Gypsum Application Research Articles

Photosynthetic Pigments, Symbiotic Traits, Yield Attributes and Nutrient Uptake of Soybean Crop as Influenced by Soil Amendments on Degraded Vertisol of Chambal Tablelands

Background: Gypsum and organic amendments are potential ameliorants for reclamation of saline and/or sodic soil conditions to improve crop productivity and soil fertility. Application of gypsum at higher dose ( greater than 1 t ha-1) with organic amendments such as FYM, crop residue on soybean crop is largely unknown for salt affected soils. Impact of these soil amendments on soybean chlorophyll pigments, symbiotic traits, nutrient uptake, nutrient harvest index, carbohydrate equivalent yield, crop productivity and economic returns is not being addressed properly. This is particularly true for oilseed crop grown under saline conditions. Methods: A field experiment was conducted for two years (2017 and 2018) to assess the impact of amendments like gypsum, crop residue (CR), farm yard manure (FYM) with recommended dose of nitrogen-phosphorus-potassium (RNPK) fertilizer dose on soybean crop in degraded vertisol with eight treatments and three replications laid in randomized block design. Result: Results revealed that among treatments, phenological traits such as total chlorophyll (1.561 and 1.593mg g-1), carotenoid (0.156 and 0.154 mg g-1) at 30DAS (days after sowing), nodulation traits (33.6 and 32.4 nodules plant-1) and dry matter accumulation (26.2 and 23.9 g plant-1 at harvest) improved significantly in RNPK+Gypsum+CR+FYM and RNPK+Gypsum+FYM treatments respectively. Combined application of fertilizers with organic and gypsum amendments increased soybean yield by the magnitude of 49-53% compared to only fertilizer applied treatments. Higher biological yield (4169-4339 kg ha-1), carbohydrate equivalent yield (258.8-266.5 kg ha-1) and nutrient uptake (118: 8:47:11 -140: 9: 57: 12 kg ha-1N:P:K:S) were observed in RNPK+Gypsum+CR±FYM treatments. Economic analysis showed higher net returns and benefit-cost ratio in RNPK+Gypsum+CR (Rs 15247 and 1.48) and RNPK+Gypsum (Rs 14499 and 1.59) treatments.

Lead and Zinc Uptake and Toxicity in Maize and Their Management

Soil contamination with heavy metals is a global problem, and these metals can reach the food chain through uptake by plants, endangering human health. Among the metal pollutants in soils, zinc (Zn) and lead (Pb) are common co-pollutants from anthropogenic activities. Thus, we sought to define the accumulation of Zn and Pb in agricultural soils and maize. Concentrations of Pb in agricultural soil (in Namibia) could reach 3015 mg/Kg, whereas concentrations of Zn in soil (in China) could reach 1140 mg/Kg. In addition, the maximum concentrations of Zn and Pb were 27,870 and 2020 mg/Kg in maize roots and 4180 and 6320 mg/Kg in shoots, respectively. Recent studies have shown that soil properties (such as organic matter content, pH, cation exchange capacity (CEC), texture, and clay content) can play important roles in the bioavailability of Zn and Pb. We also investigated some of the genes and proteins involved in the uptake and transport of Zn and Pb by maize. Among several amendment methods to reduce the bioavailability of Zn and Pb in soils, the use of biochar, bioremediation, and the application of gypsum and lime have been widely reported as effective methods for reducing the accumulation of metals in soils and plants.

New Methodologies for the Surface Application of Limestone and Gypsum in Different Crop Systems

To address the problems of soil acidity (pH values below 4.4) in surface and subsurface soil layers and improve soil chemical fertility, this study evaluated three methodologies for surface application of limestone (LS) (ensuring that calcium (Ca)2+ occupied 70%, 60% or 50% of cation exchange capacity (CEC) at a depth of 0.0–0.2 m) and gypsum (GP, phosphogypsum) (ensuring that Ca2+ occupied 60%, 50% or 40% of effective cation exchange capacity (ECEC) at a depth of 0.2–0.4 m). LS and GP were applied in a conventional pasture system (CPS), no-till system (NTS), and agropastoral system (APS) in an Arenic Hapludult in Brazil. Surface application of LS and GP using these three methodologies corrected surface and subsurface acidity and improved soil chemical fertility. Specifically, Ca2+ content increased in the CPS, NTS, and APS at a depth of 0.0–0.2 m and in the CPS and APS at a depth of 0.2–0.4 m; sulfur (S)-SO42− content and Ca2+/ECEC increased in the CPS, NTS, and APS at a depth of 0.2–0.4 m; base saturation (BS) increased and aluminum (Al)3+ content decreased in the NTS and APS at depths of 0.0–0.2 m and 0.2–0.4 m; and pH, magnesium (Mg)2+ content, CEC, Ca2+/CEC, and Mg2+/CEC increased and total acidity decreased in the NTS and APS at a depth of 0.0–0.2 m.

