Nutrient loaded seedlings reduce the need for field fertilization and vegetation management on boreal forest reclamation sites

Abstract

Tree seedlings loaded with nutrients during nursery production have shown increased growth and survival relative to standard seedlings upon outplanting. We examined outplanting performance of nutrient loaded and standard trembling aspen (Populus tremuloides) seedlings, along with composition and cover of competing vegetation, on a boreal oil sands reclamation site with two different soil types (forest floor mineral mix and peat mineral mix) and four different broadcast fertilizer applications [250 kg/ha immediately available fertilizer (IAF), 500 kg/ha IAF, 670 kg/ha controlled release fertilizer, and an unfertilized control]. Average height growth across all treatments was 19 % greater for nutrient loaded aspen seedlings than standard seedlings after two growing seasons. With respect to soil types, aspen growth was greater on peat mineral mix and seedlings growing in this soil type showed a greater response to both nutrient loading and fertilization; however, this could partially be attributed to greater cover by competing vegetation on the forest floor mineral mix. In the first growing season, trees treated with immediately available fertilizer showed the greatest growth response but in the second growing season only the controlled release fertilizer application resulted in growth rates greater than the controls. Fertilizer regime had similar effects on total cover of competing vegetation, although fertilization additionally promoted increased cover of grasses in the forest floor mineral mix. Overall, we clearly show that nutrient loaded trembling aspen seedlings can be used to offset early field fertilization needs at forest reclamation sites.

Ecohydrological functioning of an upland undergoing reclamation on post‐mining landscape of the Athabasca oil sands region, Canada

“…Because FFM had a higher availability of essential macronutrients (N–P–K), this result implies that planted‐sapling survival is influenced by a moisture deficit rather than nutrient supply. Similar results were reported by previous aspen saplings establishment studies, which demonstrated that the survival rate of planted saplings is greater under PMM than FFM, especially during the first few years following soil placement (B. D. Pinno & Errington, ; B. D. Pinno, Landhäusser, MacKenzie, Quideau, & Chow, ; Schott et al, ).…”

Effects of initial fertilizer treatment on the 10‐year growth of mixed woodland on compacted surface‐coal‐mine spoils, S. Wales

“…Here, treatment with SRF resulted in slightly lower survival for all species except Oak. Elsewhere, SRF has increased tree growth, significantly, in the first 2 years after planting but, here, SRF‐treated trees were out‐performed by those given no‐SRF (Schott, Snively, Landhäusser, & Pinno, ). A 5‐year UK overview of Birch and Willow growth on restored surface‐coal‐mine sites found no clear response to fertilizer treatment, which is also true for Years 5 and 3 data here (Good, Williams, & Moss, ).…”

Growth and competition among understory plants varies with reclamation soil and fertilization

“…Error bars indicate standard error for each species individually availability. Other studies have also found that fertilizer increased grass cover on FFMM (Schott et al 2016) and the cover of non-native species (Errington and Pinno 2016), making it harder for other vegetation to establish. In extreme cases, an understory could be irreversibly dominated by undesirable non-native species which has been shown to happen with repeated fertilizer application in prairie restoration applications (Wilson and Pinno 2013).…”

“…PMM has a high water holding capacity that has been shown to increase tree seedling establishment (Pinno and Errington 2015). If used immediately following salvage, both soil types contain native plant propagules that can aid in the restoration of boreal forest ecosystems (Schott et al 2016). The difference in nutrient profiles for these two reclamation soils has important implications for plant growth and development.…”