Effects of fertilizer and biochar applications on the relationship among soil moisture, temperature, and N2O emissions in farmland

Background Di-nitrogen oxide (N2O) emissions from soil may lead to nonpoint-source pollution in farmland. Improving the C and N content in the soil is an excellent strategy to reduce N2O emission and mitigate soil N loss. However, this method lacks a unified mathematical index or standard to evaluate its effect. Methods To quantify the impact of soil improvement (C and N) on N2O emissions, we conducted a 2-year field experiment using biochar as carbon source and fertilizer as nitrogen source, setting three treatments (fertilization (300 kg N ha−1), fertilization + biochar (30 t ha−1), control). Results Results indicate that after biochar application, the average soil water content above 20 cm increased by ∼26% and 26.92% in 2019, and ∼10% and 12.49% in 2020. The average soil temperature above 20 cm also increased by ∼2% and 3.41% in 2019. Fertigation significantly promotes the soil N2O emissions, and biochar application indeed inhibited the cumulation by approximately 52.4% in 2019 and 33.9% in 2020, respectively. N2O emissions strongly depend on the deep soil moisture and temperature (20–80 cm), in addition to the surface soil moisture and temperature (0–20 cm). Therefore, we established an exponential model between the soil moisture and N2O emissions based on theoretical analysis. We find that the N2O emissions exponentially increase with increasing soil moisture regardless of fertilization or biochar application. Furthermore, the coefficient a < 0 means that N2O emissions initially increase and then decrease. The aRU < aCK indicates that fertilization does promote the rate of N2O emissions, and the aBRU > aRU indicates that biochar application mitigates this rate induced by fertilization. This conclusion can be verified by the sensitivity coefficient (SCB of 1.02 and 14.74; SCU of 19.18 and 20.83). Thus, we believe the model can quantify the impact of soil C and N changes on N2O emissions. We can conclude that biochar does significantly reduce N2O emissions from farmland.

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Deep soil C and N pools in long-term fenced and overgrazed temperate grasslands in northwest China

Scientific Reports ◽

10.1038/s41598-019-52631-6 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 1

Author(s):

Jian-Ping Li ◽

Hong-Bin Ma ◽

Ying-Zhong Xie ◽

Kai-Bo Wang ◽

Kai-Yang Qiu

Keyword(s):

Soil Layer ◽

Northwest China ◽

Total Biomass ◽

Deep Soil ◽

Temperate Grasslands ◽

Soil Layers ◽

Soil C ◽

Soil C And N ◽

C And N ◽

The Impact

Abstract Fencing for grazing exclusion has been widely found to have an impact on grassland soil organic carbon (SOC) and total nitrogen (TN), but little is known about the impact of fenced grassland on the changes in deep soil carbon (C) and nitrogen (N) stocks in temperate grasslands. We studied the influence of 30 years fencing on vegetation and deep soil characteristics (0–500 cm) in the semi-arid grasslands of northern China. The results showed that fencing significantly increased the aboveground biomass (AGB), litter biomass (LB), total biomass, vegetation coverage and height, and soil water content and the SOC and TN in the deep soil. The belowground biomass (BGB) did not significantly differ between the fenced and grazed grassland. However, fencing significantly decreased the root/shoot ratio, forbs biomass, pH, and soil bulk density. Meanwhile, fencing has significantly increased the C and N stocks in the AGB and LB but not in the BGB. After 30 years of fencing, the C and N stocks significantly increased in the 0–500 cm soil layer. The accumulation of SOC mainly occurred in the deep layers (30–180 cm), and the accumulation of TN occurred in the soil layers of 0 to 60 cm and 160 to 500 cm. Our results indicate that fencing is an effective way to improve deep soil C and N stocks in temperate grassland of northwest China. There were large C and N stocks in the soil layers of 100 to 500 cm in the fenced grasslands, and their dynamics should not be ignored.

