scholarly journals Resilience: nitrogen limitation, mycorrhiza and long-term palaeoecological plant–nutrient dynamics

2020 ◽  
Vol 16 (1) ◽  
pp. 20190441 ◽  
Author(s):  
Michael B. Bonsall ◽  
Cynthia A. Froyd ◽  
Elizabeth S. Jeffers
Keyword(s):  
Nutrient Dynamics ◽  
Ecosystem Dynamics ◽  
Ecological Resilience ◽  
Mathematical Framework ◽  
Plant Nutrient ◽  
Available Nitrogen ◽  
Plant Soil ◽  
Mycorrhizal Associations ◽  
Plant Plant

Ecosystem dynamics are driven by both biotic and abiotic processes, and perturbations can push ecosystems into novel dynamical regimes. Plant–plant, plant–soil and mycorrhizal associations all affect plant ecosystem dynamics; however, the direction and magnitude of these effects vary by context and their contribution to ecosystem resilience over long time periods remains unknown. Here, using a mathematical framework, we investigate the effects of plant feedbacks and mycorrhiza on plant–nutrient interactions. We show evidence for strong nutrient controlled feedbacks, moderation by mycorrhiza and influence on ecological resilience. We use this model to investigate the resilience of a longitudinal palaeoecological birch– δ 15 N interaction to plant–soil feedbacks and mycorrhizal associations. The birch– δ 15 N system demonstrated high levels of resilience. Mycorrhiza were predicted to increase resilience by supporting plant–nitrogen uptake and immobilizing excess nitrogen; in contrast, long-term enrichment in available nitrogen by plant–soil feedbacks is expected to decrease ecological resilience.

Accumulation and release of plant nutrients in decomposing Scots pine needle litter. Long-term decomposition in a Scots pine forest II

1982 ◽  
Vol 60 (8) ◽  
pp. 1561-1568 ◽  
Author(s):  
Håkan Staaf ◽  
Björn Berg
Keyword(s):  
Weight Loss ◽  
Scots Pine ◽  
Nutrient Dynamics ◽  
Pine Forest ◽  
Plant Nutrient ◽  
Pine Needle ◽  
Needle Litter ◽  
Scots Pine Forest ◽  
Net Release

Plant nutrient dynamics in decomposing needle litter were measured during a 5-year period in a Scots pine forest in central Sweden. As seen over the whole 5-year period, the nutrients were retained (to a litter weight loss of about 75%) in the order Mn < Ca < K < Mg < S < N < P. During the first 1.5 years there was a net increase of N and P whereafter a net release took place. A similar but less pronounced development could be seen for S, whereas Ca, K, Mn, and Mg were released from the start of the incubation. It is suggested that P was the most limiting element for microbial activity during this first phase. There appeared to be only little initial leaching from the litter and the different behaviours of the elements could largely be explained by their concentration in litter in relation to the needs of microorganisms and to their solubility. K and Mg were the elements that were released at rates most similar to organic matter weight loss.

scholarly journals The Response of Soil Nutrients and Microbial Community Structures in Long-Term Tea Plantations and Diverse Agroforestry Intercropping Systems

2021 ◽  
Vol 13 (14) ◽  
pp. 7799
Author(s):  
Guolin Zhang ◽  
Xingbiao Chu ◽  
Hanyang Zhu ◽  
Dongsheng Zou ◽  
Longcheng Li ◽  
...  
Keyword(s):  
Microbial Community ◽  
Soil Nutrients ◽  
Nutrient Dynamics ◽  
Structural Diversity ◽  
Available Phosphorus ◽  
Community Structures ◽  
Available Nitrogen ◽  
Microbial Community Structures ◽  
Tea Plantations

