Sulfate Soils Research Articles

Effect of sulfur fertilization on the composition, functionality, and protein quality of navy beans (Phaseolus vulgaris)

AbstractBackgroundSoil sulfur deficiency leads to reduced crop yield and quality loss, which is especially critical for pulses as sulfur is a major component of methionine and cysteine. The present research evaluated the influence of sulfur fertilization on two varieties of navy beans grown at soil sulfur levels of 17, 26, 35, and 44 kg/ha by analyzing their composition, functionality, and protein quality.ResultsIncreasing the soil application of sulfur did not affect the protein content of the test navy bean flours. Methionine, cysteine, and tryptophan were limiting, and their concentrations were not enhanced by sulfur fertilization nor was protein digestibility. The oil holding capacity and emulsion stability were different among sulfur treatments; however, no clear trend was observed.ConclusionSulfur fertilization had only a minimal effect on the quality attributes of navy beans, possibly due to a combined effect of environmental factors that limited the plant's response to sulfur supply. Despite the limited change, the findings underlined the possible role of the environment (e.g., location, crop year, and other variables) in determining the sulfur fertilization response of navy beans and provided valuable insight for researchers to further investigate the topic and optimize navy bean production and quality.

Changes in sulfur in soybean rhizosphere soil and the response of microbial flora in a continuous cropping system mediated by Funneliformis mosseae.

Soybean is an S-loving crop, and continuous cropping might cause soil sulfur shortage. The primary objectives of this study are to determine whether Funneliformis mosseae (F. mosseae) can enhance the content of available S in S-deficient soil and thereby improve the sulfur utilization rate in soybean. The experiment used Heinong 48 (HN48), a soybean variety with a vast planting area in Heilongjiang Province, and F. mosseae was inoculated in the soil of soybean that had been continuously cropped for 0 and 3 years. The results of the barium sulfur turbidimetric assay show that the sulfur content in the soil and soybean was reduced by continuous cropping and increased by inoculation with F. mosseae; the results of the macro-genome sequencing technology, show that the diversity and abundance of bacteria in the soil was decreased by continuous cropping and increased by inoculation with F. mosseae. The sulfur-oxidizing bacteria (SOB) activity and sulfur-related gene expression levels were lower in the continuous crop group compared to the control group and higher in the F.mosseae-inoculated group compared to the control group. Continuous cropping reduced the sulfur content and ratio of soybean rhizosphere soil, affecting soil flora activity and thus soybean growth; F. mosseae inoculation increased the sulfur content of soybean root-perimeter soil and plants, increased the diversity and abundance of rhizosphere soil microorganisms, increased the expression of genes for sulfur transport systems, sulfur metabolism, and other metabolic functions related to elemental sulfur, and increased the species abundance and metabolic vigor of most SOB. In summary, continuous cropping inhibits soil sulfur uptake and utilization in soybean while the inoculation with F. mosseae can significantly improve this situation. This study offers a theoretical research foundation for using AMF as a bio-fungal agent to enhance soil sulfur use. It also supports the decrease of chemical fertilizers, their substitution, and the protection of native soil.

Management of plant nutrient dynamics under alkaline soils through graded application of pressmud and gypsum.

An incubation experiment was conducted to monitor the effect of different organic matter inputs with the graded application of gypsum at different time intervals on soil pH, sodium (Na) content and available plant nutrients like nitrogen (N) and sulphur (S) in alkaline soil. The experiment was formulated with nine treatments, i.e. control (T1), recommended dose of fertilizer (RDF) (T2), RDF+Gyp1 (T3), RDF+FYM5+Gyp2 (T4), RDF+FYM10+Gyp1 (T5), RDF+PM5+Gyp2 (T6), RDF+PM10+Gyp1 (T7), RDF+FYM2.5+PM2.5+Gyp2 (T8), RDF+FYM5+PM5+Gyp1 (T9) with three replications. Periodical soil samples were taken at six and twelve months intervals. Results showed that the addition of organic matter reduced the pH and Na content in the soil. More reduction was observed at one year period as compared to six months. The addition of farmyard manure (FYM) and pressmud (PM) at 10 t/ha with gypsum (1 t/ha) improved available N and available S content as compared to organic inputs (5 t/ha) with gypsum (2 t/ha) in soil. Pressmud application with FYM showed better availability of plant nutrients and a reduction of soil pH (8.39 to 7.79) and Na content from 626 to 391 mEq/L in the soil during the incubation period. During the study, the application of treatment T9 (FYM and PM in equal ratio with 1 t/ha gypsum) showed a better availability of available N (175 to 235 kg/ha) and S (15.44 to 23.24 kg/ha) and reduced the active ion concentration of Na. This study is very useful for the management of sodium toxicity, improving soil health and the mineralization rate of organic matter through the application of organic inputs for sustainable crop production.