Combined Application of Organic Amendments and Gypsum to Reclaim Saline–Alkali Soil

Saline–alkali soils have high sodicity, high pH, and high levels of soluble salts, as well as carbonates. This study aimed to evaluate the effect of cattle manure and chicken manure combined with gypsum at three levels on reclaiming a saline–alkali soil, through a soil column experiment. Combined treatments were more effective than those of sole gypsum in reducing the initial exchangeable sodium percentage (ESP) below 5%. Electrical conductivity (ECe) was lowered below 1.6 dS m−1 by all treatments, except the control. The higher effectiveness of manures combined with gypsum can be explained by their synergistic effect on Na+ displacement and subsequent soil structure improvement, leading to an enhancement in the leaching process, and then the salinity/sodicity reduction. Soluble salts and Na+ were considerably reduced in all treatments at the first leaching. Soil ESP and ECe threshold values from the US Salinity Lab classification were reached by any treatment, except the control. The addition of cattle manure or chicken manure might enhance the reclamation effect of gypsum with leaching for some saline–alkali soils.

Effect of Mulching and Gypsum Fertilizer Application on the Yield of Maize in Salinity Affected Area of Noakhali District, Bangladesh

An experiment was conducted at a salinity affected area in Hatiya, Noakhali to investigate the effect of mulching and gypsum fertilizer application on the yield of maize during December 2017 to May 2018. In this experiment two maize varieties, namely BARI hybrid bhutta-9 (V1) and NK-40 (V2) were used as planting material. Two mulching treatments, namely no mulching (M0) and mulching with water hyacinth (M1); and four gypsum levels namely 0 (G0), 50 (G1), 100 (G2) and 150 (G3) kg ha-1 were imposed. NK-40 variety showed higher number of grain lines cob-1 (13.34), number of grains line-1 (35.14), 100-grain weight (32.03 g) and grain yield (7.59 t ha-1) compared to BARI hybrid bhutta-9. Mulching with water hyacinth produced higher 100-grain weight (32.09 g) and grain yield (7.59 t ha-1) as compared to no mulching irrespective of variety. In case of gypsum, the highest grain yield (8.06 t ha-1) was obtained from 150 kg gypsum ha-1. For the interactions among varieties, mulching and gypsum fertilizer levels, the highest number of grains line-1, 100-grain weight and grain yield were 38.02, 34.33 g and 8.96 t ha-1 for V2M1G2 (NK-40, water hyacinth and 100 kg gypsum ha-1) treatment combination. The results revealed that mulching with water hyacinth alone increased 10.64% grain yield as compared to no mulching and application of gypsum fertilizer @ 150 kg ha-1 increased 33.66% grain yield compared to no gypsum application at salinity level (8.21 dSm-1). In case of the interactions among varieties, gypsum levels and mulching, grain yield increased by 65.61% in the variety NK-40 when cultivated with mulched conditions along with the application of gypsum fertilizer @ 100 kg ha-1 at salinity level (8.21 dSm-1). Therefore, it may be concluded that the yield of maize in the saline area of Noakhali, Bangladesh can be increased by adopting mulching technique and gypsum fertilizer application.

