Mark Young | The James Hutton Institute (original) (raw)

Papers by Mark Young

Nitrogen

The nitrogen applied (N-input) to cropping systems supports a high yield but generates major envi... more The nitrogen applied (N-input) to cropping systems supports a high yield but generates major environmental pollution in the form of greenhouse gas (GHG) emissions and losses to land and water (N-surplus). This paper examines the scope to meet both GHG emission targets and zero N-surplus in high-intensity, mainly cereal, cropping in a region of the Atlantic zone in Europe. A regional survey provides background to crops grown at an experimental farm platform over a run of 5 years. For three main cereal crops under standard management (mean N-input 154 kg ha−1), N-surplus remained well above zero (single year maximum 55% of N-input, five-year mean 27%), but was reduced to near zero by crop diversification (three cereals, one oilseed and one grain legume) and converted to a net nitrogen gain (+39 kg ha−1, 25 crop-years) by implementing low nitrification management in all fields. Up-scaling N-input to the agricultural region indicated the government GHG emissions target of 70% of the 199...

Plant and Soil, 2022

Purpose (1) To assess the biological N fixation (BNF) potential of varieties of faba bean (Vicia ... more Purpose (1) To assess the biological N fixation (BNF) potential of varieties of faba bean (Vicia faba L.) cropped with or without compost in an experimental field-scale rotation with no recent history of legumes, (2) to enumerate soil populations of Rhizobium leguminosarum sv. viciae (Rlv), and to genetically characterize the nodulating Rlv strains, (3) compare BNF with other sites in Britain. Methods BNF was evaluated from 2012 to 2015 using 15 N natural abundance. Treatments were either PK fertilizer or compost. Soil rhizobial populations were determined using qPCR, the symbiotic rhizobia genotyped (16 S rRNA, nodA and nodD genes), and their BNF capacity assessed ex situ. The reliance of legumes on BNF at other British sites was estimated in a single season, and their nodulating symbionts examined. Results Faba bean obtained most of its N through BNF (>80%) regardless of variety or year. N-accumulation by cvs Babylon and Boxer increased with compost treatment in 2014/2015. Rhiz...

Plants, 2021

A systematic approach to quantifying the weed–crop balance through the flux of solar radiation wa... more A systematic approach to quantifying the weed–crop balance through the flux of solar radiation was developed and tested on commercial fields in a long-established Atlantic zone cropland. Measuring and modelling solar energy flux in crop stands has become standard practice in analysis and comparison of crop growth and yield across regions, species and years. In a similar manner, the partitioning of incoming radiation between crops and the in-field plant community may provide ‘common currencies’ through which to quantify positive and negative effects of weeds in relation to global change. Here, possibilities were explored for converting simple ground-cover measures in commercial fields of winter and spring oilseed rape in eastern Scotland, UK to metrics of solar flux. Solar radiation intercepted by the crops ranged with season and sowing delay from 129 to 1975 MJ m−2 (15-fold). Radiation transmitted through the crop, together with local weed management, resulted in a 70-fold range of ...

Agronomy, 2018

The intensification of arable production since the 1950s has resulted in increases in yield but o... more The intensification of arable production since the 1950s has resulted in increases in yield but only at significant cost to the environment, raising serious concerns about long-term consequences for the sustainability of food production systems. While a range of policies and practices have been put in place to mitigate negative effects in terms of pollution, soil degradation and loss of biodiversity, their efficacy has not been properly quantified. Whole-system effects of management change are rarely studied and so trade-offs and conflicts between different components of the agricultural system are poorly understood. A long-term field platform was therefore established in which conventional arable management was compared with a low-input, integrated cropping system designed with the goal to maintain yields whilst enhancing biodiversity and minimizing environmental impact. Over the first rotation, only winter wheat yielded less under integrated management; yield was maintained for th...

Agriculture, Ecosystems & Environment, 2015

Environmental science and pollution research international, Jan 25, 2017

Environmental risk assessment of GM crops in Europe proceeds by step-wise estimation of effect, f... more Environmental risk assessment of GM crops in Europe proceeds by step-wise estimation of effect, first in the plant, then the field plot (e.g. 10-100 m(-2)), field (1000-10,000 m(-2)) and lastly in the environment in which the crop would be grown (100-10,000 km(2)). Processes that operate at large scales, such as cycling of carbon (C) and nitrogen (N), are difficult to predict from plot scales. Here, a procedure is illustrated in which plot scale data on yield (offtake) and N inputs for blight resistant (both GM and non-GM) and blight-susceptible potato are upscaled by a model of crop resource use to give a set of indicators and metrics defining N uptake and release in realistic crop sequences. The greatest potential damage to environment is due to loss of N from the field after potato harvest, mainly because of the large quantity of mineral and plant matter, high in N, that may die or be left in the field. Blight infection intensifies this loss, since less fertiliser N is taken up b...