During tea cultivation, diverse agroforestry is an important and established intercropping measure, with most studies concentrating on ecological service provision and economic returns. However, the response of soil nutrients and microbial community structures in long-term tea plantations with diverse agroforestry intercropping systems is poorly understood. In the present field study (2015), three intercropping agroforestry-tea patterns (Osmanthus-Tea (OT), Michelia-Tea (MT), Osmanthus-Michelia-Tea (OMT)) along with a study control (C) were examined in terms of these two knowledge gaps. Results showed that, in terms of tea cultivation, the OMT system is more suitable than the OT and MT systems. The OMT system significantly increased the total nitrogen (TN, 16.4%), total potassium (TK, 10.5%), available nitrogen (AN, 14.2%), available phosphorus (AP, 26.7%) and soil organic matter (SOM, 28.9%). The OMT system increased phylum Firmicutes and Bacteroidetes abundance by 35.8% and 9.6%. In addition, the OMT system enhanced the abundance of class Bacteroidia (99.5%), Erysipelotrichia (96.9%), Clostridia (93.5%) and Actinobacteria (19.6%), respectively. In general, the phylum bacteria Proteobacteria, Firmicutes, Actinobacteria accounted for the largest proportion of bacteria in all three intercropping systems. In this study, the abundance of Firmicutes, Actinobacteria, Proteobacteria, and Bacteroidetes were positively correlated with AN, SOM and TP. The results of the present study will help to develop a better understanding of the benefits imposed by different agroforestry intercropping systems on nutrient dynamics and microbial structural diversity during tea cultivation.

Can forest management based on natural disturbances maintain ecological resilience?

2006 ◽  
Vol 36 (9) ◽  
pp. 2285-2299 ◽  
Author(s):  
C Ronnie Drever ◽  
Garry Peterson ◽  
Christian Messier ◽  
Yves Bergeron ◽  
Mike Flannigan
Keyword(s):  
Nutrient Dynamics ◽  
Multiple Scales ◽  
Critical Role ◽  
Natural Disturbance ◽  
Ecological Resilience ◽  
Natural Disturbances ◽  
Resilience Theory ◽  
Managed Forests ◽  
Spatial And Temporal Scales

Given the increasingly global stresses on forests, many ecologists argue that managers must maintain ecological resilience: the capacity of ecosystems to absorb disturbances without undergoing fundamental change. In this review we ask: Can the emerging paradigm of natural-disturbance-based management (NDBM) maintain ecological resilience in managed forests? Applying resilience theory requires careful articulation of the ecosystem state under consideration, the disturbances and stresses that affect the persistence of possible alternative states, and the spatial and temporal scales of management relevance. Implementing NDBM while maintaining resilience means recognizing that (i) biodiversity is important for long-term ecosystem persistence, (ii) natural disturbances play a critical role as a generator of structural and compositional heterogeneity at multiple scales, and (iii) traditional management tends to produce forests more homogeneous than those disturbed naturally and increases the likelihood of unexpected catastrophic change by constraining variation of key environmental processes. NDBM may maintain resilience if silvicultural strategies retain the structures and processes that perpetuate desired states while reducing those that enhance resilience of undesirable states. Such strategies require an understanding of harvesting impacts on slow ecosystem processes, such as seed-bank or nutrient dynamics, which in the long term can lead to ecological surprises by altering the forest's capacity to reorganize after disturbance.

scholarly journals Cheatgrass Invasion - The Below-Ground Connection

2017 ◽  
Vol 8 (1) ◽  
pp. 27
Author(s):  
Raven Reitstetter ◽  
Rittenhouse Larry R.
Keyword(s):  
Soil Microbial Communities ◽  
Plant Growth Promoting Rhizobacteria ◽  
Invasion Success ◽  
Invasive Grass ◽  
Available Nitrogen ◽  
Soil Microbial ◽  
Plant Soil ◽  
Plant Growth Promoting ◽  
Below Ground

Plant-soil microbial feedback loops play an important role in the establishment and development of plant communities. Microbial soil communities, including pathogens, plant-growth-promoting rhizobacteria and their reciprocal interactions, can influence plant health and nutrient cycling in many ways. We are proposing a model that accounts for cheatgrass (Bromus tectorum) invasion success and long-term persistence in both disturbed and undisturbed sites. In this model cheatgrass alters soil microbial communities that favor nitrifying microorganisms, resulting in elevated NO3- levels. Increased NO3- levels, coupled with B. tectorum life history and climatic and edaphic conditions in the semi-arid western U.S., result in long-term persistence of this invasive annual. In ecosystems that lack major precipitation during the growth season, B. tectorum induced shifts in the nitrifier community result in accumulation of plant available nitrogen during the summer when native perennials are primarily dormant. Increased NO3- levels can be efficiently utilized by cheatgrass ahead of native perennials during fall and winter. Restoration and management efforts must be guided by a thorough understanding of soil microbe-cheatgrass interactions to avoid nutrient flushes resulting from freeze-thaw and wet-dry cycles that benefit this invasive grass.

