Seedling Root Growth as a Function of Soil Density and Water Content

Abstract

contorta, which had root weight, shoot weight, and stem height declines ranging from 50 to 90% resulting from Compaction caused by some intensive forest management practices compaction of several different soil types (Corns, 1988). can reduce tree growth, but growth reduction is the result of complex Although reduced growth from compaction has been interactions between soil properties and tree physiological processes, which may differ by species. We used a 7 by 7 factorial greenhouse reported across many regions, the effect on individual experiment to create a matrix of bulk density (b) and volumetric tree growth parameters is variable, and overall growth water content (v) to better understand soil compaction effects on response varies for different species and soil types. For seedling growth of: (i) ponderosa pine (Pinus ponderosa var. ponexample, shoot and root weight of Pseudotsuga menziederosa Dougl. ex Laws) grown on Dome and Cohasset soils; (ii) sii var. glauca (Beissn.) Franco and Pinus monticola shortleaf pine (Pinus echinata Mill.) on a Clarksville soil; and (iii) Dougl. ex D. Don seedlings were not affected by comloblolly pine (Pinus taeda L.) on an Argent soil. Models of root length paction after one growing season, but root volume was density (RLD) were developed using multiple regression. The general 41% less for the P. menziesii (Mirb.) Franco seedlings model of RLD ϭ b 0 ϩ b 1 v ϩ b 2 b ϩ b 3 2 v described rooting response and seedling height was 6% greater for P. monticola for the Clarksville-shortleaf and Argent-loblolly soil-species combina-(p ϭ 0.05) (Page-Dumerose et al., 1998). Corns (1988) tions (p ϭ 0.005). However, the ponderosa pine RLD response on Cohasset soil was linear and there was an interaction between v and reported that P. contorta root weight, shoot weight, stem b in the Dome soil. Shoot mass of seedlings growing within the least diameter, and stem height declined due to compaction limiting water range (LLWR) was greater than those growing outside on all four soils tested, but Picea glauca growth on two the range for all soil-species combinations except the Argent-loblolly of the soils did not decline or increased twofold. P. pine (p ϭ 0.05). The loblolly pines had greater shoot mass at v above contorta shoot weight decreased 64% on a silty clay soil the upper LLWR limits (aeration limiting). Least limiting water range when b increased from 1.2 to 1.5 Mg m Ϫ3 , while shoot has potential as a soil quality indicator, but seedling response was not weight decreased 86% on a clay loam soil compacted always associated with LLWR. Root length density (RLD) response to 1.5 Mg m Ϫ3. Wasterlund (1985) also reported species surface models in conjunction with seasonal site water data have differences with Picea abies growth being more impeded potential for determining compaction-induced soil limitations for tree by compaction than Pinus sylvestris L. growth. On sevgrowth, but need to be field tested and calibrated for both soil and species. C.M. Siegel-Issem and J.A. Burger, Dep. of Forestry...

Indicadores hídrico-mecânicos de compactação do solo e crescimento de plantas

“…Inúmeros estudos, como os de Lapen et al, 2004;Siegel-Issem et al, 2005;Collares et al, 2006;Klein & Câmara, 2007;Kaiser et al, 2009, relatam a pequena associação entre IHO e resposta das plantas. As principais críticas ao conceito do IHO são com base no argumento que o IHO representa mudança abrupta dos estresses físicos sobre o crescimento das plantas em vez de contínua e gradual (Zou et al, 2000) e que o IHO não inclui o efeito da condutividade hidráulica do solo na absorção de água pelas raízes (Håkansson & Lipiec, 2000).…”

“…Há alguns relatos que a resistência mecânica, de maneira geral, influencia o crescimento radicular no intervalo de potenciais hídricos -0,01 a -0,1 MPa, e o estresse hídrico é o principal fator em potenciais menores que -0,35 MPa (Siegel-Issem et al, 2005). De acordo com o modelo empírico de Feddes (Feddes et al, 1980), potenciais menores que -0,8 MPa podem cessar o crescimento radicular para grande número de plantas.…”

The long-term effects of silvicultural thinning and partial cutting on soil compaction in red pine (Pinus resinosa Ait.) and northern hardwood stands in the northern Great Lakes Region of the United States

“…Higher rates of hydraulic conductivity indicate less resistance to water moving through the soil, and from soil to roots. This parameter is used in soil water, nutrient, and productivity studies (Siegel-Issem et al 2005;Powers 2006). Thus, a combination of bulk density, soil PR, and hydraulic conductivity information would provide a more comprehensive assessment of thinning effects on soil physical properties and long-term stand growth.…”

Least limiting water range and physical quality of soil under groundcover management systems in citrus

“…Quantifying soil physical degradation associated with compaction and their impact in the plant growth is a complex task, which may be achieved using the least limiting water range (LLWR) concept. The LLWR is a multifactor index used for describing the soil physical quality to crop production (Lapen et Issem et al, 2005;Tormena et al, 2007). As a single index of soil physical quality, LLWR incorporates most of the critical measurable sources of stress that the soil imposes on crop growth.…”