Optimization of Plant Nutrition, 1993

Mathematical models of crop growth can provide estimates of the potential yield of potato, and al... more Mathematical models of crop growth can provide estimates of the potential yield of potato, and also the minimum, critical N-concentration required, [Nc], to attain that yield. Efficient use of nitrogen requires that the crop incorporates sufficient nitrogen to attain its potential yield and that excess uptake is avoided. Predictions of the rate of supply of nitrogen from the soil are

Optimization of Plant Nutrition, 1993

Potato leaf, stem and tuber samples have been analysed for nitrogen concentration [N], by three m... more Potato leaf, stem and tuber samples have been analysed for nitrogen concentration [N], by three methods; Kjeldahl digestion, Dumas combustion, and near infra-red reflectance (NIR) spectroscopy. Models to estimate [N] from NIR have been developed using either Kjeldahl or Dumas for calibration. Estimates of [N] from all three methods, are highly correlated. However, [N] measurements by Kjeldahl and Dumas are not in agreement. Kjeldahl has a recovery rate of ca. 98% organic-N and variable recovery of inorganic-N. Dumas measures both organic- and inorganic-N with a recovery rate of 100%. The suitability of Kjeldahl as an analytical technique must be questioned when NIR methods are available which will give accurate [N] values quickly, safely and cheaply.

Physiologia Plantarum, 2007

The extent of functional trait diversity is quantified for 157 different Capsella bursa‐pastoris ... more The extent of functional trait diversity is quantified for 157 different Capsella bursa‐pastoris (L.) medic (shepherd’s purse) accessions. These individuals encompass replicate progeny generated from seed of 53 different Capsella‘maternal lines’ that were isolated at random as they emerged from soil cores (used to estimate baseline seed bank numbers and weed diversity) at 34 different arable sites across the United Kingdom. The replicate progeny were subject to ex situ characterisation for traits determining life history and architecture. Seven leaf‐type classes were identified and representative parents of each leaf type were distinguishable using four different simple sequence repeat markers. Life‐history traits were only loosely associated with leaf shape, and cluster analysis grouped the accessions into three broad types: small plants that flowered early with intermediate reproductive output; large plants, with intermediate time to flowering and a high reproductive output; late‐...

Journal of Near Infrared Spectroscopy, 1995

Oven dried samples of leaf stem and tuber material taken from a nitrogen field experiment were an... more Oven dried samples of leaf stem and tuber material taken from a nitrogen field experiment were analysed by Dumas combustion when fresh and by near infrared (NIR) then, and in the next two years, by a number of operators who made estimates of nitrogen concentration, [N]NIR, with differing degrees of error. The errors differed between years in the case of the one operator who made estimates in two years. Leaf, stem and tuber material of high and low nitrogen concentration were treated to produce samples at various moisture contents. These samples were scanned by NIR and the spectral data were examined. Higher moisture was found to decrease the reflectance at all the wavelengths used and would, therefore, introduce error into [N]NIRestimates. The NIR calibration used was found to be applicable to cultivars in a range of maturity classes. Several recommendations are made that will help to minimise the error introduced into [N]NIRestimates from various sources.

European Journal of Agronomy, 2012

ABSTRACT Grain admixture due to gene flow of oilseed rape (OSR) could be economically damaging. D... more ABSTRACT Grain admixture due to gene flow of oilseed rape (OSR) could be economically damaging. Different strategies are currently used or proposed to manage grain quality, ranging from homogenisation at the silo level to tactical decision rules at the field level. The relevance of these general strategies was appraised in the case of genetically modified (GM) OSR in three contrasted regions in Europe: Beauce Blésoise (France), Schleswig-Flensburg (Germany), and Fife (UK). Field patterns, crop allocation and agricultural practices were derived from existing datasets and complementary field surveys. Then a gene flow simulator was used to assess how the local contexts influenced the grain admixture between GM and non-GM OSR (without separation measures). The simulations showed that grain admixtures in fields followed a leptokurtic curve. While, however, the worst case was similar in the three regions, the median differed greatly depending on contextual factors such as the size and arrangement of fields. Grain admixture very rarely exceeded the 0.9% threshold for non-GM products if assessed at the level of the silo, at which the grains from all non-GM crops were combined, while maintaining crops below the threshold at the field level required management of a few high risk situations. Analysing grain admixtures and commercial risks at different decision levels (field, silo) demonstrated the efficiency of “flexible” as opposed to “rigid” measures, but this technical analysis did not take other criteria like regulatory issues into account.