ALLELOPATHIC EFFECTS OF PARTHENIUM HYSTEROPHORUS ON GERMINATION OF SORGHUM SEEDS

2018 ◽  
Vol 6 (26) ◽  
Author(s):  
Jitendra Rajpoot
Keyword(s):  
Biological System ◽  
Growth And Development ◽  
Plant Virus ◽  
Evolutionary Origin ◽  
Plant Interactions ◽  
Biological Organization ◽  
Plant Soil ◽  
System A ◽  
Allelopathic Effects ◽  
Plant Plant

International Allelopathy Society has redefined Allelopathy as any process involving secondary metabolities produced by plants, algae, bacteria, fungi and viruses that influences the growth and development of agricultural and biological system; a study of the functions of secondary metabolities, their significance in biological organization, their evolutionary origin and elucidation of the mechanisms involving plant-plant, plant-microorganisms, plant-virus, plant-insect, plant-soil-plant interactions.

scholarly journals Long-term changes in the plant ecology of an African savanna landscape and the implications for ecosystem theory and conservation management

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
David Western ◽  
Victor N. Mose ◽  
David Maitumo ◽  
Caroline Mburu
Keyword(s):  
Human Impact ◽  
National Parks ◽  
Conservation Management ◽  
Plant Ecology ◽  
Ecological Resilience ◽  
Pasture Production ◽  
Ecosystem Theory ◽  
The Impact

Abstract Background Studies of the African savannas have used national parks to test ecological theories of natural ecosystems, including equilibrium, non-equilibrium, complex adaptive systems, and the role of top-down and bottom-up physical and biotic forces. Most such studies have excluded the impact of pastoralists in shaping grassland ecosystems and, over the last half century, the growing human impact on the world’s rangelands. The mounting human impact calls for selecting indicators and integrated monitoring methods able to track ecosystem changes and the role of natural and human agencies. Our study draws on five decades of monitoring the Amboseli landscape in southern Kenya to document the declining role of natural agencies in shaping plant ecology with rising human impact. Results We show that plant diversity and productivity have declined, biomass turnover has increased in response to a downsizing of mean plant size, and that ecological resilience has declined with the rising probability of extreme shortfalls in pasture production. The signature of rainfall and physical agencies in driving ecosystem properties has decreased sharply with growing human impact. We compare the Amboseli findings to the long-term studies of Kruger and Serengeti national parks to show that the human influence, whether by design or default, is increasingly shaping the ecology of savanna ecosystems. We look at the findings in the larger perspective of human impact on African grasslands and the world rangelands, in general, and discuss the implications for ecosystem theory and conservation policy and management. Conclusions The Amboseli study shows the value of using long-term integrated ecological monitoring to track the spatial and temporal changes in the species composition, structure, and function of rangeland ecosystems and the role of natural and human agencies in the process of change. The study echoes the widespread changes underway across African savannas and world’s rangelands, concluding that some level of ecosystem management is needed to prevent land degradation and the erosion of ecological function, services, and resilience. Despite the weak application of ecological theory to conservation management, a plant trait-based approach is shown to be useful in explaining the macroecological changes underway.

