scholarly journals The Responses of Soil N2O Emissions to Residue Returning Systems: A Meta-Analysis

2019 ◽  
Vol 11 (3) ◽  
pp. 748 ◽  
Author(s):  
Naijuan Hu ◽  
Qian Chen ◽  
Liqun Zhu

Background: Much attention has been focused on the influences of residue returning on N2O emissions. However, comprehensive quantification of the effect size on N2O emission following crop residue returning in subtropical, tropical and warm temperate conditions remains untested. Methods: To identify site-specific factors that influence N2O emission (kg N2O-N ha−1) in residue returning systems, we performed a meta-analysis involving 260 comparisons from 72 studies. Results: The data indicated that significant promoting effects were observed under residue returning by rotary tillage, no-tillage and mulch, whereas N2O release was significantly inhibited by 8% under residue returning by plough. For other contributors, the stimulatory and significant effects occurred in upland fields, under short- and medium-term residue returning durations, acidic/neutral soils, medium organic C and clay content. Nitrogen fertilizer application significantly stimulated N2O emission, even though application rate at 100–150 kg N ha−1 was inhibitory. Although a negative correlation between residue C/N ratio and N2O emission has been shown, residue returning could not reduce N2O emission with a higher C/N ratio and amount. Conclusions: Some options, such as converting residue returning methods, decreasing N fertilizer application rate, and regulating soil C/N ratio could be adopted to mitigate soil N2O emission following residue returning.

2011 ◽  
Vol 8 (8) ◽  
pp. 2377-2390 ◽  
Author(s):  
Y. Wang ◽  
G. J. Sun ◽  
F. Zhang ◽  
J. Qi ◽  
C. Y. Zhao

Abstract. Agricultural ecosystems are major sources of greenhouse gas (GHG) emissions, specifically nitrous oxide (N2O) and carbon dioxide (CO2). An important method of investigating GHG emissions in agricultural ecosystems is model simulation. Field measurements quantifying N2O and CO2 fluxes were taken in a summer maize ecosystem in Zhangye City, Gansu Province, in northwestern China in 2010. Observed N2O and CO2 fluxes were used for validating flux predictions by a DeNitrification-DeComposition (DNDC) model. Then sensitivity tests on the validated DNDC model were carried out on three variables: climatic factors, soil properties and agricultural management. Results indicated that: (1) the factors that N2O emissions were sensitive to included nitrogen fertilizer application rate, manure amendment and residue return rate; (2) CO2 emission increased with increasing manure amendment, residue return rate and initial soil organic carbon (SOC); and (3) net global warming potential (GWP) increased with increasing N fertilizer application rate and decreased with manure amendment, residue return rate and precipitation increase. Simulation of the long-term impact on SOC, N2O and net GWP emissions over 100 yr of management led to the conclusion that increasing residue return rate is a more efficient method of mitigating GHG emission than increasing fertilizer N application rate in the study area.


2011 ◽  
Vol 8 (2) ◽  
pp. 3121-3153
Author(s):  
Y. Wang ◽  
G. J. Sun ◽  
F. Zhang ◽  
J. Qi ◽  
Z. D. Feng ◽  
...  

Abstract. Agricultural ecosystems are major sources of greenhouse gas (GHG) emissions, specifically nitrous oxide (N2O) and carbon dioxide (CO2). An important method of researching GHG emissions in agricultural ecosystems is model simulation. Field measurements quantifying N2O and CO2 fluxes were taken in a summer maize ecosystem in Zhangye City, Gansu Province, in northwestern China in 2010. Observed N2O and CO2 fluxes were used for validating flux predictions by a DeNitrification-DeComposition (DNDC) model. Then the validated DNDC model was used for sensitivity tests on three variables under consideration: climatic factors, soil properties, and agricultural management. Results indicate that: (1) the factors that N2O emissions are most sensitive to nitrogen fertilizer application rate, manure amendment and residue return rate; (2) CO2 emission increases with increasing manure amendment, residue return rate and initial soil organic carbon (SOC); and (3) net global warming potential (GWP) increases with increasing N fertilizer application rate and decreases as manure amendment, residue return rate and precipitation increase. Simulation of the long-term impact on SOC, N2O and net GWP emissions over 100 yr of management led to the conclusion that increasing residue return rate is a more efficient method of mitigating GHG emission than increasing fertilizer N application rate in the study area.


