Safe Sludge Matrix guidelines followed. The experimental work presented shows that OMF can be used in sustainable crop production systems as a source of nitrogen and phosphorus for a range of agricultural crops.

The objective of this study was to investigate the rate of water infiltration into the soil under different soil compaction levels caused by livestock and farm machinery. Measurements were performed on grassland which is situated at Harper Adams University, UK. The soil type is classified as a sandy loam - Eutric Cambisols . The following treatments were evaluated: non-compacted soil, compaction by cattle hooves and compaction by tractor with trailer. Infiltration rate was measured by simplified falling-head and cone index to a depth of 0.3 m using a cone penetrometer. Results of the simplified falling-head infiltration method showed a significantly higher water infiltration rate in the non-compacted soil than the compacted soil. There was no statistical difference in the infiltration rate following compaction by cattle hooves and compaction by tractor. The mean values of water infiltration rate measured on compacted soil by cattle hooves and tractor with trailer showed 2.6% difference. The measurements of cone index showed a significant difference only in the case of compaction by cattle hooves, where a decrease of cone index values by approximately 20% in the depth from 0.15 to 0.25 m occurred. Overall it was found that the ground pressure of 200 -250 kPa reduces water infiltration properties of the soil more than 80% in comparison to the non-compacted soil.

Agricultural vehicles are getting heavy and compaction results in lower yields, poor soil structure and soil-water regimes. A number of studies have shown that the first pass causes the most damage and therefore care must be taken to ensure that when tractors enter the field they are fitted with the most appropriate running gear for the application and for the local soil conditions. Low Ground Pressure (LGP) traffic systems, including tyres and tracks, reduce the ground pressure under field traffic to minimise the risk of soil compaction. The aim of this study was to determine the effect of standard and LGP systems, including tracks and tyres on soil pressure and physical properties. The research objectives were to quantify the effect of 1) rubber tracks (16 tonne Cat Challenger 765C) compared to 2) standard tyres and 3) LGP specific tyres (12 tonne 290 HP Massey Ferguson 8480). Standard and LGP tyres were inflated to 1) high inflation pressures at 1.2 bar front, 1.5 bar rear, and 2) low inflation pressures at 0.7 bar front and rear. Soil pressure was measured using strain gauge pressure transducers at a depth of 300 mm in the centre of the wheel. Data were collected using a National Instruments CompactRio system and logged with virtual instrument software on a laptop PC. Soil physical properties were determined using a cone penetrometer. Peak soil pressures under the rubber tracks (0.27 bar) were significantly lower (<0.05) than under high inflation pressure tyre treatments (0.39 bar standard tyres; 0.48 bar LGP tyres). An increase in tyre inflation pressure resulted in an increase in soil pressure (0.39 to 0.42 bar in standard tyres; 0.36 to 0.52 bar in LGP tyres)This study concluded that both LGP tyres at low inflation pressure and tracks were suitable to minimise soil compaction on a sandy loam soil..

Traditional agricultural production in Europe involves extensive infield trafficking for soil preparation and seeding, chemical applications, harvesting, grain and straw removal. Conventional practice, which involves random trafficking and deep tillage, exposes up to 86% of the field to soil compaction in one year resulting in poor structure, water infiltration, crop growth and yield losses. This study aims to determine the interaction of 3 traffic systems 1) Random Traffic Farming (RTF); 2) Low Ground Pressure (LGP); 3) Controlled Traffic Farming (CTF) with 3 tillage systems: 1) Deep Tillage (DT) to a depth of 250 mm; 2) Shallow Tillage (ST) to a depth of 100 mm; and 3) Zero Tillage (ZT) on soil compaction and its effect on 1) crop growth and yield, 2) soil physical properties; 3) moisture regime, and 4) energy requirements. The data presented in this paper focuses on components 1-3. Trafficking increased penetration resistance of soils at depths of 100mm and 250 mm (p<0.05) and reduced water infiltration rate at the soil surface. A neutron probe was used to characterise sub-surface soil-water interactions and showed that ST resulted in the highest SMDs, whereas DT recorded the lowest. Crop growth and yield were examined using photograph analysis and harvested yields. CTF increased yields in all Tillage systems, and resulted in a 45% increase on un-trafficked soil. The results indicate that soil-water interactions and crop yield can be improved by limiting trafficking and reducing tillage.