Sulfur Leaching Rate Differs Based on Soil Characteristics in the Vidalia Region of Georgia, USA: Implications for Sweet Onion Production

ABSTRACT Onion flavors arise from the enzymatically produced volatile sulfur-containing sulfinic acids created when onion cells rupture. The concentrations of these flavor-associated compounds depend on genetic and environmental factors, with soil sulfur (S) availability as a primary contributor. To understand how leaching influences S availability in soils of southeastern Georgia, a column leaching experiment was conducted over a 13-month period using soils from six historic Vidalia onion fields. Soil S in the A horizon ranged from 21–126 kg ha−1 and 126–261 kg ha−1 for plant available and total S, respectively, and 17–541 kg ha−1 for plant available S and 46–841 kg ha−1 of total S in the B horizon. Total S decreased 32% on average over the 13-month period, ranging from 10–65 kg ha−1. Unlike studies from other regions that determined that the overwhelming majority of soil S is organically bound, 16–64% of soil S in these soils was readily plant available, suggesting that in the sandy, low organic matter (OM) soils and thermic climate of southeastern Georgia, S retention is likely controlled by the combination of soil factors including, OM, amount and type of clay, and iron and aluminum content. While the amount of S decreased in all six soils, plant available S remained between 14–46 kg ha−1 in the A horizon, indicating it may take several seasons for soil S to appreciable decrease through leaching. Sweet onion producers like those in the Vidalia region should carefully monitor S additions to promote the production of low pungency onions.

Characterization and Assessment of Synthesized Nano Sulphur in Combination with Organic Amendment on the Availability of Sulphur in Calcareous Soil

Background: Sulphur is rapidly being recognized as fourth key nutrient for plants after nitrogen, phosphorus and potassium. It functions in several critical metabolic and physiological processes, such as Chlorophyll synthesis, Protein synthesis, Activation of enzymes, Stress tolerance and Seed production. This study was carried to investigate the effect of synthesized nano sulphur in combination with organic amendment to study available sulphur status in calcareous soil. Methods: Nano sulphur was synthesized using reverse microemulsion (water-in-oil microemulsion) technique and characterized at the Centre for Agricultural Nanotechnology, TNAU, Coimbatore. An incubation experiment was carried out with synthesized nano sulphur and gypsum as sulphur source with and without FYM to determine sulphur release at various intervals (7th,15th,30th,45th and 60th days after incubation). Result: It was observed that nano sulphur applied at 40 kg S ha-1 with FYM showed high release of sulphur in calcareous soil in all intervals analysed during the experiment. The addition of organic manures aids in proliferation of heterotrophic sulphur oxidising bacteria which enhances the sulphur oxidation in alkaline soil.

Soil Sulfur Deficiency Restricts Canola (Brassica napus) Productivity in Northwestern Russia Regardless of NPK Fertilization Level

Canola cultivation at high latitudes is becoming more promising in terms of modern climate change. Sustainable crop production requires an understanding of yield-limiting factors, which need to be adjusted in agricultural management first. Therefore, our study was aimed at examining the effect of climate and soil fertility factors on the canola yield from 2012 to 2015 in northwestern Russia. Simultaneously, effectiveness of chemical fertilizer (N65P50K50 and N100P75K75) rates was tested. Studied soils had light texture, high acidity and severe sulfur deficiency. Canola yield (Y) varied from 0.81 to 1.60 t·ha−1 for the observed period. Applied fertilizer increased Y by around 30%, but this change was not significant. Climate effect testing with the FAO-AquaCrop simulation showed no noticeable water and heat stresses for the study period (0% to 20% reduction in potential Y). Among the tested soil properties, the content of organic carbon, available nitrogen and sulfur significantly correlated with Y (r = 0.58–0.66). Combining these factors together with soil pH in a path model explained 60% of variability in Y. Importantly, sulfur had the highest and most significant effect in this model. Thus, this soil parameter is the main yield-limiting factor in the study area, which must be the first to be adjusted in agricultural practice.

