The Experts below are selected from a list of 156 Experts worldwide ranked by ideXlab platform
James W Dalling - One of the best experts on this subject based on the ideXlab platform.
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plant Soil Associations in a lower montane tropical forest physiological acclimation and herbivore mediated responses to nitrogen addition
Functional Ecology, 2010Co-Authors: Kelly M Andersen, Marife D Corre, Benjamin L Turner, James W DallingAbstract:Summary 1. Soil nutrients influence plant productivity and community composition in tropical forests. In lower montane tropical forests in western Panama, the distribution of understory palm species over a scale of 1–20 km correlates with differences in Soil nitrogen (N). We hypothesized that Soil N determines seedling performance in the forest understory, and, may therefore influence species distributions along the Soil N gradient. 2. We explored the potential for N availability to generate species-habitat Associations through species-specific differences in biomass allocation, photosynthetic capacity, N use-efficiency, and susceptibility to herbivory. Seedlings of nine palm species from two sub-families and four habitat types were transplanted into N-addition and control plots at a low N site. Growth, mortality, biomass allocation, photosynthesis, foliar N content and herbivory were measured over 21 months. 3. Foliar N increased for all species (15–68%) following N addition. Most species showed strong (20–200%) increases in photosynthetic rates with N addition except two species with marginal decreases in photosynthetic rates (5–15%). However, shifts in physiological traits did not increase relative growth rate or change in biomass allocation for any species or N treatment combination. Rather, increased leaf quality contributed to greater levels of herbivory in species associated with Soils of intermediate and high inorganic N availability. 4. Thus, potential increases in overall growth with N addition were masked by herbivory, resulting in no apparent growth response with increased N. We suggest that for understory palms, and potentially other montane forest plants, distribution patterns are driven by a combination of physiological and herbivore-mediated responses to Soil nutrient availability.
Kelly M Andersen - One of the best experts on this subject based on the ideXlab platform.
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plant Soil Associations in a lower montane tropical forest physiological acclimation and herbivore mediated responses to nitrogen addition
Functional Ecology, 2010Co-Authors: Kelly M Andersen, Marife D Corre, Benjamin L Turner, James W DallingAbstract:Summary 1. Soil nutrients influence plant productivity and community composition in tropical forests. In lower montane tropical forests in western Panama, the distribution of understory palm species over a scale of 1–20 km correlates with differences in Soil nitrogen (N). We hypothesized that Soil N determines seedling performance in the forest understory, and, may therefore influence species distributions along the Soil N gradient. 2. We explored the potential for N availability to generate species-habitat Associations through species-specific differences in biomass allocation, photosynthetic capacity, N use-efficiency, and susceptibility to herbivory. Seedlings of nine palm species from two sub-families and four habitat types were transplanted into N-addition and control plots at a low N site. Growth, mortality, biomass allocation, photosynthesis, foliar N content and herbivory were measured over 21 months. 3. Foliar N increased for all species (15–68%) following N addition. Most species showed strong (20–200%) increases in photosynthetic rates with N addition except two species with marginal decreases in photosynthetic rates (5–15%). However, shifts in physiological traits did not increase relative growth rate or change in biomass allocation for any species or N treatment combination. Rather, increased leaf quality contributed to greater levels of herbivory in species associated with Soils of intermediate and high inorganic N availability. 4. Thus, potential increases in overall growth with N addition were masked by herbivory, resulting in no apparent growth response with increased N. We suggest that for understory palms, and potentially other montane forest plants, distribution patterns are driven by a combination of physiological and herbivore-mediated responses to Soil nutrient availability.
Mark A. Licht - One of the best experts on this subject based on the ideXlab platform.
