Croatan Long Term Soil Productivity (LTSP) Study

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Objectives   
The Croatan National Forest Long Term Soil Productivity study site is part of an internationally coordinated study whose objectives are to:

• Measure the interactions of soil and site disturbance on long-term productivity.
• Validate USDA Forest Service soil quality monitoring standards and develop effective monitoring techniques for evaluating the long-term impacts of management practices.
• Understanding how soil and site disturbances affect the fundamental processes controlling productivity.

Design   
The Croatan LTSP site is a 3×3 factoral split-plot design, replicated in 3 blocks. The main effects are 3 levels of organic matter removal and 3 levels of soil compaction. The split-plot effect is competition control, usually in the form of chemical herbicide. In addition, 1 treatment plot per block represents an ameliorated treatment of bedding and fertilizing.   
 

Past Research and Measurements   
Pre- and post-treatment bulk density measurements   
Pre- and post-treatment plant community descriptions   
Measurements of nitrogen and phosphorus mineralization by treatment   
Soil microarthropod abundance   
Monthly apical bud growth   
Soil moisture using time domain reflectometry (TDR) probes   
Soil strength using penetrometer   
Needle carbohydrate and nutrient concentrations   
Root growth

Current Research and Measurements   
Weather conditions   
Tree height growth   
Crown length and diameter   
Diameter at breast height   
Bulk density measurements at the 10th growing season   
Plant community descriptions at the 10th growing season   
Whole tree planted pine bimass at the 10th growing season   
Soil nutrients at the 10th growing season   
Nitrogen forms   
Soil CO2 efflux   
Rotting log decomposition   
Litter decomposition

Cooperators   
USDA Forest Service   
North Carolina State University (NCSU)   
NCSU Forest Nutrition Cooperative - member companies   
North Carolina A & T State University   
Weyerhauser Company

Other LTSP Site Locations

Map showing other LTSP site locations around North America   
California   
Idaho   
Louisiana   
Michigan   
Mississippi   
Missouri   
Texas   
Washington   
British Columbia, Canada   
Ontario, Canada