scholarly journals Genetic Linkage of Soil Carbon Pools and Microbial Functions in Subtropical Freshwater Wetlands in Response to Experimental Warming

2012 ◽  
Vol 78 (21) ◽  
pp. 7652-7661 ◽  
Author(s):  
Hang Wang ◽  
Zhili He ◽  
Zhenmei Lu ◽  
Jizhong Zhou ◽  
Joy D. Van Nostrand ◽  
...  
Keyword(s):  
Freshwater Wetlands ◽  
Experimental Warming ◽  
Functional Responses ◽  
Microbial Decomposition ◽  
Organic C ◽  
Average Percentage ◽  
Labile C ◽  
Use Efficiency ◽  
The Impact ◽  
Recalcitrant C

ABSTRACTRising climate temperatures in the future are predicted to accelerate the microbial decomposition of soil organic matter. A field microcosm experiment was carried out to examine the impact of soil warming in freshwater wetlands on different organic carbon (C) pools and associated microbial functional responses. GeoChip 4.0, a functional gene microarray, was used to determine microbial gene diversity and functional potential for C degradation. Experimental warming significantly increased soil pore water dissolved organic C and phosphorus (P) concentrations, leading to a higher potential for C emission and P export. Such losses of total organic C stored in soil could be traced back to the decomposition of recalcitrant organic C. Warming preferentially stimulated genes for degrading recalcitrant C over labile C. This was especially true for genes encoding cellobiase andmnpfor cellulose and lignin degradation, respectively. We confirmed this with warming-enhanced polyphenol oxidase and peroxidase activities for recalcitrant C acquisition and greater increases in recalcitrant C use efficiency than in labile C use efficiency (average percentage increases of 48% versus 28%, respectively). The relative abundance of lignin-degrading genes increased by 15% under warming; meanwhile, soil fungi, as the primary decomposers of lignin, were greater in abundance by 27%. This work suggests that future warming may enhance the potential for accelerated fungal decomposition of lignin-like compounds, leading to greater microbially mediated C losses than previously estimated in freshwater wetlands.

scholarly journals Nitrogen fertilization impact on soil carbon pools and their stratification and lability in subtropical wheat-mungbean-rice agroecosystems

PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0256397
Author(s):  
Rafeza Begum ◽  
Mohammad Mofizur Rahman Jahangir ◽  
M. Jahiruddin ◽  
Md. Rafiqul Islam ◽  
Md. Taiabur Rahman ◽  
...  
Keyword(s):  
Soil Quality ◽  
Crop Production ◽  
Biological Activities ◽  
Block Design ◽  
N Fertilization ◽  
Basal Respiration ◽  
Organic C ◽  
C Pools ◽  
Labile C ◽  
The Impact

Nitrogen (N) is the prime nutrient for crop production and carbon-based functions associated with soil quality. The objective of our study (2012 to 2019) was to evaluate the impact of variable rates of N fertilization on soil organic carbon (C) pools and their stocks, stratification, and lability in subtropical wheat (Triticum aestivum)—mungbean (Vigna radiata)—rice (Oryza sativa L) agroecosystems. The field experiment was conducted in a randomized complete block design (RCB) with N fertilization at 60, 80, 100, 120, and 140% of the recommended rates of wheat (100 kg/ha), mungbean (20 kg/ha), and rice (80 kg/ha), respectively. Composite soils were collected at 0–15 and 15–30 cm depths from each replicated plot and analyzed for microbial biomass (MBC), basal respiration (BR), total organic C (TOC), particulate organic C (POC), permanganate oxidizable C (POXC), carbon lability indices, and stratification. N fertilization (120 and 140%) significantly increased the POC at both depths; however, the effect was more pronounced in the surface layer. Moreover, N fertilization (at 120% and 140%) significantly increased the TOC and labile C pools when compared to the control (100%) and the lower rates (60 and 80%). N fertilization significantly increased MBC, C pool (CPI), lability (CLI), and management indices (CMI), indicating improved and efficient soil biological activities in such systems. The MBC and POC stocks were significantly higher with higher rates of N fertilization (120% and 140%) than the control. Likewise, higher rates of N fertilization significantly increased the stocks of labile C pools. Equally, the stratification values for POC, MBC, and POXC show evidence of improved soil quality because of optimum N fertilization (120–140%) to maintain and/or improve soil quality under rice-based systems in subtropical climates.