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Soil carbon and nitrogen changes as influenced by tillage and cropping systems in some Iowa Soils
Agriculture Ecosystems & Environment, 2005Co-Authors: Al-kaisi, Xinhua Yin, Mark A. LichtAbstract:Soil organic C (SOC) and total N (TN) contents play a crucial role in sustaining agricultural production systems. Short-term (10-year) management effects on SOC and TN dynamics are often complex and variable. Three experiments were conducted to evaluate short-term tillage and cropping system effects on SOC and TN within the 0‐30 cm Soil depth across Iowa. The first experiment with no-tillage and chisel plowing treatments was established in 1994 on Clarion-Nicollet-Webster (CNW), GalvaPrimghar-Sac (GPS), Kenyon-Floyd-Clyde (KFC), Marshall (M), and Otley-Mahaska-Taintor (OMT) Soil Associations under a corn (Zea mays L.)‐soybean (Glycine max (L.) Merr.) rotation. The second experiment with no-tillage, strip-tillage, chisel plowing, deep ripping, and moldboard plowing treatments was initiated in 1998 on the CNW Soil association in a corn‐soybean rotation. The third experiment consisting of smooth bromegrass (Bromus inermis Leyss.), switchgrass (Panicum virgatum L.) and corn‐soybean‐alfalfa (Medicago sativa L.) treatments was established in 1991 on Monona-Ida-Hamburg (MIH) Soil association under no-tillage management. Short-term tillage effects on SOC and TN occurred primarily at the 0‐15 cm Soil depth. Tillage effects did not vary significantly with Soil association. No-tillage resulted in greater SOC and TN contents than chisel plowing at the end of 7 years of tillage practices averaged over the CNW, GPS, KFC, M, and OMT Soil Associations. The increase in SOC and TN with no-tillage was not related to SOC and TN stratification in the Soil profile or annual C and N inputs from crop residue, but most likely due to decreased mineralization rate of Soil organic matter. However, tillage effects on SOC and TN were negligible at the end of only 3 years of tillage practices on the CNW Soil association. Smooth bromegrass and switchgrass systems resulted in greater SOC and TN contents at both 0‐15 cm and 15‐30 cm Soil depths than a corn–soybean– alfalfa rotation after 10 years of management on the MIH Soil association. Smooth bromegrass and switchgrass systems increased SOC by 2.3 and 1.2 Mg ha 1 yr 1 at the 0‐15 cm Soil depth, respectively. We conclude from these short-term experiments that reducing tillage intensity and increasing crop diversity to include perennial grasses could be effective in improving C and N sequestration in Midwest Soils. # 2004 Elsevier B.V. All rights reserved.
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Soil carbon and nitrogen changes as affected by tillage system and crop biomass in a corn-soybean rotation
Applied Soil Ecology, 2005Co-Authors: Al-kaisi, Xinhua Yin, Mark A. LichtAbstract:A wide range of tillage systems have been used by producers in the Corn-Belt in the United States during the past decade due to their economic and environmental benefits. However, changes in Soil organic carbon (SOC) and nitrogen (SON) and crop responses to these tillage systems are not well documented in a corn–soybean rotation. Two experiments were conducted to evaluate the effects of different tillage systems on SOC and SON, residue C and N inputs, and corn and soybean yields across Iowa. The first experiment consisted of no-tillage (NT) and chisel plow (CP) treatments, established in 1994 in Clarion– Nicollet–Webster (CNW), Galva–Primghar–Sac (GPS), Kenyon–Floyd–Clyde (KFC), Marshall (M), and Otley–Mahaska– Taintor (OMT) Soil Associations. The second experiment consisted of NT, strip-tillage (ST), CP, deep rip (DR), and moldboard plow (MP) treatments, established in 1998 in the CNW Soil association. Both corn and soybean yields of NT were statistically comparable to those of CP treatment for each Soil association in a corn–soybean rotation during the 7 years of tillage practices. The NT, ST, CP, and DR treatments produced similar corn and soybean yields as MP treatment in a corn–soybean rotation during the 3 years of tillage implementation of the second experiment. Significant increases in SOC of 17.3, 19.5, 6.1, and 19.3% with NT over CP treatment were observed at the top 15-cm Soil depth in CNW, KFC, M, and OMT Soil Associations, respectively, except for the GPS Soil association in a corn–soybean rotation at the end of 7 years. The NT and ST resulted in significant increases in SOC of 14.7 and 11.4%, respectively, compared with MP treatment after 3 years. Changes in SON due to tillage were similar to those observed with SOC in both experiments. The increases in SOC and SON in NT treatment were not attributed to the vertical stratification of organic C and N in the Soil profile or annual C and N inputs from crop residue, but most likely due to the decrease in Soil organic matter mineralization in wet and cold Soil conditions. It was concluded that NT and ST are superior to CP and MP in increasing SOC and SON in the top 15 cm in the short-term. The adoption of NT or CP can be an effective strategy in increasing SOC and SON in the Corn-Belt Soils without significant adverse impact on corn and soybean yields in a corn–soybean rotation. # 2005 Elsevier B.V. All rights reserved.
