The Role of Dissolved CH4 in Soil Solution in the CH4 Emission from Water-Saving Irrigated Rice Fields

2011 ◽  
Vol 148-149 ◽  
pp. 977-982
Author(s):  
Dao Xi Li
Keyword(s):  
Soil Solution ◽  
Early Stage ◽  
Dominant Role ◽  
Water Layer ◽  
Water Saving ◽  
Rice Fields ◽  
Chromatography Method ◽  
Soil Layers ◽  
Soil Solutions

To examine how the dissolved CH4 in soil solution would affect the CH4 emission from rice field, fluxes of CH4 emission were measured by using a manually closed static chamber-gas chromatography method, and the dissolved CH4 in soil solution was obtained through shaking soil solutions, which were extracted from different paddy soil layers by a soil solution sampler with suction and pressure. The results show that the CH4 fluxes from rice fields and the concentration of dissolved CH4 in soil solution are both reduced significantly under the water-saving irrigation as compared to the traditional flooded irrigation. Under the water-saving irrigation, naturally receding water-layer during the early stage leads to an earlier peak of CH4 flux, but dramatically reduces the concentration of dissolved CH4 in soil solution. The maximum concentration is shifted to about 20-cm depth soil layers, and the relationship between CH4 emissions and dissolved CH4 in soil solution can be estimated using an exponential function of dissolved CH4 in soil solution at the depth of about 20 cm (R2＝0.89, p4 in soil solution plays a more dominant role in CH4 emission under the water-saving irrigation than that under continuously flooded irrigation.

Soil solution chemistry of an Adirondack Spodosol: lysimetry and N dynamics

1990 ◽  
Vol 20 (6) ◽  
pp. 818-824 ◽  
Author(s):  
J. P. Shepard ◽  
M. J. Mitchell ◽  
T. J. Scott ◽  
C. T. Driscoll
Keyword(s):  
New York ◽  
Spatial Variation ◽  
Soil Solution ◽  
Dominant Role ◽  
Nitrogen Dynamics ◽  
Solution Chemistry ◽  
Ceramic Plate ◽  
Coefficients Of Variation ◽  
Soil Solutions

Solutes were monitored from the soil of a beech–maple forest and an adjacent lake at the Huntington Forest in the Adirondack Mountains of New York. The predominant ions were Ca2+ and SO42−. For soil solutions collected by lysimeters, the highest concentrations of most ions (H+, K+, NH4+, Ca2+, Mg2+, and NO3−) occurred in O horizon leachates, and the lowest concentrations beneath the spodic B horizon. However, Al and SO42− concentrations were highest beneath the B horizon. Concentrations of NO3− showed distinct seasonal variation. Values reached 60 μequiv. L−1 in the spring and decreased to near zero late in the growing season. Coefficients of variation (CV) differed among horizons. The E horizon was generally most variable (CV, 17 to 199%) and the B horizon the least (CV 19 to 166%). Variation was especially high for NO3− and NH4+, which had minimum CVs of 124% and 122%, respectively. Variation in these ions was likely due to the dominant role of biological processes in affecting nitrogen dynamics. Differences in soil solution concentrations among six soil pits were mainly due to spatial variation in soil properties rather than differences among the four types of lysimeters (tension, zero tension, fritted glass, and ceramic plate). Nitrogen species showed the greatest response to the installation of lysimeters, with elevated concentrations of NO3− (120 to 160 μequiv. L−1) observed during the first 2 years after installation. The high temporal and spatial variation of NO3− as well as its generation following lysimeter installation has important implications in assessing nitrogen dynamics of forest ecosystems.

INFLUENCE OF SALTS IN ASSOCIATION WITH MONOCALCIUM AND DIAMMONIUM PHOSPHATES ON THE CHEMICAL CHARACTERISTICS AND MOVEMENT OF SOIL SOLUTION

1965 ◽  
Vol 45 (2) ◽  
pp. 139-152 ◽  
Author(s):  
Herman A. Hamilton ◽  
D. J. Lathwell
Keyword(s):  
Soil Solution ◽  
Soil Layer ◽  
Calcium Sulphate ◽  
Natural Soil ◽  
Soil Layers ◽  
Soil Solutions ◽  
Soluble Phosphorus ◽  
Loam Soil ◽  
Filter Papers ◽  
Chloride Salts