Sewage sludge, a waste material commonly known as biosolids, has good potential as a valuable agricultural resource, providing that its nutrient imbalances could be overcome. Sewage sludge is rich in phosphorus but low in nitrogen and potassium. Technology exists to supplement sewage sludge with mineral fertilizers, such as urea and muriate of potash as sources of nitrogen and potassium, respectively, to produce an organo-mineral fertilizer with balanced crop nutrient requirements. Here, an experimental plot trial set up in 2008 was established at Broxton, Cheshire, UK, to compare crop yield response for typical crop varieties. Crops included wheat, oilseed rape, barley, beans and forage maize, treated with conventional fertilizer and organo-mineral fertilizer. The organo-mineral fertilizer is a nutrient-balanced sludge-based product produced by drying digested sewage sludge cake at 80 °C in a tumbling evaporator, which produces sludge granules of 3–6 mm in diameter. Analysis was carried out on soil NPK and crop yield. N use efficiency was measured to assess N uptake. Results show that there is no significant difference in crop yield between treatments over the three trial years, with the exception of one crop. This finding demonstrates that the new organo-fertilizer is as efficient as conventional fertilizers. Moreover, levels of heavy metal in soil did not exceed permissible levels. The novelty of this research lies in the fact that it is the first field scale trial of a modified sewage sludge product that has the potential to transform a hitherto waste product into a practical fertilizer product. We conclude that the organo-mineral fertilizer is a promising alternative product for sustainable agriculture.

Cell immobilisation provides the opportunity to reduce the cost of producing bioethanol from lignocellulosic biomass such as oilseed rape (OSR) straw, in addition to enhancing operational stability. Bioethanol fermentation of OSR straw hydrolysate by free and immobilised Saccharomyces cerevisiae was studied. Cells were either entrapped in alginate beads or Lentikat (R) discs or immobilised as a biofilm on spent grains, Leca, or reticulated foam. The overall aims of the research were to compare bioethanol yields produced from free and immobilised systems, and to identify the most suitable immobilisation technique in terms of bioethanol yield and longevity of the immobilised cell system. Cell entrapment in alginate beads and Lentikat (R) discs resulted in significantly higher bioethanol yields compared to when cells were free in suspension or immobilised as a biofilm on a support material. The maximum amount of bioethanol produced by cells immobilised in alginate beads and Lentikat (R) discs were 169.26 +/- 0.24 and 165.13 +/- 0.67 g bioethanol kg(-1) OSR straw after 3 h and 7 h of fermentation, respectively. Due to the high mechanical stability and bioethanol yield, immobilisation of S. cerevisiae in Lentikat (R) discs was considered the most appropriate immobilisation technique for bioethanol production. (C) 2013 Elsevier Ltd. All rights reserved.

Agricultural production systems are increasingly characterised by extensive in-field trafficking of larger and heavier field machinery. The random nature of trafficking, covering 80-90% of the field area, that is characteristic of commercial practice, inevitably leads to negative impacts on soil, water and crop characteristics because of degraded soil structures, impeded root development, yield losses, water infiltration and pollution. Remedial action requires energy, time and cost. The future development of a sustainable agricultural sector needs to balance an increase in production whilst protecting the environment. Emerging technologies and engineering solutions have stimulated a recent shift towards reduced tillage methods and coupled with the development of traffic management systems, aided by Precision Agriculture (PA), aim to reduce the severity of compaction on cropped areas whilst improving efficiency and sustainability. Low Ground Pressure (LGP) systems can facilitate random trafficking and are often used to access fields during wet conditions whilst minimising the negative effects of field traffic. Alternatively, Controlled Traffic Farming (CTF) which is used predominantly in Australia confines field traffic to permanent wheel-ways and significantly reduces the total area trafficked to circa. 30% depending on working widths used. A multidisciplinary long-term project established at Harper Adams University (UK) in October 2011 is investigating the interaction between traffic and tillage on soil, crop and energy responses in a randomised and replicated study to determine the effects of Random Traffic Farming (RTF), Controlled Traffic Farming (CTF) and Low Ground Pressure (LGP) systems with Deep, Shallow and Zero Tillage. The aim of this study is to develop an integrated mechanisation system to optimise soil and water resources, crop growth, yields, system performance and economics in commercial agricultural practice.

The aim of the study was to evaluate continuous bioethanol production from oilseed rape (OSR) straw hydrolysate using Saccharomyces cerevisiae cells immobilised in Lentikat® discs. The study evaluated the effect of dilution rate (0.25, 0.50, 0.75 and 1.00 h(-1)), substrate concentration (15, 22, 40 and 60 g L(-1)) and cell loading (0.03, 0.16 and 0.24 g d.c.w.mL(-1) Lentikat®) on bioethanol production. Volumetric productivity was found to increase with increasing substrate concentration from 15 g L(-1) to 60 g L(-1). A maximum volumetric productivity of 12.88 g L(-1)h(-1) was achieved at a substrate concentration of 60 g L(-1) and at a dilution rate of 0.5h(-1). An overall mass balance for bioethanol production was created to determine the energy recovery from bioethanol and concluded that a biorefinery approach might be the most appropriate option for maximising the energy recovery from OSR straw.