Environmental Science and Pollution Research, 2008

Background, aim and scope In a gradualist approach to the introduction of crop biotechnology, the... more Background, aim and scope In a gradualist approach to the introduction of crop biotechnology, the findings of experimentation at one scale are used to predict the outcome of moving to a higher scale of deployment. Movement through scales had occurred for certain genetically modified herbicide-tolerant (GMHT) crops in the UK as far as large-scale field trials. However, the land area occupied by these trials was still <1% of the area occupied by the respective non-GM crops. Some means is needed to predict

Ecological Modelling, 2011

This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit:

Ecological Modelling, 2008

Data mining techniques were applied to model the presence and abundance of volunteer oilseed rape... more Data mining techniques were applied to model the presence and abundance of volunteer oilseed rape (OSR) (Brasica napus L.) in the seedbank at 257 arable fields used for baseline sampling in the UK's Farm Scale Evaluations of genetically modified herbicide tolerant (GMHT) crops. Constructed models were supported by statistical tests. Volunteer OSR was most likely present if a previous OSR crop had been grown in the same field, but it was also present at sites where it had not been grown in the previous 8 years (24% of all fields). In 136 fields where it was found, it showed a slow decline in abundance since the last crop. However, data mining indicated previously unfound correlations between oilseed rape abundance, total seedbank and several other factors, notably percent of nitrogen and percent of carbon in the soil, all of which were smallest in the centre of arable production in southern England and greatest in the surrounding southwest , west and north. In a separate analysis, its abundance was also associated with particular plant life history groups, which include broadleaf weeds such as Capsella and Matricaria species, having a similar phenology to oilseed rape, between rapidly developing annuals and the biennials and perennials. The findings are a reference point in the evolution of oilseed rape as a weed and potential GM impurity. Data mining approaches provide models that may be used to assess the status of volunteer OSR in other countries or at a later time in the UK.

Agriculture, Ecosystems & Environment, 2010

The diversity and abundance of the within-field seedbank and emerged weed flora, were measured in... more The diversity and abundance of the within-field seedbank and emerged weed flora, were measured in over 100 fields from conventional, integrated and organic farms across the arable east of Scotland. Both seedbank and emerged flora showed significant responses to a management intensity gradient from farms with high agrochemical inputs and winter cropping to those with no inorganic inputs, spring cropping and mixed farming practices. The emerged weed flora was more affected by recent agrochemical inputs than was the seedbank, which is buffered by the persistence of weed seeds in the soil. The seedbank was more strongly influenced by soil characteristics, such as % organic carbon and % total nitrogen, than by management. Overall farming approach (categorised here as organic, integrated and conventional) appeared to exert a selection pressure on the species composition of the seedbank, building up different communities under the three farming approaches over time. These effects were scale dependent. At a within-field scale, species richness was greatest in organic farms where there was a greater abundance of weeds. At a regional and landscape scale, species richness was greater in integrated and conventional farms. This was particularly evident in integrated farms which represented a greater range of crop types and cropping practices between fields than either conventional of organic farms alone. Increasing the diversity of cropping practices between fields may offer a complementary approach to reducing agrochemical inputs for enhancing arable biodiversity across landscapes.

Agricultural and Forest Entomology, 2011

Aphid population dynamics in crops are often driven by interactions with their host plants, which... more Aphid population dynamics in crops are often driven by interactions with their host plants, which can be extensively influenced by environmental change. Protective environments (i.e. plastic tunnels) are now frequently used for soft fruit production, which may affect the localized climate and alter such interactions. This two year study on red raspberry (Rubus idaeus) addressed how protected environments affected two aphid species; the large raspberry aphid Amphorophora idaei (LRA) and the small raspberry aphid Aphis idaei (SRA). Temperatures were higher (up to 7–10 °C) in tunnels compared with the field. Plants in tunnels grew approximately 1.4 cm/week faster and had lower (approximately 35%) foliar amino acid concentrations than plants in the field. Aphids affected plant growth differently depending on growing environment; they promoted plant growth by 18–37% in tunnels, although they had no such effect in the field. Aphids reduced total and essential amino acid concentrations, wi...