2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Ashebir Getie ◽  
Alemayehu Kiflu ◽  
Gashaw Meteke

Crop response to phosphorus (P) application is often erratic in most acidic soil types. The main processes for P losses from agricultural fields are fixation, crop removal, erosion, surface runoff, and subsurface leaching. The purpose of this experiment was to evaluate adsorption properties of selected soils, determine the external phosphorous requirements (EPRs) of the soils, and identify factors contributing to P sorption in two soils in North Ethiopia. In this experiment, separately weighed 1 g soil samples were equilibrated with KH2PO4 at rates of 0.5, 5, 10, 20, 30, 40, and 50 mg PL−1. The P sorption data were fitted well with both Langmuir and Freundlich models with average r2 values of 0.91 and 0.88, respectively. The adsorption maximum (Xm) of the Langmuir isotherm ranged from 588.20 mg P kg−1 soil in Luvisols to 833.3 mg P kg−1 soil in Nitisols. The EPRL values ranged between 86.20 to 93.28 mg P kg−1 for soils of the study area. Among the soil properties, clay content and Ex. Al were positively correlated with Xm. The path analysis revealed that clay, pH, and Av. P had a direct effect on P sorption parameters. The EPRL of the studied soils was 3.44 to 3.6 times greater than the blanket P fertilizer rate recommendation. It is concluded that P sorption models can effectively be used to discriminate soils based on P fixation ability. The result further indicates that the current P fertilizer application rate of 50 kg P ha−1 being practiced across all soil types should be revised after validating the models and EPR values estimated in this study for each soil both under greenhouse and in-the-field conditions.


Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1368
Author(s):  
Wenzheng Tang ◽  
Wene Wang ◽  
Dianyu Chen ◽  
Ningbo Cui ◽  
Haosheng Yang ◽  
...  

In order to meet the growing food demand of the global population and maintain sustainable soil fertility, there is an urgent need to optimize fertilizer application amount in agricultural production practices. Most of the existing studies on the optimal K rates for apple orchards were based on case studies and lack information on optimizing K-fertilizer management on a regional scale. Here, we used the method of combining meta-analysis with the K application rate-yield relationship model to quantify and summarize the optimal K rates of the Loess Plateau and Bohai Bay regions in China. We built a dataset based on 159 observations obtained from 18 peer-reviewed literature studies distributed in 15 different research sites and evaluated the regional-scale optimal K rates for apple production. The results showed that the linear plus platform model was more suitable for estimating the regional-scale optimal K rates, which were 208.33 and 176.61 kg K ha−1 for the Loess Plateau and Bohai Bay regions of China, respectively. Compared with high K application rates, the optimal K rates increased K use efficiency by 45.88–68.57%, with almost no yield losses. The optimal K rates also enhanced the yield by 6.30% compared with the low K application rates.


Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 740
Author(s):  
Ken Okamoto ◽  
Shinkichi Goto ◽  
Toshihiko Anzai ◽  
Shotaro Ando

