How Do Soil Depth and Plant Community
Affect Festuca Growth in Rebuilt Native Grassland?

Picture

Figure 1: Festuca

Urbanization can affect natural ecosystem by eliminating the majority of native species, changing the richness and composition of the species. There are some restoration efforts to reduce the effects of urban expansion on native ecosystem, including protecting natural habitat and re-establishing modified habitat (McKinney, 2002). Therefore, rebuilding a native ecosystem has become very important. To
re-establish natural ecosystem many factors, including soil and plant community, should be studied.

Soil can influence plant growth by providing air, water and nutrients (Bronick & Lal, 2005). Inadequate soil depth can limit plant development, by restricting root growth. The relationships between soil depth and plant growth should be studied to improve the management of plant growth (Passioura, 1991). 
Picture

Figure 2: "a) shallow soil without a B horizon has low water storage and can restrict root growth and b) deeper soil with all three horizons with no physical constraints to root growth"(Reference:senrm.sa.gov.au).

Plant community may also have important effects on plant survival. Plants can regenerate both sexually and vegetatively. Sexual regeneration can happen by seed, while vegetative regeneration is a form of asexual reproduction in plants. This ability may increase competition among species.

Picture

Figure 3: Rhizomatous grass

To find the relationships between soil depth and plant growth in different plant communities a site in south Edmonton is being studied. This site is located in residential development area. 20 monitoring blocks have been set up in rebuilt native grassland. Each block has 2 plots, one containing rhizomatous species, and the other containing only non-rhizomatous species. The blocks are located in different soil depths across a range of 10 to 150 cm.

For this project, height and width of one late-successional native grass (Festuca Hallii) have been measured in the two deepest blocks and the two most shallow blocks.

Festuca hallii was selected because it is a 'late successional' grass in Rough Fescue prairie. The late successional species are key to the long-term success of the project persist in grassland. Festuca is commercially difficult to obtain and must be planted at the beginning of the project.

To examine the effect of soil depth and plant community(rhizomatous and non-rhizomatous) on Festuca growth, multi-way ANOVA was performed seperately for Festuca height and Festuca width. Also multi-way ANOVA was repeated for all species height to analyze other species with respect to soil depth and plant community effects.

I observed larger height of Festuca in rhizomatous community than in non-rhizomatous community and higher width in shallow soil than in deep soil. Also interaction effect was found between soil depth and different species. For example, in some species, larger height can be seen in shallow soil than in deep soil and in some other species there were no interaction
 

The results of the statistical analysis indicated the significant effect of plant community on Festuca height and the significant effect of soil depth on Festuca width. 

" This is a class exercise based on modified or randomly generated datasets. "