The effects of lime, gypsum and lime/gypsum combinations, after 2.5 years, on two sodic soils under dryland cropping conditions in the Macquarie Valley, NSW (original) (raw)
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Agronomy, 2020
Surface (0–10 cm) and subsoil (soil layers below 10 cm) acidity and resulting aluminum (Al) toxicity reduce crop grain yields. In South Western Australia (SWA), these constraints affect 14.2 million hectares or 53% of the agricultural area. Both lime (L, CaCO3) and gypsum (G, CaSO4) application can decrease the toxic effect of Al, leading to an increase in crop grain yields. Within the region, it is unclear if G alone or the combined use of L and G has a role in alleviating soil acidity in SWA, due to low sulfate S (SO4–S) sorption properties of the soil. We present results from three experiments located in the eastern wheatbelt of SWA, which examined the short-term (ST, 2 growing seasons), medium-term (MT, 3 growing seasons), and long-term (LT, 7 growing seasons over 10 years) effects of L and G on grain yield and plant nutrient concentrations. Despite the rapid leaching of SO4–S and no self-liming impact, it was profitable to apply G, due to the significant ST grain yield response...
Soil Research, 2014
This paper determines the influence of lime and gypsum on the rehabilitation of a degraded sodic soil in a semiarid environment 12 years after application. The aim was to assess rehabilitation strategies for sodic soils as alternatives to the application of gypsum alone. An experimental site was used where lime and gypsum combinations (L0G0, lime 0 t ha -1 and gypsum 0 t ha -1 ; L0G1, L0G2.5, L0G5, L1G0, L2.5G0, L5G0, L1G1, L2.5G1) had been applied 12 years prior, in 1994. An earlier study had reported on the effects after 3 years of the chemical ameliorants and tillage on a range of soil physical and chemical properties at the site. The current study, sampled in 2006, assessed the effects after 12 years of lime and gypsum on soil chemistry, stability, hydraulics, vegetative growth and soil respiration. Calcium, primarily from lime, was observed to have a major effect on soil health. Significant effects on soil chemistry were limited to increases in exchangeable calcium and decreases in exchangeable magnesium, although aggregate stability in water and hydraulic conductivity were significantly improved where L5G0 was applied. Vegetation patch width, total nitrogen and carbon, and soil respiration were significantly improved where lime had been added at 2.5 or 5 t ha -1 . As no lime could be detected in the soil 12 years after application, it was deduced that lime had acted as a catalyst for increased functionality in soil and vegetation interactions. This increased soil functionality resulted in an increased rate of lime dissolution in the soil.
Agronomy
Soil acidity or aluminum (Al) toxicity is a major limitation to crop production. In this paper, we examine the effects of surface-applied lime and gypsum on soil profile chemical properties that affect Al toxicity in short-term (1 year), medium-term (2 years and 8 months) and long-term (10 years) experiments. Sulfate applied to the soil surface as gypsum was leached rapidly to a depth of 40 cm in the short-term despite relatively low amounts (279 mm) of rainfall. In the medium and long-term experiments, 28–54% of the sulfate applied as gypsum was retained in the 0–50 cm soil layer due to adsorption and precipitation reactions. The combined application of lime and gypsum increased soil calcium, to a depth of 30 cm in the short-term and to a depth of 50 cm in the medium and long-terms. Increases in soil sulfate and calcium were associated with greater electrical conductivity to a depth of 50 cm for all sampling times. Application of lime alone had no impact on soil Al, pH, and calcium...
Sustainable Agriculture Research
Soil acidity is one of the major soil constraints for the grain-growing industry in Australia and around the globe. While surface liming is widely adopted, it has been proven ineffective for the timely amelioration of subsoil acidity. There is a growing interest in finding alternative approaches for the effective amelioration of subsoil acidity, especially for low-rainfall regions. In a controlled environment and a field experiment, we examined whether the combined application of lime and gypsum would be more effective than lime alone under no-till (NT) and shallow strategic tillage (ST) systems for reducing the impact of soil acidity and increasing grain yield. The controlled environment experiment highlighted that lime increased soil pH and decreased the soil exchangeable aluminium concentration (EAC) which resulted in significantly better root growth. In the field experiment, we found that the lime plus gypsum treatment, in most cases, did not significantly affect grain yield, wa...