Changes in chemical nature of soil organic carbon in Vertisols under wheat in south-eastern Queensland

Soil Research ◽  
2001 ◽  
Vol 39 (2) ◽  
pp. 343 ◽  
Author(s):  
J. O. Skjemstad ◽  
R. C. Dalal ◽  
L. J. Janik ◽  
J. A. McGowan
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Plant Material ◽  
Turnover Rate ◽  
High Energy ◽  
Resistant Plant ◽  
Microbial Decomposition ◽  
Organic C ◽  
The Impact ◽  
C Nmr

The impact of cropping and cultivation (up to 50 years) on the nature and pool structure of organic C in two different soil types was investigated using a combination of physical and chemical fractionations and solid-state 13 C NMR spectroscopy. NMR spectroscopy revealed that aryl C contributed significantly to the organic C in the Waco soil (Pellustert) but not in the Langlands-Logie soil (Chromustert). The aryl C content of both soils was largely preserved despite the significant decrease in total organic C, following cultivation, although other organic forms appeared to rapidly decline at similar rates to one another. High energy UV photo-oxidation along with solid-state 13 C NMR spectroscopy demonstrated that the aryl C was mainly charcoal (char) in the <53 mm fraction of the soils which appeared to be highly resistant to microbial decomposition. Char C content of the Waco soil remained near 6.0 g C/kg soil and near 2.0 g C/kg soil for the Langlands-Logie soil. This char was evident to a depth of at least 30 cm in both soils. Fractionation yielded 4 organic C fractions: particulate organic C, humic C, char C, and physically protected C. By equating these fractions to the resistant plant material (particulate organic C), humic pool (humic C), and inert pool (char C) of the RothC soil C turnover model and comparing a number of simulations with measured fractions, we showed that the inert pool equated well with the measured char C. The measured particulate organic C fraction was of an appropriate size to represent the resistant plant material pool of the model but appeared to have a much slower turnover rate. Similarly, the measured humic pool was of a similar size to that required by the model but was more labile (faster turnover rate) than that used in the RothC model. This may be due to a combination of the labile proteinaceous nature of this pool and its lower than expected protection by physical association with the smectitic clay matrix.

scholarly journals Does the Construction and Operation of High-Speed Rail Improve Urban Land Use Efficiency? Evidence from China

Land ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 303
Author(s):  
Xinhai Lu ◽  
Yifeng Tang ◽  
Shangan Ke
Keyword(s):  
Economic Growth ◽  
Land Use ◽  
High Speed ◽  
Urban Land ◽  
Urban Land Use ◽  
Western China ◽  
High Speed Rail ◽  
Land Use Efficiency ◽  
Use Efficiency ◽  
The Impact

The construction and operation of high-speed rail (HSR) has become an important policy for China to achieve efficiency and fairness and promote high-quality economic growth. HSR promotes the flow of production factors such as labor and capital and affects economic growth, and may further affect urban land use efficiency (ULUE). To explore the impact of HSR on ULUE, this paper uses panel data of 284 cities in China from 2005 to 2018, and constructs Propensity Score Matching-Differences in Differences model to evaluate the effect of HSR on ULUE. The result of entire China demonstrates that the HSR could significantly improves the ULUE. Meanwhile, this paper also considers the heterogeneity of results caused by geographic location, urban levels and scales. It demonstrates that the HSR has a significantly positive effect on ULUE of Eastern, Central China, and large-sized cities. However, in Western China, in medium-sized, and small-sized cities, the impact of HSR on ULUE is not significant. This paper concludes that construction and operation of HSR should be linked to urban development planning and land use planning. Meanwhile, the cities with different geographical locations and scales should take advantage of HSR to improve ULUE and promote urban coordinated development.

Labour-use Efficiency of Assam Gramin Vikash Bank: Branch- and District-level Analysis

2021 ◽  
pp. 232102222110243
Author(s):  
Mohuya Deb Purkayastha ◽  
Joyeeta Deb ◽  
Ram Pratap Sinha
Keyword(s):  
Efficiency Score ◽  
Significant Variable ◽  
Data Envelopment ◽  
Tobit Regression ◽  
Second Stage ◽  
Time Period ◽  
Use Efficiency ◽  
The Mean ◽  
The Impact ◽  
Observation Period

The present study estimated labour-use efficiency of 48 branches of Assam Gramin Vikash Bank at its branch level, covering three districts of Barak Valley, which falls under Silchar region of the bank for the time period from 2010–2011 to 2017–2018. The study applied data envelopment analysis for estimating labour-use efficiency. In the second stage, the study applied censored Tobit regression for determining the impact of several contextual variables on efficiency. The study reveals that the mean labour-use efficiency score of the selected branches is 76% when averaged for the in-sample branches over the observation period. Results of the Tobit regression identified cluster 2 and total business of the branches as the significant factors for determining efficiency and the number of employees as a significant variable influencing inefficiency. JEL Classifications: G2, G20, G21, J3

Long-term effects of fertilisers and organic sources on soil organic carbon fractions under a rice–wheat system in the Indo-Gangetic Plains of north-west India