Fertilizer application during sugarcane cultivation is a main source of nitrogen (N) loads to groundwater on small islands in southwestern Japan. The aim of this study was to quantify the effect of reducing the N fertilizer application rate on sugarcane yield, N leaching, and N balance. We conducted a sugarcane cultivation experiment with drainage lysimeters and different N application rates in three cropping seasons (three years). N loads were reduced by reducing the first N application rate in all cropping seasons. The sugarcane yields of the treatment to which the first N application was halved (T2 = 195 kg ha−1 N) were slightly lower than those of the conventional application (T1 = 230 kg ha−1 N) in the first and third seasons (T1 = 91 or 93 tons ha−1, T2 = 89 or 87 tons ha−1). N uptake in T1 and T2 was almost the same in seasons 1 (186–188 kg ha−1) and 3 (147–151 kg ha−1). Based on the responses of sugarcane yield and N uptake to fertilizer reduction in two of the three years, T2 is considered to represent a feasible fertilization practice for farmers. The reduction of the first N fertilizer application reduced the underground amounts of N loads (0–19 kg ha−1). However, application of 0 N in the first fertilization would lead to a substantial reduction in yield in all seasons. Reducing the amount of N in the first application (i.e., replacing T1 with T2) improved N recovery by 9.7–11.9% and reduced N leaching by 13 kg ha−1. These results suggest that halving the amount of N used in the first application can improve N fertilizer use efficiency and reduce N loss to groundwater.


2021 ◽  
Author(s):  
Rose Abramoff ◽  
Bertrand Guenet ◽  
Haicheng Zhang ◽  
Katerina Georgiou ◽  
Xiaofeng Xu ◽  
...  

<p>Soil carbon (C) models are used to predict C sequestration responses to climate and land use change. Yet, the soil models embedded in Earth system models typically do not represent processes that reflect our current understanding of soil C cycling, such as microbial decomposition, mineral association, and aggregation. Rather, they rely on conceptual pools with turnover times that are fit to bulk C stocks and/or fluxes. As measurements of soil fractions become increasingly available, soil C models that represent these measurable quantities can be evaluated more accurately. Here we present Version 2 (V2) of the Millennial model, a soil model developed to simulate C pools that can be measured by extraction or fractionation, including particulate organic C, mineral-associated organic C, aggregate C, microbial biomass, and dissolved organic C. Model processes have been updated to reflect the current understanding of mineral-association, temperature sensitivity and reaction kinetics, and different model structures were tested within an open-source framework. We evaluated the ability of Millennial V2 to simulate total soil organic C (SOC), as well as the mineral-associated and particulate fractions, using three soil fractionation data sets spanning a range of climate and geochemistry in Australia (N=495), Europe (N=176), and across the globe (N=730). Millennial V2 (RMSE = 1.98 – 4.76 kg, AIC = 597 – 1755) generally predicts SOC content better than the widely-used Century model (RMSE = 2.23 – 4.8 kg, AIC = 584 – 2271), despite an increase in process complexity and number of parameters. Millennial V2 reproduces between-site variation in SOC across a gradient of plant productivity, and predicts SOC turnover times similar to those of a global meta-analysis. Millennial V2 updates the conceptual Century model pools and processes and represents our current understanding of the roles that microbial activity, mineral association and aggregation play in soil C sequestration.</p>


Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1277
Author(s):  
Cheng-Hsien Lin ◽  
Richard H. Grant ◽  
Cliff T. Johnston

Nitrous oxide (N2O) emissions from agricultural soil are substantially influenced by nitrogen (N) and field management practices. While routinely soil chambers have been used to measure emissions from small plots, measuring field-scale emissions with micrometeorological methods has been limited. This study implemented a backward Lagrangian stochastic (bLS) technique to simultaneously and near-continuously measure N2O emissions from four adjacent fields of approximately 1 ha each. A scanning open-path Fourier-transform infrared spectrometer (OP-FTIR), edge-of-field gas sampling and measurement, locally measured turbulence, and bLS emissions modeling were integrated to measure N2O emissions from four adjacent fields of maize production using different management in 2015. The maize N management treatments consisted of 220 kg NH3-N ha−1 applied either as one application in the fall after harvest or spring before planting or split between fall after harvest and spring before planting. The field preparation treatments evaluated were no-till (NT) and chisel plow (ChP). This study showed that the OP-FTIR plus bLS method had a minimum detection limit (MDL) of ±1.2 µg m−2 s−1 (3σ) for multi-source flux measurements. The average N2O emission of the four treatments ranged from 0.1 to 2.3 µg m−2 s−1 over the study period of 01 May to 11 June after the spring fertilizer application. The management of the full-N rate applied in the fall led to higher N2O emissions than the split-N rates applied in the fall and spring. Based on the same N application, the ChP practice tended to increase N2O emissions compared with NT. Advection of N2O from adjacent fields influenced the estimated emissions; uncertainty (1σ) in emissions was 0.5 ± 0.3 µg m−2 s−1 if the field of interest received a clean measured upwind background air, but increased to 1.1 ± 0.5 µg m−2 s−1 if all upwind sources were advecting N2O over the field of interest. Moreover, higher short-period emission rates (e.g., half-hour) were observed in this study by a factor of 1.5~7 than other micrometeorological studies measuring N2O-N loss from the N-fertilized cereal cropping system. This increment was attributed to the increase in N fertilizer input and soil temperature during the measurement. We concluded that this method could make near-continuous “simultaneous” flux comparisons between treatments, but further studies are needed to address the discrepancies in the presented values with other comparable N2O flux studies.


