Nutrient response to soil and litter metabolic activity in a transect across a seasonal wetland

Many wetlands in the interdunal depression of coastal sand dunes of the Swan Coastal Plain are surrounded by partially vegetated catchments. Although litter can be an important source of nutrients, little is known about litter related microbial activity in these catchments, especially its role in regulating nutrient concentrations in soils during the wet season. Heterotrophic microbial activity and phosphorus (P) dynamics were monitored before and after the onset of the wet season along transects from a vegetated catchment to the lakebed in Thomsons Lake, south-western Australia. Microbial activity was measured in the field as CO2 efflux (range from 47 to 176 mg CO2 m–2 h–1) and in the laboratory as substrate-induced-respiration (SIR; range from 11 to 133 μg g–1 h–1). Substrate-induced-respiration was positively correlated with soil organic content, and was concentrated in surface soils. In contrast, in the exposed lakebed most microbial biomass was below the surface, in the 10–30 cm depth zone. There were significant changes in nutrient dynamics in response to soil microbial activity. Before rain, P extracted by anion exchange membrane (PAEM) was well correlated with site litter and plant debris (r2 = 0.90, P�<�0.001), suggesting that PAEM in soils was litter-sourced. This relationship was modified during the wet season: there was an overall increase in microbial biomass P (PMB; from average 7.5 μg g–1 to 21.6 μg g–1), and a decrease in PAEM : PMB in surface soils. Along the study transect, the assimilation index PAEM : PMB declined towards the wetland, where soils were more silty and organic, and CO2 production was significantly higher. Our data suggest that heterotrophic microbial activity has a significant role in regulating P flux from catchment litter during the wet season, which would affect the mobility of litter-sourced P from catchment to the wetland.

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Sediment metabolism in a transitional continental - marine area: The Albufera of Majorca (Balearic Islands, Spain)

Marine and Freshwater Research ◽

10.1071/mf9950045 ◽

1995 ◽

Vol 46 (1) ◽

pp. 45 ◽

Cited By ~ 13

Author(s):

P Lopez ◽

M Vidal ◽

X Lluch ◽

JA Morgui

Keyword(s):

Oxygen Consumption ◽

Pore Water ◽

Respiratory Quotient ◽

Nutrient Dynamics ◽

Anaerobic Respiration ◽

Ammonium Phosphate ◽

Nutrient Concentrations ◽

Co2 Efflux ◽

Marine Areas ◽

Diffusive Fluxes

The concentrations of nutrients in sediment pore water and the fluxes of nutrients at the water-sediment interface were measured in a channel that joins continental and marine areas in the Albufera of Majorca in order to evaluate the role of sediments in the nutrient dynamics in this system. Upstream, surficial pore water presented lower values of Eh, which became negative in summer, whereas downstream Eh remained positive. Nutrient concentrations were especially high upstream, reaching 1000 mol L-1 of NH4 and 75 μmol L-1 of PO4 during summer. In summer, measured fluxes showed intense respiration upstream, with an oxygen consumption of 130 mg m-2 h-1 and a respiratory quotient near 4, which indicates dominance of anaerobic respiration. Total CO2 efflux and nutrient fluxes were also high, reaching 30.50 mmol m-2 h-1 for CO2, >2000 μmol m-2 h-1 for NH4 and 58 μmol m-2 h-1 for PO4. A substantial amount of the total CO2 efflux (14 mmol m-2 h-1) was due to calcium carbonate redissolution. Downstream, oxygen consumption, respiratory quotient and ammonium fluxes were lower (around 70 mg m-2 h-1, between 2 and 3, and <20 μmol m-2 h-1, respectively), which indicates a moderate rate of decomposition activity and suggests denitrification as the main respiratoy process. Differences between fluxes measured 'in situ' and those calculated from pore-water concentrations indicated non-diffusive fluxes upstream and suggest substantial denitrifying activity downstream. Extra keywords: benthic chambers, sediment fluxes, pore water, ammonium, phosphate.

