Water : soil ratio influences aqueous phase chemistry of indigenous copper and zinc in soils

Soil Research ◽  
1997 ◽  
Vol 35 (4) ◽  
pp. 687 ◽  
Author(s):  
Amir Fotovat ◽  
Ravendra Naidu ◽  
Malcolm E. Sumner
Keyword(s):  
Soil Moisture ◽  
Organic Ligand ◽  
Marked Change ◽  
Field Capacity ◽  
Soil Extract ◽  
Alkaline Soils ◽  
Equilibrium Solutions ◽  
Solution Ph ◽  
Minor Elements ◽  
The Relationship

The effect of dilution on the composition of soil solutions of 8 contrasting soils ranging in pH from 5·3 to 8·8 with reference to zinc (Zn) and copper (Cu) was studied. Soil samples were equilibrated with water in various water:soil ratios for 24 h. Equilibrium solutions were extracted and analysed for dissolved organic carbon (DOC), and major and minor elements. The separation of the soil solution at field capacity (FC) was carried out by a drainage method. Although the concentration of ions decreased upon dilution, the total quantity of sodium (Na), potassium (K), Zn, Cu, and DOC extracted per unit of soil weight increased. In contrast, the total quantity of Ca and Mg decreased in most soils. The ratio of Zn and Cu to Ca correlated to dilution level, whereas the ratio of Zn to monovalent cations decreased in low pH soils. The relationship between the quantity of Zn and Cu at different levels of the water : soil ratio in the soils studied showed that the concentration of these trace metals at FC soil moisture can be estimated from the soil extract. Increases in soil moisture content led to a marked change in the ion-pair, free hydrated metal concentrations, and complexation. Log Zn2+ was linearly related to solution pH. Zinc solubility was not consistent with published solubilities of any common minerals. Also, Zn solubility in alkaline soils tended to be higher than reported values in the literature, indicating that soluble metal–organic ligand complexation was underestimated in these soils. The relationship between pH and log Zn2+ was affected by dilution in several ways.

A carbon-based method for estimating the wetness of forest surface soil horizons

2007 ◽  
Vol 37 (4) ◽  
pp. 846-852 ◽  
Author(s):  
Donald S. Ross
Keyword(s):  
Soil Moisture ◽  
Water Content ◽  
Field Capacity ◽  
Least Squares Regression ◽  
Soil C ◽  
Soil Calcium ◽  
The Relationship ◽  
Water Holding ◽  
Soil Moisture Retention ◽  
Gravimetric Water Content

The degree of wetness in forest surface soils has an effect on chemical and biological processes but is not easily measured. The high spatial variability in carbon (C) concentration creates high variability in water-holding capacity, and gravimetric water content is not informative. Local hydrology can create patchiness in soil moisture, with saturated soils often found near well-drained ones. When sampling to measure such factors as nitrification potential, it would be advantageous to have a simple metric that reflects the relative wetness of the soil. The relationship between C concentration (range 51.5–520.8 g·kg–1) and gravimetric water content was found to be linear for a set of 113 H- and A-horizon samples assumed to be at field capacity. The wetness ratio is defined as the actual water content of a sample divided by the water content predicted by the least squares regression equation based on C concentration (soil water content (kg·kg–1) = 0.080 + 0.0057 soil C concentration (g·kg–1)). Soil moisture retention curves were developed for a small number of samples in the range of 0 to about –10 kPa and showed that the equation predicted that water would be held at relatively high potential. In samples taken from 10 watersheds in the northeastern USA, wetness ratios between 1.25 and 3.1 were associated with soils identified in the field as ranging from wet to boglike. A median ratio of 0.49 was found in a watershed sampled after an extended dry period. At the Sleepers River Research Watershed, high wetness ratios were associated with a high soil calcium concentration, presumably from enriched groundwater. The ratio should be a useful measurement in watershed studies.