2019 ◽  
Vol 11 (4) ◽  
pp. 1165 ◽  
Author(s):  
Haixia Wu ◽  
Yan Ge

This paper takes 516 households who planted wheat in Heyang County, Shaanxi Province in 2018, as samples to construct three policy environments: Technological guidance for planting, subsidies for organic fertilizer application, and agricultural tailwater discharge standards. The experimental choice method was used to empirically analyze policy preferences during the process of fertilizer reduction. The results indicate that households show different preferences for the three policy settings: The fertilizer application rate is reduced by 6.98% if providing full technological guidance for farmers throughout the wheat planting process and is reduced by 5.18% under the background of providing appropriate organic fertilizer subsidies. The agricultural tailwater discharge standards have the least impact on the reducing level of chemical fertilizer application, with decreasing amounts of only 1.85% and 0.77% under the second-level and the first-level agricultural tailwater discharge standards, respectively. These results indicate that households in Heyang County, Shaanxi Province, demonstrate a low willingness to accept the agricultural tailwater discharge standards in order to cut down on the amount of chemical fertilizer application and the agricultural non-point source pollution. Therefore, compared with a compounded annual growth rate (CAGR) of 1% of fertilizer usage nationwide according to the Chinese Ministry of Agriculture, given the current planting environment and policies design, providing comprehensive technological guidance as well as price subsidies for the organic fertilizer can significantly and robustly reduce the excessive application of fertilizer in Heyang County, Shaanxi Province, under the best scenario, thereby further alleviating agricultural non-point source pollution.


Soil Research ◽  
2016 ◽  
Vol 54 (5) ◽  
pp. 598 ◽  
Author(s):  
Peter Grace ◽  
Iurii Shcherbak ◽  
Ben Macdonald ◽  
Clemens Scheer ◽  
David Rowlings

As a significant user of nitrogen (N) fertilisers, the Australian cotton industry is a major source of soil-derived nitrous oxide (N2O) emissions. A country-specific (Tier 2) fertiliser-induced emission factor (EF) can be used in national greenhouse gas inventories or in the development of N2O emissions offset methodologies provided the EFs are evidence based. A meta-analysis was performed using eight individual N2O emission studies from Australian cotton studies to estimate EFs. Annual N2O emissions from cotton grown on Vertosols ranged from 0.59kgNha–1 in a 0N control to 1.94kgNha–1 in a treatment receiving 270kgNha–1. Seasonal N2O estimates ranged from 0.51kgNha–1 in a 0N control to 10.64kgNha–1 in response to the addition of 320kgNha–1. A two-component (linear+exponential) statistical model, namely EF (%)=0.29+0.007(e0.037N – 1)/N, capped at 300kgNha–1 describes the N2O emissions from lower N rates better than an exponential model and aligns with an EF of 0.55% using a traditional linear regression model.


2002 ◽  
Vol 94 (6) ◽  
pp. 1393-1399 ◽  
Author(s):  
Nathan A. Slaton ◽  
Charles E. Wilson ◽  
Richard J. Norman ◽  
Sixte Ntamatungiro ◽  
Donna L. Frizzell

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