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Water relations and mineral nutrition of Triodia grasses on desert dunes and interdunes

Australian Journal of Botany ◽

10.1071/bt07156 ◽

2008 ◽

Vol 56 (5) ◽

pp. 408 ◽

Cited By ~ 19

Author(s):

Alasdair M. Grigg ◽

Erik J. Veneklaas ◽

Hans Lambers

Keyword(s):

Plant Species ◽

Soil Depth ◽

Water Status ◽

Sand Dunes ◽

Temporal Distribution ◽

Nutrient Concentrations ◽

Wet Season ◽

Water Storage Capacity ◽

Foliar Nutrient ◽

Desert Dunes

Desert dunes and interdunes provide habitat heterogeneity and profoundly influence the spatial and temporal distribution of water and nutrients throughout the landscape. These underlying physical processes shape the plant species composition and their ecophysiology. Spinifex grasses dominate the vegetation throughout much of Australia and are categorised into two groups; ‘soft’ species occur mostly in northern, subtropical to semiarid regions, whereas ‘hard’ species occur mostly throughout the dry centre and southern interior. This study examined the water and nutrient relations and leaf anatomy of dominant ‘soft’ and ‘hard’ spinifex in the Great Sandy Desert, where their distributions overlap. The ‘soft’ species, Triodia schinzii (Henrard) Lazarides, occurs only on sand dunes, whereas the ‘hard’ species, T. basedowii E.Pritz., is restricted to the flat interdunes. We proposed two hypotheses: 1) that the dune species, T. schinzii would display more favourable water status and 2) the interdune species, T. basedowii would display higher leaf nutrient concentrations. Triodia schinzii displayed significantly less negative leaf water potentials at predawn and at midday (–0.4 and –2.0 MPa, respectively) than T. basedowii (–0.9 and –3.0 MPa, respectively) throughout the middle of the dry season. Photosynthesis rates were also significantly higher in T. schinzii than T. basedowii in the wet season (140 v. 84 nmol g–1 s–1), but there were no significant differences between species in leaf conductance. Leaf δ13C composition confirmed anatomical observations that both species were C4 and supported the finding that T. schinzii displayed significantly greater photosynthetic water-use efficiency during the wet season than T. basedowii. In general, foliar nutrient concentrations were not significantly different between species; however, both species exhibited especially low leaf P and to a lesser extent N. We conclude that water is more readily available in the dune than the interdune as a result of greater soil depth and associated water storage capacity. These properties are considered the main factors influencing plant species distribution. Given the climatic and geographic distribution of these two Triodia species, it is suggested that sand dunes provide a mesic corridor for T. schinzii to extend its range from higher rainfall areas into the arid interior.

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Seasonal variations in the water quality of six tropical micro- and mesotidal estuaries along the central west coast of India

Marine and Freshwater Research ◽

10.1071/mf17181 ◽

2018 ◽

Vol 69 (9) ◽

pp. 1418 ◽

Cited By ~ 3

Author(s):

Lina L. Fernandes ◽

Pratima M. Kessarkar ◽

Suresh Suja ◽

Durbar Ray ◽

Mithila Bhat

Keyword(s):

West Coast ◽

Nutrient Dynamics ◽

Nutrient Concentrations ◽

Wet Season ◽

Salinity Stratification ◽

West Coast Of India ◽

Estuarine Mixing ◽

Run Off ◽

Water Columns ◽

Mixing Diagrams

Seasonal nutrient dynamics were investigated in four rivers with a microtidal range (Terekhol, Chapora, Sal and Talpona rivers) and were compared with those of two rivers with a mesotidal range (Zuari and Mandovi rivers) along the central west coast of India. Rainfall and freshwater discharge during the wet season led to salinity stratification of the water columns at the mouths of these rivers. Nutrient concentrations in all rivers were higher during the wet season than in the dry season due to considerable land run-off. Based on the estuarine mixing diagrams of the nutrients with regard to salinity, the mesotidal rivers showed greater flushing capacity and acted as corridors for the passage of nutrients between the estuary and open ocean. Conversely, of the microtidal rivers, the Terekhol and Chapora seemed to retain nutrients, whereas there was no indication of the presence of a nutrient sink or source in the Talpona River. The Sal River was eutrophic with high nutrient levels and acted as a source of phosphorus and nitrogen. Thus, the present study clearly illustrates the important role played by minor river estuaries in modifying nutrient concentrations during their transport from rivers to coastal waters and vice versa.

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Organic acid adsorption and mineralization in oxisols with different textures

Revista Brasileira de Ciência do Solo ◽

10.1590/s0100-06832013000400015 ◽

2013 ◽

Vol 37 (4) ◽

pp. 976-985 ◽

Cited By ~ 9

Author(s):

Felipe Vaz Andrade ◽

Eduardo de Sá Mendonça ◽

Ivo Ribeiro da Silva

Keyword(s):

