Premium
Effects of experimental soil frost on the fine‐root system of mature Norway spruce
Author(s) -
Gaul Dirk,
Hertel Dietrich,
Leuschner Christoph
Publication year - 2008
Publication title -
journal of plant nutrition and soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 1436-8730
DOI - 10.1002/jpln.200700284
Subject(s) - snow , picea abies , frost (temperature) , coring , environmental science , soil water , soil horizon , soil science , agronomy , geology , botany , biology , mechanical engineering , drilling , engineering , geomorphology
Abstract Soil‐frost events may influence the dynamics of fine roots and therefore affect root‐derived C fluxes to the soil. We studied the impact of soil frost on the fine‐root dynamics of Norway spruce ( Picea abies [L.] Karst.) by a replicated snow‐removal experiment in a mature forest in SE Germany. Snow removal in the three treatment plots reduced soil temperature significantly with minima <–5.5°C in the O layer while the snow‐covered control plots never reached temperatures below the freezing point. Sequential soil coring in the O layer at the beginning and at the end of the soil‐frost period as well as after thawing revealed that the soil frost treatment increased fine‐root mortality by 29%. However, enhanced fine‐root production in the snow‐removal plots nearly compensated for the fine‐root losses caused by low temperatures. These findings were confirmed by minirhizotron observations in the O layer and the upper 25 cm of the mineral soil showing that relative fine‐root loss was by far higher in the snow‐removal plots than in the control plots. Compensatory fine‐root production in the snow‐removal plots exceeded fine‐root production in the control plots during a period of 8 weeks after the soil frost application by 39% in the O layer while it was similar in both plot types in the mineral soil. Sequential coring and minirhizotron observations led to substantially different fine root–longevity estimates for the soil frost period. However, in both cases, the snow‐removal treatment was characterized by a significant reduction in root longevity indicating a faster fine‐root turnover. As a consequence, experimental soil frost enhanced the C input to the soil via root death at our study site by approx. 42 g m –2 and stimulated the C investment towards the root system of the spruce trees due to a higher sink activity.