Wednesday, November 15, 2006

Diagnosis of Nutrient Deficiencies in Loblolly Pine Using Foliar Techniques.

Robert Sypert and Thomas Fox. Virginia Tech, Forestry Dept, 228 Cheatham Hall, Blacksburg, VA 24061

Identifying nutrient deficiencies and the likelihood of a growth response following fertilization in loblolly pine stands in the South has proven difficult.  Several techniques have been used to identify nutrient limitations in individual stands. A study was established using single-tree fertilization with various combinations macro- and micro- nutrients to evaluate the effectiveness of nutrient critical levels, DRIS, vector analysis, and changes in total branch foliage mass and area to identify nutrient deficiencies. Study sites were located in South Carolina, Georgia, Alabama, and Texas in loblolly pine plantations ranging from 6 to 10 years old.  The most sensitive diagnostic tool was the increase in total branch foliage weight following fertilization.  Foliar critical levels and vector analysis were less effective at diagnosing nutrient deficiencies. DRIS proved unreliable as a diagnostic tool in these loblolly pine stands, probably because reliable norms could not be developed.

Handout (.pdf format, 128.0 kb)