Organic Acids ◽

Organic Acid ◽

Factorial Design ◽

Microbial Activity ◽

Carbon Mineralization ◽

Co2 Production ◽

Co2 Efflux ◽

Adsorption Sites ◽

Nutritional Conditions ◽

Soil Adsorption

Organic acids play an important role in the nutritional conditions of plants. Their relevance is related to their formation dynamics, mineralization rate and adsorption by soil colloids. This study was carried out to evaluate the dynamics of mineralization and adsorption of organic acid (acetic acid - AA, citric acid - CA and humic acid - HA) applied to the soil. Samples of two Oxisols were used: Rhodic Haplustox (LV) and Typic Haplustox (LVA). The mineralization experiment was arranged in a 2 x 3 x 5 factorial design, based on the factors: two soils (LV and LVA) x three organic acid (OA) types (AA, CA and HA) x five OA rates (0, 1, 2, 4, and 8 mmol dm-3). Organic carbon mineralization in samples was measured by the C-CO2 efflux, produced by the microbial activity, in a 30-day (measurements after 4, 8, 12, 21, and 30 days) and in a 4-day experiment (measured after 24, 48, 72 and 96 h). Organic acid adsorption was tested in a 2 x 2 x 5 x 4 factorial design, with the factors and levels: two Oxisols; two organic acids (AA and CA); five OA rates (0, 1, 2, 4, and 8 mmol dm-3) and four adsorption periods (6, 24, 48, and 72 h). The C-CO2 production of soil treated with CA was highest. In the adsorption experiment, the affinity of CA to soil adsorption sites was greatest. The adsorption of organic acids to soils may be an important mechanism by which bioavailability and thus mineralization capacity by microbial activity are reduced.

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Effects of fire regimes on herbaceous biomass and nutrient dynamics in the Brazilian savanna

International Journal of Wildland Fire ◽

10.1071/wf10136 ◽

2013 ◽

Vol 22 (3) ◽

pp. 368 ◽

Cited By ~ 25

Author(s):

Immaculada Oliveras ◽

Sergio T. Meirelles ◽

Valter L. Hirakuri ◽

Cenira R. Freitas ◽

Heloisa S. Miranda ◽

...

Keyword(s):

Aboveground Biomass ◽

Nutrient Dynamics ◽

Community Dynamics ◽

Fire Regime ◽

Dry Season ◽

Brazilian Savanna ◽

Nutrient Concentrations ◽

Total Biomass ◽

Long Term Effects ◽

Wet Season

This study explores the long-term effects of fire treatments on biomass and nutrient pools in an open savanna from Central Brazil. Treatments included early, middle and late dry season burns every 2 years, a middle dry season burn every 4 years, and protection from fire on five 4-ha plots. We quantified aboveground biomass of graminoids and forbs/sub-shurbs, and their nutrient concentrations and stocks in both dry and wet seasons, and below-ground biomass down to 30-cm depth. We found strong differences between wet and dry season, with biomass and nutrient concentrations being highest in the wet season, across all fire treatments. Fire treatments had significant effects on plant nutrient stocks and root distribution, although total biomass was not affected. Concentrations of the most volatile nutrients (N, S, K and P) were higher in the herbaceous aboveground biomass of the quadrennial and the unburnt plots, suggesting that increases in fire frequency would reduce the amount of nutrients in aboveground biomass and increase the concentration of fine roots at the soil surface. Results highlight the role of fire in maintaining community dynamics in the Brazilian savanna. Overall, the quadrennial burn appears to be the optimal fire regime in open Cerrado vegetation.

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Microbial Respiration and Enzyme Activity Downstream from a Phosphorus Source in the Everglades, Florida, USA

Land ◽

10.3390/land10070696 ◽

2021 ◽

Vol 10 (7) ◽

pp. 696

Author(s):

Sanku Dattamudi ◽

Saoli Chanda ◽

Leonard J. Scinto

Keyword(s):

Nutrient Dynamics ◽

Microbial Respiration ◽

Organic Matter Content ◽

Physicochemical Analysis ◽

Matter Content ◽

Enzyme Assays ◽

Co2 Efflux ◽

Soil Organic Matter Content ◽

Phosphorus Source ◽

P Distribution

Northeast Shark River Slough (NESS), lying at the northeastern perimeter of Everglades National Park (ENP), Florida, USA, has been subjected to years of hydrologic modifications. Construction of the Tamiami Trail (US 41) in 1928 connected the east and west coasts of SE Florida and essentially created a hydrological barrier to southern sheet flow into ENP. Recently, a series of bridges were constructed to elevate a portion of Tamiami Trail, allow more water to flow under the bridges, and attempt to restore the ecological balance in the NESS and ENP. This project was conducted to determine aspects of soil physiochemistry and microbial dynamics in the NESS. We evaluated microbial respiration and enzyme assays as indicators of nutrient dynamics in NESS soils. Soil cores were collected from sites at certain distances from the inflow (near canal, NC (0–150 m); midway, M (150–600 m); and far from canal, FC (600–1200 m)). Soil slurries were incubated and assayed for CO2 emission and β-glucoside (MUFC) or phosphatase (MUFP) activity in concert with physicochemical analysis. Significantly higher TP contents at NC (2.45 times) and M (1.52 times) sites than FC sites indicated an uneven P distribution downstream from the source canal. The highest soil organic matter content (84%) contents were observed at M sites, which was due to higher vegetation biomass observed at those sites. Consequently, CO2 efflux was greater at M sites (average 2.72 µmoles g dw−1 h−1) than the other two sites. We also found that amendments of glucose increased CO2 efflux from all soils, whereas the addition of phosphorus did not. The results indicate that microbial respiration downstream of inflows in the NESS is not limited by P, but more so by the availability of labile C.

