Self-Renewal of Invasive Goldenrods (Solidago spp.) as a Result of Different Mechanical Management of Fallow

Abstract

The spread of invasive plants is one of the most significant causes of biodiversity loss in natural, semi-natural, and anthropogenic habitats in Poland. This two-year study aimed to assess the rate of self-renewal of Canadian goldenrod (Solidago canadensis L.) and giant goldenrod (S. gigantea Aiton), and the possibility of achieving full generative development on fallow land restored to agricultural use with mechanical treatments. The following research objects were examined: the control (no mechanical treatments); one-time mowing; two-time mowing; one-time mowing plus one-time rotary tilling; and one-time mowing plus two-time rotary tilling. The phenological development of Solidago spp. was observed every 14 days from June to September each year. In October of each growing season, the aboveground parts of goldenrods’ biomass were measured, and selected morphological parameters were assessed. Two-time mowing and one-time mowing with two-time rotary tilling resulted in the highest reductions in the share of goldenrods in the generative stages of development, of 64.0% and 51.7% compared to the control, respectively. The two-time mowing treatment was the most effective at inhibiting goldenrods’ biomass accumulation, with a 57.7–77.0% decrease in biomass compared to the control. This treatment also reduced the number of flowering shoots and inflorescence lengths of both Solidago species.

Physicochemical Properties of Biochar Produced from Goldenrod Plants

“…Goldenrod belongs to the Asteraceae family, comes from North America, and is the most common invasive plant in Europe [ 29 , 30 ]. Goldenrods colonize wastelands and arable green areas, especially where the use of turf was abandoned by grazing or mowing.…”

“…Goldenrod is characterized by high plasticity and adapts to various habitat conditions by increasing the growth of shoots and inflorescences as well as strengthening the rhizomes. It is also resistant to extreme habitat conditions and distinguished by its rapid growth and high invasiveness [ 29 , 31 ]. It seems, therefore, that due to the high fertility of this plant its cultivation for energy purposes is justified.…”

Survey of the Solidago canadensis L. Morphological Traits and Essential Oil Production: Aboveground Biomass Growth and Abundance of the Invasive Goldenrod Appears to Be Reciprocally Enhanced within the Invaded Stands

“…A. invaded stands within the protected, vulnerable, and natural value areas, or those needing to be restored, should receive intensive management, including mowing two times per year, plus shallow ploughing/rotary tilling [21], applied, at the latest, when the inflorescences are already yellow, but before the full opening of the petals [22]; and B.…”

“…Accordingly, a measure of the goldenrod biomass growth directly reflects the success of this invasive neophyte on the local scale and quasi predicts the future course of the invasion. Equally, the morphological features survey gives a basis for balanced and optimized management of Solidago and, subsequently, feedback on the effectiveness of various management practices applied with the aim of reducing goldenrod biomass or restoring the invaded plots [20][21][22].…”

“…The following traits were directly determined using the dried plant material: (11) weight of the dried stem; (12) overall weight of the dried assimilating, green, leaves; (13) overall weight of the dried, non-assimilating, brown, leaves; and (14) weight of the dried inflorescence. On the basis of the obtained results, we counted: (15) number of all leaves, as the sum of the assimilating, green, and non-assimilating, brown, all numbers of leaves; (16) weight of the all leaves in fresh condition; (17) weight of the all leaves after drying out, as the sum of the weights of assimilating, green, and non-assimilating, brown, leaves; (18) average weight of the single assimilating, green, leaf in the fresh condition; (19) average weight of the single assimilating, green, leaf after drying out; (20) average weight of the single non-assimilating, brown, leaf in the fresh condition; (21) average weight of the single non-assimilating, brown, leaf after drying out, where average weight of the single leaf was determined as the ratio of the leaves' overall weight and the leaves' number; and (22) weight of the entire plant after drying out, as the sum of the dried stem, all leaves, and inflorescence weights. Relative water content (%) was counted for (23) stem; (24) all leaves; (25) inflorescence; and (26) entire plant using following formula:…”