Soil Research ◽  
2017 ◽  
Vol 55 (3) ◽  
pp. 296 ◽  
Author(s):  
D. Das ◽  
B. S. Dwivedi ◽  
V. K. Singh ◽  
S. P. Datta ◽  
M. C. Meena ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Crop Yields ◽  
Soil Depth ◽  
Farmyard Manure ◽  
Microbial Biomass C ◽  
Gangetic Plain ◽  
Organic C ◽  
Labile C ◽  
Labile C Fractions

Decline in soil organic carbon (SOC) content is considered a key constraint for sustenance of rice–wheat system (RWS) productivity in the Indo-Gangetic Plain region. We, therefore, studied the effects of fertilisers and manures on SOC pools, and their relationships with crop yields after 18 years of continuous RWS. Total organic C increased significantly with the integrated use of fertilisers and organic sources (from 13 to 16.03gkg–1) compared with unfertilised control (11.5gkg–1) or sole fertiliser (NPKZn; 12.17gkg–1) treatment at 0–7.5cm soil depth. Averaged across soil depths, labile fractions like microbial biomass C (MBC) and permanganate-oxidisable C (PmOC) were generally higher in treatments that received farmyard manure (FYM), sulfitation pressmud (SPM) or green gram residue (GR) along with NPK fertiliser, ranging from 192 to 276mgkg–1 and from 0.60 to 0.75gkg–1 respectively compared with NPKZn and NPK+cereal residue (CR) treatments, in which MBC and PmOC ranged from 118 to 170mgkg–1 and from 0.43 to 0.57gkg–1 respectively. Oxidisable organic C fractions revealed that very labile C and labile C fractions were much larger in the NPK+FYM or NPK+GR+FYM treatments, whereas the less-labile C and non-labile C fractions were larger under control and NPK+CR treatments. On average, Walkley–Black C, PmOC and MBC contributed 29–46%, 4.7–6.6% and 1.16–2.40% towards TOC respectively. Integrated plant nutrient supply options, except NPK+CR, also produced sustainable high yields of RWS.

Impact of Minor Irrigation on Agricultural Production: An Inter-Crop Analysis in Odisha

2021 ◽  
pp. 298-304
Keyword(s):  
Water Availability ◽  
Agricultural Production ◽  
The Other ◽  
Farm Households ◽  
Input Use ◽  
Irrigation Potential ◽  
Use Efficiency ◽  
The Impact ◽  
Upstream Control ◽  
Minor Irrigation

The study examined the impact of minor irrigation on agricultural production and evaluated the gap between IPC and IPU in the Keonjhar district of Odisha. For this rationale, data were collected from 210 farm households through the primary survey. In support of the analysis, the Cobb Douglas model and factor analysis were used. The results revealed that the input use efficiency had a positive and significant impact on paddy production the most in all the MIPs regions compared to the other crops. However, the study indicated that insufficient water availability was the major cause behind the gap between irrigation potential created and utilised. Thus, minor irrigation played a crucial role in enhancing agricultural production in hilly regions. With the enthusiastic participation of planners, effective working of Pani Panchayats, canals, and upstream control, NGOs' involvement can achieve selfsufficiency in agricultural production by encouraging minor irrigation projects in the hilly province.

scholarly journals Comparison of Factors Affecting Crash Severities in Hit-and-Run and Non-Hit-and-Run Crashes

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Bei Zhou ◽  
Zongzhi Li ◽  
Shengrui Zhang
Keyword(s):  
Comparison Group ◽  
Reference Group ◽  
Multinomial Logistic Regression ◽  
Crash Severity ◽  
Property Damage ◽  
Average Percentage ◽  
Crash Data ◽  
Hit And Run ◽  
The Impact ◽  
Average Percentage Deviation

A hit-and-run (HR) crash occurs when the driver of the offending vehicle flees the crash scene without reporting it or aiding the victims. The current study aimed at contributing to existing literatures by comparing factors which might affect the crash severity in HR and non-hit-and-run (NHR) crashes. The data was extracted from the police-reported crash data from September 2017 to August 2018 within the City of Chicago. Two multinomial logistic regression models were established for the HR and NHR crash data, respectively. The odds ratio (OR) of each variable was used to quantify the impact of this variable on the crash severity. In both models, the property damage only (PDO) crash was selected as the reference group, and the injury and fatal crash were chosen as the comparison group. When the injury crash was taken as the comparison group, it was found that 12 variables contributed to the crash severities in both HR and NHR model. The average percentage deviation of OR for these 12 variables was 34%, indicating that compared with property damage, HR crashes were 34% more likely to result in injuries than NHR crashes on average. When fatal crashes were chosen as the comparison group, 2 variables were found to be statistically significant in both the HR and the NHR model. The average percentage deviation of OR for these 2 variables was 127%, indicating that compared with property damage, HR crashes were 127% more likely to result in fatalities than NHR crashes on average.

scholarly journals Influence of phytohormones on vegetative propagation of different forms of pannonian thyme (Thymus pannonicus All.)