Brassica napus L. (canola/oilseed rape) straw presents a suitable alternative combustion fuel due to its availability, relatively high calorific value and low moisture content. Pelletization enabled the bulk density of canola straw to be improved, enhancing its potential as an alternative combustion fuel. The aim of the research was to study the changes in the quality properties (i.e. abrasion resistance, compressive strength, particle density and pellet dimensions) of canola straw pellets during storage over a period of 48weeks. The storage of canola straw pellets did not affect the abrasion resistance of the pellets. Whilst the particle density and compressive strength varied with length of pellet storage, no trend in these variations was observed. The length of the pellets decreased during storage due to breakage, whilst, the diameter did not vary during storage.

Global cultivation of canola increased by approximately 22% between 2000 and 2009, due to increased demand for canola oil for biodiesel production and as an edible oil. In 2009 over 290,000 km2 of canola was cultivated globally. In contrast to oilseed, the commercial market for canola straw is minimal and it is generally ploughed back into the field. The high carbohydrate content (greater than 50 % by dry weight) of canola straw suggests it would be a good feedstock for second-generation bioethanol production. There are four major steps involved in bioethanol production from lignocellulosic materials: (i) pretreatment, (ii) hydrolysis, (iii) fermentation, and (iv) further purification to fuel grade bioethanol through distillation and dehydration. Previous research demonstrated a glucose yield of (440.6 ± 14.9) g kg−1 when canola straw was treated using alkaline pretreatment followed by enzymatic hydrolysis. Whilst bioethanol can be produced using cells free in solution, cell immobilization provides the opportunity to reduce bioethanol production costs by minimizing the extent to which down-stream processing is required, and increasing cellular stability against shear forces. Furthermore, the immobilization process can reduce substrate and product inhibition, which enhances the yield and volumetric productivity of bioethanol production during fermentation, improves operational stability and increases cell viability ensuring cells can be used for several cycles of operation. Previous research used cells of Saccharomyces cerevisiae immobilized in Lentikat® discs to convert glucose extracted from canola straw to bioethanol. In batch mode a yield of (165.1 ± 0.1) g bioethanol kg−1 canola straw was achieved. Continuous fermentation is advantageous in comparison to batch fermentation. The amount of unproductive time (e.g. due to filling, emptying and cleaning) is reduced leading to increased volumetric productivity. The higher volumetric productivity of continuous fermentation means that smaller reactor vessels can be used to produce the same amount of product. This reduces the capital costs associated with a fermentation plant. Research demonstrated a higher bioethanol yield was attained (224.7 g bioethanol kg−1 canola straw) when glucose was converted to bioethanol using immobilized cells in packed-bed continuous flow columns. On an energy generation basis, conversion of 1 kg of canola straw to bioethanol resulted in an energy generation of 6 MJ, representing approximately 35% energy recovery from canola straw. The amount of energy recovered from canola straw could be improved by increasing the amount of energy recovered as bioethanol and by utilising the process by-products in a biorefinery concept.

Brassica napus L. (canola/oilseed rape) straw presents a suitable alternative combustion fuel due to its availability, relatively high calorific value and low moisture content. Pelletization enabled the bulk density of canola straw to be improved, enhancing its potential as an alternative combustion fuel. The aim of the paper was to determine the effect of on-farm storage on the gross calorific value, ash content, volatile content and elemental composition of canola straw bales (stored for up to 20 months) and pellets (stored for up to 12 months). Statistically significant changes occurred to the elemental composition of straw bales and pellets during on-farm storage, but these changes were not of practical significance in terms of the materials suitability as a combustion fuel.

The effect of on-farm storage on microbial growth on baled and pelletised Brassica napus (oilseed rape/canola) straw was investigated. Canola straw collected in 2008 and 2009 was stored baled in an open shed for 3, 4, 7, 10 and 20 months in 2008 and for 1 and 3 months in 2009. Pellets were produced from straw stored for 3, 7, and 10 months in 2008 and straw stored for 3 months in 2009, and stored for up to 48 weeks.The moisture content (MC), water activity (a(w)), bacterial and fungal colony-forming units (CFU), and carbon-to-nitrogen ratio (C:N) of canola straw bales and pellets were measured during storage. In addition, temporal environmental conditions (ambient temperature and relative humidity) and bale temperature were monitored. The moisture content showed a tendency to stabilise during storage, with an equilibrium moisture content of approximately 155 g kg (-1) total weight for straw bales and 110 g kg (1) total weight for straw pellets. Consequently, the water activity of canola straw bales remained below 0.8 and that of pellets below 0.66 during storage, providing an explanation for relatively low microbial growth. The number of bacterial and fungal CFU present in the straw bales and pellets followed the trend of ambient relative humidity and no correlation was found with the C:N ratio of the biomass. Canola straw pellets were considered a superior combustion fuel to straw bales due to lower moisture content and less microbial deterioration during storage. (C) 2011 Elsevier Ltd. All rights reserved.

