Flooded rice soils of Northern Australia. II. Chemical profiles

Soil Research ◽  
1972 ◽  
Vol 10 (1) ◽  
pp. 53
Author(s):  
BG Williams
Keyword(s):  
Carbon Dioxide ◽  
Root Distribution ◽  
Calcareous Soil ◽  
Surface Soil ◽  
Specific Conductivity ◽  
Northern Australia ◽  
Bicarbonate Concentration ◽  
Rice Soils ◽  
Flooded Rice ◽  
Chemical Profiles

Changes in chemical and electrochemical properties of a flooded calcareous soil sown to rice were monitored during the season of flooding. Considerable variations in specific conductivity, individual cation concentrations, bicarbonate concentration, and carbon dioxide pressures were observed within the soil profile to depths of 30 cm. Redox potential and pH tended to be uniform within a profile except when CaSO4 or H2SO4 were added to the surface soil. Both field and pot experiments showed profile variations in soil properties and the significance of this is discussed in terms of the root distribution of rice.

Flooded rice soils of Northern Australia. 1. Changes in salinity

Soil Research ◽  
1972 ◽  
Vol 10 (1) ◽  
pp. 43 ◽  
Author(s):  
BG Williams
Keyword(s):  
Soil Solution ◽  
Specific Conductivity ◽  
Northern Territory ◽  
Soil Profiles ◽  
Northern Australia ◽  
Rice Soils ◽  
Growing Period ◽  
Flooded Rice ◽  
Ion Species ◽  
Total Salinity

Soil salinity, pH, and Eh were determined in two soil types on the Adelaide River plains (Northern Territory) throughout the growing period of a rice crop. Both the total salinity, as indicated by specific conductivity values of the soil solution, and individual ion species were followed at 30 sites in each soil. The results demonstrated the existence of salt gradients within the soil profiles and these gradients, together with the total salt concentration and ion ratios, remained relatively constant throughout the growing season. The results are discussed in terms of experimental methods commonly employed for determining the effects of soil solution properties on rice culture.

Increased P diffusion as an explanation of increased p availability in flooded rice soils

1976 ◽  
Vol 45 (2) ◽  
pp. 365-377 ◽  
Author(s):  
F. T. Turner ◽  
J. W. Gilliam
Keyword(s):  
P Availability ◽  
Rice Soils ◽  
Flooded Rice ◽  
P Diffusion

scholarly journals Catchment properties and the photosynthetic trait composition of freshwater plant communities

Science ◽  
2019 ◽  
Vol 366 (6467) ◽  
pp. 878-881 ◽  
Author(s):  
L. L. Iversen ◽  
A. Winkel ◽  
L. Baastrup-Spohr ◽  
A. B. Hinke ◽  
J. Alahuhta ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Plant Species ◽  
Plant Communities ◽  
Aquatic Plants ◽  
Land Plants ◽  
Carbon Limitation ◽  
Bicarbonate Concentration ◽  
Anthropogenic Changes ◽  
Freshwater Plants

Unlike in land plants, photosynthesis in many aquatic plants relies on bicarbonate in addition to carbon dioxide (CO2) to compensate for the low diffusivity and potential depletion of CO2 in water. Concentrations of bicarbonate and CO2 vary greatly with catchment geology. In this study, we investigate whether there is a link between these concentrations and the frequency of freshwater plants possessing the bicarbonate use trait. We show, globally, that the frequency of plant species with this trait increases with bicarbonate concentration. Regionally, however, the frequency of bicarbonate use is reduced at sites where the CO2 concentration is substantially above the air equilibrium, consistent with this trait being an adaptation to carbon limitation. Future anthropogenic changes of bicarbonate and CO2 concentrations may alter the species compositions of freshwater plant communities.