Vertical and lateral movements of nitrate, phosphate and sulphate in soils around manure dumpsites and the potential environmental implications.

Monitoring and quantification of nutrient movement in soils could help farmers and policy makers to formulate effective nutrient loss reduction strategies and waste management. The study was conducted to monitor and quantify vertical and lateral movements of nitrate-nitrogen (NO3-N), phosphate (PO4) and sulphate-sulphur (SO4-S) in soils around manure dumpsites in Abeokuta, southwest Nigeria. The dumpsites investigated include a flush-type poultry litter, poultry litter mixed with beddings of wood shavings and cattle and pig waste open dumpsites. Soils were sampled at depths of 0-20, 20-40, 40-60 and 60-80cm and at distances 2, 4, 6, 8, 10, 20, 40, 60 and 80m away from the dumpsites. Soil samples were analysed for some physical and chemical properties and NO3-N, PO4 and SO4-S contents. Results indicated that there were more nutrients in the soil around the poultry manure slurry dumpsite compared with others while the soil pH increased with increase in soil depth, across dump sites. There was evidence of leaching of salts, and this correlated positively with the soil organic matter content (r = 0.41, p < 0.01). The soils were polluted with NO3-N, PO4 and SO4-S as deep as 80-cm depth; these nutrient amounts were higher than the maximum allowable (40, 15 and 7mgkg-1, respectively) for southwest Nigerian soils. Due to high soil organic matter and for agronomic considerations, the soils are only suitable for cultivation at depths below 40cm and 8m away from the dump sites. There was significant pollution of the soils with nitrate, phosphate and sulphate, within 80m distance from the dump site. This has serious implications for ground water recharges and shallow well sunk around these areas. There is potential risk of NO3-N, PO4 and SO4-S consumption through such water sources.

Changes in Soil Sulphur Fractions as Influenced by Nutrient Management Practices in Mulberry

Sulphur (S) plays a vital role in improving the quality of mulberry leaves because of its involvement in protein synthesis. The knowledge of different pools of S in soils and its bioavailability for mulberry nutrition is thus, required for optimizing S fertilization. Hence, the present study was designed to ascertain the influence of chemical fertilizer and farmyard manure (both are S sources) on S fractions and its bioavailability in soils. In this regard, four nutrient management practices viz., control (without any chemical fertilizers and organic manures), recommended doses of N, P and K fertilizers (100% RDF), 80% RDF, 60% RDF with four mulberry varieties viz., V-1, G-4, AGB-8 and MSG-2 besides a fallow were considered for the study. Furthermore, the bioavailability of S in soils was tested using four commonly used chemical extractants viz., CaCl2, NaHCO3, AB-DTPA and Mehlich-3 (with different modes and chemistry of extraction). Organic S was the dominant fraction in the experimental soils accounting for 94.7% of total soil S while the inorganic fraction constituted only 5.3% that includes water soluble, sorbed and carbonate occluded S. Lowest amount of organic S content in soils of unmanured control (579.6 mg kg−1) was observed while the 100% RDF treatment (673.2 mg kg−1) maintained a higher content of soil organic S. High amount of sorbed and occluded S was observed in control plot compared to other fertilizer treatments (100% RDF, 80% RDF and 60% RDF). There was a gradual decline in soil S fractions when the fertilizer inputs were reduced to 60% suggesting that recommended doses of fertilizer inputs could maintain the soil S fractions. In addition, the extractable fractions of S were influenced by the fertilizer application rates and the extractability of all four extractants decreased with the reduction in fertilizer inputs. The amount of S extracted by all four chemical extractants followed the order of NaHCO3 &gt; Mehlich-3 &gt; AB-DTPA &gt; CaCl2 across the tested soils. Dynamic relationships among the extractants indicated that they could extract the S from the same pools in soil. Of the four extractants tested for evaluating plant available S, Mehlich-3 showed a higher degree of correlations with plant tissue S concentration and applied S through chemical fertilizers and farmyard manure. Furthermore, it could maintain strong correlations with water soluble and organic S fractions which were found to contribute significantly to plant S concentration. Thus, Mehlich-3 can be recommended for the assessment of bioavailable S for the nutrition of mulberry.