The objective of the research was to investigate the effect of biomass loading, acid concentration and pretreatment time on the yield of sugars obtained after acid pre-treatment and enzymatic hydrolysis of oilseed rape (OSR) straw. The highest concentration of glucose (313.4 +/- 7.53 mg g(-1) biomass) extracted after hydrolysis was achieved when OSR straw was pre-treated for 90 min; a glucan conversion efficiency of 81%. The highest concentration of sugars extracted immediately after pre-treatment was achieved with a pre-treatment time of 60 min. Pre-treatment energy efficiency in terms of total yield of sugars per MJ of energy consumed was higher when OSR straw was pre-treated for 60 min compared to 90 min even though the conversion of sugar extracted was lower at 60 min. (C) 2011 Elsevier Ltd. All rights reserved.

Earthworms are a vital constituent of the soil ecosystem and influence many soil properties and processes including structure, aeration and drainage. Intensive cultivations have been shown to affect earthworms directly through injury and fatalities and indirectly by changing their habitat, altering soil temperature, soil moisture and the availability of food. The encouragement of sustainable agriculture has resulted in increased interest and research into conservation tillage, a practise that allows earthworm populations to increase gradually in under-populated soils. Conservation tillage techniques when compared with conventional tillage utilising the mouldboard plough have been shown to have a positive impact on earthworm populations. The importance of previous management practises, in particular the influence of crop rotations and crop residue disposal, are also considered within the chapter. The combination of minimal soil disturbance coupled with the utilisation of favourable crop rotations and crop residue disposal also promote earthworm abundance, because of increased organic matter (on and in the soil) and reduced soil disturbance.

The objective of the research was to investigate the effect of biomass loading, alkali (NaOH) concentration and pre-treatment time on the yield of glucose obtained following alkaline pre-treatment and enzymatic hydrolysis of oilseed rape (OSR) straw. A maximum glucose yield of (440.6±14.9)g glucose kg−1 biomass was obtained when OSR straw was pre-treated at a biomass loading of 50gkg−1 and an alkali concentration of 0.63moldm−3 NaOH for 30min. The energy efficiency of glucose extraction (0.39kg glucose MJ−1 consumed) was highest when OSR straw was pre-treated at a biomass loading of 50gkg−1 and an alkali concentration of 0.63 or 0.75moldm−3 for 30min. The study demonstrated alkaline pre-treatment of OSR straw is superior to acid pre-treatment in terms of glucose yield and energy efficiency.

Oilseed rape (OSR) straw represents a potential feedstock for bioethanol production. Unlike carbohydrate feedstocks, lignocellulosic feedstocks must be pre-treated prior to hydrolysis and fermentation. The current study investigates the effect of acid pre-treatment conditions on the amount of glucose extracted from OSR straw following hydrolysis. Glucose yield after enzymatic hydrolysis (using cellulose and β glucosidase at 50OC) was studied by varying biomass concentration (5, 10, 15% w/w), acid concentration (1, 1.5, 2, 2.5 and 3% w/w) and pre-treatment time (10, 30, 60 and 90 min) during pre-treatment at 130OC. The maximum glucose recovery was 62% of the cellulose content of OSR straw at 5% (w/w) biomass concentration, 2.5% (w/w) acid concentration and pre-treatment time of 90 min.

In the United Kingdom there is not a significant market for oilseed rape (OSR) straw, and a large proportion of it is chopped and incorporated into the soil. Thus, the development of a market for OSR straw as a fuel would add value to the gross margin of the crop at farm level. This review paper has shown that OSR straw represents a huge potential to be used as an energy source in the UK due to its potential availability, environmental benefits, income to the farmer and relatively high gross calorific value. Its low bulk density could make storage, transport and handling economically inefficient. Converting the straw into higher density products, such as pellets or briquettes, represents a possible alternative. Alternatively, even though the chemical composition of OSR straw has shown to be significantly different to other cereals straw (e.g. higher Sulphur content) adequate adjustments in the combustion process, will make it a suitable fuel.