Vector Analysis Identify Loblolly Pine (Pinus taeda L.) Phosphorus Deficiency on a Beauregard Soil

Abstract

We studied the response of densely stocked one-year-old loblolly pine (Pinus taeda L.) to N and P fertilizers on a Beauregard silt loam (fine silty, siliceous, thermic, Plinthaquic Paleudults). A continuous function" experimental design with three replications was used. Each replication consisted of 12 m X 12 m plots, with three trees planted within a square meter area for each treatment. Ten levels each of N and P were applied. Application rates ranged from: 0 to 240 Kg ha^-1 N, and 0 to 900 Kg ha^-1 P. Potassium was applied at a uniform rate of 50 Kg ha^-1. Phosphorus and K application rates were based upon adsorption isotherms, while N application rates were based upon a previous study on the same soil. Vector analysis provides an opportunity to simultaneously compare plant growth, nutrient concentration and nutrient content on one graph. Vector analysis revealed that P application increased P concentration, P content and dry weight showing unfertilized trees were deficient in P. Nitrogen-only application had an antagonistic effect on P by decreasing P concentration, P content and dry weight. Enhanced growth was observed when both N and P were applied in combinations.

Citation

Bekele, A.; Hundall, W.H.; Tiarks, A.E. 1999. Vector Analysis Identify Loblolly Pine (Pinus taeda L.) Phosphorus Deficiency on a Beauregard Soil. Paper presented at the Tenth Biennial Southern Silvicultural Research Conference, Shreveport, LA, February 16-16, 1999