scholarly journals Slow movement of alkali from surface-applied lime warrants the introduction of strategic tillage for rapid amelioration of subsurface acidity in south-western Australia

Soil Research ◽  
2021 ◽  
Vol 59 (1) ◽  
pp. 97 ◽  
Author(s):  
G. Azam ◽  
C. Gazey
Keyword(s):  
Soil Ph ◽  
Soil Acidity ◽  
Soil Column ◽  
Cost Effective ◽  
Triticum Aestivum L ◽  
Vertical Movement ◽  
Deep Tillage ◽  
Subsurface Soil ◽  
Speed Up ◽  
Series Of Experiments

Conventional surface-application of agricultural lime takes many years to increase pH deeper in the soil profile, which is a barrier to increased adoption of liming. We conducted a series of experiments to measure the rate of vertical movement of alkali and identify the factors that determine this movement into the subsurface, to evaluate the feasibility of ameliorating acidic subsurface soil using residual (undissolved) lime (CaCO3) at Wongan Hills (30.85°S, 116.74°E) and Merredin (31.48°S, 118.21°E) and to test whether deep tillage and lime incorporation can significantly speed up the amelioration of subsurface soil acidity at Kalannie (30.42°S, 117.29°E). Multiple applications of lime to the surface of the soil at higher rates (total 6–8.5 Mg ha–1) significantly increased subsurface soil pH but only in the 0.10–0.20 m depth by 0.049 pH units per year over 10–24 years. A large proportion of the surface-applied lime was stratified in the top few centimetres of the soil and incorporation of this undissolved lime with a rotary hoe to a depth of 0.25 m significantly increased soil pH (by 0.63 units) within a year in the Wongan Hills field experiment. Deep incorporation of 6 Mg ha–1 lime to a depth of 0.45 m through excavation and spading with a small rotary hoe also increased soil pH by more than a unit and decreased Al concentration to below the toxic level within two months in the Kalannie experiment, allowing wheat (Triticum aestivum L.) plants to produce root systems up to 0.59 m deep compared with 0.26 m for the control. Our soil column leaching experiment indicated that surface incorporation of lime in higher rainfall regions can be useful to treat subsurface soil acidity but that the rate of improvement in subsurface pH was slow. Therefore, deeper incorporation of lime using cost-effective strategic deep tillage is likely to be necessary.

Using electro-magnetic induction technology to identify sampling sites for soil acidity assessment and to determine spatial variability of soil acidity in rice fields

2007 ◽  
Vol 47 (2) ◽  
pp. 208 ◽  
Author(s):  
B. W. Dunn ◽  
H. G. Beecher
Keyword(s):  
Spatial Variability ◽  
Soil Ph ◽  
Magnetic Induction ◽  
Soil Acidity ◽  
Surface Soil ◽  
Cost Effective ◽  
Soil Sampling ◽  
Irrigated Agriculture ◽  
Sampling Protocols ◽  
Electro Magnetic

Irrigated agriculture has contributed to increasing topsoil acidity, which in turn can increase acidification of the subsoil. Lime is typically applied at a uniform rate to raise the pH of the soil, with no accounting for the variation in soil acidity that may exist within a field. Current commercial sampling protocols use surface soil composites taken across the whole field or in parts of fields where visual soil differences are apparent. Current liming recommendations may not account for in-field soil pH spatial variability, especially if the variability is not related to visual differences. Three studies were undertaken over 10 fields, to investigate the potential of using electro-magnetic induction instruments (Geonics EM38 and EM31) to target soil sampling in order to identify differences in soil acidity within flood-irrigated fields in southern New South Wales (NSW), Australia. Within individual fields, large differences in surface soil acidity were identified and a strong relationship (r2 = 0.49 to 0.91) between the soil’s apparent electrical conductivity and soil pH was found. It is proposed that fields from southern NSW that have grown rice, be divided into zones to soil sample for acidity assessment, based on EM instrument readings. Proposed ECa levels for the delineation of zones are <80, 80–140 and >140 mS/m for EM31v and <80, 80–110 and >110 mS/m for EM38v. Many rice growers in southern NSW currently have EM maps of their fields. Using these maps to target soil sampling for soil acidity would be a more cost-effective method of determining the spatial variability of soil acidity in a field than grid sampling. Knowledge of the variability of soil acidity within the field would potentially allow the application of appropriate lime rates, relative to soil pH and cation exchange capacity to all parts of the field. This knowledge could make the variable application of lime a cost effective approach, compared with whole field management approaches.

