Potential for utilization of wood ash on coastal arenosols with limited buffer capacity in KwaZulu-Natal and its effect on eucalypt stand nutrition and growth
Date
2017
Journal Title
Journal ISSN
Volume Title
Publisher
Italian Society of Silviculture and Forest Ecology
Abstract
ENGLISH ABSTRACT: A field trial was established to test the effects of various wood ash and fertilizer
application rates on the nutrition and early growth of a clonal Eucalyptus grandis × urophylla stand near Richards Bay, KwaZulu-Natal province, South
Africa. The trial consisted of wood ash treatments of 0, 0.3, 0.6 and 1.2 t ha-1, combined with fertilizer treatments of no fertilizer (control), 150 g tree-1 of
conventional ammonium sulphate fertilizer or 320 g tree-1 of controlled release fertilizer mixture containing N, P and a balanced suite of several plant
nutrients. The experiment was conducted on a young sandy soil of aeolian origin with a very low buffer capacity. Ash application rates were chosen after a
pilot study was conducted to test the effect of CaCO3 on the soil reaction. At 4 and 8 months after treatment, soil heavy metal concentrations for cadmium
(Cd), mercury (Hg), chromium (Cr) and lead (Pb) levels were substantially lower than toxic levels. Foliar heavy metal concentrations (for the same elements)
were less than 1mg kg-1 at both time intervals. The wood ash induced a temporary liming effect up to 8 months after application. Foliar nutrient assessments
revealed sub-optimal nutrient concentrations for phosphorous (P), potassium (K) and zinc (Zn) at 4 months and K at 8 months of age. The positive
growth responses (expressed as a biomass index) at 8 months, ranged between 13% and 683% relative to the untreated control. At 21 months, the growth
response to ash and fertilizer combinations ranged from -0.5% to 50% relative to the control. This research demonstrated that 1.2 t ha-1 of wood ash can
safely be disposed of on a typical, poorly buffered Zululand coastal sand with
little environmental risk and minimal growth suppression, provided that it is
balanced with an appropriate NPS plus trace element fertilizer mixture.
Description
CITATION: Scheepers, G. P. & Du Toit, B. 2017. Potential for utilization of wood ash on coastal arenosols with limited buffer capacity in KwaZulu-Natal and its effect on eucalypt stand nutrition and growth. iForest: Biogeosciences and Forestry, 10:180-188, doi:10.3832/ifor2146-009.
The original publication is available at http://iforest.sisef.org
The original publication is available at http://iforest.sisef.org
Keywords
Wood ash, Eucalyptus grandis, Heavy metals, Fertilization of plants, Woods (Forests)
Citation
Scheepers, G. P. & Du Toit, B. 2017. Potential for utilization of wood ash on coastal arenosols with limited buffer capacity in KwaZulu-Natal and its effect on eucalypt stand nutrition and growth. iForest: Biogeosciences and Forestry, 10:180-188, doi:10.3832/ifor2146-009