On the use of response models in mixture experiments
- 31 March 1987
- journal article
- research article
- Published by Springer Nature in Oecologia
- Vol. 72 (1), 95-103
- https://doi.org/10.1007/bf00385051
Abstract
Methods for assessing mixtures and their dynamic interaction over time are proposed, based on response functions relating biomass yield of each species to the densities of the component species. This approach allows a number of different facets of mixtures to be studied in a common framework. Two examples are given. Substitution rates between species and perceived densities for individuals in mixture are defined. These measure the impact of their environment on individuals. The relative resource total (RRT), is suggested as an index of whether species are capturing the same resource amount in mixture as in pure stand. Two indices of the comparative performance of species over time are proposed. The two examples, one with cattle and sheep and the other a plant mixture diallel with 6 genotypes illustrate the use of the methods. In the animal example the maximum yield mixture was calculated, the species perceptions of each other assessed and it is shown that mixing increased the resource capture by up to 17%. In general, the smaller species performed relatively better in mixture over the experimental period. In the plant example, individual plant size varied considerably over genotypes and this was reflected in their perceptions of each other, but not in their pure stand or mixed crop yield potential. Most genotype pairs showed antagonistic behaviour, whether measured by crop yield potential or by the index of resource capture. These conclusions are contrasted with those from an analysis of the data using substitutive methods.Keywords
This publication has 15 references indexed in Scilit:
- On Difficulties with Replacement-Series Methodology in Mixture ExperimentsJournal of Applied Ecology, 1986
- Importance and Measurement of Mixture Effects in Grazing SystemsPublished by Springer Nature ,1986
- On the Analysis of Competition Within Two-Species Mixtures of PlantsJournal of Applied Ecology, 1985
- A Reinterpretation of Yield Relationships in Replacement Series ExperimentsJournal of Applied Ecology, 1984
- On the Ecological Meaning of Ratio (De Wit) Diagrams in Plant EcologyEcology, 1981
- The Concept of a ‘Land Equivalent Ratio’ and Advantages in Yields from IntercroppingExperimental Agriculture, 1980
- Use of a Systematic Spacing Design as an Aid to the Study of Inter-cropping: Some General ConsiderationsExperimental Agriculture, 1978
- Design and analysis of mixed grazing experimentsAnimal Science, 1976
- Competition Among Crop and Pasture PlantsAdvances in Agronomy, 1963
- The Compound Interest Law and Plant GrowthAnnals of Botany, 1919