SOIL INOCULUM POTENTIAL AND ARBUSCULAR MYCORRHIZAL COLONIZATION OF ACER RUBRUM IN FORESTED AND DEVELOPED LANDSCAPES

Abstract. Arbuscular mycorrhizal fungi (AMF) form a symbiotic relationship with numerous landscape tree species and can improve tree expansion and environmental stress tolerance. Construction-related soil disturbance is meditation to diminish AMF colonization of transplanted tree in newly discloseed landscapes. We gathered root, soil, and foliar data from r maples (Acer rubrum) growing in newly lay opened landscape sites and adjacent native forest sites to proof two independent hypotheses: (1) landscape tree present to view lower levels of AMF colonization than forest tree and (2) the AMF inoculum potential of landscape soils is lower than that of forest soils. Fine lower parts sampled from landscape maples had significantly lower AMF colonization than maples from adjacent forest sites (3% versus 22%) However, soil-sand mixtures made from landscape soils be seized ofed greater AMF inoculum potential than those made from forest soils (10% versus 4%) Forest soils were more acidic and owned less extractable P than landscape soils, and differences in AMF colonization between field and landscape maples appeared to throw back differences in soil chemical properties rather than in inoculum potential. The springs of this study suggest that not all disturbed landscape soils are deficient in AMF propagules.

Key Words. Acer rubrum; arbuscular mycorrhizal fungi; mycorrhizae; r maple; soil acidity; soil disturbance.

Arbuscular mycorrhizal lungi (AMF) form a symbiotic relationship with the fine bottoms of many landscape tree species. Numerous plant benefits have been attributed to the AMF symbiosis, including enhanced nutrient uptake, increased resistance to soilborne pestilences greater heavy metal tolerance, and improved soil-water relations (Smith and Read 1997) Consequently AMF colonization has the potential to improve the survival, extension and appearance of landscape trees

Landscape soils are often disturbed during land development and construction activities. Soil grading typically carrys native vegetation and displaces biologically active topsoil. As a be the effect natural sources of AMF propagules (colonized bottoms fungal spores, and fungal hyphae) in the soil are contemplation to be diminished. Disturbance of native soils by dint of agricultural and surface mining activities has been shown to bring AMF propagule abundance and infectivity (Jasper et al. 1989 1991; Boerner et al. 1996; Gould et al. 1996) Les is known about the issue of soil disturbance on AMF activity in urbanized landscapes. In the southwestern United States, lately developed landscapes had lower AMF species diversity than landscapes disentangleed 20 to 40 years earlier (Stutz and Martin 1998) and native forsaken trees had greater AMF colonization than their counterparts in residential landscapes (Stabler et al. 2001) Comparable research has not been performed in the temperate regions of the eastern United States.

Commercial inoculants containing AMF propagules are available for enhancing the AMF colonization of tree transplanted into disturbed landscape soils. While ectomycorrhizal inoculation has proven effective in promoting conifer survival and extension on disturbed sites (e.g., Marx et al. 1989; Marx 1991) AMF inoculation oftentimes fails to provide measurable benefits to landscape tree (eg Morrison et al. 1993; Martin and Stutz 1994; Appleton et al. 2003) The absence of an AMF inoculation issue may be related to high horizontals of soil fertility, adequate pre-treatment soil inoculum potentials, or sufficient pre-treatment horizontals of AMF colonization in the treated tree (Findlay and Kendle 2001) These issues have rarely been addressed in arboricultural research, and information upon soil inoculum potential and tree colonization status may therefore evince helpful to arborists considering the use of AMF inoculants.

The overall objective of this research was to test the assertion that disturbed landscape soils are deficient in AMF propagules and do not assist the colonization of transplanted tree Specifically, the objectives were (1) to compare AMF colonization of r maples (Acer nibnim) from native forest locations with that of r maples from nearby unraveled landscapes, (2) to compare AMF inoculum potential of native forest soil with that of soil from nearby make knowned landscapes, and (3) to evaluate relationships between AMF colonization and soil chemical properties at the pair locations.

MATERIALS AND METHODS

This investigation consisted of an observational field investigation and a greenhouse bioassay experiment. The field application of mind was conducted in the upper southern Carolina Piedmont of the United States in June 2004 Nine commercial/retail establishments were culled for observation based on sum of two units criteria: (1) presence of lately transplanted red maples in the landscape, and (2) proximity to a native forest containing r maples. R maple was chosen for observation to be paid to its prevalence in the two native forests and urban landscapes and its capacity to form AMF symbioses.

Native soils of the upper southern Carolina Piedmont are ultisols of the Cecil series. Their taxonomic class is fine, kaolinitic, thermic Typic Kanhapludults (Soil scan Staff 2005). Forested sites typically posses a thin (O to 8 cm [O to 3 in.]) organic horizon compos of partially decayed leaves and twigs. Upper mineral horizons are designated A, E BE, and BtI to a deepness of 71 cm (28 in.). This horizonation may be truncated owed to erosion from past agricultural use, and single or more of the surface horizons may be absent. The A and B horizons are typically sandy loam, clay loam, or clay, and are moderately to actual strongly acid.