The influence of surface incorporated lime and gypsiferous by-products on surface and subsurface soil acidity. II. Root growth and agronomic implications

Soil Research ◽  
1999 ◽  
Vol 37 (1) ◽  
pp. 181 ◽  
Author(s):  
N. S. Bolan ◽  
H. L. Wang ◽  
M. J. Hedley ◽  
D. J. Horne
Keyword(s):  
Root Growth ◽  
Root Elongation ◽  
Soil Acidity ◽  
Soil Column ◽  
The Self ◽  
Molar Ratio ◽  
Root Penetration ◽  
Lime Treatment ◽  
Subsurface Soil ◽  
By Products

Lucerne (Medicago sativa. L) root elongation in acid soils amended by gypsiferous coal combustion by-products was investigated in a glasshouse study. Lime, fluidised bed boiler ash (FBA), and flue gas desulfurisation gypsum (FGDG) were mixed into the surface 50 mm of either an Allophanic (the Patua sand loam) or an Ultic (the Kaawa clay loam) soil column, at rates containing calcium equivalent to 5000 kg/ha of CaCO3. Lucerne was grown on each column after it was leached with 400 mm of water. Whereas the lime treatment had no effect on root elongation in the acidic subsurface of the Patua soil, the FBA and FGDG treatments significantly improved lucerne root penetration into the subsurface soil (P < 0·05). This was due to the ‘self-liming effect’ induced by sulfate adsorption. Regression analysis indicated that the molar ratio of labile monomeric aluminium and calcium in soil solution (Al : Ca) was a good indicator of the degree of root growth into subsurface soil layers (R2= 0·94). In contrast, topsoil incorporated amendments did not influence root penetration into the acidic subsurface of the Kaawa soil, which is dominated by permanently charged clay minerals. The ‘self-liming effect’ caused by gypsum application is not a sustainable practice. Lime should be applied to neutralise the topsoil acidity, when gypsum is used as subsurface soil acidity ameliorant. FBA, which contains both lime and gypsum, can meet these requirements.

The use of Ca-modified, brown-coal-derived humates and fulvates for treatment of soil acidity

Soil Research ◽  
2002 ◽  
Vol 40 (7) ◽  
pp. 1171 ◽  
Author(s):  
Damayanthi Peiris ◽  
Antonio F. Patti ◽  
W. Roy Jackson ◽  
Marc Marshall ◽  
Christopher J. Smith
Keyword(s):  
Brown Coal ◽  
Soil Ph ◽  
Soil Acidity ◽  
Soil Column ◽  
Chemical Properties ◽  
Soil Surface ◽  
Al Content ◽  
Exchangeable Ca ◽  
Exchangeable Al ◽  
Over The Top

Previous workers have demonstrated the amelioration of soil acidity with Ca-saturated, at least slightly soluble, organic materials. This study investigated the effectiveness of a new source of such materials, the humate- or fulvate-rich products of oxidation (hydrogen peroxide) of Loy Yang brown coal. The products were characterised by physical and spectroscopic measurements and by elemental analysis. Two products, one approximately half fulvate (fulvate-rich), the other predominantly humate (humate-rich) were mixed with CaCl2 and then used to treat columns of an acid red podzol soil from Book Book, NSW. Leachate fractions were collected and analysed for pH, ionic strength, and concentration of Ca, Mg, K, Mn, Fe, and Al. After leaching (3 pore volumes), each soil column was sectioned and exchangeable Ca and Al contents were determined. The results were compared with those obtained from lime-treated and untreated columns.The Ca-fulvate-rich product was the most effective in lowering the exchangeable Al content of the soil whilst increasing exchangeable Ca and soil pH. About 90% of the reduction in exchangeable Al was due to loss of Al in the leachate rather than immobilisation. The pH increased over the top 15 cm of the column from 3.8 ± 0.1 to 4.5–5.4. The Ca-humate-rich oxidised product was less effective in ameliorating soil acidity, as expected from its chemical properties, but it increased soil pH (to 4.0–4.7) and exchangeable Ca in the top 6 cm of the column and decreased exchangeable Al in the top 12 cm. More of the reduction in exchangeable Al than for the treatment with Ca-fulvate-rich material was due to conversion to an immobile form. This material was superior to lime, which only gave significant improvement near the soil surface. The leachates from treated columns contained the same amounts of Mg, Mn, and K as a control, but more Fe was leached from treated columns, particularly that treated with the Ca-fulvate-rich product.

