296 Fite et al.: Soil Decompaction and Amendment Process for Urban Trees Soil Nutrient Levels The A treatment had little effect on soil nutrient concentra- tions (Table 3; Table 4). The M treatment occasionally altered individual nutrients at specific sites [e.g., increased Calcium (Ca) and Magnesium (Mg) in Boston and Anderson, de- creased NO3 -N in Pittsburgh)]. The AFM treatment increased levels of two soil nutrients in Myrtle Beach and Pittsburgh, 4–5 nutrients in Anderson, and 6–7 nutrients in Boston, de- pending on the year (Table 3; Table 4). By contrast, the fertilizer-only treatment increased levels of 2–3 soil nutri- ents at Myrtle Beach, 1–3 nutrients in Pittsburgh, 0–1 nu- trients in Anderson, and zero nutrients in Boston. Because the specific prescription fertilizer materials differed among sites (see Table 2), each site will be discussed separately. In Anderson, AFM increased soil levels of five nutrients in 2007 [Phosphorus (P), Potassium (K), Zinc (Zn), Copper (Cu), and Mg] and four nutrients in 2008 (P, K, Mg, and Zn). In contrast, broadcast application of the same fertilizer mate- rials to the root zone without the organic matter addition (F treatment) only increased K in 2007 and had no effect in 2008. In Boston, AFM increased soil levels of seven nutri- ents in 2007 [(P, K, Ca, Mg, Zn, Manganese (Mn), and Bo- ron (B)] and six nutrients in 2008 (P, Ca, Mg, Zn, Mn, and B). AFM decreased Cu in 2007. In contrast, the F treatment had no effect on soil nutrients in Boston. N, K, Mg, and B) and 2008 (K, Mg, Zn, and B). There was also a marked lowering of soil pH relative to control in the F treatment (4.8, versus 6.1 for control) and an increase in Mn and Cu. It is thought that sulfur may have been over- applied in the F treatment, resulting in markedly decreased soil pH and concomitant changes in nutrient availability. F treatment decreased levels of four nutrients in 2007 (NO3 In Myrtle Beach, whose sandy soil had the low- est pre-treatment nutrient levels, AFM increased lev- els of two nutrients in 2007 and 2008 (Mg and Mn). In 2008, AFM also decreased levels of soil P. The F treat- ment increased levels of three nutrients in 2007 (Zn, Mn, and Cu) and two nutrients in 2008 (Zn and Mn). In Pittsburgh, which had the highest pre-treatment soil nutrient levels, AFM increased one nutrient in 2007 (P) and two nutrients in 2008 (P and Mn). AFM, F, and M also de- creased Nitrate Nitrogen (NO3 -N) in 2007. Surprisingly, the - Figure 1. Soil strength measured with Clegg impact hammer at individual sites in the spring of 2006, 2007, and 2008. Within a site and year, treatment means with different letters are significantly different (Fisher’s LSD P < 0.05; N = 10 for each bar). ©2011 International Society of Arboriculture Figure 2. Percent soil organic matter at individual sites in spring 2007 and 2008. Within a site and year, treatment means with dif- ferent letters are significantly different (Fisher’s LSD P < 0.05; N = 10 for each bar).
November 2011
| Title Name |
Pages |
Delete |
Url |
| Empty |
Search Text Block
Page #page_num
#doc_title
Hi $receivername|$receiveremail,
$sendername|$senderemail wrote these comments for you:
$message
$sendername|$senderemail would like for you to view the following digital edition.
Please click on the page below to be directed to the digital edition:
$thumbnail$pagenum
$link$pagenum
Your form submission was a success. You will be contacted by Washington Gas with follow-up information regarding your request.
This process might take longer please wait
