Inter-Rotational Effects of Fertilizer and Herbicide Treatments on the Understory Vegetation Community in Juvenile Loblolly Pine (Pinus taeda L.) Stands
Subedi, P., E.J. Jokela and J.G. Vogel. 2017.
Abstract
Two randomized, complete block design experiments were established in north Florida to examine the inter-rotational effects of fertilization and herbicide applications
on understory community responses in 2-year-old Pinus taeda L. stands. One experiment was left untreated (carryover [C]; CC, CF, CW, and CFW) and the second received
the same first-rotation treatments - control (C), fertilizer (F), herbicide (W), and fertilizer and weed control (FW)- in the second rotation. In both experiments, herbicide
applications alone and when combined with fertilization suppressed woody species such as Ilex glabra (L.) A. Gray and Serenoa repens (W. Bartram) Small (CFW: 0.26;
FW: 0.01 Mg ha-1 biomass) but favored graminoids such as Andropogon virginicus L. var. glaucus Hack. and Dichanthelium acuminatum (Sw.) Gould & C.A. Clark (CFW:
3.1; FW: 1.1 Mg ha-1 biomass). Although the CW (0.99) and W (0.99) treatments did not affect understory diversity (H'), the CFW (0.45) and FW (0.5) treatments
exhibited reductions compared with the CF (1.24) and F (1.33) treatments, respectively. In both experiments, fertilizer alone did not affect understory composition and
diversity compared with the control. These results suggest that intensive additions of either herbicide alone or in combination with fertilization affected understory
composition and diversity in the subsequent rotation.
Key Words
sustainability, species richness, diversity, biomass, nutrients
