Tree – Open Grassland Structure Drives Carbon And Nitrogen Cycling In Mediterranean Wood Pastures of The Iberian Peninsula

Abstract Purpose: Mediterranean wood pastures are the largest agroforestry system in Europe. Traditional silvo-pastoral uses shaped these systems into a mosaic of trees and open grassland. However, little is known about how this structure may influence ecosystem carbon (C) and nitrogen (N) dynamics, considering different canopy types and interactions with the herbaceous layer.Aims: To unravel the canopy effect on C and N dynamics (1) under representative canopy types, including traditional Quercus stands and Pinus pinea L. plantations; and (2) in interaction with the herbaceous plant functional types (PFT).Methods: We analysed C and N content and the isotopic natural abundance on soil and plant materials at the open grassland and under the different tree canopies.Results: Under the canopy, soil C and N content, and N availability for the herbaceous layer increased. The canopy effect performed differences between Quercus and P. pinea plots, as detected on the belowground biomass C content. Also, the canopy effect was more pronounced with increasing environmental constraints, highlighting the relevance of trees in more restrictive environments. PFT ecophysiological characteristics interacted with tree canopies, as reflected the enhanced efficiency taking-up N, and/or exploiting symbiotic N of grasses, which was probably one of the causes of their dominancy under the canopy, at higher N availability.Conclusion: Changes in the tree coverage and tree species will significantly change ecosystem C and N storage and cycling. Therefore, it is highly advisable to preserve a balance between trees and open grassland, and traditional Quercus stands, to keep ecosystem services provisioning.

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The combination of residue quality, residue placement and soil mineral N content drives C and N dynamics by modifying N availability to microbial decomposers

Soil Biology and Biochemistry ◽

10.1016/j.soilbio.2021.108434 ◽

2021 ◽

pp. 108434

Author(s):

Bruno Chaves ◽

Marciel Redin ◽

Sandro José Giacomini ◽

Raquel Schmatz ◽

Joël Léonard ◽

...

Keyword(s):

N Availability ◽

Soil Mineral N ◽

Residue Quality ◽

Soil Mineral ◽

Mineral N ◽

N Dynamics ◽

N Content ◽

C And N ◽

C And N Dynamics

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Preferential protein depolymerization as a preservation mechanism for vascular litter decomposing in <i>Sphagnum</i> peat

10.5194/bg-2019-176 ◽

2019 ◽

Cited By ~ 1

Author(s):

Hendrik Reuter ◽

Julia Gensel ◽

Marcus Elvert ◽

Dominik Zak

Keyword(s):

Protein Content ◽

Litter Breakdown ◽

N Dynamics ◽

N Content ◽

Sphagnum Peat ◽

Elemental Analyses ◽

Microbial Carbon ◽

C And N ◽

Microbial C ◽

Microbial N

Abstract. Nitrogen (N) dynamics in Phragmites australis litter due to anaerobic decomposition in three anoxic wetland substrates were analyzed by elemental analyses and infrared spectroscopy (FTIR). After 75 days of decomposition, a relative accumulation of bulk N was detected in most litters, but N accumulated less when decomposition took place in a more N-poor environment. FTIR was used to quantify the relative content of proteins in litter tissue and revealed a highly linear relationship between bulk N content and protein content. Changes in bulk N content thus paralleled and probably were governed by changes in litter protein content. Such changes are the result of two competing processes within decomposing litter: enzymatic protein depolymerization as a part of the litter breakdown process and microbial protein synthesis as a part of microbial biomass growth within the litter. Assuming microbial homeostasis, DNA signals in FTIR spectra were used to calculate the amount of microbial N in decomposed litter which ranged from 14 to 42 % of the total litter N for all leaf samples. Microbial carbon (C) content and resultant calculated carbon-use efficiencies (CUEs) indicate that microbial N in litter accumulated according to predictions of the stoichiometric decomposition theory. Subtracting microbial C- and N-contributions from litter, however, revealed decomposition site dependent variations in the percentual amount of remaining, still unprocessed plant N compared to remaining plant C, an indicator for preferential protein depolymerization. For all leaf litters, the coefficient of preferential protein depolymerization (α), which relates N-compound depolymerization to C-compound depolymerization, ranged from 0.74–0.88 in a nutrient-rich detritus mud to 1.38–1.82 in Sphagnum peat, the most nutrient-poor substrate in this experiment. Preferential protein depolymerization leads to a gradual N depletion of decomposing litter which we propose as a preservation mechanism for vascular litter decomposing in Sphagnum peat.