Investigation of Solid–Liquid Phase Equilibria of Mg2+, NH4+//Cl–, SO42–H2O at T = 303.15 K and P = 88.35 kPa

Nitrogen and magnesium compound fertilizer is an important and efficient fertilizer in the fertilizer industry. It can solve the problem of lack of sulfur, magnesium, and nitrogen in soil. MgCl2 can react with (NH4)2SO4 to produce Mg–N compound fertilizer. Therefore, the solid–liquid equilibrium data and physical properties (density and viscosity) of the quaternary system Mg2+, NH4+//Cl–, SO42––H2O and its ternary subsystems Mg2+, NH4+//Cl––H2O and Mg2+//Cl–, SO42––H2O at T = 303.15 K ± 0.05 K and P = 88.35 kPa were studied by an isothermal stripping equilibrium method. According to the experimental data, the phase diagram and physical property composition diagram of each system were drawn. The ternary subsystem Mg2+, NH4+//Cl––H2O contains two invariant points and three crystallization regions. The ternary system Mg2+//Cl–, SO42––H2O contains four invariant points and five crystallization regions. The quaternary system Mg2+, NH4+//Cl–, SO42––H2O contains seven invariant points and nine crystallization regions. MgCl2·NH4Cl·6H2O and MgSO4·(NH4)2SO4·6H2O exist in the quaternary system, and the quality of crops can be significantly improved by using the latter kind of complex salt. Therefore, this project is of great significance for the production of N–Mg compound fertilizers from magnesium resources in salt lake or other underground brines.

Pod and Seed Production Potential of Vegetable Pea (Pisum sativum L.) as Influenced by Different Levels of Sulphur and Boron in Calcareous Soil of North Bihar

Background: Vegetable pea is one of the relevant vegetable crops grown in the cool season all over the India. Sulphur deficiency is becoming more prevalent in Bihar due to the less use of boron and sulphur-containing fertilizer in calcareous soils and the consequent decrease in sulphur and boron nutrients. On the other hand, organic matter-rich manures, are utilized in very small quantities which is a source of a macro-and micronutrients, including sulphur and boron. As a consequence, soils have become deficient in sulphur and boron, which is detrimental to crop production. In the absence of these sulphur and boron in the soil, different legume crops such as vegetable pea suffer from reduced growth, yield and nodule formation. Methods: In this field investigation during 2020-2022, experiments were conducted in Factorial Randomized Block Design using fifteen different combinations of Boron and Sulphur doses in Azad Pea-3 variety of vegetable pea in three replications and different pod and seed yield attributing traits were studied. Result: Among the different treatments, it has been inferred that treatment combination 40 kg S ha-1 + 2 kg B ha-1 exhibited superiority over rest of the treatment combinations with respect to pod and seed yield attributes of vegetable pea.

Changes in Soil Sulfate Sulfur Content as an Effect of Fertilizer Granules Containing Elemental Sulfur, Halloysite and Phosphate Rock

With a shortage of sulfur in the soil and an increasing world population and, thus, food consumption volume, the demand for this important nutrient is likely to increase, both globally and regionally. The purpose of this model incubation study was to evaluate the effect of fertilizer granule applications containing elemental sulfur, halloysite and phosphate rock on the content of the bioavailable form of sulfur and phosphorus, as well as dehydrogenase activity and pH value of two soils differing in granulometric composition and chemical parameters. In addition to the standard procedure of analysis of variance, the authors propose various methods of advanced statistical analysis: regression modeling, including simple regression and multiple regression, or multivariate methods of grouping objects and traits resulting in the creation of heatmaps. With respect to the control, the application of fertilizer granules generally had no significant effect on the content of available phosphorus and the activity of dehydrogenase, and had little effect on the degree of acidity of the soils tested. There was a greater effect of introducing fertilizer granules on the content of sulfate sulfur in heavy soil than in medium soil. Using advanced statistical techniques revealed relationships between the studied soil parameters and changes in their values as affected by the experimental factors.

STATUS AND FORMS OF SULPHUR IN SOILS OF WUDIL AND GAYA, KANO STATE, NIGERIA.

