Utilization of waste materials to promote hardwood tree growth

Abstract

Land application of wastes can increase the growth of crops. This study was conducted to evaluate the influence of various waste products on the growth of trees. Two sites, one in northeast Alabama growing sycamore (Platanus occidentalis L.) and the other in west Tennessee growing cottonwood (Populus deltoides Bartr. ex Marsh.), were studied. At the Alabama site, 3 yr of replicated field plots were evaluated to assess the influence of scrubber gypsum, wood ash, and containerboard sludge on the growth of sycamore on a Decatur soil. Compared to the control treatment, a mulch application of scrubber gypsum at a rate of 672 Mg/ha improved the volume response of sycamore after 3 yr. There was no volume response to liming, whether agricultural lime or wood ash was used, and sycamore did not respond to nitrogen (N) in the containerboard sludge treatment. Further investigations into the use of scrubber gypsum applied at high rates as a mulch in combination with weed control appear warranted from these studies. On a Memphis-Loring soil at the Tennessee site, organic N amendments, whether swine waste or sewage, were superior to ammonium nitrate in terms of volume response of cottonwood. Averaged across the three application rates, swine effluent increased volume growth of cottonwood by nearly 18% relative to comparable N additions from ammonium nitrate whereas municipal sewage sludge increased volume growth by almost 4% compared to ammonium nitrate treatments.