Soil seals in tropical tall grass pastures of northern Australia

Soil Research ◽  
1979 ◽  
Vol 17 (3) ◽  
pp. 483 ◽  
Author(s):  
J Mott ◽  
BJ Bridge ◽  
W Arndt
Keyword(s):  
Surface Soil ◽  
Seedling Emergence ◽  
Perennial Grass ◽  
Soil Surface ◽  
Mechanical Impedance ◽  
Organic Carbon Content ◽  
Grass Cover ◽  
Northern Australia ◽  
Tall Grass ◽  
Pastoral Management

Stable bare degraded areas exist in the lightly grazed perennial grass understorey existing in the eucalypt woodlands of northern Australia. Examination of these areas showed large differences in infiltration which led to increased runoff from the bare sites. However, there was little difference in soil composition between grass-covered and degraded sites apart from a higher organic carbon content in surface soil under grass. Micromorphological examination showed that soil without grass cover had lost its original open structure in the surface layers, developing a surface seal. The surface soil of the bare sealed area was shown to slake readily under quick wetting in contrast to soil surface under grass cover which did not slake. Heavy grazing of the grass understorey destroyed grass clumps within two wet seasons. Once the clumps were killed the soil surface quickly collapsed to form sealed areas, with the same properties as those occurring in ungrazed sites. The persistence of the bare sealed areas is attributed to seed removal during runoff, high temperatures and low moisture content in the sealed layer, as well as mechanical impedance preventing seedling emergence. As re-establishment of native grasses is difficult in this region, care must be taken in pastoral management to prevent the formation of degraded sites, which may take many years to re-vegetate.

Carbon dioxide removal using low bicarbonate dialysis in rodents

Perfusion ◽  
2019 ◽  
Vol 34 (7) ◽  
pp. 578-583 ◽  
Author(s):  
Lien H Vu ◽  
John A Kellum ◽  
William J Federspiel ◽  
Matthew E Cove
Keyword(s):  
Carbon Dioxide ◽  
In Vitro Study ◽  
Blood Gases ◽  
Carbon Dioxide Removal ◽  
Low Flow ◽  
Sprague Dawley ◽  
Bicarbonate Concentration ◽  
Extracorporeal Carbon Dioxide Removal ◽  
Arterial Ph

Background: Extracorporeal carbon dioxide removal may be used to manage hypercapnia, but compared to dialysis, it’s not widely available. A recent in vitro study showed that dialysis with low bicarbonate dialysates removes CO2. Objective: To show that bicarbonate dialysis removes CO2 in an animal model to validate in-vitro findings and quantify the effect on arterial pH. Methods: Male Sprague-Dawley hypercapnic rats were dialyzed with either a conventional dialysate (PrismasolTM) or a bicarbonate-free dialysate (Bicarb0). The effect of dialysis on standard blood gases and electrolytes was measured. Results: Partial pressure of CO2 and bicarbonate concentration in blood decreased significantly after exposure to Bicarb0 compared to PrismasolTM (filter outflow values 12.8 vs 81.1 mmHg; p < 0.01 for CO2 and 3.5 vs 22.0 mmol/L; p < 0.01 for bicarbonate). Total CO2 content of blood was reduced by 459 mL/L during dialysis with Bicarb0 (filter inflow 546 ± 91 vs filter outflow 87 ± 52 mL/L; p < 0.01), but was not significantly reduced with PrismasolTM. Conclusions: Bicarbonate dialysis removes CO2 at rates comparable to existing low-flow ECCO2R.

Processes of nitrogen loss from fertilizers applied to flooded rice fields on a calcareous soil in north-central China

1988 ◽  
Vol 18 (2) ◽  
pp. 101-115 ◽  
Author(s):  
Z. L. Zhu ◽  
G. X. Cai ◽  
J. R. Simpson ◽  
S. L. Zhang ◽  
D. L. Chen ◽  
...  
Keyword(s):  
Calcareous Soil ◽  
Nitrogen Loss ◽  
Rice Fields ◽  
Central China ◽  
North Central ◽  
Flooded Rice
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