Nathan G. Swenson - One of the best experts on this subject based on the ideXlab platform.
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Phylogenetic analysis of local-scale tree Soil Associations in a lowland moist tropical forest.
PloS one, 2010Co-Authors: Laura A. Schreeg, W. John Kress, David Erickson, Nathan G. SwensonAbstract:Background: Local plant-Soil Associations are commonly studied at the species-level, while Associations at the level of nodes within a phylogeny have been less well explored. Understanding Associations within a phylogenetic context, however, can improve our ability to make predictions across systems and can advance our understanding of the role of evolutionary history in structuring communities. Methodology/Principal Findings: Here we quantified evolutionary signal in plant-Soil Associations using a DNA sequencebased community phylogeny and several Soil variables (e.g., extractable phosphorus, aluminum and manganese, pH, and slope as a proxy for Soil water). We used published plant distributional data from the 50-ha plot on Barro Colorado Island (BCI), Republic of Panama´. Our results suggest some groups of closely related species do share similar Soil Associations. Most notably, the node shared by Myrtaceae and Vochysiaceae was associated with high levels of aluminum, a potentially toxic element. The node shared by Apocynaceae was associated with high extractable phosphorus, a nutrient that could be limiting on a taxon specific level. The node shared by the large group of Laurales and Magnoliales was associated with both low extractable phosphorus and with steeper slope. Despite significant node-specific Associations, this study detected little to no phylogeny-wide signal. We consider the majority of the ‘traits’ (i.e., Soil variables) evaluated to fall within the category of ecological traits. We suggest that, given this category of traits, phylogeny-wide signal might not be expected while nodespecific signals can still indicate phylogenetic structure with respect to the variable of interest. Conclusions: Within the BCI forest dynamics plot, distributions of some plant taxa are associated with local-scale differences in Soil variables when evaluated at individual nodes within the phylogenetic tree, but they are not detectable by phylogenywide signal. Trends highlighted in this analysis suggest how plant-Soil Associations may drive plant distributions and diversity at the local-scale.
Al-kaisi - One of the best experts on this subject based on the ideXlab platform.