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Effect of elevated tropospheric ozone on soil carbon and nitrogen: A meta-analysis

Environmental Research Letters ◽

10.1088/1748-9326/ac49b9 ◽

2022 ◽

Author(s):

Enzhu Hu ◽

Zhimin Ren ◽

Xiaoke Wang ◽

Hongxing Zhang ◽

Weiwei Zhang

Keyword(s):

Tropospheric Ozone ◽

Terrestrial Ecosystem ◽

Soil N ◽

N Dynamics ◽

Organic C ◽

Soil C ◽

Soil C And N ◽

C And N ◽

The Impact ◽

C And N Dynamics

Abstract Elevated tropospheric ozone concentration ([O3]) may substantially influence the belowground processes of the terrestrial ecosystem. Nevertheless, a comprehensive and quantitative understanding of the responses of soil C and N dynamics to elevated [O3] remains elusive. In this study, the results of 41 peer-reviewed studies were synthesized using meta-analytic techniques, to quantify the impact of O3 on ten variables associated with soil C and N, i.e., total C (TC, including soil organic C), total N (TN), dissolved organic C (DOC), ammonia N (NH4 +), nitrate N (NO3 -), microbial biomass C (MBC) and N (MBN), rates of nitrification (NTF) and denitrification (DNF), as well as C/N ratio. The results depicted that all these variables showed significant changes (P < 0.05) with [O3] increased by 27.6 ± 18.7 nL/L (mean ± SD), including decreases in TC, DOC, TN, NH4 +, MBC, MBN and NTF, and increases in C/N, NO3 - and DNF. The effect sizes of TN, NTF, and DNF were significantly correlated with O3 fumigation level and experimental duration (P < 0.05). Soil pH and climate were essential in analyses of O3 impacts on soil C and N. However, the responses of most variables to elevated [O3] were generally independent of O3 fumigation method, terrestrial ecosystem type, and additional [CO2] exposure. The altered soil C and N dynamics under elevated [O3] may reduce its C sink capacity, and change soil N availability thus impact plant growth and enhance soil N losses.

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Soil carbon and nitrogen in pasture soil reforested with eucalyptus and guachapele

Revista Brasileira de Ciência do Solo ◽

10.1590/s0100-06832008000300033 ◽

2008 ◽

Vol 32 (3) ◽

pp. 1253-1260 ◽

Cited By ~ 33

Author(s):

Fabiano de Carvalho Balieiro ◽

Marcos Gervasio Pereira ◽

Bruno José Rodrigues Alves ◽

Alexander Silva de Resende ◽

Avílio Antonio Franco

Keyword(s):

Panicum Maximum ◽

Soil Organic C ◽

Total N ◽

Organic C ◽

Soil C ◽

C Stocks ◽

Soil C And N ◽

C And N ◽

Mixed Plantation ◽

The Impact

In spite of the normally low content of organic matter found in sandy soils, it is responsible for almost the totality of cation exchange capacity (CEC), water storage and availability of plant nutrients. It is therefore important to evaluate the impact of alternative forest exploitation on the improvement of soil C and N accumulation on these soils. This study compared pure and mixed plantations of Eucalyptus grandis and Pseudosamanea guachapele, a N2-fixing leguminous tree, in relation to their effects on soil C and N stocks. The studied Planosol area had formerly been covered by Panicum maximum pasture for at least ten years without any fertilizer addition. To estimate C and N contents, the soil was sampled (at depths of 0-2.5; 2.5-5.0; 5.0-7.5; 7.5-10.0; 10.0-20.0 and 20.0-40.0 cm), in pure and mixed five-year-old tree plantations, as well as on adjacent pasture. The natural abundance 13C technique was used to estimate the contribution of the soil organic C originated from the trees in the 0-10 cm soil layer. Soil C and N stocks under mixed plantation were 23.83 and 1.74 Mg ha-1, respectively. Under guachapele, eucalyptus and pasture areas C stocks were 14.20, 17.19 and 24.24 Mg ha-1, respectively. For these same treatments, total N contents were 0.83; 0.99 and 1.71 Mg ha-1, respectively. Up to 40 % of the soil organic C in the mixed plantation was estimated to be derived from trees, while in pure eucalyptus and guachapele plantations these same estimates were only 19 and 27 %, respectively. Our results revealed the benefits of intercropped leguminous trees in eucalyptus plantations on soil C and N stocks.

