11 research outputs found
The population dynamics of weeds in winter wheat
SIGLEAvailable from British Library Document Supply Centre-DSC:DXN004564 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
Scale, experimental design and the detection of interspecific competition within plant communities
The impact of future socio-economic and climate changes on agricultural land use and the wider environment in East Anglia and North West England using a metamodel system
This paper describes a procedure to use a model interactively to investigate
future land use by studying a wide range of scenarios defining climate,
technological and socio-economic changes. A full model run of several hours has
been replaced by a metamodel version which takes a few seconds, and provides the
user with an immediate visual output and with the ability to examine easily
which factors have the greatest effect. The Regional Impact Simulator combines a
model of agricultural land use choices linked with models of urban growth,
flooding risk, water quality and consequences for wildlife to estimate plausible
futures of agricultural land on a timescale of 20â50 years. The model examines
the East Anglian and North West regions of the United Kingdom at a grid
resolution of 5 Ă 5 km, and for each scenario estimates the most likely cropping
and its profitability at each location, and classifies land use as arable,
intensive or extensive grassland or abandoned. From a modelling viewpoint the
metamodel approach enables iteration. It is thus possible to determine how
product prices change so that production meets demand. The results of the study
show that in East Anglia cropping remains quite stable over a wide range of
scenarios, though grassland is eliminated in scenarios with the 2050s High
climate scenario â almost certainly due to the low yield in the drier
conditions. In the North West there is a very much greater range of outcomes,
though all scenarios suggest a reduction in grassland with the greatest in the
2050s High climate scenario combined with the âRegional Stewardshipâ
(environmental) socio-economic scenario. The effects of the predicted changes in
land use on plant species showed suitability for species to vary greatly,
particularly between the socio-economic scenarios, due to detrimental effects
from increases in nitrogen fertilisation. A complete simulation with the
Regional Impact Simulator takes around 15 seconds (computer-dependent), which
users who responded felt was adequate or better than adequate. The main areas
for future improvement, such as the speed of the system, user interaction and
the accuracy and detail of the modelling, are c
Scale, Experimental Design and the Detection of Ineterspecific Competition within Plant Communities
Modelling the effects of sub-lethal doses of herbicide and nitrogen fertilizer on crop?weed competition
Application method of nitrogen fertilizer affects weed growth and competition with winter wheat
An introduction to the farm-scale evaluations of genetically modified herbicide-tolerant crops
1. Several genetically modified herbicide-tolerant (GMHT) crops have cleared most of the regulatory hurdles required for commercial growing in the United Kingdom. However, concerns have been expressed that their management will have negative impacts on farmland biodiversity as a result of improved control given by the new herbicide regimes of the arable plants that support farmland birds and other species of conservation value. 2. The Farm-Scale Evaluations (FSE) project is testing the null hypothesis that there is no difference between the management of GMHT varieties of beet, oilseed rape and maize and that of comparable conventional varieties in their effect on the abundance and diversity of arable plants and invertebrates. The FSE also aims to estimate the magnitude and consider the implications of any differences that are found. 3. The experimental design of the FSE is a randomized block, with two treatments allocated at random to half-fields. The target sample is around 60-75 fields for each crop, selected to represent variation of geography and intensity of management across Britain. The experimental crops are managed by commercial farmers as if under commercial conditions. 4. Biodiversity indicators have been selected from plants and terrestrial invertebrates to identify differences between crop management regimes that may result in important ecological changes over larger scales of space and time. Field sampling is at fixed points, mainly along transects from the field boundary, starting before the crop is sown and continuing into following crops. 5. Synthesis and applications. The FSE is best considered as an investigation into the effects of contrasting crop management regimes on farmland biodiversity, rather than a study of the effects of genetic modification. It could become a model for future studies of ecological effects of the way we use and manage agricultural land