Agronomy, 2021
Aluminum (Al) toxicity imposes a significant limitation to crop production in South Western Australia. This paper examines the impact of surface-applied lime and gypsum on soil solution chemistry in the short term (1 year) and the long-term (10 years) in water limited environments. In the experiments, we measured soil solution chemistry using a paste extract on soil profile samples collected to a depth of 50 cm. We then used the chemical equilibrium model MINTEQ to predict the presence and relative concentrations of Al species that are toxic to root growth (Al associated with Al3+ and AlOH2 or Toxic-Al) and less non-toxic forms of Al bound with sulfate, other hydroxide species and organic matter. A feature of the soils used in the experiment is that they have a low capacity to adsorb sulfate. In the short term, despite the low amount of rainfall (279 mm), sulfate derived from the surface gypsum application is rapidly leached into the soil profile. There was no self-liming effect, as...
The Chemistry of the Reclamation of Sodic Soils with Gypsum and Lime
Soil Science Society of America Journal, 1980
Sodic soil reclamation was theoretically evaluated assuming equilibrium chemistry and piston movement of soil solution. The effective solubility of gypsum when mixed with a sodic soil is increased because the exchange phase acts as a sink for Ca 2 * until both the gypsum dissolution and exchange reactions reach equilibrium. The electrical conductivity of a soil solution in equilibrium with both gypsum and an exchangeable sodium fraction (£ Na) of 0.0 and 0.43 is 2.3 and 14 dS nr 1. Thus, mixing gypsum into the soil hastens reclamation and provides higher solution concentrations for the maintenance or improvement o£ the soil hydraulic conductivity. The amount of gypsum dissolved, expressed in moles of charge (equivalents), is a linear function of the moles of exchangeable Na + replaced; r 2 values typically exceeded 0.98. The slope of the regression line decreased with increasing final E Na. Typical values were 1.40, 1.27, and 1.20 moles of charge gypsum dissolved per mole of exchangeable sodium replaced at final £ N .'s of 0.05, 0.10, and 0.15. The inclusion of lime equilibrium reduces these slopes by 3, 6, and 9% for P 0 o a 's of 1, 4, and 10 kPa (1, 4, and 10% CO 2). Gypsum requirements for calcareous, sodic soils based on quantitative replacement of exchangeable sodium should be increased by factors of 1.3 to 1.1 depending on the desired final levels of exchangeable sodium.
Changes in a Sodic Soil After Gypsum Application Under Dryland Conditions
European Scientific Journal, 2014
In the Province of Cordoba Argentina there are 2.803.000 ha of soils that are sodic from a depth of around 20 cm, 93.000 of which are in San Martin department where the study area is situated. These soils, generally loam-textured soils, occur in mildly depressed areas. Paddocks frequently show uneven crop growth, named "patchy growth", where sectors of lower plants alternate with sectors of higher plants that look normal (N). The main objective of this study is, then, to evaluate the effect of gypsum on soil properties. The treatments were MD (maximum dose) at a rate of 3350 kg ha-1 , AD (agronomic dose) at a rate of 1340 kg ha-1 of gypsum and C without gypsum. Gypsum was spread manually over the soil. Three years later, more gypsum was applied to AD (1340 kg ha-1). Five years after the first application of gypsum, in the second horizon, the higher dose of gypsum (MD) lowered soil pH (H 2 O), soil strength and water content held at all matric potentials, and also increased soil permeability increased. The lower and partitioned dose (AD) had a detrimental or no effect on the properties evaluated. Probably the lower dose was insufficient to modify the subsuperficial permeability and leaching was decreased.
