Soil respiration and N2O emission in croplands under different ploughing practices: a case study in south-east China

Soil Research ◽  
2009 ◽  
Vol 47 (2) ◽  
pp. 198 ◽  
Author(s):  
Shutao Chen ◽  
Yao Huang
Keyword(s):  
Soil Respiration ◽  
Soil Temperature ◽  
Agricultural Soils ◽  
Field Measurements ◽  
Triticum Aestivum L ◽  
N2o Emission ◽  
Cropping Season ◽  
Significant Difference

Studies on the CO2 and N2O emission patterns of agricultural soils under different ploughing practices may provide an insight into the potential and magnitude of CO2 and N2O mitigation in highly managed farmland soils. In this study, field measurements of soil respiration and N2O flux with different ploughing depths were performed in the 2003–04 wheat (Triticum aestivum L.), 2004 maize (Zea mays L.), and 2004–05 wheat seasons. Soil temperature and moisture were simultaneously measured. Results showed that, in each cropping season, the seasonal variation in soil respiration developed with a similar pattern for different treatments, which was primarily regulated by soil temperature. This work demonstrates that ploughing depth can influence long-term loss of carbon from soil, but this was contingent on preceding cropping types. Given the same preceding cropping practice, no significant difference in N2O emission was found among different ploughing depths in each cropping season.

scholarly journals Long-Term Performance of Trestle Bridges: Case Study of an Indonesian Marine Port Structure

2020 ◽  
Vol 8 (5) ◽  
pp. 358 ◽  
Author(s):  
Yusak Oktavianus ◽  
Massoud Sofi ◽  
Elisa Lumantarna ◽  
Gideon Kusuma ◽  
Colin Duffield
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Service Life ◽  
Field Measurement ◽  
Field Measurements ◽  
Element Analysis ◽  
Moment Capacity ◽  
Non Destructive

A precast reinforced concrete (RC) T-beam located in seaport Terminal Peti Kemas (TPS) Surabaya built in 1984 is used as a case study to test the accuracy of non-destructive test techniques against more traditional bridge evaluation tools. This bridge is mainly used to connect the berth in Lamong gulf and the port in Java Island for the logistic purposes. The bridge was retrofitted 26 years into its life by adding two strips of carbon fiber reinforced polymer (CFRP) due to excessive cracks observed in the beams. Non-destructive field measurements were compared against a detailed finite element analysis of the structure to predict the performance of the girder in terms of deflection and moment capacity before and after the retrofitting work. The analysis was also used to predict the long-term deflections of the structure due to creep, crack distribution, and the ultimate moment capacity of the individual girder. Moreover, the finite element analysis was used to predict the deflection behavior of the overall bridge due to vehicle loading. Good agreement was obtained between the field measurement and the analytical study. A new service life of the structure considering the corrosion and new vehicle demand is carried out based on field measurement using non-destructive testing. Not only are the specific results beneficial for the Indonesian port authority as the stakeholder to manage this structure, but the approach detailed also paves the way for more efficient evaluation of bridges more generally over their service life.

scholarly journals Measurements of soil respiration and simple models dependent on moisture and temperature for an Amazonian southwest tropical forest

2009 ◽  
Vol 6 (3) ◽  
pp. 6147-6177 ◽  
Author(s):  
F. B. Zanchi ◽  
H. R. da Rocha ◽  
H. C. de Freitas ◽  
B. Kruijt ◽  
M. J. Waterloo ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Respiration ◽  
Soil Temperature ◽  
Field Measurements ◽  
Dry Season ◽  
Wet Season ◽  
Hourly Data ◽  
Fresh Litter ◽  
Favorable Conditions