Synergizing Microbial Enriched Municipal Solid Waste Compost and Mineral Gypsum for Optimizing Rice-Wheat Productivity in Sodic Soils

Municipal solid waste management and poor fertility status of sodic soils are two important issues experienced by all developing nations including India. Disposal of municipal solid waste (MSW) being produced in huge amounts is a challenging task for researchers and policy makers. Reclamation of salt affected soils with chemical amendments is a costly affair for resource-poor farmers. Composting of MSW and its enrichment with microbes is one of the options for its recycling and utilization for the reclamation of salt-affected soils. A field experiment was conducted in sodic soil to study the performance of microbial enriched municipal solid waste compost (EMSWC) alone and in combination with a reduced dose of gypsum on growth, yield, nutrient uptake, and grain quality of rice and wheat. The experiment was conducted for three consecutive years from 2018 to 2019 and 2020 to 2021 at ICAR Central Soil Salinity Research Institute, Research farm, Shivri, Lucknow, India, in sodic soil having pH 9.2, electrical conductivity (EC) 1.14 dSm−1, exchangeable sodium percentage (ESP) 48, and organic carbon 0.30%. There were six treatments consisting of control, recommended dose of gypsum (50% GR), and enriched and un-enriched MSW compost with reduced dose of gypsum (25% GR). Based on the results pertaining to plant growth, yield-attributing characters, and yields, the treatment T6 (application of microbial enriched MSW compost @ 10 t ha−1 in conjunction with gypsum @25% GR) performed the best. Grain yield of rice and wheat (5.45 and 3.92 t ha−1) with treatment T6 was 29.45% and 110.75% higher over control (T1) and 29.45% and 110.06% over the recommended dose of gypsum (T2). Maximum nutrient content and N, P, and K uptake in rice-wheat grain and straw was observed with the treatment T6 (MSW compost plus gypsum @ 25 GR). However, the highest Na content and Na: K ratio in plant parts were recorded in treatment T2. The highest positive net return and benefit to cost (B/C) ratio were observed in treatment T6 followed by T5 and the lowest in treatment T1 (control), whereas negative return was calculated in treatment of gypsum alone (T2). This shows that the cost of sodic soil reclamation with application of gypsum was not recovered until the second year of cultivation. The results of this study showed significant impacts in MSW management for regaining the productivity potential of sodic soils.

Effect of Application of Gypsum and Farmyard Manure on Rice (Oryza sativa L.) Nitrogen Use Efficiency under Saline sodic soil at Amibara, Ethiopia

Effect of Application of Gypsum and Farmyard Manure on Rice (Oryza sativa L.) Nitrogen Use Efficiency under Saline sodic soil at Amibara, Ethiopia

Effect of Farm Yard Manure and Gypsum on Yield of Sorghum and Soil Properties in Saline Sodic Soils of Raya Alamata District, Northern Ethiopia

A field experiment was conducted in Raya Alamata district, northern Ethiopia to investigate the effect of sole and combined application of FYM and gypsum on saline sodic soils on yield of sorghum by supplying different rates of farmyard manure (FYM) and/or gypsum (CaSO4.2H2O) application alone or both mixtures using a randomized complete block design for three consecutive years. The treatment used included: control, three FYM rates alone, two gypsum rates alone and six combination of FYM and gypsum with a total of 12 treatments. Each treatment was replicated three times to yield 36 experimental plots. The result indicated that, there was no significant difference between treatments in the first and second year of cropping season. However, the effect the amendments were shown in the third year of the cropping season, and hence, the treatment effect of the combined application of FYM and gypsum were more effective and improved soil properties and increased the yield of sorghum. In addition, compared to all other treatments, the combined application of 4 tha -1 FYM + 100% GR followed by 8 tha -1 FYM + 100% GR resulted the highest grain yield of sorghum and reduced the sodium induced hazards than all other treatments. Hence, it is recommended as the best treatment in the improvement of saline sodic soils of the district. Keywords: Gypsum; Farmyard manure; Sorghum; Soil amendment; Soil properties DOI: 10.7176/JNSR/13-11-01 Publication date: June 30 th 2022

Вплив диференціювання доз хімічного меліоранту на показники галогенезу темно-каштанового солонцюватого ґрунту

