Organic Matter Management Effects On Site Sustainability and Productivity in a Loblolly Pine (Pinus taeda L.) Plantation.

Soil organic matter can serve as an indicator of soil “quality” and contributes largely to the productivity of the soil. Changes in soil organic matter stemming from changes in management practices can influence long-term site productivity and sustainability. Forest floor and logging residue removal has been shown to have no effect as well as negative effects when evaluating current literature. These effects or lack of are expected to vary by soil type, soil fertility and levels of forest floor removed. A study was designed to determine if the management of post harvest forest floor and organic matter significantly affect site productivity and sustainability. The study is located in Pamlico County, NC in a 4 year old loblolly pine (Pinus taeda L.) plantation. Thirty plots were established in a randomized complete block design with 6 treatments and 5 replications or blocks. The treatments were set up as a 3x2 factorial and imposed after harvest and immediately before planting the current rotation as follows: a) Removed treatment, all forest floor and slash material were removed using rakes to remove and tarps to carry the material (Mixed and Non-Mixed), b) Control treatment, the forest floor and slash material were unaltered (Mixed and Non-Mixed), and c) Doubled treatment, all forest floor and slash material coming from the removed treatment were uniformly added (Mixed and Non-Mixed).Foliar nutrition, forest floor and soil nutrient pools were inventoried throughout stand development. Thus far there have been no effects of the mixing treatment. The forest floor has decomposed at the same rate regardless of initial mass retained. The greater the forest floor retention (double treatment) resulted in greater mineral soil total carbon (C) and nitrogen (N) pools and greater available N. There was no effect of forest floor retention on tree growth at age 3. Results from initiation thru year 4 of this study will be presented and summarized. Thus far the study results imply that there are some positive effects of organic matter retention on site sustainability and productivity.