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Seasonal changes in water quality and macrophytes and the impact of cattle on tropical floodplain waterholes

Marine and Freshwater Research ◽

10.1071/mf12114 ◽

2012 ◽

Vol 63 (9) ◽

pp. 788 ◽

Cited By ~ 17

Author(s):

N. E. Pettit ◽

T. D. Jardine ◽

S. K. Hamilton ◽

V. Sinnamon ◽

D. Valdez ◽

...

Keyword(s):

Water Quality ◽

Seasonal Changes ◽

Aquatic Macrophyte ◽

Plant Cover ◽

Critical Role ◽

Dry Season ◽

Nutrient Concentrations ◽

Wet Season ◽

Dry Tropics ◽

The Impact

The present study indicates the critical role of hydrologic connectivity in floodplain waterholes in the wet–dry tropics of northern Australia. These waterbodies provide dry-season refugia for plants and animals, are a hotspot of productivity, and are a critical part in the subsistence economy of many remote Aboriginal communities. We examined seasonal changes in water quality and aquatic plant cover of floodplain waterholes, and related changes to variation of waterhole depth and visitation by livestock. The waterholes showed declining water quality through the dry season, which was exacerbated by more frequent cattle usage as conditions became progressively drier, which also increased turbidity and nutrient concentrations. Aquatic macrophyte biomass was highest in the early dry season, and declined as the dry season progressed. Remaining macrophytes were flushed out by the first wet-season flows, although they quickly re-establish later during the wet season. Waterholes of greater depth were more resistant to the effects of cattle disturbance, and seasonal flushing of the waterholes with wet-season flooding homogenised the water quality and increased plant cover of previously disparate waterholes. Therefore, maintaining high levels of connectivity between the river and its floodplain is vital for the persistence of these waterholes.

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MICROBIAL ACTIVITY AND MYCORRHIZAL POTENTIAL OF FOUR OVERBURDEN TYPES USED IN THE RECLAMATION OF EXTRACTED OIL SANDS

Canadian Journal of Soil Science ◽

10.4141/cjss83-035 ◽

1983 ◽

Vol 63 (2) ◽

pp. 363-375 ◽

Cited By ~ 10

Author(s):

R. M. DANIELSON ◽

S. VISSER ◽

D. PARKINSON

Keyword(s):

Microbial Biomass ◽

Microbial Activity ◽

Plant Species ◽

Oil Sands ◽

Microbial Respiration ◽

Bottom Layer ◽

Jack Pine ◽

Litter Bags ◽

Mycorrhizal Development ◽

Slender Wheatgrass

Slender wheatgrass and jack pine were grown in the greenhouse in cores containing a bottom layer of extracted oil sands with four overburdens individually layered over the sand. The overburdens included a muskeg peat, two shallow mineral overburdens and a deep overburden. Mycorrhizal development, microbial respiration and biomass and the degree of decomposition of slender wheatgrass roots in litter bags were determined in each plant species-overburden combination. Both ecto- and vesicular-arbuscular (VA) mycorrhizal inoculum was present in all four overburdens. The symbionts of slender wheatgrass were the "fine endophyte" and Glomus aggregatum. VA development was very low in peat whereas plants in the shallow overburdens became heavily mycorrhizal. Infection did not spread from the overburden layer to roots in the tailing sand. Jack pine roots in the peat and two shallow overburdens were heavily infected after 4 months. The most common symbiont was an ascomycete known as the E-strain. Microbial respiration was highest in the peat and was not influenced by plant species. Microbial biomass was also highest in the peat and much lower in the mineral overburdens. Only in the peat was the amount of microbial biomass larger with slender wheatgrass than with jack pine. Slender wheatgrass roots decomposed most rapidly in the peat overburden and least rapidly in the deep overburden. Key words: Microbial activity, jack pine, slender wheatgrass, mycorrhizae, reclamation, oil sands

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

10.5194/egusphere-egu21-15676 ◽

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

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&#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.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.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.

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