Goal. To establish the patterns of influence of different doses of gypsum on salt and physicochemical parameters of dark-chestnut weakly alkaline soil (pH, content of water-soluble salts, and absorbed cations) and the degree of their heterogeneity. Methods. Field — to study the effect of gypsum on the properties of dark-chestnut soil, laboratory analytical — to determine salt and physicochemical parameters, mathematical and statistical — to assess the reliability of research results. Results. The application of calcium ameliorant (gypsum) caused a decrease in the reaction of the soil solution by 0.5 – 0.7 pH units, as well as desalination of the soil in absolute and relative alkalinity. There were no changes in the content of toxic salts in the soil. The variegation of the soil in terms of water pH tended to decrease and was weak before and after the experiment. Gypsum reduced the degree of heterogeneity of both alkalinity indicators to weak (reduction of coefficients of variation from 12.01 to 7.29% and from 11.97 to 6.94%), but the differentiation of gypsum application doses did not help to equalize the alkalinity of dark-chestnut soil compared to the variants, where the improver was applied evenly. Conclusions. The soil in the variants with average maximum and differentiated levels of gypsum application passed into the category of non-alkaline. According to the effect of desalination, the options with average and differentiated levels of gypsum application were almost the same. However, the average dose of gypsum in the variant with a differentiated level of application was 0.86 t/ha less. The alkalinity indicators in the variants with the minimum and maximum levels of gypsum application were most equalized. Differentiation of gypsum application doses in comparison with variants of its uniform application did not affect the degree of heterogeneity of alkalinity indicators of dark-chestnut soil.

Gypsum amendment influences performance and mineral absorption in wheat cultivars grown in normal and saline‐sodic soils

AbstractIn arid and semi‐arid regions, soil salinity and sodicity are the most common constraints to agriculture production, in particular in North Africa. The effect of gypsum application has been widely studied in saline‐sodic soils. However, the gypsum amendment's influence on the performance, productivity and mineral absorption of salt‐sensitive and tolerant wheat cultivars in both saline‐sodic and normal soils under field conditions has not yet been investigated. A two‐season (2016–17 and 2017–18) field experiment was undertaken to investigate the impact of gypsum on wheat growth, yield and minerals uptake for salt‐tolerant and sensitive cultivars grown in normal (EC = 1.3 dS m−1, pH = 8.4 and ESP = 7.1–8.0%) and saline‐sodic soils (EC = 5.8–6.2 dS m−1, pH = 8.8 and ESP = 19.3–22.4%) in the western Nile delta, Egypt. The gypsum requirement was applied to decrease the initial ESP from 19.3–22.4 to 10.0% was calculated for 0.3 m soil depth. Gypsum application (6.0 and 4.7 ton ha1, for the first and second season, respectively) reduced soil pH, EC and ESP of saline‐sodic soil by 31.6, 7.3 and 39.0%, respectively (two‐season mean). Furthermore, gypsum application increased Ca2+, Mg2+ and K+ in the flag leaf by 54.7, 24.5 and 45.7%, respectively (2‐season mean) under saline‐sodic soil. While, in the normal soil, gypsum application increased Ca2+, Mg2+ and K+ by 67.3, 32.7 and 78.7%, respectively. In contrast, gypsum applications decreased Na+ and Cl− content by 17.2 and 15.0% and by 40.0 and 35.5%, respectively, in the saline‐sodic and normal soil, respectively. Under saline‐sodic and normal soils, gypsum application significantly increased the K/Na ratio by 90.0 and 175.2%, respectively (2‐season mean). Interestingly, across cultivars, gypsum amendment increased grain yield by 20.7% (6.9 to 8.3 t ha−1) for normal soil and by 8.0% (5.8 to 6.3 t ha−1) for saline‐sodic soil. The positive impact of gypsum was more pronounced under the normal soil and for the salt‐sensitive cultivars than in saline‐sodic soil and for salt‐tolerant cultivars. Growers can cultivate salt‐tolerant cultivars and use gypsum as a precaution to reduce saline‐sodicity build‐up and to increase nutrient absorption.

Experimental Study and Mechanism Analysis of Preparation of α-Calcium Sulfate Hemihydrate from FGD Gypsum with Dynamic Method.

Flue-gas desulphurization (FGD) gypsum is a highly prevalent industrial by-product worldwide, which can be an excellent alternative to natural gypsum due to its high content of CaSO4·2H2O. The preparation of α-calcium sulfate hemihydrate is a high-value pathway for the efficient use of FGD gypsum. Here, a dynamic method, or an improved autoclaved process, was used to produce α-calcium sulfate hemihydrate from FGD gypsum. In this process, the attachment water of the mixture of FGD gypsum and crystal modifiers was approximately 18%, and the pH value was approximately 6.0. The mixture did not need to be pressed into bricks or made into slurry, and it was directly sent into the autoclave reactor for reaction. It was successfully applied to the practical production and application of FGD gypsum, citric acid gypsum and phosphogypsum. In this work, the compositions and morphology of the product at different stages of the reaction were examined and compared. In particular, single-crystal diffraction was used to produce the crystal structure of CaSO4·0.5H2O, and the results were as follows: a = 13.550(3); b = 13.855(3); c = 12.658(3); β = 117.79(3)°; space group C2. The preferential growth along the c-axis and the interaction mechanism between the carboxylate groups and the crystal were discussed throughout the analysis of the crystal structure.