Abstract. Soil respiration plays a significant role in the carbon cycle of Amazonian tropical forests, although in situ measurements have only been poorly reported and the dependence of soil moisture and soil temperature also weakly understood. This work investigates the temporal variability of soil respiration using field measurements, which also included soil moisture, soil temperature and litterfall, from April 2003 to January 2004, in a southwest Brazilian tropical rainforest near Ji-Paraná, Rondônia. The experimental design deployed five automatic (static, semi-opened) soil chambers connected to an infra-red CO2 gas analyzer. The mean half-hourly soil respiration showed a large scattering from 0.6 to 18.9 μmol CO2 m−2 s−1 and the average was 8.0±3.4 μmol CO2 m−2 s−1. Soil respiration varied seasonally, being lower in the dry season and higher in the wet season, which generally responded positively to the variation of soil moisture and temperature year round. The peak was reached in the dry-to-wet season transition (September), this coincided with increasing sunlight, evapotranspiration and ecosystem productivity. Litterfall processes contributed to meet very favorable conditions for biomass decomposition in early wet season, especially the fresh litter on the forest floor accumulated during the dry season. We attempted to fit three models with the data: the exponential Q10 model, the Reichstein model, and the log-soil moisture model. The models do not contradict the scattering of observations, but poorly explain the variance of the half-hourly data, which is improved when the lag-time days averaging is longer. The observations suggested an optimum range of soil moisture, between 0.115

N2O emission and governing factors on arable fields

2020 ◽  
Author(s):  
Márton Dencső ◽  
Szandra Baklanov ◽  
Ágota Horel ◽  
Györgyi Gelybó ◽  
Eszter Tóth
Keyword(s):  
Soil Column ◽  
Field Measurements ◽  
N2o Emission ◽  
Column Experiments ◽  
Soil N ◽  
Undisturbed Soil ◽  
Arable Fields ◽  
Set Up ◽  
And Training

<p>This study focuses on the soil N<sub>2</sub>O emission of arable fields. We initially set up several soil column experiments in laboratory and based on these findings we started field measurements in a long term tillage experiment at Józsefmajor Experimental and Training Farm, Hungary. For the column experiments we collected undisturbed soil columns (d=10 cm, h=10 cm) from mouldboard ploughing (P) and no-till (NT) treatments.  We investigated the effect of different fertilizer doses (40, 80, 160, 240 kg h<sup>-1</sup> N), soil water content (SWC) and different tillage methods on soil N<sub>2</sub>O emission.</p><p>We found a nonlinear response of N<sub>2</sub>O emission on the applied fertilizer doses. The moderately fertilized (80-160 kg ha<sup>-1</sup> N) samples had the highest N<sub>2</sub>O emissions. Samples from NT had higher N<sub>2</sub>O emission than samples from P. We found better correlation between N<sub>2</sub>O emission and SWC in NT (R<sup>2</sup> is between 0.47 and 0.62) than in the P (R<sup>2</sup> is between 0.01 and 0.35).  The N<sub>2</sub>O emission values showed high spatial variability. The field measurements showed similar findings of N<sub>2</sub>O emission compared to the column experiments. In 2020 we intend to continue the field measurements and include further investigations of governing factors of soil N<sub>2</sub>O emission.</p>

Case study of zero-tillage organic soybean production in Brazil

Soil Research ◽  
2016 ◽  
Vol 54 (2) ◽  
pp. 166 ◽  
Author(s):  
J. N. Landers ◽  
M. Challiol ◽  
L. Vilela ◽  
S. Lanz
Keyword(s):  
Weed Control ◽  
Conservation Agriculture ◽  
Shock Treatment ◽  
Environmental Services ◽  
Zero Tillage ◽  
Policy Makers ◽  
Soybean Production ◽  
Significant Difference

In the absence of the herbicide option, weed control is the major constraint to organic soybean production in southern Brazil and eastern Paraguay. A joint entrepreneurial initiative introduced innovative 6000-V electro-shock desiccation for pre-plant weed control in organic soybeans, under zero-tillage–conservation agriculture, complemented by already-proven inter-row cultivation and biological control methods for insects and diseases. To develop an efficient operating procedure, a field trial with the electro-shock treatment was carried out and showed 78.6% overall weed control 28 days after electro-shock treatment, and no significant difference between operating speeds of 3.42, 9.49 and 16.57 km h−1. Further research is required to improve equipment performance and prove the medium- and long-term economic and social benefits to policy-makers, in order to justify environmental services payments for this environmentally friendly system.

scholarly journals Nitrous oxide production in boreal soils with variable organic matter content at low temperature – snow manipulation experiment