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The Impact of Elevated Atmospheric [CO2] on Soil C and N Dynamics: A Meta-Analysis

Managed Ecosystems and CO2 - Ecological Studies ◽

10.1007/3-540-31237-4_21 ◽

2006 ◽

pp. 373-391 ◽

Cited By ~ 13

Author(s):

K. -J. van Groenigen ◽

M. -A. de Graaff ◽

J. Six ◽

D. Harris ◽

P. Kuikman ◽

...

Keyword(s):

Meta Analysis ◽

Atmospheric Co2 ◽

N Dynamics ◽

Soil C ◽

Elevated Atmospheric Co2 ◽

Soil C And N ◽

C And N ◽

The Impact ◽

C And N Dynamics

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Impact of elevated CO2 and temperature on soil C and N dynamics in relation to CH4 and N2O emissions from tropical flooded rice (Oryza sativa L.)

The Science of The Total Environment ◽

10.1016/j.scitotenv.2013.05.035 ◽

2013 ◽

Vol 461-462 ◽

pp. 601-611 ◽

Cited By ~ 46

Author(s):

P. Bhattacharyya ◽

K.S. Roy ◽

S. Neogi ◽

P.K. Dash ◽

A.K. Nayak ◽

...

Keyword(s):

Oryza Sativa L ◽

N2o Emissions ◽

N Dynamics ◽

Soil C ◽

Flooded Rice ◽

Soil C And N ◽

C And N ◽

Ch4 And N2o ◽

Elevated Co2 And Temperature ◽

C And N Dynamics

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Mineralization Patterns of Maize Straw in Fluvio-Aquatic Soil as Determined by Isotopic Traces

Sustainability ◽

10.3390/su12020621 ◽

2020 ◽

Vol 12 (2) ◽

pp. 621

Author(s):

Lixia Zhu ◽

Jutian Chen ◽

Lili Li ◽

Fuli Zhang ◽

Tianxue Liu

Keyword(s):

Priming Effect ◽

Plant Residues ◽

N2o Emissions ◽

Isotopic Tracers ◽

Soil C ◽

Residue Decomposition ◽

Positive Balance ◽

Maize Straw ◽

Soil C And N ◽

C And N

The mineralization of plant residues results in changes in soil C and N. However, it is difficult to determine the origins of C and N from either soil organic matter mineralization or residue decomposition using traditional methods. An incubation experiment containing two treatments (blank soil (BS) and soil with 6% maize straw (MS)) was conducted to assess the contributions of maize straw to gas emissions, and to soil organic carbon (SOC) and total nitrogen (TN) using isotopic tracers. About 11.5% of maize straw C was sequestered in soil, the cumulative amount of C emitted from MS was 2.5-fold higher than that in BS treatment. A positive priming effect of maize straw on native SOC in the first 14 days was observed, and then became negative, indicating the potential for a positive balance of SOC storage. Cumulative N2O emissions in MS markedly decreased by 22.4% compared with BS, and the loss of N via N2O in MS was approximately 3.3%. Maize straw significantly increased soil TN and contributed 15.8% to TN at day 120. Our study clearly demonstrated that the different dynamics of 13C and 15N in the soils and gases indicated differences of maize straw C and N during decomposition. Maize straw C preferred to contribute to CO2 emissions, while maize straw N contributed more to soil TN.

