Biostimulants and Soil Amendments Affect Two-year Posttransplant Growth of Red Maple and Washington Hawthorn

Abstract

<jats:p>Humate-based products have been aggressively marketed as biostimulants that increase plant growth. Little data are available on their effect on tree establishment or their interaction with fertilizer and irrigation regimes. This experiment tested several types of biostimulants on posttransplant growth of <jats:italic>Acer rubrum</jats:italic> L. (red maple) and <jats:italic>Crataegus phaenopyrum</jats:italic> (Blume) Hara (Washington hawthorn) trees, both with and without irrigation and fertilization. Soil treatments were applied at planting as: 1) control (native backfill only); 2) compost (native backfill + yard-waste compost); 3) peat (native backfill + Canadian sphagnum peat); 4) granular humate, 100 g/tree; 5) granular humate, 200 g/tree; and 6) liquid humate +, a proprietary liquid mixture of humate, kelp extract, thiamine, and intermediate “metabolites.” Irrigation regime × soil treatment interaction was significant for red maple, but soil treatments did not increase height, stem diameter, top dry mass, or root length. For Washington hawthorn, soil treatments did not increase height, stem diameter, or root length, but top dry mass in all treatments as a group and in humate-treated trees in particular was greater than that of controls. Roots of peat-treated trees of both species were longer than those in other treatments. Granular humate applied at 200 g/tree increased total root length more than did 100 g/tree in Washington hawthorn but not in red maple. Fertilizing at planting with N at 14.5 g·m<jats:sup>-2</jats:sup> had no effect on any parameter measured for either species.</jats:p>

A Meta-Analysis and Review of Plant-Growth Response to Humic Substances

“…Furthermore, the fact that the number of studies examining woody perennials was low (ns=3) and the rates of BC-derived HS used on this plant type were relatively high (>300 mg kg), means that these results are not fully representative of HS interaction with woody perennials. Nevertheless, in each of these studies a dose-response trend was observed (Kelting et al, 1998;Marino et al, 2008;Vallini et al, 1993), implying a causal relationship and again emphasising the importance of application rate in determining the growth response.…”

Physical and mechanical properties of washed sediment mixed with organic matter

“…(2005) also showed that the presence of peat particles protects soil from degradation resulting in a larger pore size distribution. Sphagnum peat used as a soil ameliorant (25% by volume) increases tree root length in the first 2 years following transplanting (Kelting et al. , 1998).…”

Composted Amendment Affects Soil Quality and Hedges Performance in the Mediterranean Urban Landscape

“…Compost has been receiving a renewed attention not only in horticulture but also in the context of urban landscaping and restoring disturbed urban soils, to address environmental issues as well as to improve tree growth ( Kelting et al 1999). The obtained physicochemical results in table 2 show a clear increase of mean values for all the tested parameters with increasing rates of SSC; an increase of soil moisture after compost application is considered to have a very important effect on urban sandy soil in the dry months of the year, from April to October, in Southern Italy.…”