2020 ◽  
Vol 26 (2) ◽  
pp. 39-52
Author(s):  
Vladimir Filipović ◽  
Vladan Ugrenović ◽  
Zoran Maksimović ◽  
Vera Popović ◽  
Danica Paunović ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Root Hairs ◽  
Morphological Properties ◽  
Naphthalene Acetic Acid ◽  
Plant Establishment ◽  
Rooted Cuttings ◽  
Average Percentage ◽  
Plant Collection ◽  
Rooting Of Cuttings ◽  
The Impact

The paper examined the impact of the application of three different phytohormones (INCIT 2, INCIT 5 and INCIT 8, all based on a-Naphthalene Acetic Acid (NAA)), with the cuttings of two forms of Pannonian thyme (the L-16 form, with hairy leaves, and the L-9 form, with hairless leaves), established during two periods (March and May), on the percentage of the rooted cuttings and the morphological properties of the seedlings. As the control, the variant without the application of the phytohormones was taken. The research was conducted in the period from 2019 to 2020, in a plastic greenhouse, using the plant collection of the Institute for Medicinal Plants Research "Dr Josif Pančić", which is located in Pančevo city, Serbia (44°52'20"N; 20°42'06"E; 74 m.a.s.l.). For this research was used the Pannonian thyme species (Thymus pannonicus All.) from the Lamiaceae family, which is grown and produced at the Institute. Plant establishment was carried out in four repetitions with 33 cuttings per each variant. Standard measures of care were used during the period of production of Pannonian thyme. The measurement was performed after 60 days from the date of conducted the experiment. The following parameters were measured: the percentage of rooted cuttings (%), the mass of the rooted plantlings (g), the mass of roots (g), the length of rooting (cm) and the number of root hairs of the formed rootings. The measuring was done using a ruler, millimetre paper and an analytical balance. Given the results achieved, INCIT 2 proved to be the most suitable phytohormone for the rooting of Pannonic thyme cuttings, with the average percentage of rooted cuttings of 61.3%. The lowest rooting percentage was recorded in the control variant, only 29.4%. Satisfactory rooting was found in the cuttings treated with INCIT 8 (57.6%). The L-16 form cuttings showed a higher rooting rate, an average of 53.8%, whereas the L-9 form cuttings had a lower average percentage of rooted cuttings (45.0%) for both plant establishment periods. Greater success and quality in the rooting of cuttings was recorded in the second (May) period of plant establishment, averaging 58.1%, which was higher by 17.4% than the percentage of rooted cuttings in the first establishment period (40.7%). It is important to note that the rooting of the L-9 form was significantly higher in the second establishment period (58.1%) than that in the first establishment period (31.9%).

scholarly journals Diffuse light weakens the dorsoventral asymmetry of photosynthesis in sorghum leaves

2018 ◽  
Author(s):  
Xiaolin Wang ◽  
Huifeng Yan ◽  
Yuanzheng Li
Keyword(s):  
Stomatal Density ◽  
Transmitted Light ◽  
Energy Crop ◽  
Diffuse Light ◽  
Use Patterns ◽  
Use Efficiency ◽  
Stomatal Sensitivity ◽  
The Impact ◽  
Changing Light ◽  
Sorghum Bicolor L

Dorsoventral asymmetry of photosynthesis is important for light use patterns, but the asymmetry changes with environments. Photosynthetic asymmetry was have been intensively studied for their role in light use efficiency, but less is know about the impact of light properties on asymmetry. Aimed at the current changing fraction of diffuse light in sky radiation, this study investigated dorsoventral asymmetry of photosynthetic traits in direct, diffuse and self-transmitted light (residual light intercepted by one surface) respectively in an important food and energy crop, Sorghum bicolor L. An unique designed method was used to investigate the specific gas exchange of two surfaces in different light properties. We found that anatomical and morphological traits were obviously different in sorghum leaves, which might cause the photosynthetic asymmetry, the variation of photosynthetic rates and stomatal conductance was significant between two surfaces in direct and self-transmitted light, but insignificant in diffuse light. The abaxial stomatal sensitivity of single stoma was lower, while the higher stomatal density in abaxial surface compensated the weakness in stomatal sensitivity. Comparing to direct and self-transmitted light, diffuse light reduced the stomatal sensitivity, while the degree of decline was higher in adaxial surface, which caused weak dorsoventral asymmetry in photosynthesis. Taken together, the finding of this study suggested that stomatal sensitivity determined the degree of dorsoventral asymmetry in the susceptibility to light properties. The different stomatal sensitivity regulated photosynthetic variation, which was benefit to remain high photosynthetic rate in high and changing light. The findings provided new insight in to dorsoventral asymmetry and impact of diffuse light on photosynthesis in isobilateral leaves.

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