The effects of soil amendments of mycorrhizae and growth of Quercus rubra L. (northern red oak) seedlings

Plots were established in the spring of 1996 in an area of old fields south of Hutcheson Memorial Forest, in central New Jersey where studies are being done to assess the effect of soil amendments on secondary succession. The goal of this experiment was to study the effects of the soil amendments pine bark chips and elemental sulfur on mycorrhizae and vegetation, and to relate these findings to secondary succession. Half of the plots were established in an area where these amendments had been applied in 1989, and the other half of the plots were established in an adjacent area where the amendments were applied in 1996. The plots were established in each area with amendments of sulfur, mulch, and a control with no amendment, and were replicated three times. Elemental sulfur was applied at a rate of 3900 kg/ha and pine bark chips were applied to cover 75% of the soil surface. Soil samples were taken to assess for presence of arbuscular mycorrhizae (AM) from spring through fall of 1996 and spring through fall of 1997. Oak seedlings were planted into each of the plots to measure growth and assess for the presence and morphotype of ectomycorrhizae (ECM). Growth of the oak seedlings was measured from the fall of 1996 through the fall of 1998 and ECMs were assessed in the fall of 1996, spring and fall of 1997, and fall of 1998. Leaf nutrient analysis of oak seedling leaves was measured in the fall of 1996 and spring and fall of 1997.; Throughout the experiment, no differences were seen in any of the parameters measured in the mulch treatment as compared to the control. The application of sulfur lowered the pH of the plots from approximately 5.4 (before application) to 3.7 (the year following application). The numbers of the AM were unaffected by any of the treatments. The treatments also had no affect on the numbers of the ECM, however, the morphotype community composition was affected by the sulfur treatment. The community composition of ECMs in the sulfur was different from that of the mulch and control. The growth of the oak seedlings was also affected by the sulfur treatment. The oak seedlings in the sulfur plots were taller, had greater canopy area, and greater numbers of leaves than those in the mulch and control. Leaf nutrient analysis showed greater PO₄ and N concentration in the leaves from the oak seedlings grown in the sulfur plots than in those from oak seedlings grown in the sulfur or control.; The desired outcome of succession from old field in this area of New Jersey is eastern deciduous forest. Enhanced growth of the oak seedlings and a shift in ECM morphotypes in the sulfur plots could indicate an accelerated shift toward this goal.