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Precipitation patterns and N availability alter plant-soil microbial C and N dynamics

Plant and Soil ◽

10.1007/s11104-021-05015-7 ◽

2021 ◽

Author(s):

Ilonka C. Engelhardt ◽

Pascal A. Niklaus ◽

Florian Bizouard ◽

Marie-Christine Breuil ◽

Nadine Rouard ◽

...

Keyword(s):

N Availability ◽

N Dynamics ◽

Precipitation Patterns ◽

Soil Microbial ◽

Plant Soil ◽

C And N ◽

Microbial C ◽

C And N Dynamics

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Nitrogen Availability from Liquid Organic Fertilizers

HortTechnology ◽

10.21273/horttech.20.1.169 ◽

2010 ◽

Vol 20 (1) ◽

pp. 169-172 ◽

Cited By ~ 11

Author(s):

T.K. Hartz ◽

R. Smith ◽

M. Gaskell

Keyword(s):

Ammonium Sulfate ◽

Drip Irrigation ◽

Incubation Temperature ◽

Organic Fertilizers ◽

N Recovery ◽

N Availability ◽

Mineral N ◽

Plant Materials ◽

N Content ◽

Organically Managed

Limited soil nitrogen (N) availability is a common problem in organic vegetable production that often necessitates additional N fertilization. The increasing use of drip irrigation has created a demand for liquid organic fertilizers that can be applied with irrigation. The N availability of three liquid organic fertilizers was evaluated in an incubation study and a greenhouse bioassay. Phytamin 801 contained fishery wastes and seabird guano, while Phytamin 421 and Biolyzer were formulated from plant materials. The fertilizers ranged from 26 to 60 g·kg−1 N, 8% to 21% of which was associated with particulate matter large enough to potentially be removed by drip irrigation system filtration. The fertilizers were incubated aerobically in two organically managed soils at constant moisture at 15 and 25 °C, and sampled for mineral N concentration after 1, 2, and 4 weeks. In the greenhouse study, these fertilizers and an inorganic fertilizer (ammonium sulfate) were applied to pots of the two organically managed soils with established fescue (Festuca arundinacea) turf; the N content of clippings was compared with that from unfertilized pots after 2 and 4 weeks of growth. Across soils and incubation temperatures, the N availability from Phytamin 801 ranged from 79% to 93% of the initial N content after 1 week, and 83% to 99% after 4 weeks. The plant-based fertilizers had significantly lower N availability, but after 4 weeks, had 48% to 92% of initial N in mineral form. Soil and incubation temperature had modest but significant effects on fertilizer N availability. Nitrification was rapid, with >90% of mineral N in nitrate form after 1 week of incubation at 25 °C, or 2 weeks at 15 °C. N recovery in fescue clippings 4 weeks after application averaged 60%, 38%, and 36% of initial N content for Phytamin 801, Phytamin 421, and Biolyzer, respectively, equivalent to or better than the N recovery from ammonium sulfate.

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Tree - Open Grassland Mosaics Drive the Herbaceous Structure and Diversity in Mediterranean Holm Oak Meadows

10.21203/rs.3.rs-754237/v1 ◽

2021 ◽

Author(s):

Mercedes Ibañez ◽

Cristina Chocarro ◽

María José Leiva ◽

Maria Teresa Sebastià

Keyword(s):