An investigation study was carried out to determine the status and forms of sulphur in soils of Wudil and Gaya, Kano state, Nigeria. Soils were collected using grid sampling method across two farming communities, Gaya and Wudil Local Government areas of Kano state. A total of 297 samples were collected at a depth of 0 - 30 cm. The samples were subjected to routine soil tests while the forms of sulphur were determined using turbidmetric method. Descriptive analysis was used for the interpretation of the data. The result obtained showed that soils from both locations were sandy loam with slightly acidic to neutral pH and low content of organic matter (0.38 and 0.24%) and nitrogen (0.06 and 0.04%). The sulphur level in both locations was sufficient. Differences in the concentration of the forms of sulphur were observed. Total sulphur had the highest amount of sulphur 498.30 mg kg-1, while non-sulphate sulphur had the least amount 0.74 mg kg-1. The low amounts of adsorbed and non-sulphate sulphur observed were attributed to the texture (sandy loam) and pH (6.24 and 6.99) of the soil. It can be concluded that the sulphur levels in both locations; Gaya and Wudil were high. Therefore, management strategies that will enable sulphur mineralization in the soil should be maintained by farmers to enhance availability of sulphate in the soil.

Mercury and Sulfur Redox Cycling Affect Methylmercury Levels in Rice Paddy Soils across a Contamination Gradient.

Methylmercury (MeHg) contamination in rice via paddy soils is an emerging global environmental issue. An understanding of mercury (Hg) transformation processes in paddy soils is urgently needed in order to control Hg contamination of human food and related health impacts. Sulfur (S)-regulated Hg transformation is one important process that controls Hg cycling in agricultural fields. In this study, Hg transformation processes, such as methylation, demethylation, oxidation, and reduction, and their responses to S input (sulfate and thiosulfate) in paddy soils with a Hg contamination gradient were elucidated simultaneously using a multi-compound-specific isotope labeling technique (200HgII, Me198Hg, and 202Hg0). In addition to HgII methylation and MeHg demethylation, this study revealed that microbially mediated reduction of HgII, methylation of Hg0, and oxidative demethylation-reduction of MeHg occurred under dark conditions; these processes served to transform Hg between different species (Hg0, HgII, and MeHg) in flooded paddy soils. Rapid redox recycling of Hg species contributed to Hg speciation resetting, which promoted the transformation between Hg0 and MeHg by generating bioavailable HgII for fuel methylation. Sulfur input also likely affected the microbial community structure and functional profile of HgII methylators and, therefore, influenced HgII methylation. The findings of this study contribute to our understanding of Hg transformation processes in paddy soils and provide much-needed knowledge for assessing Hg risks in hydrological fluctuation-regulated ecosystems.

Responses of Lotus pedunculatus to sulphur fertiliser and defioliation regime in acid soils at low temperature

The potential for Lotus pedunculatus is greatest in acid soils on hill and high country, but requires establishment success, nutrient supply and grazing management. This work investigated the role of sulphur fertiliser and the influence of defoliation regime on production of Lotus in low pH, high aluminium soils. Yields measured in year one were positively related to soil sulphate but not phosphorus. Sulphur, applied at two sites (low or high productivity) at 0, 24 or 78 kg S/ha, failed to alter yield over three years. The site, at 1000 m a.s.l., had base vegetation of unimproved tussock, low soil pH and P (4.8 and 7 respectively) and high Al (30-40 ppm). Yields ranged between 1900 and 3200 kg DM/ha/annum and was reduced when initial plant numbers were lower. Lotus contributed 65- 85% of the herbage for grazing (excluding tussocks). Yields were maximised by defoliation to 2 cm height each season or once in autumn. Establishing high plant numbers increased productivity. Single, late season grazing promoted rhizome development and resulted in the highest yields by year 3. Grazing to 2 or 5 cm residual once a season produced similar herbage, but lower rhizome development.