EFFECTS OF SOIL ACIDITY ON RHIZOBIA NUMBERS, NODULATION AND NITROGEN FIXATION BY ALFALFA AND RED CLOVER

1977 ◽  
Vol 57 (2) ◽  
pp. 197-203 ◽  
Author(s):  
W. A. RICE ◽  
D. C. PENNEY ◽  
M. NYBORG
Keyword(s):  
Nitrogen Fixation ◽  
Soil Ph ◽  
Soil Acidity ◽  
Field Experiments ◽  
Rhizobium Meliloti ◽  
Acid Soils ◽  
Red Clover ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
Greenhouse Experiments

The effects of soil acidity on nitrogen fixation by alfalfa (Medicago sativa L.) and red clover (Trifolium pratense L.) were investigated in field experiments at 28 locations, and in greenhouse experiments using soils from these locations. The pH of the soils (limed and unlimed) varied from 4.5 to 7.2. Rhizobia populations in the soil, nodulation, and relative forage yields (yield without N/yield with N) were measured in both the field and greenhouse experiments. Rhizobium meliloti numbers, nodulation scores, and relative yields of alfalfa decreased sharply as the pH of the soils decreased below 6.0. For soils with pH 6.0 or greater, there was very little effect of pH on any of the above factors for alfalfa. Soil pH in the range studied had no effect on nodulation scores and relative yields of red clover. However, R. trifolii numbers were reduced when the pH of the soil was less than 4.9. These results demonstrate that hydrogen ion concentration is an important factor limiting alfalfa growth on acid soils of Alberta and northeastern British Columbia, but it is less important for red clover. This supports the continued use of measurements of soil pH, as well as plant-available Al and Mn for predicting crop response to lime.

AN ASSESSMENT OF THE SOIL ACIDITY PROBLEM IN ALBERTA AND NORTHEASTERN BRITISH COLUMBIA

1977 ◽  
Vol 57 (2) ◽  
pp. 157-164 ◽  
Author(s):  
D. C. PENNEY ◽  
M. NYBORG ◽  
P. B. HOYT ◽  
W. A. RICE ◽  
B. SIEMENS ◽  
...  
Keyword(s):  
British Columbia ◽  
Soil Ph ◽  
Soil Acidity ◽  
Field Experiments ◽  
Trifolium Pratense ◽  
Acid Soil ◽  
Acid Soils ◽  
Red Clover ◽  
Hordeum Vulgare L ◽  
Crop Species

The amount of cultivated acid soil in Alberta and northeastern British Columbia was estimated from pH values of farm samples analyzed by the Alberta Soil Testing Laboratory, and the effect of soil acidity on crops was assessed from field experiments on 28 typical acid soils. The field experiments consisted of two cultivars of barley (Hordeum vulgare L.) and one cultivar each of rapeseed (Brassica campestris L.), red clover (Trifolium pratense L.) and alfalfa (Medicago sativa L.) grown with and without lime for 2 yr. There are about 30,000 ha of soils with a pH of 5.0 or less where soil acidity seriously restricts yields of all four crop species. There are approximately 300,000 ha with a soil pH of 5.1–5.5 where liming will on the average increase yields of alfalfa by 100%, yields of barley by 10–15%, and yields of rapeseed and red clover by 5–10%. There are a further 1,600,000 ha where soil pH ranges from 5.6 to 6.0 and liming will increase yields of alfalfa by approximately 50% and yields of barley, rapeseed and red clover by at least 4–5%.