Nutrient cycling differs between cropped soils with century-old and recently pyrolyzed biochar

2021 ◽  
Author(s):  
Victor Burgeon ◽  
Julien Fouché ◽  
Sarah Garré ◽  
Ramin Heidarian-Dehkordi ◽  
Gilles Colinet ◽  
...  
Keyword(s):  
Nutrient Cycling ◽  
Soil Solution ◽  
Nutrient Dynamics ◽  
Chemical Properties ◽  
Crop Productivity ◽  
Nutrient Concentrations ◽  
Soil Productivity ◽  
Long Term Effects ◽  
Mitigation And Adaptation

&lt;p&gt;The amendment of biochar to soils is often considered for its potential as a climate change mitigation and adaptation tool through agriculture. Its presence in tropical agroecosystems has been reported to positively impact soil productivity whilst successfully storing C on the short&amp;#8201;and long-term. In temperate systems, recent research showed limited to no effect on productivity following recent biochar addition to soils. Its long-term effects on productivity and nutrient cycling have, however, been overlooked yet are essential before the use of biochar can be generalized.&lt;/p&gt;&lt;p&gt;Our study was set up in a conventionally cropped field, containing relict charcoal kiln sites used as a model for century old biochar (CoBC, ~220 years old). These sites were compared to soils amended with recently pyrolyzed biochar (YBC) and biochar free soils (REF) to study nutrient dynamics in the soil-water-plant system. Our research focused on soil chemical properties, crop nutrient uptake and soil solution nutrient concentrations. Crop plant samples were collected over three consecutive land occupations (chicory, winter wheat and a cover crop) and soil solutions gathered through the use of suctions cups inserted in different horizons of the studied Luvisol throughout the field.&lt;/p&gt;&lt;p&gt;Our results showed that YBC mainly influenced the soil solution composition whereas CoBC mainly impacted the total and plant available soil nutrient content. In soils with YBC, our results showed lower nitrate and potassium concentrations in subsoil horizons, suggesting a decreased leaching, and higher phosphate concentrations in topsoil horizons. With time and the oxidation of biochar particles, our results reported higher total soil N, available K and Ca in the topsoil horizon when compared to REF, whereas available P was significantly smaller. Although significant changes occurred in terms of plant available nutrient contents and soil solution nutrient concentrations, this did not transcend in variations in crop productivity between soils for neither of the studied crops. Overall, our study highlights that young or aged biochar behave as two distinct products in terms of nutrient cycling in soils. As such the sustainability of these soils differ and their management must therefore evolve with time.&lt;/p&gt;

Long-Term Effects of Grazing and Haying on Soil Nutrient Dynamics in Forage-Based Beef Cattle Operations

2007 ◽  
Vol 29 (3) ◽  
pp. 115-134 ◽  
Author(s):  
Gilbert C. Sigua ◽  
Mary J. Williams ◽  
Samuel W. Coleman
Keyword(s):  
Beef Cattle ◽  
Nutrient Dynamics ◽  
Soil Nutrient ◽  
Long Term Effects

scholarly journals Mathematical Framework for Breathing Chimera States

2022 ◽  
Vol 32 (2) ◽  
Author(s):  
O. E. Omel’chenko
Keyword(s):  
Coupled Oscillators ◽  
Analytic Solution ◽  
Coarse Grained ◽  
Mathematical Framework ◽  
Intensive Study ◽  
Phase Oscillators ◽  
Chimera States ◽  
The Subject ◽  
Self Consistency

AbstractAbout two decades ago it was discovered that systems of nonlocally coupled oscillators can exhibit unusual symmetry-breaking patterns composed of coherent and incoherent regions. Since then such patterns, called chimera states, have been the subject of intensive study but mostly in the stationary case when the coarse-grained system dynamics remains unchanged over time. Nonstationary coherence–incoherence patterns, in particular periodically breathing chimera states, were also reported, however not investigated systematically because of their complexity. In this paper we suggest a semi-analytic solution to the above problem providing a mathematical framework for the analysis of breathing chimera states in a ring of nonlocally coupled phase oscillators. Our approach relies on the consideration of an integro-differential equation describing the long-term coarse-grained dynamics of the oscillator system. For this equation we specify a class of solutions relevant to breathing chimera states. We derive a self-consistency equation for these solutions and carry out their stability analysis. We show that our approach correctly predicts macroscopic features of breathing chimera states. Moreover, we point out its potential application to other models which can be studied using the Ott–Antonsen reduction technique.

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