Species Richness ◽

Aboveground Biomass ◽

Holm Oak ◽

Valuable Resource ◽

Herbaceous Layer ◽

Local Conditions ◽

Canopy Effect ◽

Tree Canopies ◽

Tree Coverage ◽

Structure Diversity

Abstract Background: Mediterranean holm oak meadows are semi‑natural savannah‑like agroecosystems that result from traditional silvo‑pastoral practices, which shaped these systems into a mosaic of trees and open grassland. However, traditional silvo-pastoral uses are declining with the implications that this may have on the herbaceous layer, a very biodiverse and valuable resource of these systems. Here, we aim at assessing the influence of the tree – open grassland mosaic on the structure, diversity, and composition of the herbaceous layer. Specifically, assessing the canopy effect (a) under representative Iberian canopy types, considering traditional Quercus species stands and Pinus pinea plantations at different locations; and (b) along seasonality. Results: The different components of the herbaceous layer performed differential responses to the presence/absence of tree canopies, as for instance shows the dominance of grasses under the canopy, while legumes and forbs were favoured in the open grassland. Also, there was a certain a reduction in the species richness in P. pinea dominated plots compared to plots dominated by Quercus species. There was a reduction of the aboveground biomass under the canopy at the more environmentally constrained location. Such canopy effects were generally more pronounced in spring that in autumn.Conclusion: It is highly advisable preserve the tree – open grassland mosaic and traditional Quercus species stands to maximize and preserve plant specific and functional diversity. The the optimum tree coverage might be dependent, not only on the primary ecosystem service (i. e. forage provision), but also on local conditions.

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Separate effects of the biochemical quality and N content of crop residues on C and N dynamics in soil

Biology and Fertility of Soils ◽

10.1007/s00374-007-0169-y ◽

2007 ◽

Vol 43 (6) ◽

pp. 797-804 ◽

Cited By ~ 23

Author(s):

S. Sall ◽

I. Bertrand ◽

J. L. Chotte ◽

S. Recous

Keyword(s):

Crop Residues ◽

N Dynamics ◽

N Content ◽

C And N ◽

Biochemical Quality ◽

C And N Dynamics

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Microbial biomass C and N dynamics, and 15N incorporation into microbial biomass under faba bean, canola, barley, and summer fal- low in a Gray Luvisol

Applied Environmental Biotechnology ◽

10.26789/aeb.2017.01.007 ◽

2017 ◽

Vol 2 (2) ◽

pp. 47-58

Author(s):

Ji-Dong Gu ◽

◽

William B McGill ◽

◽

Keyword(s):

Microbial Biomass ◽

Faba Bean ◽

Microbial Biomass C ◽

N Dynamics ◽

C And N ◽

Gray Luvisol ◽

C And N Dynamics

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Plant and soil nitrogen in oligotrophic boreal forest habitats with varying moss depths: does exclusion of large grazers matter?

Oecologia ◽

10.1007/s00442-021-04957-0 ◽

2021 ◽

Author(s):

Maria Väisänen ◽

Maria Tuomi ◽

Hannah Bailey ◽

Jeffrey M. Welker

Keyword(s):

Boreal Forest ◽

Vascular Plant ◽

Soil N ◽

Inorganic N ◽

N Dynamics ◽

N Content ◽

Feather Moss ◽

Foliar N ◽

Plant Soil ◽

Plant Soil Interactions

AbstractThe boreal forest consists of drier sunlit and moister-shaded habitats with varying moss abundance. Mosses control vascular plant–soil interactions, yet they all can also be altered by grazers. We determined how 2 decades of reindeer (Rangifer tarandus) exclusion affect feather moss (Pleurozium schreberi) depth, and the accompanying soil N dynamics (total and dissolvable inorganic N, δ15N), plant foliar N, and stable isotopes (δ15N, δ13C) in two contrasting habitats of an oligotrophic Scots pine forest. The study species were pine seedling (Pinus sylvestris L.), bilberry (Vaccinium myrtillus L.), lingonberry (V. vitis-idaea L.), and feather moss. Moss carpet was deeper in shaded than sunlit habitats and increased with grazer exclusion. Humus N content increased in the shade as did humus δ15N, which also increased due to exclusion in the sunlit habitats. Exclusion increased inorganic N concentration in the mineral soil. These soil responses were correlated with moss depth. Foliar chemistry varied due to habitat depending on species identity. Pine seedlings showed higher foliar N content and lower foliar δ15N in the shaded than in the sunlit habitats, while bilberry had both higher foliar N and δ15N in the shade. Thus, foliar δ15N values of co-existing species diverged in the shade indicating enhanced N partitioning. We conclude that despite strong grazing-induced shifts in mosses and subtler shifts in soil N, the N dynamics of vascular vegetation remain unchanged. These indicate that plant–soil interactions are resistant to shifts in grazing intensity, a pattern that appears to be common across boreal oligotrophic forests.

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