Soil acidity amelioration improves N and C cycles in the short term in a system with soybean followed by maize-guinea grass intercropping

Lime application has been associated with N and C losses from agricultural systems through NO3– leaching, N2O and CO2 emissions. However, we hypothesized that in an intensive crop system where soybean is grown in rotation with maize intercropped with a forage grass, liming associated with the application of gypsum to ameliorate the subsoil, and N fertilization increase soil N and C by improving root and crop growth. To evaluate the interaction of lime, gypsum and N fertilizer on soil and N and C partial balances, an experiment was carried out under no-till, where soybean was grown in rotation with maize intercropped with Guinea grass (Megathyrsus maximus cv Tanzânia) as relay crop. Lime and gypsum were applied before soybean planting in October 2016 and October 2017. Two N rates (0 and 160 kg ha−1 yr−1 of N as ammonium sulphate) were applied to maize annually. Outputs through N-NO3– leaching, N-N2O emission and N-NH3 volatilization did not exceed 30 kg ha−1 of N in two years. The N exported in grains consisted in 96% of the N output and was greater with fertilizer and lime. Soil acidity amelioration and N-fertilization favoured soil C fixation with high plant biomass production (C in plant residue, roots, and grains), while soil C-CO2 emission was not affected, and soil C increased. Although the partial N balance was negative, there was an increase in soil N, probably due to biological N fixation by soybean, which was not considered in the partial balance. We concluded that lime and gypsum application, along with an adequate N fertilization, to a tropical highly-weathered soil with soybean cropped in rotation with maize-guinea grass intercropping benefit N and C cycles and the environment in the short-term, increasing soil N and C stocks and reducing GHG emitted to the atmosphere.

Soil Attributes and Productivity of Sorghum as a Function of Gypsum and Potassium Doses

ABSTRACT This study aimed to evaluate the influence of gypsum application in association with potassium doses in the cerrado soil chemical attributes and sorghum grain yield. The experiment was conducted in a Latosol of a Cerrado biome in a 5 × 5 factorial scheme, being five doses of gypsum (0, 500, 1,000, 2,000, 4,000 kg ha−1) and five doses of potassium (0, 100, 180, 240, 360 kg ha−1 of potassium dioxide – K2O) as potassium chloride in a complete block design, with four replications. Sorghum yield and soil chemical modifications after crop cultivation in the 0–0.2 and 0.2–0.4 m layers were evaluated. Sorghum yield was not influenced by the factors assessed. The highest dose of gypsum increased the concentration of calcium and sulfur and raised the sum of bases and base saturation in both soil layers evaluated. In the 0.2–0.4 m layer, the highest dose of gypsum increased the availability of phosphorus and sulfur by 32.5% and 681%, respectively. The gypsum shifted the K+ from the 0–0.2 to the 0.2–0.4 m soil layer, demonstrating the importance of performing combined gypsum and potassium chloride applications in soils with low potassium (K) content in order to avoid the K+ depletion in the superficial soil layer of cerrado.

Soil acidity and soy phytometry under application of limestone and agricultural gypsum

The soybean is one of the main agricultural crops in Brazil, because the use of its grains is an important source of protein and vegetable oil. One of the main limiting factors for obtaining high yields in soybean in tropical soils is related to the need to correct soil acidity. The objective of this study was to evaluate the growth of (Glycine max (L.) Merrill) and the variation of soil pH values under the application of limestone and agricultural gypsum. The experimental design was completely randomized, distributed in a 4x4 factorial scheme. The treatments consisted of doses of 0, 1.5, 3.0 and 4.5 t ha-1 of only limestone, only gypsum and the combination of limestone and gypsum, repeated four times, totaling 64 experimental units. The soil pH was evaluated at 30, 45, 60, 75 days before sowing. The growth variables were: number of pods, shoot dry mass, root dry mass, root length and shoot/root ratio. The variables pH 75 days, root length and shoot/root ratio were significantly influenced by the treatments, alone or in interaction. For pH 30, pH 45 and pH 60 days, number of pods and shoot dry mass, there were isolated effects of treatments for gypsum and limestone. In root dry mass, the effect of the treatment was verified only with the use of limestone. As a conclusion, the application of limestone and gypsum reduces the soil acidity, obtaining higher pH values from the doses of 3000 kg ha-1, with the combination of limestone and gypsum. The use of gypsum consortium with limestone promotes significant results in the growth of soybean plants.

