Mid-rotation fertilization and liming of Pinus taeda: growth, litter, fine root mass, and elemental composition

Abstract

Forest floor litter can influence biogeochemical cycling and root growth in Pinus taeda systems, especially on low soil fertility sites. The impact of fertilization and liming on forest floor litter (quantity, elemental composition and root presence) was evaluated in a Pinus taeda stand in southern Brazil. A nutrient omission experiment was initiated in November 2008 on an 11 year-old Pinus taeda plantation. The experiment was a randomized block design with seven treatments and four blocks. The treatments were: complete (macro + micro + lime); minus macronutrients; minus micronutrients; minus K; minus Zn; minus lime; and control. In 2012, forest floor litter samples were collected, divided by layer (new litter, old litter, coarse fragmented forest layer > 2mm, fine fragment forest floor N>Fe>P>Ca>K>Mg>Mn under control conditions and C>N>Ca>Mg>P>Fe>Mn>K for the complete treatment. Occurrence of needle chlorosis, similar to that reported for Mg, and low growth under lime omission indicate that Mg was a major factor limiting growth. Fertilization and liming affected the bio-cycling of nutrients, Al toxicity, and root growth.

Keywords

• Nutrient Concentration
• Litter
• Ca:Al Ratio
• Forest Management