2009 ◽  
Vol 6 (11) ◽  
pp. 2461-2473 ◽  
Author(s):  
M. Maljanen ◽  
P. Virkajärvi ◽  
J. Hytönen ◽  
M. Öquist ◽  
T. Sparrman ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Soil Temperature ◽  
Low Temperatures ◽  
Agricultural Soils ◽  
Winter Season ◽  
N2o Emission ◽  
N2o Emissions ◽  
Peat Soils ◽  
Snow Manipulation ◽  
Boreal Soils

Abstract. Agricultural soils are the most important sources for the greenhouse gas nitrous oxide (N2O), which is produced and emitted from soils also at low temperatures. The processes behind emissions at low temperatures are still poorly known. Snow is a good insulator and it keeps soil temperature rather constant. To simulate the effects of a reduction in snow depth on N2O emission in warming climate, snow pack was removed from experimental plots on three different agricultural soils (sand, mull, peat). Removal of snow lowered soil temperature and increased the extent and duration of soil frost in sand and mull soils. This led to enhanced N2O emissions during freezing and thawing events. The cumulative emissions during the first year when snow was removed over the whole winter were 0.25, 0.66 and 3.0 g N2O-N m−2 yr−1 in control plots of sand, mull and peat soils, respectively. In the treatment plots, without snow cover, the respective cumulative emissions were 0.37, 1.3 and 3.3 g N2O-N m−2 yr−1. Shorter snow manipulation during the second year did not increase the annual emissions. Only 20% of the N2O emission occurred during the growing season. Thus, these results highlight the importance of the winter season for this exchange and that the year-round measurements of annual N2O emissions from boreal soils are integral for estimating their N2O source strength. N2O accumulated in the frozen soil during winter and the soil N2O concentration correlated with the depth of frost but not with the winter N2O emission rates per se. Also laboratory incubations of soil samples showed high production rates of N2O at temperatures below 0°C, especially in the sand and peat soils.

Using Hypnosis, Technique Refinement, and Self-Modeling to Enhance Self-Efficacy: A Case Study in Cricket

2006 ◽  
Vol 20 (1) ◽  
pp. 94-110 ◽  
Author(s):  
Jamie B. Barker ◽  
Marc V. Jones
Keyword(s):  
Self Efficacy ◽  
Single Subject ◽  
Post Intervention ◽  
Significant Difference ◽  
Long Term Follow Up ◽  
Data Points ◽  
Run Up ◽  
The Impact

The present paper reports the impact of hypnosis, technique refinement, and selfmodeling on the self-efficacy levels of a cricket leg-spin bowler. A single-subject (A-B) design was employed with the collection of 8 baseline data points and 16 post-intervention data points that included 8 data points collected 7 months after the intervention. The intervention comprised three aspects. Aspect one focused on using hypnosis and self-hypnosis to increase self-efficacy. Aspect two was based around refining the bowler’s technique, focusing on the run-up, head position, and follow-through. Aspect three focused on self-modeling through the use of an edited videotape. The results revealed a significant difference between pre and post-intervention self-efficacy levels. This positive change was maintained in the long-term follow-up data. Also an increase in bowling performance was noted across the intervention. A number of consultancy issues are presented surrounding the use of hypnosis as part of a multimodal intervention.

How does biochar affect soil respiration?

2020 ◽  
Author(s):  
Adam Kubaczyński ◽  
Anna Walkiewicz ◽  
Małgorzata Brzezińska ◽  
Bogusław Usowicz
Keyword(s):  
Climate Change ◽  
Soil Respiration ◽  
Agricultural Soils ◽  
Satellite Monitoring ◽  
Low Oxygen ◽  
Short Term ◽  
Chromatography Method ◽  
Wide Range ◽  
The Impact