Soil Moisture Influence on Treatment and Extraction of DDT from Soils

1972 ◽  
Vol 55 (3) ◽  
pp. 532-536 ◽  
Author(s):  
R G Nash ◽  
W G Harris
Keyword(s):  
Soil Moisture ◽  
Extraction Method ◽  
Near Field ◽  
Field Capacity ◽  
Clay Soils ◽  
Extraction Column ◽  
Alkaline Soils ◽  
Moist Condition ◽  
Moisture Influence ◽  
Column Extraction

Abstract An investigation was conducted to determine techniques which prevented p,p’-DDT conversion to p,p’-DDE during (a) extraction of highly alkaline soils and (b) DDT treatment of highly alkaline soils. Moistening soils to near field capacity reduced DDT conversion to DDE during treatment and a new column extraction method was developed which prevented further conversion during extraction. Column extraction is more rapid than Soxhlet or shake extraction and requires less expensive equipment. However, column extraction was less efficient: about 4% DDT remained after extraction of incubated soils, whereas only about 1% remained in Soxhlet-extracted soils, except for clay soils in which both methods of extraction were low. Alkaline soils apparently can be extracted safely with either Soxhlet or column extraction without conversion of DDT to DDE, providing the soils have equilibrated in a moist condition.

scholarly journals Drainage criteria for soil workability.

1979 ◽  
Vol 27 (1) ◽  
pp. 27-35
Author(s):  
L.K. Smedema
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Soil Management ◽  
Field Capacity ◽  
Design Criteria ◽  
Plastic Limit ◽  
Drainage Design ◽  
Relationship Of ◽  
The Relationship

Drainage requirements for workability are formulated on the basis of the soil moisture content at the lower plastic limit, and the relationship of the latter value to field capacity is investigated. Current drainage design criteria are analysed with respect to soil workability requirements; it is concluded that there is little technical and even less economic scope for improving soil workability by adopting stricter criteria, leading to narrower drain spacings. However, a case can be made for increasing the drain depth in medium and heavy textured soils beyond the commonly applied depth of about 100 cm, in the Netherlands. The effects of soil management on soil workability are briefly discussed. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Dissipation and Phytotoxicity of Sodium Azide in Soil

Weed Science ◽  
1976 ◽  
Vol 24 (3) ◽  
pp. 312-315 ◽  
Author(s):  
M. L. Ketchersid ◽  
M. G. Merkle
Keyword(s):  
Soil Moisture ◽  
Sodium Azide ◽  
Normal Growth ◽  
Field Capacity ◽  
Alkaline Soils ◽  
Moist Soil ◽  
Moist Environment ◽  
Dry Soil ◽  
Germination And Growth ◽  
Plant Germination

The dissipation of sodium azide (NaN3) from soil was significantly affected by pH, soil moisture, and relative humidity (RH). Loss was more rapid from acid than from alkaline soils. Moist soil (20 to 60% field capacity) or air dry soil in a moist environment (100% RH) lost NaN3more rapidly than air dry soil in a dry (0% RH) environment. However, dissipation was decreased when soil moisture exceeded 60% field capacity. Degree of leaching and phytotoxicity of NaN3was not affected by soil pH. Bioassay studies indicated that 10 ppm NaN3in the soil significantly reduced germination and growth in plant species tested. At concentrations of NaN3below 10 ppm, plant germination was often delayed but normal growth occurred after NaN3dissipation.

EFFECTS OF MOISTURE, ADDED NO3−, AND MACERATED ROOTS ON NO3− TRANSFORMATION AND REDOX POTENTIAL IN SURFACE AND SUBSURFACE SOILS

1973 ◽  
Vol 53 (2) ◽  
pp. 219-230 ◽  
Author(s):  
L. D. BAILEY ◽  
E. G. BEAUCHAMP
Keyword(s):  
Soil Moisture ◽  
Redox Potential ◽  
Field Capacity ◽  
Soil Samples ◽  
Saturated Soil ◽  
Moisture Level ◽  
Soil Moisture Level ◽  
Soil Systems ◽  
Corn Roots ◽  
The Relationship

