Terrestrial Ecosystem Nitrogen Fluxes via the Atmosphere-Land System

Geographical distribution of contributions in the Research Topic.

Editorial

27 April 2022

Editorial: Terrestrial Ecosystem Nitrogen Fluxes via the Atmosphere-Land System

Anna Andreetta

Lourdes Morillas

and

Silvana Munzi

959 views

1 citations

Editors

Anna Andreetta

University of Cagliari

Impact

Original Research

29 March 2022

Conservation Agriculture With Optimum Fertilizer Nitrogen Rate Reduces GWP for Rice Cultivation in Floodplain Soils

M. M. R. Jahangir

, 9 more and

C. Müller

Wetland rice cultivation contributes significantly to global warming potential (GWP), an effect which is largely attributed to emissions of methane (CH₄). Emerging technologies for wetland rice production such as conservation agriculture (CA) may mitigate greenhouse gas (GHG) emissions, but the effects are not well defined. Investigations were carried out in an irrigated rice (Boro rice) field in the fifth crop after conversion of conventional tillage (CT) to strip tillage (ST). Two crop residue levels (low versus high, LR versus HR) and three nitrogen (N) application rates (N1 = 108, N2 = 144, and N3 = 180 kg N ha⁻¹) were laid out in a split-plot experiment with three replicates. Yield-scaled GHG emissions and GWP were estimated to evaluate the impacts of CA on mitigating CH₄ and N₂O emissions in the rice paddy field. There was a 55% higher N₂O emission in ST with HR coupled with N3 than that in CT with LR coupled with N1. The N₂O emission factors ranged from 0.43 to 0.75% in ST and 0.45 to 0.59% in CT, irrespective of the residue level and N rate. By contrast, CH₄ emissions were significantly lower in CA than in the conventional practices (CT plus LR). The ST with LR in N2 reduced the GWP by 39% over the GWP in CT with HR in N1 and 16% over the conventional practices. Based on our investigation of the combination of tillage, residue, and N rate treatments, the adoption of CA with high and low residue levels reduced the GWP by 10 and 16%, respectively, because of lower CH₄ and N₂O emissions than the current management practices. The relatively high N₂O emission factors suggest that mitigation of this GHG in wetland rice systems needs greater attention.

3,138 views

12 citations

15N recoveries in wheat/vegetable grain/stem/leaves, straw and roots in the three crop rotations at Jiangjin, Shayang and Rugao. Note: RW = rice–wheat rotation. RV = rice–vegetable rotation. MW = maize–wheat rotation. Error bars present the standard error of the measurements from three replicates. R = reduced fertilizer input. T = traditional fertilizer input. Different small letters above the bars denote significance at the 5% level. Cro = crop system. Fer = fertilization. Cro × Fer = the interactions of crop rotation and fertilization. ns, * and ** mean no significance, p < 0.05 and p < 0.01.

Original Research

28 March 2022

Impact of Nutrient Management on Wheat/Vegetable Yields and the Fate of 15N-Labeled Fertilizer in the Yangtze River Basin

Sen Wang

, 9 more and

Xue Jun Liu

2,397 views

3 citations

Original Research

22 March 2022

Nutrient Management Drives the Direction and Magnitude of Nitrous Oxide Flux in Crop Residue-Returned Soil Under Different Soil Moisture

Sangeeta Lenka

, 6 more and

Dharmendra Singh

Crop residues as key organic carbon inputs have the potential for soil carbon sequestration. However, previous studies have shown an inconsistent effect of residue return on the direction and magnitude of soil nitrous oxide (N₂O) emission. We used a laboratory-based soil incubation study to test the response of N₂O emission to crop residue type, soil moisture, and how nutrient management modulates these responses. In this study, we incorporated crop residues with different qualities (wheat, rice, soybean, and maize) at two soil moisture contents {80% field capacity (FC) and 60% FC} and under seven nutrient levels: N0P0K0 (no nutrients), N0PK, N100PK, N150PK, N100PK + manure@ 5 Mg ha⁻¹, N100PK + biochar@ 5 Mg ha⁻¹, and N150PK + biochar@ 5 Mg ha⁻¹. The results demonstrated significant (p < 0.01) differences in the magnitude of N₂O emissions among treatments. However, only the interaction effect of residue × nutrient and nutrient × moisture was significant (p < 0.05). N100PK and N150PK at 80% FC mitigated N₂O emission by approximately 20% in wheat residue-amended soil (cf. control soil without residue). In contrast, maize residue amendment (cf. control soil) increased N₂O emission by 130% under N0P0K0 and 80% FC. Residue effects were negatively correlated with the C:N ratio, and a strong positive correlation (p < 0.01) was obtained between N₂O emission and CO₂ respiration, labile carbon, mineral N, and residue total nitrogen (TN). When no nutrients were added, N₂O emission was higher in residue returned soil. However, cumulative fluxes of N₂O decreased by 6–17% when maize and wheat residues (cf. control soil) were applied with nutrients. Negative fluxes of N₂O indicating consumption were observed in every treatment after 57 days of incubation and were most pronounced in control soil without residue and nutrients. Decreasing the soil moisture from 80% FC to 60% FC, the N₂O consumption rate increased by 6.6 times across residue types and nutrient management. The regression analysis and structural equation modeling (SEM) results showed that residue TN, soil CO₂ emission, NO₃-N, and labile SOC were the key predictor variables and could explain 82% variability in the soil N₂O emission in the Vertisols of Central India. The results suggested that nutrient addition (NPK) could alter the magnitude and direction of soil N₂O flux by residue type and soil moisture by influencing the underlying soil microbial processes of the C and N cycle in the Vertisol of subtropical India.