Various salts thoroughly mixed with monocalcium phosphate monohydrate (MCP) and diammonium phosphate (DP) were made to react with moist Lima silt loam soil arranged in 5-mm layers and separated by filter papers. After a reaction period of 3 weeks, soil moisture, pH, hot nitric acid-soluble phosphorus, and sodium bicarbonate-soluble phosphorus were determined in the different layers. As compared with MCP, the more soluble salts in association with MCP enhanced soil solution movement away from the fertilizer layer, and there was considerably greater movement of soil solution from the fertilizer layer with DP compared with MCP. The movement of soil solution with DP was attendant with greater movement of phosphorus into soil layers than for MCP, with the result that phosphorus was distributed into a greater volume of soil. When calcium sulphate was associated with DP, movement of soil solution and the diffusion of phosphorus into soil layers was markedly restricted because of massive precipitation reactions. At the soil layer closest to the MCP–fertilizer layer, a pH of 2.8 units developed. These very acid conditions were in every case ameliorated when MCP was associated with different soils. No changes in the natural soil pH were occasioned by the use of DP.By sampling soil solutions with filter papers at increasing distances from a fertilizer layer containing MCP, considerable amounts of Al, Fe, Mn, and Ca were detected. When various salts were associated with MCP, the amounts of soluble constituents moved to greater distances than with pure MCP, thereby effecting a greater diffusion of potentially toxic elements into a greater volume of soil. Chloride salts were particularly effective in causing the diffusion of manganese away from the fertilizer layer. No measurable amounts of Al, Fe, or Mn were found in soil solutions when DP reacted in soil.

Effect of Water-Saving Irrigation on CH4 Emissions from Rice Fields

2011 ◽  
Vol 396-398 ◽  
pp. 1950-1958
Author(s):  
Dao Xi Li
Keyword(s):  
Field Experiments ◽  
Organic Matter Content ◽  
Shallow Groundwater ◽  
Water Layer ◽  
Weather Conditions ◽  
Matter Content ◽  
Water Saving ◽  
Rice Fields ◽  
Irrigation Water Use ◽  
Water Treatments

Although water saving irrigation (WSI) has been widely used in China, there is limited understanding on the effect of such a practice on the CH4emission in rice fields. Consequently it is difficult to estimate the regionSubscript textal distribution of CH4emissions in space and time from rice fields across China. Two water treatments (controlled irrigation (CI), a routine WSI practice in China, and a traditional continuous flooded irrigation (FI)) were used to examine diurnal and seasonal variations of CH4emissions in field experiments in Kunshan, east China. The heavy loams in the site have organic matter content of 30.3 g/kg while percolation rates in the shallow groundwater range from 2 to 10 mm per day. Gas samples were collected and analyzed using a static chamber technique and a Gas Chromatograph system respectively. The results show that under WSI conditions, the diurnal variation of CH4 emissions presented regular afternoon-maximum mode during the initial and middle tillering stage, which mainly depends on air temperature. Only one peak of CH4 emission occurred in initial/middle tillering growth stage of rice season under CI conditions, which is mainly regulated by drainage or water layer receding. For CI, seasonal CH4emission is 2.4 g•m-2~24.5g•m-2, and the seasonal average flux is 0.8 mg•m-2•h-1~8.15 mg•m-2•h-1, which is 39-85% lower than that for FI. CI has more mitigation potential than midseason drainage. Furthermore, CI significantly reduces irrigation water use while maintains rice yields, even increases yields under atrocious weather conditions. A hydrologic characterization and spatial distribution of rice field in China is needed to assess the extent and magnitude of potential emission reduction in the region.

scholarly journals Measuring of nitrogen leaching using ceramic suction cups at different locations

2001 ◽  
pp. 10-17
Author(s):  
István Jászberényi ◽  
Jakab Loch ◽  
Wulf Bartolomaeus ◽  
Detloff Köppen
Keyword(s):  
Soil Solution ◽  
Nitrogen Leaching ◽  
Groundwater Table ◽  
Upward Movement ◽  
Soil Layers ◽  
Climate Conditions ◽  
Nitrate N ◽  
N Concentration ◽  
Soil Solutions ◽  
Suction Cups