Samples of the Ap, BA, and Bt horizons of a Huron soil were used to study in the laboratory the effects of three moisture levels, added KNO3, and macerated corn roots on NO3− transformation and redox potential (Eh). The soil systems were incubated at 30 C in an atmosphere of 21% O2 and 79% He. Without the addition of NO3− and soil moisture level equivalent to one-half field capacity [Formula: see text] and field capacity (FC), NO3− accumulation occurred. Adding KNO3 alone or KNO3 and macerated roots, and increasing the moisture to twice field capacity (2FC) resulted in NO3− reduction. The relationship between Eh and NO3− reduction and accumulation was similar for the three soil samples. The rate of NO3− reduction or accumulation was stimulated by the addition of macerated roots and was in the order Ap > BA > Bt. NO3− accumulation was accompanied by an increase in Eh from 400 to 430 mV. [Formula: see text] and FC only a portion of the added NO3− was reduced, and the Eh decreased from 400 to 350 mV and was poised thereafter. In saturated soil (2FC) the Eh decreased from positive values to negative values. However in the BA and Bt soils treated with NO3−, macerated roots, or both, the Eh was temporarily poised at 200 mV until all NO3− was reduced.

scholarly journals Bromus-Poaresponse to defoliation intensity and frequency under three soil moisture levels

2002 ◽  
Vol 82 (2) ◽  
pp. 365-370 ◽  
Author(s):  
N. T. Donkor ◽  
E. W. Bork ◽  
R. J. Hudson
Keyword(s):  
Soil Moisture ◽  
Crude Protein ◽  
Poa Pratensis ◽  
Field Capacity ◽  
Kentucky Bluegrass ◽  
Bromus Inermis ◽  
Neutral Detergent Fiber ◽  
Moisture Regime ◽  
Boreal Ecosystems ◽  
The Relationship

Smooth brome (Bromus inermis Leyss.) and Kentucky bluegrass (Poa pratensis L.) are important herbage for livestock and wildlife in Aspen-Boreal ecosystems in central Alberta, but there is paucity of information on the relationship between soil moisture and defoliation regimes on herbage production in these ecosystems. In a greenhouse experiment, we evaluated the effect of Bromus-Poa defoliation frequencies (2 or 4 wk) and intensities (2.5, 7.5, or 15 cm above the soil surface) under three soil moisture regimes [field capacity (wet), 50% field capacity (moist), 20% field capacity (dry)] on dry matter (DM) yield. Crude protein (CP) content, crude protein yield (CPY) and neutral detergent fiber (NDF) were also determined for herbage harvested. Total accumulated shoot DM decreased under defoliation compared to the undefoliated control, was higher if plants were clipped every 4 wk, rather than 2 wk, and increased with increasing soil moisture availability. Defoliation regimes decreased root DM Compared to the undefoliated control. Soil moisture regime did not significantly affect below-ground DM production, but root:shoot ratio increased significantly with decreasing moisture supply. The average CP content of grasses ranged from 12 to 23%, but was adequate to meet crude protein requirements of growing, pregnant or lactating grazing cattle (Bos spp.) The CPY decreased with increasing moisture stress, and was greatest when plants were clipped at a 7.5-cm height. Shoot NDF concentration increased with decreasing clipping frequency. These result indicate the need to investigate the relationship between soil moisture and management practices that affect the productivity of tame pastures in Aspen-Boreal ecosystems. Key words: Bromus inermis, Poa pratensis, crude protein, neutral detergent fiber, water

Soil Moisture Deficits in South-Central Sweden

1989 ◽  
Vol 20 (2) ◽  
pp. 109-122 ◽  
Author(s):  
Lotta Andersson
Keyword(s):  
Soil Moisture ◽  
Field Capacity ◽  
Interannual Variations ◽  
Neutron Probe ◽  
South Central ◽  
Normal Ranges ◽  
Moisture Fluxes ◽  
In The Beginning ◽  
Probe Measurements ◽  
Different Parts

Some commonly used assumptions about climatically induced soil moisture fluxes within years and between different parts of a region were challenged with the help of a conceptual soil moisture model. The model was optimised against neutron probe measurements from forest and grassland sites. Five 10 yrs and one 105 yrs long climatic records, from the province of Östergötland, situated in south-central Sweden, were used as driving variables. It was concluded that some of the tested assumptions should not be taken for granted. Among these were the beliefs that interannual variations of soil moisture contents can be neglected in the beginning of the hydrological year and that soils usually are filled up to field capacity after the autumn recharge. The calculated climatic induced dryness was estimated to be rather insensitive to the choice of climatic stations within the region. Monthly ranges of soil moisture deficits (1883-1987) were shown to be skewed and it is therefore recommended to use medians and standard deviations in statistical analyses of “normal” ranges of soil moisture deficits.