Geoderma, 2019
An 18-year field experiment was conducted on a highly acidic soil in the mixed farming zone of southeastern Australia. The experiment was a fully phased design with three major treatment contrasts: perennial systems versus annual systems; unlimed versus limed treatments; and permanent pasture versus pasture-crop rotations. The hypotheses tested in this study were that a) perennial systems would be less acidifying than annual systems, and b) surface liming would lead to amelioration of subsurface soil acidity over time. Results showed that there was no significant difference in soil pH in terms of acidification rate and amelioration rate between perennial and annual systems, thus we rejected the first hypothesis. However, both perennial and annual systems did acidify or re-acidify soil. The re-acidification rate was at least 0.09 pH units per year in the 0-0.10 m depth under the limed treatment. The acidification rate was 0.005 pH units per year in the 0.10-0.20 m depth under the unlimed treatment. The vigorous lime regime of maintaining pH ≥5.5 (measured in 0.01 M CaCl 2) in the 0-0.10 m depth increased soil pH in the 0.10-0.20 m depth at a rate of the 0.04 pH units per year, hence we accepted the second hypothesis. There was clear evidence of alkali movement vertically over time, but it was confined within the top 0.30 m depth over the 18-year period of experiment. It is recommended that soil should be limed regularly to maintain pH ≥5.5 to keep the system productive and sustainable.
Soil Research, 2022
Context In Sweden, mixtures of 80–85% ground limestone and 15–20% slaked lime (hereafter, ‘structure lime’) are used in subsidised environmental schemes to improve aggregate stability and mitigate phosphorus losses on clay soils. Aims This study investigated different rates of structure lime application and soil variables on aggregate stability on clay soils, and whether soil properties can predict aggregate stability following structure liming. Methods Increasing application rates of 0–16 t ha−1 of structure lime (SL0, SL4, SL8 and SL16) were tested in 30 field trials in Sweden. Soil aggregates (2–5 mm) were collected 1 year after liming and subjected to two rainfall events in a rain simulator. Key results Leachate turbidity after the second simulated rainfall event decreased significantly (13% and 20%, respectively, in SL8 and SL16) compared with SL0, indicating improved aggregate stability. There was a near-significant interaction (P = 0.056) between treatment and trial. Grouping...
Surface soil acidity and fertility in the central-western wheatbelt of New South Wales
Australian Journal of Experimental Agriculture, 2007
Documentation of the chemical fertility status of the soils is sparse for the western and central-western wheatbelt of New South Wales, Australia. We examined properties of the surface soils (0-10 cm) from central-western NSW by collating two published and nine unpublished datasets of soil analyses representing about 2800 soil samples. The emphasis was on the red soils used extensively for cropping. The surface soils of central-western NSW have low phosphorus (47% of soils) and sulfur (70% of soils <5 mg S/kg using KCl-40 analysis) status and commonly have organic carbon of about 1%. Surface soil acidity was a substantial problem with 56% of soils (0-10 cm) having a pH Ca <5.0. Sodic and dispersive soils are also of concern in this area and these soils have received little attention or research. Approximately 5% of surface (0-10 cm) soils had an exchangeable sodium percentage of ≥6% (sodic). Salinity of surface soils was of minor significance compared with other soil problems in the area, although isolated areas occur. These results indicated that lime applications in this area are likely to benefit crop and pasture production. Additional use of phosphorus and sulfur fertilisers and agricultural practices which increase or maintain organic carbon will also need to be adopted to improve pasture and crop production. The use of gypsum and/or lime on sodic soils may also need to be addressed. As a priority, we suggest the benefits of lime application to crop yield be examined. The application of lime to the 0-10 cm soil should ultimately arrest acidification of the subsurface soil (10-20 cm depth) through downward movement of the lime effect. Further examination of gypsum applications to dispersive sodic soils and the evaluation of sulfur deficiency in the field for pastures and canola are also priority areas of likely agricultural relevance.