Environmental Science and Pollution Research, 2010

Nitrogen

The nitrogen applied (N-input) to cropping systems supports a high yield but generates major envi... more The nitrogen applied (N-input) to cropping systems supports a high yield but generates major environmental pollution in the form of greenhouse gas (GHG) emissions and losses to land and water (N-surplus). This paper examines the scope to meet both GHG emission targets and zero N-surplus in high-intensity, mainly cereal, cropping in a region of the Atlantic zone in Europe. A regional survey provides background to crops grown at an experimental farm platform over a run of 5 years. For three main cereal crops under standard management (mean N-input 154 kg ha−1), N-surplus remained well above zero (single year maximum 55% of N-input, five-year mean 27%), but was reduced to near zero by crop diversification (three cereals, one oilseed and one grain legume) and converted to a net nitrogen gain (+39 kg ha−1, 25 crop-years) by implementing low nitrification management in all fields. Up-scaling N-input to the agricultural region indicated the government GHG emissions target of 70% of the 199...

Plant and Soil, 2022

Purpose (1) To assess the biological N fixation (BNF) potential of varieties of faba bean (Vicia ... more Purpose (1) To assess the biological N fixation (BNF) potential of varieties of faba bean (Vicia faba L.) cropped with or without compost in an experimental field-scale rotation with no recent history of legumes, (2) to enumerate soil populations of Rhizobium leguminosarum sv. viciae (Rlv), and to genetically characterize the nodulating Rlv strains, (3) compare BNF with other sites in Britain. Methods BNF was evaluated from 2012 to 2015 using 15 N natural abundance. Treatments were either PK fertilizer or compost. Soil rhizobial populations were determined using qPCR, the symbiotic rhizobia genotyped (16 S rRNA, nodA and nodD genes), and their BNF capacity assessed ex situ. The reliance of legumes on BNF at other British sites was estimated in a single season, and their nodulating symbionts examined. Results Faba bean obtained most of its N through BNF (>80%) regardless of variety or year. N-accumulation by cvs Babylon and Boxer increased with compost treatment in 2014/2015. Rhiz...

Plants, 2021

A systematic approach to quantifying the weed–crop balance through the flux of solar radiation wa... more A systematic approach to quantifying the weed–crop balance through the flux of solar radiation was developed and tested on commercial fields in a long-established Atlantic zone cropland. Measuring and modelling solar energy flux in crop stands has become standard practice in analysis and comparison of crop growth and yield across regions, species and years. In a similar manner, the partitioning of incoming radiation between crops and the in-field plant community may provide ‘common currencies’ through which to quantify positive and negative effects of weeds in relation to global change. Here, possibilities were explored for converting simple ground-cover measures in commercial fields of winter and spring oilseed rape in eastern Scotland, UK to metrics of solar flux. Solar radiation intercepted by the crops ranged with season and sowing delay from 129 to 1975 MJ m−2 (15-fold). Radiation transmitted through the crop, together with local weed management, resulted in a 70-fold range of ...

Agronomy, 2018

The intensification of arable production since the 1950s has resulted in increases in yield but o... more The intensification of arable production since the 1950s has resulted in increases in yield but only at significant cost to the environment, raising serious concerns about long-term consequences for the sustainability of food production systems. While a range of policies and practices have been put in place to mitigate negative effects in terms of pollution, soil degradation and loss of biodiversity, their efficacy has not been properly quantified. Whole-system effects of management change are rarely studied and so trade-offs and conflicts between different components of the agricultural system are poorly understood. A long-term field platform was therefore established in which conventional arable management was compared with a low-input, integrated cropping system designed with the goal to maintain yields whilst enhancing biodiversity and minimizing environmental impact. Over the first rotation, only winter wheat yielded less under integrated management; yield was maintained for th...

Agriculture, Ecosystems & Environment, 2015

Environmental science and pollution research international, Jan 25, 2017

Environmental risk assessment of GM crops in Europe proceeds by step-wise estimation of effect, f... more Environmental risk assessment of GM crops in Europe proceeds by step-wise estimation of effect, first in the plant, then the field plot (e.g. 10-100 m(-2)), field (1000-10,000 m(-2)) and lastly in the environment in which the crop would be grown (100-10,000 km(2)). Processes that operate at large scales, such as cycling of carbon (C) and nitrogen (N), are difficult to predict from plot scales. Here, a procedure is illustrated in which plot scale data on yield (offtake) and N inputs for blight resistant (both GM and non-GM) and blight-susceptible potato are upscaled by a model of crop resource use to give a set of indicators and metrics defining N uptake and release in realistic crop sequences. The greatest potential damage to environment is due to loss of N from the field after potato harvest, mainly because of the large quantity of mineral and plant matter, high in N, that may die or be left in the field. Blight infection intensifies this loss, since less fertiliser N is taken up b...

