search for: arabl

...e/R/R-2.5.0/Data/Worms.txt", header = T) > worms Field.Name Area Slope Vegetation Soil.pH Damp Worm.density 1 Oak.Mead 3.1 2 Grassland 3.9 F 2 2 Church.Field 3.5 3 Grassland 4.2 F 3 3 Ashurst 2.1 0 Arable 4.8 F 4 4 Field.Name Area Slope Vegetation Soil.pH Damp Worm.density 5 Nash's.Field 3.6 11 Grassland 4.1 F 4 6 Silwood.Bottom 5.1 2 Arable 5.2 F 7 7 Nursery.Field 2.8 3 Grassland 4.3 F...

...Field.Name Area Slope Vegetation Soil.pH Damp Worm.density 9 The.Orchard 1.9 0 Orchard 5.7 FALSE 9 16 Water.Meadow 3.9 0 Meadow 4.9 TRUE 8 10 Rookery.Slope 1.5 4 Grassland 5.0 TRUE 7 2 Silwood.Bottom 5.1 2 Arable 5.2 FALSE 7 4 Rush.Meadow 2.4 5 Meadow 4.9 TRUE 5 and here is the correct set of rows, but in the wrong order, using unique =20 worms[rev(order(Worm.density)),] [unique(Vegetation),] Field.Name Area Slope Vegetation Soil.pH Damp Worm.density 16...

...le I get the error-term right in aov(), in lme() it appears impossible to get as expected. I would be greatful for any help. My experiment aimed to identify whether two fixed factors (habitat type and soil type) affect the development of plants. I took soil from six random sites each of two types (arable and grassland) and transplanted them back into the sites of origin in such way that in each of the sites there were six pots containing arable soil and six pots of grassland soil, each containing a seedling. With aov(), I got the analysis as I expected, with habitat type tested against destinatio...

...seem too simplistic and discard most variables with the result that there is no predictive power in the result. I would expect that there will be interactions between variables eg. if the vegetation is grassland then the vegetation height variable will mediate the interaction, if the vegetation is arable then crop type will be more significant. Would it be possible to use GLM or GAM models for this type of predictive modelling? Any assistance would be greatly appreciated - it's several years since I last used R for this type of work and unfortunately I don't have the support network of a...

...pe) > habitat=factor(habitat) > destination=factor(destination) > origin=factor(origin) > summary(aov(response~soiltype*habitat+Error(destination+origin))) > anova(lme(response~soiltype*habitat,random=~1|destination/origin)) > # > #"habitat" type is either 'arable' or 'grassland' > #"destination" indicates what site the soil was transplanted into, and is considered a random factor within habitat type > #"soiltype" is either 'arable' or 'grassland' > #"origin" indicates what site the soil...

...though this seemed to avoid the memory problem, it ran so slowly that it wasn't much use for someone with deadlines to meet... I don't have formal training in programming, so if there's something handy I should read, do let me know. Thanks, Richard Gunton. Postdoctoral researcher in arable weed ecology, INRA Dijon. [[alternative HTML version deleted]]

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