Soil acidity in 1970 and 1989 in a coniferous forest in southwest Finland

1998 ◽  
Vol 78 (3) ◽  
pp. 477-479 ◽  
Author(s):  
C. J. Westman ◽  
S. Jauhiainen
Keyword(s):  
Key Words ◽  
Soil Ph ◽  
Soil Acidity ◽  
Mineral Soil ◽  
Coniferous Forest ◽  
Soil Layers ◽  
Water Suspension ◽  
Ph Values ◽  
Humus Layer ◽  
Repeated Sampling

Forest soil pH in southwest Finland was measured with identical sampling and analysing methods in 1970 and 1989. The acidity of the organic humus layer increased significantly as pH values measured on water and on salt suspensions decreased between the two sampling dates. For the mineral soil layers, no unambiguous trend was found. pH values measured on salt suspension tended to be unchanged or lower, while pH on water suspension in some soil layers were even higher in 1989 than in 1970. Key words: pH, repeated sampling

scholarly journals Modifications of phosphorus in Latosol as a function of humic acids and acidity

2018 ◽  
Vol 22 (7) ◽  
pp. 488-492 ◽  
Author(s):  
Márcia H. Beck ◽  
Pedro A. V. Escosteguy ◽  
Deborah P. Dick
Keyword(s):  
Factorial Design ◽  
Humic Acids ◽  
Soil Ph ◽  
Crucial Role ◽  
Soil Acidity ◽  
Ph Value ◽  
P Availability ◽  
Soil P ◽  
P Content

ABSTRACT The effect of humic acids (HA) on phosphorus (P) availability is still contradictory; thus, it is necessary to identify the conditions that play a crucial role in this effect. The aim of this study was to investigate the effect of HA application, combined with doses of P, on the content of this nutrient in a Latosol with and without acidity correction. Two experiments were carried out, one with HA from peat and another with HA from mineral charcoal (leonardite). Doses of these acids (0; 1.12 and 5.62 mg C g-1 of soil) and P (26.2 and 104.7 mg P g-1 of soil, 1 and 4-fold higher than recommended, respectively) were tested at soil pH 4.5 and 7.0, in a three-factorial design. The soil was incubated for 20 days and the soil-P content was measured by Mehlich-1 and remaining-P tests. The effect of HAs on P availability varied with the P doses and soil acidity. Humic acids application increases P content in Latosol when P dose is higher than recommended and there is no acidity correction (pH 4.5). However, there is no effect of HAs application on soil-P content when applying the recommended amount of this nutrient, irrespective of the pH value.

An Experimental Study of Compatibility for Metallic Inserts Bonded into CFRP Laminates Soaked in Aircraft Fuel

2015 ◽  
Vol 1095 ◽  
pp. 518-522
Author(s):  
Xue Mei Chen ◽  
Jing Liu ◽  
Jing Xu ◽  
Hui Zhang ◽  
Feng Tao He ◽  
...  
Keyword(s):  
Cost Effective ◽  
Structural Components ◽  
Interference Fit ◽  
Cfrp Laminates ◽  
Aircraft Fuel ◽  
Mechanical And Physical Properties ◽  
Series Of Experiments ◽  
Breakaway Torque ◽  
Torque Values ◽  
Push Out

CFRP laminates are used for various aircraft structural components because of their good mechanical and physical properties. Metallic inserts are one kind of aerospace fasteners, which are usually installed in the metallic components by an interference fit. However, when metallic inserts are installed in the CFRP laminates by the traditional installing way, delamination and low efficiencies are troublesome. Therefore, excellent quality and cost effective installing metallic inserts into the CFRP laminates remains a challenge. In this paper, a series of experiments were carried out to study the compatibility for metallic inserts bonded into the CFRP laminates soaked in the aircraft fuel. The experimental results show that the push-out values and breakaway torque values of metallic inserts bonded in the CFRP laminates soaked in the fuel are not reduced compared with these values of sample was not prepared in that way.