Optimization of Plant Nutrition, 1993

Mathematical models of crop growth can provide estimates of the potential yield of potato, and al... more Mathematical models of crop growth can provide estimates of the potential yield of potato, and also the minimum, critical N-concentration required, [Nc], to attain that yield. Efficient use of nitrogen requires that the crop incorporates sufficient nitrogen to attain its potential yield and that excess uptake is avoided. Predictions of the rate of supply of nitrogen from the soil are

Optimization of Plant Nutrition, 1993

Potato leaf, stem and tuber samples have been analysed for nitrogen concentration [N], by three m... more Potato leaf, stem and tuber samples have been analysed for nitrogen concentration [N], by three methods; Kjeldahl digestion, Dumas combustion, and near infra-red reflectance (NIR) spectroscopy. Models to estimate [N] from NIR have been developed using either Kjeldahl or Dumas for calibration. Estimates of [N] from all three methods, are highly correlated. However, [N] measurements by Kjeldahl and Dumas are not in agreement. Kjeldahl has a recovery rate of ca. 98% organic-N and variable recovery of inorganic-N. Dumas measures both organic- and inorganic-N with a recovery rate of 100%. The suitability of Kjeldahl as an analytical technique must be questioned when NIR methods are available which will give accurate [N] values quickly, safely and cheaply.

Physiologia Plantarum, 2007

The extent of functional trait diversity is quantified for 157 different Capsella bursa‐pastoris ... more The extent of functional trait diversity is quantified for 157 different Capsella bursa‐pastoris (L.) medic (shepherd’s purse) accessions. These individuals encompass replicate progeny generated from seed of 53 different Capsella‘maternal lines’ that were isolated at random as they emerged from soil cores (used to estimate baseline seed bank numbers and weed diversity) at 34 different arable sites across the United Kingdom. The replicate progeny were subject to ex situ characterisation for traits determining life history and architecture. Seven leaf‐type classes were identified and representative parents of each leaf type were distinguishable using four different simple sequence repeat markers. Life‐history traits were only loosely associated with leaf shape, and cluster analysis grouped the accessions into three broad types: small plants that flowered early with intermediate reproductive output; large plants, with intermediate time to flowering and a high reproductive output; late‐...

Journal of Near Infrared Spectroscopy, 1995

Oven dried samples of leaf stem and tuber material taken from a nitrogen field experiment were an... more Oven dried samples of leaf stem and tuber material taken from a nitrogen field experiment were analysed by Dumas combustion when fresh and by near infrared (NIR) then, and in the next two years, by a number of operators who made estimates of nitrogen concentration, [N]NIR, with differing degrees of error. The errors differed between years in the case of the one operator who made estimates in two years. Leaf, stem and tuber material of high and low nitrogen concentration were treated to produce samples at various moisture contents. These samples were scanned by NIR and the spectral data were examined. Higher moisture was found to decrease the reflectance at all the wavelengths used and would, therefore, introduce error into [N]NIRestimates. The NIR calibration used was found to be applicable to cultivars in a range of maturity classes. Several recommendations are made that will help to minimise the error introduced into [N]NIRestimates from various sources.

European Journal of Agronomy, 2012

ABSTRACT Grain admixture due to gene flow of oilseed rape (OSR) could be economically damaging. D... more ABSTRACT Grain admixture due to gene flow of oilseed rape (OSR) could be economically damaging. Different strategies are currently used or proposed to manage grain quality, ranging from homogenisation at the silo level to tactical decision rules at the field level. The relevance of these general strategies was appraised in the case of genetically modified (GM) OSR in three contrasted regions in Europe: Beauce Blésoise (France), Schleswig-Flensburg (Germany), and Fife (UK). Field patterns, crop allocation and agricultural practices were derived from existing datasets and complementary field surveys. Then a gene flow simulator was used to assess how the local contexts influenced the grain admixture between GM and non-GM OSR (without separation measures). The simulations showed that grain admixtures in fields followed a leptokurtic curve. While, however, the worst case was similar in the three regions, the median differed greatly depending on contextual factors such as the size and arrangement of fields. Grain admixture very rarely exceeded the 0.9% threshold for non-GM products if assessed at the level of the silo, at which the grains from all non-GM crops were combined, while maintaining crops below the threshold at the field level required management of a few high risk situations. Analysing grain admixtures and commercial risks at different decision levels (field, silo) demonstrated the efficiency of “flexible” as opposed to “rigid” measures, but this technical analysis did not take other criteria like regulatory issues into account.