<p>Agricultural soils are an important landscape element in terms of climate change and this ecosystem is considered as a one of the major source of greenhouse gases (GHGs). Soil may be also a sink for GHGs, from this reason so many research projects are focused on determination of factors and conditions affecting gas exchange. Biochar is produced from biomass that has been pyrolysed in a zero or low oxygen availability. It is currently widely considered as a stable addition to the soil, which not only improve its fertility, but also can mitigate climate change. Considering landscape elements, the char also prevents carbon loss from forest soils. Higher microbial activity is usually associated with higher carbon dioxide (CO<sub>2</sub>) production (soil respiration). One of the most important questions is how does biochar influence production of GHGs such as CO<sub>2</sub>? Which doses have a critical meaning for CO<sub>2</sub> emission? The aim of our study was to determine the effect of wide range doses of biochar (produced from sunflower husks) (from 1 to 100 Mg ha<sup>-1</sup>) to Haplic Luvisol soil from fallow fields. We investigated the changes of CO<sub>2</sub> emission during laboratory incubation using gas chromatography method. In short-term incubations soil respiration was positively correlated with increasing biochar dose, while during long-term (several years) observation, the impact of biochar dose on the amount of emitted CO<sub>2</sub> was not so significant. It is worthwhile to conduct short- term and long-term field studies in this area.</p><p>Research was partially conducted under the project “Water in soil - satellite monitoring and improving the retention using biochar” no. BIOSTRATEG3/345940/7/NCBR/2017 which was financed by Polish National Centre for Research and Development in the framework of “Environment, agriculture and forestry” - BIOSTRATEG strategic R&D programme.</p>

Soil Respiration and its Controlling Factors in Six Coastal Young Monoculture Plantations

2013 ◽  
Vol 726-731 ◽  
pp. 3751-3756
Author(s):  
Xiang Rong Cheng ◽  
Mu Kui Yu ◽  
Tong Gui Wu ◽  
Zong Xing Wang
Keyword(s):  
Soil Respiration ◽  
Soil Temperature ◽  
Soil Nutrients ◽  
Significant Relationship ◽  
Root Biomass ◽  
Abiotic Factors ◽  
Controlling Factors ◽  
Area Index ◽  
Gap Fraction ◽  
Significant Difference

Biotic and abiotic factors how to influence soil respiration in different young monoculture plantations are not clearly understood. Soil respiration and its controlling factors were studied in six monoculture plantations in the coastal area of Shanghai, China. Soil respiration was significant difference among six stands. Variations of soil respiration in six plots were not directly related to changes in soil water content, but significant relationship was observed between soil respiration and soil temperature. The variation of soil respiration was firmly correlated to the variation of leaf area index (LAI) or gap fraction (GF), soil respiration enhanced with the increase of GF (or decreasing LAI). The microclimate within forest and soil temperature also had positively correlation with soil respiration, but which mainly were affected by GF or LAI. There was no significant relationship between soil respiration and either root biomass or soil nutrients.

Caregivers' Perceptions of Speech-Language Pathologist Talk About Child Language and Literacy Disorders

2020 ◽  
Vol 29 (4) ◽  
pp. 2049-2067
Author(s):  
Karmen L. Porter ◽  
Janna B. Oetting ◽  
Loretta Pecchioni
Keyword(s):  
Language And Literacy ◽  
Collective Case Study ◽  
Study Approach ◽  
School Aged Children ◽  
Speech Language Pathologist ◽  
Therapy Goals ◽  
Semistructured Interviews ◽  
Types Of Information

Purpose This study examined caregiver perceptions of their child's language and literacy disorder as influenced by communications with their speech-language pathologist. Method The participants were 12 caregivers of 10 school-aged children with language and literacy disorders. Employing qualitative methods, a collective case study approach was utilized in which the caregiver(s) of each child represented one case. The data came from semistructured interviews, codes emerged directly from the caregivers' responses during the interviews, and multiple coding passes using ATLAS.ti software were made until themes were evident. These themes were then further validated by conducting clinical file reviews and follow-up interviews with the caregivers. Results Caregivers' comments focused on the types of information received or not received, as well as the clarity of the information. This included information regarding their child's diagnosis, the long-term consequences of their child's disorder, and the connection between language and reading. Although caregivers were adept at describing their child's difficulties and therapy goals/objectives, their comments indicated that they struggled to understand their child's disorder in a way that was meaningful to them and their child. Conclusions The findings showed the value caregivers place on receiving clear and timely diagnostic information, as well as the complexity associated with caregivers' understanding of language and literacy disorders. The findings are discussed in terms of changes that could be made in clinical practice to better support children with language and literacy disorders and their families.

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