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Moderate drought alters biomass and depth distribution of fine roots in N orway spruce
Author(s) -
Konôpka B.,
Lukac M.
Publication year - 2013
Publication title -
forest pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.535
H-Index - 49
eISSN - 1439-0329
pISSN - 1437-4781
DOI - 10.1111/efp.12005
Subject(s) - coring , biomass (ecology) , environmental science , agronomy , soil horizon , soil water , growing season , water content , biology , soil science , geology , mechanical engineering , drilling , geotechnical engineering , engineering
Summary A rain shelter experiment was conducted in a 90‐year‐old N orway spruce stand, in the K ysucké B eskydy M ts ( S lovakia). Three rain shelters were constructed in the stand to prevent the rainfall from reaching the soil and to reduce water availability in the rhizosphere. Fine root biomass and necromass were repeatedly measured throughout a growing season by soil coring. We established the quantities of fine root biomass (live) and necromass (dead) at soil depths of 0–5, 5–15, 15–25 and 25–35 cm. Significant differences in soil moisture contents between control and drought plots were found in the top 15 cm of soil after 20 weeks of rainfall manipulation (lasting from early J une to late O ctober). Our observations show that even relatively light drought decreased total fine root biomass from 272.0 to 242.8 g m −2 and increased the amount of necromass from 79.2 to 101.2 g m −2 in the top 35 cm of soil. Very fine roots ( VFR ), that is, those with diameter up to 1 mm, were more affected than total fine roots defined as 0–2 mm. The effect of reduced water availability was depth‐specific; as a result, we observed a modification of vertical distribution of fine roots. More roots in drought treatment were produced in the wetter soil horizons at 25–35 cm depth than at the surface. We conclude that fine and VFR systems of N orway spruce have the capacity to re‐allocate resources to roots at different depths in response to environmental signals, resulting in changes in necromass to biomass ratio.