Environmental Science and Pollution Research, 2008

Background, aim and scope In a gradualist approach to the introduction of crop biotechnology, the... more Background, aim and scope In a gradualist approach to the introduction of crop biotechnology, the findings of experimentation at one scale are used to predict the outcome of moving to a higher scale of deployment. Movement through scales had occurred for certain genetically modified herbicide-tolerant (GMHT) crops in the UK as far as large-scale field trials. However, the land area occupied by these trials was still <1% of the area occupied by the respective non-GM crops. Some means is needed to predict

Ecological Modelling, 2011

This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit:

Ecological Modelling, 2008

Data mining techniques were applied to model the presence and abundance of volunteer oilseed rape... more Data mining techniques were applied to model the presence and abundance of volunteer oilseed rape (OSR) (Brasica napus L.) in the seedbank at 257 arable fields used for baseline sampling in the UK's Farm Scale Evaluations of genetically modified herbicide tolerant (GMHT) crops. Constructed models were supported by statistical tests. Volunteer OSR was most likely present if a previous OSR crop had been grown in the same field, but it was also present at sites where it had not been grown in the previous 8 years (24% of all fields). In 136 fields where it was found, it showed a slow decline in abundance since the last crop. However, data mining indicated previously unfound correlations between oilseed rape abundance, total seedbank and several other factors, notably percent of nitrogen and percent of carbon in the soil, all of which were smallest in the centre of arable production in southern England and greatest in the surrounding southwest , west and north. In a separate analysis, its abundance was also associated with particular plant life history groups, which include broadleaf weeds such as Capsella and Matricaria species, having a similar phenology to oilseed rape, between rapidly developing annuals and the biennials and perennials. The findings are a reference point in the evolution of oilseed rape as a weed and potential GM impurity. Data mining approaches provide models that may be used to assess the status of volunteer OSR in other countries or at a later time in the UK.

Agriculture, Ecosystems & Environment, 2010

The diversity and abundance of the within-field seedbank and emerged weed flora, were measured in... more The diversity and abundance of the within-field seedbank and emerged weed flora, were measured in over 100 fields from conventional, integrated and organic farms across the arable east of Scotland. Both seedbank and emerged flora showed significant responses to a management intensity gradient from farms with high agrochemical inputs and winter cropping to those with no inorganic inputs, spring cropping and mixed farming practices. The emerged weed flora was more affected by recent agrochemical inputs than was the seedbank, which is buffered by the persistence of weed seeds in the soil. The seedbank was more strongly influenced by soil characteristics, such as % organic carbon and % total nitrogen, than by management. Overall farming approach (categorised here as organic, integrated and conventional) appeared to exert a selection pressure on the species composition of the seedbank, building up different communities under the three farming approaches over time. These effects were scale dependent. At a within-field scale, species richness was greatest in organic farms where there was a greater abundance of weeds. At a regional and landscape scale, species richness was greater in integrated and conventional farms. This was particularly evident in integrated farms which represented a greater range of crop types and cropping practices between fields than either conventional of organic farms alone. Increasing the diversity of cropping practices between fields may offer a complementary approach to reducing agrochemical inputs for enhancing arable biodiversity across landscapes.

Agricultural and Forest Entomology, 2011

Aphid population dynamics in crops are often driven by interactions with their host plants, which... more Aphid population dynamics in crops are often driven by interactions with their host plants, which can be extensively influenced by environmental change. Protective environments (i.e. plastic tunnels) are now frequently used for soft fruit production, which may affect the localized climate and alter such interactions. This two year study on red raspberry (Rubus idaeus) addressed how protected environments affected two aphid species; the large raspberry aphid Amphorophora idaei (LRA) and the small raspberry aphid Aphis idaei (SRA). Temperatures were higher (up to 7–10 °C) in tunnels compared with the field. Plants in tunnels grew approximately 1.4 cm/week faster and had lower (approximately 35%) foliar amino acid concentrations than plants in the field. Aphids affected plant growth differently depending on growing environment; they promoted plant growth by 18–37% in tunnels, although they had no such effect in the field. Aphids reduced total and essential amino acid concentrations, wi...

Environmental Science and Pollution Research, 2010