Response of Forest Ecosystems to Decreasing Atmospheric Nitrogen Deposition

Nitrogen deposition has serious consequences to global change. Excessive nitrogen deposition leads to nitrogen saturation in forests, resulting in soil acidification, nitrate leaching, an increase in nitrous oxide emissions, and a decrease in plant species diversity and vegetation productivity. Under the reduction of atmospheric nitrogen deposition in Europe, North America, and China, summarizing the response of forests to decreasing nitrogen deposition can not only improve the knowledge framework of the impact of nitrogen deposition on forests, but also evaluate the effects of emission abatement actions, as well as provide scientific basis for future air pollution control. This study reviewed the response of soil, surface water, nitrogen cycle, and vegetation of temperate forests in Europe and North America and subtropical forests in southwest China to the reduction in atmospheric nitrogen pollution gases and thus nitrogen deposition. The soil water nitrogen concentration responded rapidly to the nitrogen deposition reduction, although the trend was inconsistent. The soil acidification and nitrogen cycles showed a delayed response of recovery from high nitrogen deposition. The nitrogen mineralization and immobilization, soil carbon retention, and net primary production might take decades to respond to the nitrogen deposition reduction. However, the soil inorganic nitrogen pool and nitrogen leaching decreased with the decline in nitrogen deposition, although a one-or two-year lag existed. The surface water nitrogen concentration was closely related to nitrogen status in forests. After the nitrogen deposition decreased, the nitrogen leaching and thus the surface water nitrogen concentration decreased in the areas with historically high nitrogen deposition. However, the low surface water nitrogen concentration in the nitrogen-limited forests was not significantly affected by the nitrogen deposition changes. The recovery of surface water acidification was affected by soil sulfur desorption/mineralization and nitrification/denitrification. The foliar nitrogen concentration decreased with the decline in nitrogen deposition. The nitrogen-saturated forests and regional surface water in southwest China showed a recovery trend from high nitrogen deposition, as a consequence of the implementation of the Total Emissions Control of Air Pollutants and later the Action Plan of Air Pollution Prevention and Control.

Responses of some soil enzymes and cotton plant to foliar application of ferrous sulfate in a calcareous alkaline soil

Ferrous sulfate application is important in improvement of agricultural production, elimination of micronutrient deficiencies in human and animal populations, and promotion of sustainable food and feed production. This study was carried out to investigate the effects of different doses of foliar iron sulfate (FeSO4) applications on cotton plant yield and yield components, soil enzyme activity and chlorophyll content (SPAD value) and Normalized Difference Vegetation Index (NDVI) values of cotton plants. The results of both growing periods indicated that 0.4% FeSO4 application dose was more effective than the other doses compared to the control (Co), therefore, the evaluations were carried out based on 0.4% FeSO4 application dose. The application dose increased the cotton yield by 20.53 and 19.08% in the 2020 and 2021 season, respectively. The SPAD value increased by 54.88 and 98.68% in the 2020 and 2021 season. The NDVI values were 0.83 and 0.85 in the 2020 and 2021 seasons, respectively. Soil enzymes responded positively to FeSO4 application. The urease enzyme activity at this application dose varied between 17.81 and 18.76 µg N g−1 dry soil h−1 (13.73 to 26.33% increase compared to Co), and the highest value was recorded in 2021. The Dehydrogenase (DHG) enzyme activity was between 18.38 and 16.05 µg TPF g−1 dry soil 24 h−1 (39.8 and 46.30% increase compared to Co). The Catalase enzyme activity (CAT) was 36.40 and 38.73 ml O2 g−1 dm 5 min−1 in (51.23 and 39.32% compared to control) and the highest value was recorded in 2021. Nitrate Reductase Activity (NRA) was 18.66 and 17.14 µg N g−1 dm 2 h−1 in 2020 and 2021 seasons. The values of NRA were 54.11 and 59.54% lower in 2020 and 2021 seasons compared to the NRA in Co.

SOIL TILLAGE VARIANTS AND SULPHUR FERTILIZATION AFFECT NODULATION, N2 FIXATION AND YIELD OF BAMBARA GROUNDNUT (Vigna subterreana) IN SOUTHEAST NIGERIA