scholarly journals Determination of critical pH and Al concentration of acidic Ultisols for wheat and canola crops

2016 ◽  
Author(s):  
Abdulaha-Al Baquy ◽  
Jiu-Yu Li ◽  
Chen-Yang Xu ◽  
Khalid Mehmood ◽  
Ren-Kou Xu
Keyword(s):  
Soil Ph ◽  
Crop Production ◽  
Soil Acidity ◽  
Production Systems ◽  
Southern China ◽  
Chemical Properties ◽  
Dry Weight ◽  
Hydrated Lime ◽  
Dry Land

Abstract. Soil acidity has become a serious constraint in dry land crop production systems of acidic Ultisols in tropical and subtropical regions of southern China, where winter wheat and canola are cultivated as important rotational crops. Regardless of other common existing concerns in acidic Ultisols of southern China, it needs to be investigated whether soil acidity has any effect on wheat and canola growth. There is little information on the determination of critical soil pH as well as aluminium (Al) concentration for wheat and canola crops. The objective of this study was to determine the critical soil pH and exchangeable aluminium concentration (AlKCl) for wheat and canola production. Two pot cultures with two Ultisols from Hunan and Anhui were conducted for wheat and canola crops in a controlled growth chamber, with a completely randomized design. A soil pH gradient ranging from 3.7 (Hunan) and 3.97 (Anhui) to 6.5, with three replications, was used as a treatment. Aluminium sulfate (Al2(SO4)3) and hydrated lime (Ca(OH)2) were used to obtain the target soil pH levels. Plant height, shoot dry weight, root dry weight, and chlorophyll content (SPAD value) of wheat and canola were adversely affected by soil acidity in both locations. The critical soil pH and AlKCl of the Ultisol from Hunan for wheat were 5.29 and 0.56 cmol kg−1, respectively. At Anhui, the threshold soil pH and AlKCl for wheat were 4.66 and 2.36 cmol kg−1, respectively. On the other hand, the critical soil pH for canola was 5.65 and 4.87 for the Ultisols from Hunan and Anhui, respectively. The critical soil exchangeable Al for canola cannot be determined from the experiment of this study. The results suggested that the critical soil pH and AlKCl varied between different locations for the same variety of crop, due to the different soil types and their other soil chemical properties. The critical soil pH for canola was higher than that for wheat for both Ultisols, thus canola was more sensitive to soil acidity. Therefore, we recommend that liming should be undertaken to increase soil pH if it falls below these critical soil pH levels for wheat and canola production.

scholarly journals Silica-encapsulated DNA tracers for measuring aerosol distribution dynamics in real-world settings

2021 ◽  
Author(s):  
Anne M Luescher ◽  
Julian Koch ◽  
Wendelin J Stark ◽  
Robert N Grass
Keyword(s):  
Real World ◽  
Complex Dynamics ◽  
Quantitative Polymerase Chain Reaction ◽  
Cost Effective ◽  
Confined Space ◽  
Aerosol Dynamics ◽  
Novel Approach ◽  
Aerosol Distribution ◽  
Wide Range ◽  
Series Of Experiments

Aerosolized particles play a significant role in human health and environmental risk management. The global importance of aerosol-related hazards, such as the circulation of pathogens and high levels of air pollutants, have led to a surging demand for suitable surrogate tracers to investigate the complex dynamics of airborne particles in real-world scenarios. In this study, we propose a novel approach using silica particles with encapsulated DNA (SPED) as a tracing agent for measuring aerosol distribution indoors. In a series of experiments with a portable setup, SPED were successfully aerosolized, re-captured and quantified using quantitative polymerase chain reaction (qPCR). Position-dependency and ventilation effects within a confined space could be shown in a quantitative fashion achieving detection limits below 0.1 ng particles per m3 of sampled air. In conclusion, SPED show promise for a flexible, cost-effective and low-impact characterization of aerosol dynamics in a wide range of settings.

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