Ceramic suction cups were used for the measurement of N-concentration in soil solutions under different soil and climate conditions in both field experiments of Rostock University and Agricultural University of Debrecen (Hungary). Depending on the soil utilisation the change in the N concentration of the soil solution can be proved on both sites.The experimental field of Rostock University can be characterised by its high groundwater table. The nitrogen concentration of soil solutions in the different soil layers were determined by the trend downward of water. In the dactylis (Dactilis glomerata) experiment, the quadruple treatments involved the following: with and without N-fertiliser, with and without harvesting, respectively. In the lower soil layers, the least rising N concentrations were established in case of the treatment without N-fertiliser combined with harvesting. The nitrogen leaching calculated from the infiltrated water quantity and the nitrate N concentration increased in the following order: without N-fertiliser, with harvesting < without N-fertiliser, without harvesting < with N-fertiliser, with harvesting << with N-fertiliser, without harvesting.The field experiment site of Debrecen can be characterised by a low groundwater table. The effect of N-fertilisation on the nitrate-N concentration of soil solution in the soil layers can be stated unanimously. Permanent nitrate-N leaching cannot be established due to the water upward movement under semiarid climate conditions. Intermittently transfer of nitrate-N between the soil layers is probable in cases of remarkable precipitation.

Chronic Pain: Fundamental Scientific Considerations, Specifically for Legal Claims

2013 ◽  
Vol 18 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Robert J. Barth
Keyword(s):  
Health Outcomes ◽  
Pain Perception ◽  
Driving Forces ◽  
Psychological Treatment ◽  
Dominant Role ◽  
Meta Analysis ◽  
General Medicine ◽  
Pain Syndrome ◽  
Problematic Relationship

Abstract Scientific findings have indicated that psychological and social factors are the driving forces behind most chronic benign pain presentations, especially in a claim context, and are relevant to at least three of the AMA Guides publications: AMA Guides to Evaluation of Disease and Injury Causation, AMA Guides to Work Ability and Return to Work, and AMA Guides to the Evaluation of Permanent Impairment. The author reviews and summarizes studies that have identified the dominant role of financial, psychological, and other non–general medicine factors in patients who report low back pain. For example, one meta-analysis found that compensation results in an increase in pain perception and a reduction in the ability to benefit from medical and psychological treatment. Other studies have found a correlation between the level of compensation and health outcomes (greater compensation is associated with worse outcomes), and legal systems that discourage compensation for pain produce better health outcomes. One study found that, among persons with carpal tunnel syndrome, claimants had worse outcomes than nonclaimants despite receiving more treatment; another examined the problematic relationship between complex regional pain syndrome (CRPS) and compensation and found that cases of CRPS are dominated by legal claims, a disparity that highlights the dominant role of compensation. Workers’ compensation claimants are almost never evaluated for personality disorders or mental illness. The article concludes with recommendations that evaluators can consider in individual cases.

НЕКОТОРЫЕ ОСОБЕННОСТИ РАСПРОСТРАНЕННОСТИ РЕСПИРАТОРНОЙ АЛЛЕРГИИ НА ЮГЕ РОССИИ

2019 ◽  
Author(s):  
D.Sh. Macharadze
Keyword(s):  
Dominant Role ◽  
Pollen Allergy ◽  
Respiratory Allergy ◽  
House Dust Mites ◽  
Dust Mites ◽  
The Past ◽  
Regional Features ◽  
Respiratory Allergies ◽  
Southern Russia

В обзорной статье приведены данные по распространенности респираторной аллергии - аллергического ринита и бронхиальной астмы на юге России, опубликованные за последние десятилетия. Показана доминирующая роль пыльцевой аллергии практически во всем южном регионе России. В Чеченской Республике у больных респираторной аллергией обнаружена сходная частота встречаемости сенсибилизации к клещам домашней пыли и пыльце злаковых трав (51,1 и 52,5 соответственно), тогда как сенсибилизация к пыльце амброзии и полыни встречалась в 3 раза реже (26,6 и 20,7 соответственно) по сравнению с соседними регионами юга России. Эти данные демонстрируют климатогеографические, экологические и другие региональные особенности в распространении респираторной аллергии.The review article presents data on the prevalence of respiratory allergy - allergic rhinitis and bronchial asthma in southern Russia, published over the past decades. The dominant role of pollen allergy is shown in almost the entire southern region of Russia. In the Chechen Republic, sensitization to house dust mites and grass pollen was found in patients with respiratory allergy equally (51.1 and 52.5, respectively), whereas ragweed and mugwort sensitization was 3 times less (26.6 and 20.7, respectively) compared with the neighboring regions of southern Russia. These data demonstrate climate-geographical, environmental and other regional features in the prevalence of respiratory allergies.

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