Effects of Early, Small-Scale Nitrogen Addition on Germination and Early Growth of Scots Pine (Pinus sylvestris) Seedlings and on the Recruitment of the Root-Associated Fungal Community

Abstract

Scots pine (Pinus sylvestris L.) is one of the most economically important species to the Swedish forest industry, and cost-efficient planting methods are needed to ensure successful reestablishment after harvesting forest stands. While the majority of clear-cuts are replanted with pre-grown seedlings, direct seeding can be a viable option on poorer sites. Organic fertilizer has been shown to improve planted seedling establishment, but the effect on direct seeding is less well known. Therefore, at a scarified (disc trencher harrowed) clear-cut site in northern Sweden, we evaluated the effect of early, small-scale nitrogen addition on establishment and early recruitment of fungi from the disturbed soil community by site-planted Scots pine seeds. Individual seeds were planted using a moisture retaining germination matrix containing 10 mg nitrogen in the form of either arginine phosphate or ammonium nitrate. After one growing season, we collected seedlings and assessed the fungal community of seedling roots and the surrounding soil. Our results demonstrate that early, small-scale N addition increases seedling survival and needle carbon content, that there is rapid recruitment of ectomycorrhizal fungi to the roots and rhizosphere of the young seedlings and that this rapid recruitment was modified but not prevented by N addition.

Soil Microbiome Influences on Seedling Establishment and Growth of Prosopis chilensis and Prosopis tamarugo from Northern Chile

“…Genomic DNA, PCR amplification and sequencing were performed following the method from Castro et al [ 83 ]. Briefly, DNA from mortar-ground freeze-dried roots was extracted using a Cetyl TrimethylAmmonium Bromide (CTAB) based method [ 84 ].…”

“…The Illumina data were processed using the pipeline proposed by Castro et al [ 83 ] using QIIME2 [ 89 ] version 2019.1. Briefly, raw sequence data were imported using the q2-import plugin using the setting for Illumina fastq files, followed by denoising with DADA2 [ 90 ] via q2-dada2 denoise-paired, setting truncation at 301 bp for the forward read and 300 for reverse.…”

Effect of arginine-phosphate addition on early survival and growth of Scots pine, Norway spruce and silver birch

“…With the faster initial growth and the genetic benefit gained from higher survival of the planted seedlings as compared to the naturally regenerated trees that become incorporated and kept in the stand where planted seedlings perish, the rotation period is expected to shorten as well. So far, there are only few studies in field conditions to test the effect of AP on forest generation success, where it has been demonstrated that survival and early growth after planting and sowing of Scots pine seedlings in north Sweden can be enhanced by the addition of AP (Castro et al 2021;Häggström et al 2021;Domevščik et al 2023). However, it is not known if the same effect might occur in this species in southern Sweden; nor if the regeneration of Norway spruce and silver birch might be equally enhanced.…”