|CARPENTER, TODD - N.C. STATE UNIV
|TRETTIN, CARL - US FOREST SERVICE
|VERPRASKAS, MICHAEL - N.C. STATE UNIV
|MAGUIRE, RORY - VIRGINIA TECH UNIV
Submitted to: Soil Science Society of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 7/1/2007
Publication Date: 11/1/2007
Citation: Carpenter, T., Israel, D.W., Trettin, C., Verpraskas, M., Maguire, R. 2007. Late-Rotation Nitrogen Management in Deciduous Short Rotation Woody Crops. Soil Science Society of America Annual Meeting. 215.7. Session: Soil Carbon and Nitrogen Dynamics. Division SO7. Forest, Range, and Wildlife Soils.
Technical Abstract: Idle agricultural land has the potential for producing woody crops as an energy or chemical feedstock. Short rotation woody crops (SRWCs) may improve soil health, water quality, and sequester soil carbon in these intensively farmed fields. Frequently, nitrogen is the limiting nutrient in these systems. While fertilization trials have been conducted on SRWC plantation hardwoods in the southern US, most have focused solely on fertilization during establishment and early development (1-6 yrs). While those studies show a response to N additions, nitrogen demands are greatest following canopy closure in hardwood plantations (e.g., typically 4-7 yrs). Thus, managing the N supply in mid- to late-rotation should maximize productivity. It is also hypothesized that the availability of N from litter and soil is asynchronous with the needs of the crop. The goal of this study is to develop the basis for managing nutrient availability in mid-rotation SRWC plantations to increase productivity and reduce the time to develop a commercially harvestable crop, while enhancing soil productivity potential of old agricultural fields. The study site is located in Sumter County, South Carolina, in the upper coastal plain. The statistical design was a RCBD of seven treatments with three replications applied to two species (Sycamore and Sweetgum). The treatments applied were a control, 30, 50 and 80 kg N ha-1. These rates were also applied as a biennial split application. Fertilizer response was measured by DBH and tree height, porous cup lysimeters were installed at two depths to track N movement through the profile, leaf tissue samples were analyzed to determine uptake, and a net mineralization study was also conducted. Data were compared with historical data for this site where possible.