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Soil carbon and nitrogen changes as influenced by tillage and cropping systems in some Iowa Soils
Agriculture Ecosystems & Environment, 2005Co-Authors: Al-kaisi, Xinhua Yin, Mark A. LichtAbstract:Soil organic C (SOC) and total N (TN) contents play a crucial role in sustaining agricultural production systems. Short-term (10-year) management effects on SOC and TN dynamics are often complex and variable. Three experiments were conducted to evaluate short-term tillage and cropping system effects on SOC and TN within the 0‐30 cm Soil depth across Iowa. The first experiment with no-tillage and chisel plowing treatments was established in 1994 on Clarion-Nicollet-Webster (CNW), GalvaPrimghar-Sac (GPS), Kenyon-Floyd-Clyde (KFC), Marshall (M), and Otley-Mahaska-Taintor (OMT) Soil Associations under a corn (Zea mays L.)‐soybean (Glycine max (L.) Merr.) rotation. The second experiment with no-tillage, strip-tillage, chisel plowing, deep ripping, and moldboard plowing treatments was initiated in 1998 on the CNW Soil association in a corn‐soybean rotation. The third experiment consisting of smooth bromegrass (Bromus inermis Leyss.), switchgrass (Panicum virgatum L.) and corn‐soybean‐alfalfa (Medicago sativa L.) treatments was established in 1991 on Monona-Ida-Hamburg (MIH) Soil association under no-tillage management. Short-term tillage effects on SOC and TN occurred primarily at the 0‐15 cm Soil depth. Tillage effects did not vary significantly with Soil association. No-tillage resulted in greater SOC and TN contents than chisel plowing at the end of 7 years of tillage practices averaged over the CNW, GPS, KFC, M, and OMT Soil Associations. The increase in SOC and TN with no-tillage was not related to SOC and TN stratification in the Soil profile or annual C and N inputs from crop residue, but most likely due to decreased mineralization rate of Soil organic matter. However, tillage effects on SOC and TN were negligible at the end of only 3 years of tillage practices on the CNW Soil association. Smooth bromegrass and switchgrass systems resulted in greater SOC and TN contents at both 0‐15 cm and 15‐30 cm Soil depths than a corn–soybean– alfalfa rotation after 10 years of management on the MIH Soil association. Smooth bromegrass and switchgrass systems increased SOC by 2.3 and 1.2 Mg ha 1 yr 1 at the 0‐15 cm Soil depth, respectively. We conclude from these short-term experiments that reducing tillage intensity and increasing crop diversity to include perennial grasses could be effective in improving C and N sequestration in Midwest Soils. # 2004 Elsevier B.V. All rights reserved.
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Soil carbon and nitrogen changes as affected by tillage system and crop biomass in a corn-soybean rotation
Applied Soil Ecology, 2005Co-Authors: Al-kaisi, Xinhua Yin, Mark A. LichtAbstract:A wide range of tillage systems have been used by producers in the Corn-Belt in the United States during the past decade due to their economic and environmental benefits. However, changes in Soil organic carbon (SOC) and nitrogen (SON) and crop responses to these tillage systems are not well documented in a corn–soybean rotation. Two experiments were conducted to evaluate the effects of different tillage systems on SOC and SON, residue C and N inputs, and corn and soybean yields across Iowa. The first experiment consisted of no-tillage (NT) and chisel plow (CP) treatments, established in 1994 in Clarion– Nicollet–Webster (CNW), Galva–Primghar–Sac (GPS), Kenyon–Floyd–Clyde (KFC), Marshall (M), and Otley–Mahaska– Taintor (OMT) Soil Associations. The second experiment consisted of NT, strip-tillage (ST), CP, deep rip (DR), and moldboard plow (MP) treatments, established in 1998 in the CNW Soil association. Both corn and soybean yields of NT were statistically comparable to those of CP treatment for each Soil association in a corn–soybean rotation during the 7 years of tillage practices. The NT, ST, CP, and DR treatments produced similar corn and soybean yields as MP treatment in a corn–soybean rotation during the 3 years of tillage implementation of the second experiment. Significant increases in SOC of 17.3, 19.5, 6.1, and 19.3% with NT over CP treatment were observed at the top 15-cm Soil depth in CNW, KFC, M, and OMT Soil Associations, respectively, except for the GPS Soil association in a corn–soybean rotation at the end of 7 years. The NT and ST resulted in significant increases in SOC of 14.7 and 11.4%, respectively, compared with MP treatment after 3 years. Changes in SON due to tillage were similar to those observed with SOC in both experiments. The increases in SOC and SON in NT treatment were not attributed to the vertical stratification of organic C and N in the Soil profile or annual C and N inputs from crop residue, but most likely due to the decrease in Soil organic matter mineralization in wet and cold Soil conditions. It was concluded that NT and ST are superior to CP and MP in increasing SOC and SON in the top 15 cm in the short-term. The adoption of NT or CP can be an effective strategy in increasing SOC and SON in the Corn-Belt Soils without significant adverse impact on corn and soybean yields in a corn–soybean rotation. # 2005 Elsevier B.V. All rights reserved.