scholarly journals Regression Models for Soil Water Storage Estimation Using the ESA CCI Satellite Soil Moisture Product: A Case Study in Northeast Portugal

Water ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 37
Author(s):  
Tomás de Figueiredo ◽  
Ana Caroline Royer ◽  
Felícia Fonseca ◽  
Fabiana Costa de Araújo Schütz ◽  
Zulimar Hernández
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Regression Models ◽  
Meteorological Data ◽  
Water Storage ◽  
Model Performance ◽  
Soil Water Balance ◽  
Soil Water Storage ◽  
The Relationship

The European Space Agency Climate Change Initiative Soil Moisture (ESA CCI SM) product provides soil moisture estimates from radar satellite data with a daily temporal resolution. Despite validation exercises with ground data that have been performed since the product’s launch, SM has not yet been consistently related to soil water storage, which is a key step for its application for prediction purposes. This study aimed to analyse the relationship between soil water storage (S), which was obtained from soil water balance computations with ground meteorological data, and soil moisture, which was obtained from radar data, as affected by soil water storage capacity (Smax). As a case study, a 14-year monthly series of soil water storage, produced via soil water balance computations using ground meteorological data from northeast Portugal and Smax from 25 mm to 150 mm, were matched with the corresponding monthly averaged SM product. Linear (I) and logistic (II) regression models relating S with SM were compared. Model performance (r2 in the 0.8–0.9 range) varied non-monotonically with Smax, with it being the highest at an Smax of 50 mm. The logistic model (II) performed better than the linear model (I) in the lower range of Smax. Improvements in model performance obtained with segregation of the data series in two subsets, representing soil water recharge and depletion phases throughout the year, outlined the hysteresis in the relationship between S and SM.

scholarly journals Spatiotemporal Variation of the Burned Area and Its Relationship with Climatic Factors in Central Kazakhstan

2021 ◽  
Vol 13 (2) ◽  
pp. 313
Author(s):  
Yongfang Xu ◽  
Zhaohui Lin ◽  
Chenglai Wu
Keyword(s):  
Soil Moisture ◽  
Relative Humidity ◽  
Central Asia ◽  
Climatic Factors ◽  
Spatiotemporal Variation ◽  
Lower Atmosphere ◽  
Burned Area ◽  
Circulation Index ◽  
Precipitation Anomalies ◽  
The Relationship

Central Asia is prone to wildfires, but the relationship between wildfires and climatic factors in this area is still not clear. In this study, the spatiotemporal variation in wildfire activities across Central Asia during 1997–2016 in terms of the burned area (BA) was investigated with Global Fire Emission Database version 4s (GFED4s). The relationship between BA and climatic factors in the region was also analyzed. The results reveal that more than 90% of the BA across Central Asia is located in Kazakhstan. The peak BA occurs from June to September, and remarkable interannual variation in wildfire activities occurs in western central Kazakhstan (WCKZ). At the interannual scale, the BA is negatively correlated with precipitation (correlation coefficient r = −0.66), soil moisture (r = −0.68), and relative humidity (r = −0.65), while it is positively correlated with the frequency of hot days (r = 0.37) during the burning season (from June to September). Composite analysis suggests that the years in which the BA is higher are generally associated with positive geopotential height anomalies at 500 hPa over the WCKZ region, which lead to the strengthening of the downdraft at 500 hPa and the weakening of westerlies at 850 hPa over the region. The weakened westerlies suppress the transport of water vapor from the Atlantic Ocean to the WCKZ region, resulting in decreased precipitation, soil moisture, and relative humidity in the lower atmosphere over the WCKZ region; these conditions promote an increase in BA throughout the region. Moreover, the westerly circulation index is positively correlated (r = 0.53) with precipitation anomalies and negatively correlated (r = −0.37) with BA anomalies in the WCKZ region during the burning season, which further underscores that wildfires associated with atmospheric circulation systems are becoming an increasingly important component of the relationship between climate and wildfire.

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