Biomeliorant for the restoration of saline and degraded soils in the arid zone

The methods of gypsum application in degraded soils to increase and restore saline and degraded soils, to grow vegetables and fruits in the arid zone are considered in the paper. The issues of soil alkalinity reduction to increase soil fertility with the use of a new biomeliorant at standard of ST RK 2208-2012 containing phosphogypsum, calcium, sulfur and cattle manure with the addition of crushed camel thorn were studied. According to calculations this meliorant application reduces the loss of nitrogen and organic matter by 40%,, which being a highly effective fertilizer that improves the physico-chemical and biological properties of the soil, which contributes to an increase in crop yields. Field studies have shown that the joint anaerobic fermentation of phosphogypsum and manure, camel thorn led to intensive aggregation and the creation of favorable conditions of the soil structure for the crops. The results showed that the biomeliorant application into the soil led to a noticeable improvement in its structure, increases alkalinity, soils become more fertile and crop yields increase.

Soil OC and N Stocks in the Saline Soil of Tunisian Gataaya Oasis Eight Years after Application of Manure and Compost

Soil organic matter plays an important role in improving soil properties, crop productivity and is a key constituent and driver of the global carbon cycle. Nevertheless, relatively limited quantitative information is available on the organic carbon (OC) stocks and the actual potentials for OC and total nitrogen (N) sequestration under arid cropping systems. In this study, we evaluated the immediate and long-term (after eight years) effects of compost or manure additions, at a rate of 100 t ha−1, on the soil OC and N stocks in the Gataaya oasis in Southern Tunisia. The oasis had been abandoned and no additions had taken place in the 10 years prior to experiment. Soil samples were taken systematically every 10 cm up to a depth of 50 cm. After adding compost (CMP) and manure (MAN) in 2013, the bulk density (BD) decreased in the surface layers, especially at the 0–10 cm soil layer where it declined from 1.53 g cm−3 to 1.38 g cm−3 under compost and 1.41 g cm−3 under manure. Soil OC and N stocks, however, increased after adding compost and manure. Manure contributed more to OC stock increase than compost, with +337 and +241%, respectively. Correspondingly, the N stock increased by + 47 and +12%, respectively, due to manure and compost. After four years, compared to 2013 stocks, the decrease in OC stock was almost identical with −43 (CMP) and −41% (MAN). However, N stock seemed more stable under compost compared to manure, with −2 and −19%, respectively. After eight years, the N stock remained higher in the deepest layer 30–50 cm compared to other layers. This suggested that high gypsum application can inhibit N mineralization. The initial enhanced OC stock after the organic amendment, both for compost and for manure, was very quickly lost and after eight years had virtually returned to the initial OC state by the end of the eight years. Therefore, these oasis ecosystems require a near annual supply of exogenous organic material to maintain OC at an enhanced level. After eight years, manure amendment was found to be better than compost for increasing soil OC (3.16 against 1.86 t/ha, respectively) and for increasing N (0.35 against 0.18 t/ha, respectively). However, the cost and availability make the amendment with compost more interesting in oasis (400 Tunisian dinars/t for compost against 1016 Tunisian dinars/t for manure).

The short-term effects of surface-applied dolomitic lime and gypsum on soil chemical properties and yields of sugarcane ratoon crops in KwaZulu-Natal, South Africa

This study investigated the effects of surface-application of lime and gypsum on soil properties and yields of ratoon sugarcane crops. Treatments involved once-off surface application of dolomitic lime (L), gypsum (G) and dolomitic lime plus gypsum (LG) in factorial combination, with four replications. Soil chemical properties were measured on samples collected at intervals of 20 between depths of 0 and 80 cm in the first and fifth years after treatment application. Yield parameters were measured annually. In the first year, treatment effects were mainly restricted to a depth of 0–20 cm. The LG increased pH(CaCl2) from 3.9 to 4.5, and calcium from 123 to 350 mg L−1. Little treatment effect was observed on yield parameters in the first year. In the fifth year, L and LG generally showed similar impacts on soil properties. The L treatment led to markedly increased pH(CaCl2) and calcium and somewhat decreased magnesium levels in the topsoil. The sucrose and cane yields in LG were significantly higher than in other treatments, which all had similar results. It was, therefore, concluded that LG may be a viable option for the correction of soil acidity through surface application in the sugarcane ratoon crops grown in the sandy soils of KwaZulu-Natal.