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SOIL C AND N AS INDICATORS OF VINEYARD SOIL QUALITY IN THE RAVNI KOTARI REGION OF CROATIA

10.1130/abs/2020se-345231 ◽

2020 ◽

Author(s):

Sonia C. Clemens ◽

◽

Mia Brkljaca ◽

Delaina Pearson ◽

C. Brannon Andersen

Keyword(s):

Soil Quality ◽

Soil C ◽

Vineyard Soil ◽

Soil C And N ◽

C And N

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Spatially Related Sampling Uncertainty in the Assessment of Labile Soil Carbon and Nitrogen in an Irish Forest Plantation

Applied Sciences ◽

10.3390/app11052139 ◽

2021 ◽

Vol 11 (5) ◽

pp. 2139

Author(s):

Junliang Zou ◽

Bruce Osborne

Keyword(s):

Spatial Variability ◽

Soil Carbon ◽

Sampling Effort ◽

Limited Information ◽

Sampling Area ◽

Soil C ◽

Distribution Maps ◽

Soil C And N ◽

C And N ◽

Highly Correlated

The importance of labile soil carbon (C) and nitrogen (N) in soil biogeochemical processes is now well recognized. However, the quantification of labile soil C and N in soils and the assessment of their contribution to ecosystem C and N budgets is often constrained by limited information on spatial variability. To address this, we examined spatial variability in dissolved organic carbon (DOC) and dissolved total nitrogen (DTN) in a Sitka spruce forest in central Ireland. The results showed moderate variations in the concentrations of DOC and DTN based on the mean, minimum, and maximum, as well as the coefficients of variation. Residual values of DOC and DTN were shown to have moderate spatial autocorrelations, and the nugget sill ratios were 0.09% and 0.10%, respectively. Distribution maps revealed that both DOC and DTN concentrations in the study area decreased from the southeast. The variability of both DOC and DTN increased as the sampling area expanded and could be well parameterized as a power function of the sampling area. The cokriging technique performed better than the ordinary kriging for predictions of DOC and DTN, which are highly correlated. This study provides a statistically based assessment of spatial variations in DOC and DTN and identifies the sampling effort required for their accurate quantification, leading to improved assessments of forest ecosystem C and N budgets.

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Environmental Impact of Rotationally Grazed Pastures at Different Management Intensities in South Africa

Animals ◽

10.3390/ani11051214 ◽

2021 ◽

Vol 11 (5) ◽

pp. 1214

Author(s):

Hendrik P. J. Smit ◽

Thorsten Reinsch ◽

Pieter A. Swanepoel ◽

Ralf Loges ◽

Christof Kluß ◽

...

Keyword(s):

South Africa ◽

N Fertilization ◽

Yield Response ◽

N2o Emissions ◽

Pasture Management ◽

N Losses ◽

Enteric Fermentation ◽

Soil C ◽

Grazed Pastures ◽

Soil C And N

Nitrogen fertilization, irrigation and concentrate feeding are important factors in rotational pasture management for dairy farms in South Africa. The extent to which these factors affect environmental efficiency is subject to current and intense debate among scientists. A three-year field study was conducted to investigate the yield response of different N-fertilizer treatments (0 (N0), 220 (N20), 440 (N40), 660 (N60) and 880 (N80) kg N ha−1 year−1) on grazed pastures and to calculate the carbon footprint (CF) of milk produced. Excessive N-fertilization (N60 and N80) did not increase herbage dry matter and energy yields from pastures. However, N80 indicated the highest N-yield but at the same time also the highest N surpluses at field level. A maximum fertilizer rate of 220 kg ha−1 year−1 (in addition to excreted N from grazing animals) appears sufficient to ensure adequate herbage yields (~20 t DM ha−1 year−1) with a slightly positive field-N-balance. This amount will prevent the depletion of soil C and N, with low N losses to the environment, where adequate milk yields of ~17 t ECM ha−1 with a low CF (~1.3 kg CO2 kg ECM−1) are reached. Methane from enteric fermentation (~49% ± 3.3) and N2O (~16% ± 3.2) emissions from irrigated pastures were the main contributors to the CF. A further CF reduction can be achieved by improved N-fertilization planning, low emission irrigation techniques and strategies to limit N2O emissions from pasture soils in South Africa.

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