Management efficiency can increase crop productivity through enhanced N2 fixation in the plant-soil system. This study examined soil tillage variants and sulphur fertilization effects on nodulation, N2 fixation effectiveness and yield of Bambara groundnut [Vigna subterranea] in a degraded Ultisol in Agbani Enugu, Southeast Nigeria. Twenty-four experimental units were laid out in a Randomized Complete Block Design (RCBD). The six treatments comprised No-Till+No Gypsum (NTGo), No-Till+Gypsum1 (NTG1), No-Till+Gypsum2 (NTG2), Till+No Gypsum (TGo), Till+Gypsum1 (TG1), and Till+Gypsum2 (TG2). No-till+gypsum2 plots had significantly higher soil N content than each corresponding No-till+no gypsum plot by 15-40 %. At 30 DAP, the plots treated with till+gypsum1 (21 kg/ha), till+gypsum2 (42 kg/ha), no-till+gypsum2 (42 kg/ha), no-till+gypsum1 (21 kg/ha), and till+no gypsum had 62-63 % higher soil sulphur content (P= 0.05) than the control plots. The nodule count per plant in plots treated with no-till+gypsum2 (42 kg/ha) was greater than that in the control plot, plots with no-till+gypsum1 (21 kg/ha), and plots with till+gypsum2 (42 kg/ha) by 72-74 % at 30, 60, and 90 DAP across two seasons. Compared to the untreated plots, nodulation effectivity was raised by 79-89 % in the No-till+gypsum2 plot. The plots treated with no-till+gypsum2 (42 kg/ha) had the highest yield (0.94 t/ha), followed by plots treated with no-till+gypsum1 (42 kg/ha) with 0.93 t/ha dry seed yield and till+gypsum2 (42 kg/ha) with 54-55 % greater yield (P=0.05) than the control plot. Sulphur treatment boosted nodulation by 68 % and nodule effectiveness by about 78 %. The no-till+Gypsum2 application enhanced the average yield of Bambara groundnuts by 56 %. The soil application of S enhanced the amount of accessible S in the soil. Results show that the tillage system and S fertilization impact Bambara groundnut on degraded Ultisols. Dry matter yield was best with a high S supply in both S increments and no-till systems. The number and effectiveness of nodules increased at different S rates and no-tillage. Because of the increased S application rate, there was a considerable increase in N accumulation due to a greater N2 fixation rate. The study recommends using no-till systems and sulphur fertilization practices to enhance crop productivity, especially in degraded Ultisols. The study provides valuable insights into sustainable agriculture practices that boost yields while conserving soils.

Influence of Long-Term Organic Fertilization on Changes in the Content of Various Forms of Sulfur in the Soil under Maize Monoculture

Sulfur nutrition is a crucial part of proper crop growth. In this study, we investigated the influence of organic fertilizers in a long-term field experiment (23 years) with continuous maize monoculture. We focused on: (a) changes in the soil sulfur fraction pools, (b) the balance of total sulfur inputs and outputs, and (c) sulfur uptake by maize. The following treatments were selected: unfertilized control (Control), urea and ammonium nitrate (UAN), UAN and wheat straw (UAN + St), sewage sludge (SS), farmyard manure (FYM), and slurry (Slurry). Using sequential extraction, we determined water-soluble (SW—in water), adsorbed (Sads—in 0.032 mol L−1 NaH2PO4), and available (Sav = SW + Sads) sulfur content. Microwave-assisted digestion in an Aqua regia solution was used to measure the pseudo-total sulfur content (Spt). Organic-bound sulfur (Sorg) was calculated as a difference between Spt and Sav. We found that average biomass yields responded to a uniform 120 kg N ha−1 year−1 dose, rather than the dose of S in fertilizers, with an increase over the Control by 34–49%. The effect of an additional 33.5 kg N ha−1 year−1 on UAN + St treatment was not significant. Average sulfur uptake responded to increased yields (69-121% higher than Control), rather than the sulfur application, with the exception of SS, where the dose of sulfur was high enough to cause an additional uptake. In the topsoil, we discovered a significant decrease over time (from 1997 to 2019) in water-soluble (SW), adsorbed (Sads), available (Sav), and pseudo-total (Spt) fractions on all treatments to 29, 59, 37, and 82% of their initial values, respectively. For all treatments, the proportion of Sorg in Spt increased over time, which was caused by the decrease in mineral fractions (SW, Sads, Sav). The absolute content of Sorg decreased over time for all treatments except SS and FYM to about 85% of the initial value. Using the simple balancing method, we calculated that UAN + St, SS, FYM, and Slurry treatments annually lost 8.04, 66.1, 21.4, and 26.8 kg of S ha−1, respectively. This loss was attributed to the decrease in atmospheric depositions, as well as the release of sulfur from soil organic matter (for UAN + St and Slurry treatments) and a high proportion of easily mineralizable and inorganic sulfur from the SS treatment. Generally, the FYM fertilizer provided the highest potential for maintaining soil Spt status.

