University of Georgia
Studies on Reforesting Reclaimed Lands
The University of Georgia has been involved in studies in cooperation with the China Clay Producers Association (CCPA) for the past several years with regard to the growth of pine trees on reclaimed lands. The CCPA members are anxious to improve the growth of pine trees on reclaimed lands to exceed the growth rate on undisturbed lands.

The following is an update on the latest study which was initiated in the summer of 1997.

    University of Georgia Reclamation Update
    by Kathleen McEvoy

    What soil preparation measures improve survival and growth of loblolly pine seedlings on kaolin mined areas? Are certain grasses that are beneficial for wildlife also better at controlling erosion? Will application of a composted paper mill by-product, that adds organic matter and nutrients, have a positive effect on reclamation success? The University of Georgia (UGA), with help from the Georgia China Clay Producers Association, is actively pursuing answers to these questions. Such answers will lead to better reclamation practices on kaolin mined areas.

    Successful kaolin mine reclamation requires good soil conditions for plant growth, vegetation establishment for erosion control, and an environment that enhances biological processes. During reclamation, soil can be compacted, which decreases the soil pore space. This limits water holding capacity and soil rooting volume resulting in reduced root growth and seedling success. Soil tillage helps correct these adverse conditions and is particularly important during the critical first years of reclamation. Two tillage practices are being studied, subsoiling and disking. Subsoiling, as its name implies, breaks up the subsoil layer to a depth of about 18 inches. This can have a greater impact on development of seedling roots than any other soil tillage treatment. Subsoiling increases the soil volume available to roots and improves their ability to reach water and nutrients. With the expected drought summer 1998, it will be important to observe if the seedlings planted on subsoiled areas have greater growth. Disking, the other tillage practice being studied, improves rooting conditions in the soil surface. This increases the volume of large pores in the surface soil which allows for more water and air transport. Research being conducted will compare the two tillage treatments and their effectiveness in ameliorating soil conditions in kaolin mined areas.

    Vegetative cover, particularly grass species, can reduce soil erosion and prevent sediment loss into rivers and streams. Immediate establishment of grass is critical after the land is disturbed. A vegetative cover not only protects the soil, it can provide habitat and forage for wildlife. Current research conducted by UGA focuses on the establishment of grasses that are beneficial for wildlife yet effective for controlling erosion. The study site is located on an area that was previously mined for kaolin. Three seed mixtures are being compared, two fall wildlife seed mixtures and one mixture commonly use by the kaolin mining companies. The wildlife mixtures are rated by individuals from the Natural Resources Conservation Service and industry as being very good for deer, rabbits, and turkeys in areas with moderate potential for erosion. Loblolly pine trees were planted this winter after the vegetative cover was established. We will measure pine tree growth and also compare the competition between grass and tree seedlings for nutrients and water. Results from this segment of the study are still being collected and analyzed and will be posted at a later date.

    An opportunity for immediate amendment of the kaolin mined spoil can result from the use of a composted paper mill by-product mixed with chicken litter. Too often, these kind of materials end up in landfills. This material acts as a mulch, which helps retain soil moisture and decreases soil temperatures. Both can have a positive effect on root growth. This material is also a source of nutrients, such as nitrogen. Previous studies indicate improved soil physical properties and increased plant growth with the use of a composted papermill by-product. We will measure the effects of the composted material on loblolly pine growth.

    Funding from the China Clay Producers Association makes this research possible. Continued dedication and innovative thinking is required to advance mine reclamation as well as promote education. Specific questions regarding this research project may be addressed to mcevoy@arches.uga.edu.

    About the Author

    China Clay Producers Association
    Lee Lemke
    Executive Vice President
    113 Arkwright Landing
    Macon, Georgia 31210
    Telephone 478-757-1211
    Fax 478-757-1949
    Email:
    info@georgiamining.org

 

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