Uptake and timing of calcium in runner peanut (Arachis hypogaea L.)

Peanut production in the southeastern United States is often limited due to low Ca availability. Gypsum and lime are common Ca supplements for peanut, but the indeterminate nature of peanut and variable solubility of these products adds uncertainty to timing of Ca amendments. Two sets of field trials were performed in southern Alabama from 2012 to 2014 under both irrigated and non-irrigated conditions using two runner-type peanut cultivars (Georgia-06G and Georgia Greener) to determine Ca uptake patterns and timing of amendments. Calcium uptake was evaluated by pod development stage with four soil Ca treatments: 560 and 1120 kg ha −1 gypsum applied at early bloom, 1120 kg ha −1 lime at planting, and an untreated control. Developmental stages were determined by the hull scrape method. The timing of gypsum and lime was evaluated using metrics of peanut yield, grade, germination, and seed Ca. Treatments included a single application of gypsum at planting and early bloom, split applications of gypsum at planting/early bloom and early/mid-bloom, lime at planting, lime at planting plus gypsum at early bloom, and an untreated control. Results suggested that peanut absorbed Ca throughout the entire growing season and that seed Ca concentration could be used as an indicator of early-season seed quality. Split applications of gypsum at early/mid-bloom tended to have a superior performance than a single application at planting or early bloom and split applications at planting/early bloom. Supplemental gypsum at early bloom combined with lime at planting further increased Ca availability under non-irrigated conditions relative to the lime-only treatment. This study provided helpful information for Ca nutrient management for peanut.

Gypsum application lowers cadmium uptake in cacao in soils with high cation exchange capacity only: A soil chemical analysis

AbstractSoil liming to lower cadmium (Cd) bioavailability is challenged in perennial cacao orchards by the low penetration of lime in soils, not reaching deeper roots. Some studies suggest that gypsum (CaSO4) could reduce Cd uptake by enhanced Ca2+:Cd2+ competition at the root surface. A pot experiment was conducted to identify soil conditions affecting gypsum efficacy in cacao plantlets (5‐month‐old CCN‐51). Plants grew for 115 days in soils sampled from six locations with variable cation exchange capacity (CEC, 6–50 cmolc.kg−1) and soil solution Ca2+ (1.3–17 mM). Soils were either mixed or not mixed with a dose equivalent to 4.0 Mg gypsum ha−1. Leaf Cd concentration in plants grown on gypsum applied soils was statistically lower compared to unamended soils in only one of the six soils. The reduction factor of leaf Cd concentrations due to gypsum (RF = control/amended Cd concentration ratio) ranged from 2.32 (high effect) to 0.76 (no effect), and it was positively correlated with the Ca2+ in the solution of the unamended soil (R2 = 0.58) and with increasing CEC (R2 = 0.52), that is, gypsum only reduced Cd bioavailability in high CEC soils, confirming a trend found in earlier publications. Soil solution analyses showed that gypsum application enhanced total dissolved Cd by forming CdSO40 complexes with, in some cases, even enhanced Cd2+ ion activities, likely related to Ca2+‐induced Cd2+ mobilisation. Data suggest that Ca2+ derived from gypsum has counteracting effects on Cd mobilisation and ion competition at the root surface. The former reactions are less pronounced in high CEC soils. More research is needed to unravel gypsum effects on high Ca2+ soils to corroborate our findings.Highlights The effect of soil properties on the efficacy of gypsum to reduce Cd uptake in cacao was studied. Gypsum only reduced Cd uptake in cacao in the soil sample with highest CEC and highest Ca in solution. This finding implies a possible competition between Ca2+ and Cd2+ for root uptake in cacao.

Impact of Flue Gas Desulfurization Gypsum Applications to Corn-Soybean Plots on Surface Runoff Water Quality

Impact of Flue Gas Desulfurization Gypsum Applications to Corn-Soybean Plots on Surface Runoff Water Quality