3,132 views

17 citations

Original Research

20 September 2021

Good Agreement Between Modeled and Measured Sulfur and Nitrogen Deposition in Europe, in Spite of Marked Differences in Some Sites

Aldo Marchetto

, 13 more and

Peter Waldner

Atmospheric nitrogen and sulfur deposition is an important effect of atmospheric pollution and may affect forest ecosystems positively, for example enhancing tree growth, or negatively, for example causing acidification, eutrophication, cation depletion in soil or nutritional imbalances in trees. To assess and design measures to reduce the negative impacts of deposition, a good estimate of the deposition amount is needed, either by direct measurement or by modeling. In order to evaluate the precision of both approaches and to identify possible improvements, we compared the deposition estimates obtained using an Eulerian model with the measurements performed by two large independent networks covering most of Europe. The results are in good agreement (bias <25%) for sulfate and nitrate open field deposition, while larger differences are more evident for ammonium deposition, likely due to the greater influence of local ammonia sources. Modeled sulfur total deposition compares well with throughfall deposition measured in forest plots, while the estimate of nitrogen deposition is affected by the tree canopy. The geographical distribution of pollutant deposition and of outlier sites where model and measurements show larger differences are discussed.

3,093 views

11 citations

Measured and simulated daily N2O emissions from non-fertilized soils (No fert) and soils fertilized with 90 kg N ha−1 (Fert-90) or 180 kg N ha−1 (Fert-180) in spring. In all soils straw was quantified and either removed (-str) or placed back in the respective fertilized soils (+str). Sampling period was from August 2013 to March 2014 and August 2014 to March 2015. Numbers above the panel describe the quality of the COUP model for the respective fertilizer treatment. Error bars show the standard error of mean of each treatment (n = 3).

Original Research

17 January 2022

Climate Overrides Effects of Fertilizer and Straw Management as Controls of Nitrous Oxide Emissions After Oilseed Rape Harvest

Sarah Köbke

, 4 more and

Klaus Dittert

5,301 views

4 citations

Original Research

10 August 2021

Nitrogen Deposition Effects on Soil Properties, Microbial Abundance, and Litter Decomposition Across Three Shrublands Ecosystems From the Mediterranean Basin

Mauro Lo Cascio

, 12 more and

Simone Mereu

Atmospheric nitrogen (N) inputs in the Mediterranean Basin are projected to increase due to fossil fuel combustion, fertilizer use, and the exacerbation of agricultural production processes. Although increasing N deposition is recognized as a major threat to ecosystem functioning, little is known about how local environmental conditions modulate ecosystem function response to N addition, particularly in the context of Mediterranean-Basin ecosystems. Here, we assess how N addition affects important ecosystem properties associated with litter decomposition, soil physical-chemical properties, soil extracellular enzymatic activity and microbial abundance across three long-term N addition experimental sites in the Mediterranean Basin. Sites were located in El Regajal (Madrid, Spain), Capo Caccia (Alghero, Italy), and Arrábida (Lisbon, Portugal) and are all representative of Mediterranean shrublands. No common pattern for litter decomposition process or other studied variables emerged among the control plots of the studied sites. Nitrogen supply only affected soil pH, a major driver of decomposition, in two out of three experimental sites. Moreover, when we explored the role of N addition and soil pH in controlling litter decay, we found that the effects of these factors were site-dependent. Our results point out to local ecosystem features modulating N addition effects in controlling litter decomposition rates in Mediterranean ecosystems, suggesting that the responses of soil functioning to N deposition are site-dependent. These findings provide further knowledge to understand contrasting ecosystem responses to N additions based on a single field experiments.

5,066 views

15 citations

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