Spatio-temporal variability of available sulphur and micronutrients (Zn, Fe, Cu, Mn, B and Mo) in soils of a hilly region of northern India

Knowledge about spatio-temporal variabilities of plant available (hereafter called available) nutrients in soils is important for undertaking revised and efficient site-specific soil nutrient management practices in order to achieve higher crop production and nutrient use efficiency in different parts of the world. Despite emerging deficiencies of available sulphur (AS) and micronutrients in various soil-crop situations, the information pertaining to temporal changes in spatial variability of AS and available micronutrients in soils of different parts of the world is limited due to scarce studies in the said area. The present study was carried out to assess and compare the status and spatial as well as temporal distribution pattern of AS, available micronutrients, and some selected soil properties [soil pH, electrical conductivity (EC), and soil organic carbon (SOC)] in cultivated soils of a hilly region of India, in 6 years (2015–2021). We also visualized correlations among soil properties, AS, and available micronutrients, and studied spatial structures of the soil parameters. We collected altogether 2, 871 (1, 127 in 2015 and 1, 774 in 2021) georeferenced representative topsoil (0–15 cm depth) samples from cultivated areas of Uttarakhand state of India and analysed. Soil properties, AS and available micronutrients exhibited moderate variability with coefficient of variation (CV) values ranging from 10 to 100%. The mean values of AS and available micronutrients in 2015 and 2021 differed significantly, as revealed by t-test. The mean concentrations of AS (13.2 mg kg−1), available iron (AFe) (36.5 mg kg−1), available boron (AB) (0.92 mg kg−1) and available molybdenum (AMo) (0.40 mg kg−1) in 2021 were significantly lower than the concentrations of AS (44.7 mg kg−1), AFe (42.8 mg kg−1), AB (1.46 mg kg−1), and Amo (0.94 mg kg−1) in 2015. The AS concentration was positively and significantly correlated (r = 0.064 p < 0.05 in 2015, r = 0.261 p < 0.01 in 2021) with soil pH and negatively and significantly correlated (r = −0.082 p < 0.01 in 2015, r = −0.125 p < 0.01 in 2021) with SOC in both the years. There were positive and significant correlations of SOC with available zinc (AZn) (r = 0.111 p < 0.01), available copper (ACu) (r = 0.062 p < 0.05) and AB (r = 0.159 p < 0.01) in 2015 and with AZn (r = 0.101 p < 0.01), AFe (r = 0.187 p < 0.01), ACu (r = 0.164 p < 0.01), available manganese (AMn) (r = 0.169 p < 0.01) and AMo (r = 0.266 p < 0.01) in 2021. The exponential model was found to be best fitted for all of soil parameters with lower MSE values (−0.007 to 0.006 in 2015 and −0.010 to 0.012 in 2021) in both the years of estimation. The nugget/sill ratios (varied from 0.32 to 0.74 in 2015 and from 0.29 to 0.57 in 2021) indicated the moderate spatial dependence for all the soil parameters except AFe (nugget/sill ratio 0.14, strong spatial dependence) in 2015 and EC (nugget/sill ratio 0.24, strong spatial dependence) in 2021.There were varied distribution patterns of soil properties, AS and available micronutrients in the study area for both the years of estimation. The distribution patterns of AS, AB and AMo changed to a greater extent over the period of time. Thus, the study highlighted the change in spatial variability of AS and available micronutrients in the study area over a period of 6 years.

Characterization of methanotrophic community and activity in landfill cover soils under dimethyl sulfide stress

Landfill cover soil is the environmental interface between landfills and the atmosphere and plays an important role in mitigating CH4 emission from landfills. Here, stable isotope probing microcosms with CH4 or CH4 and dimethyl sulfide (DMS) were carried out to characterize activity and community structure of methanotrophs in landfill cover soils under DMS stress. The CH4 oxidation activity in the landfill cover soils was not obviously influenced at the DMS concentration of 0.05%, while it was inhibited at the DMS concentrations of 0.1% and 0.2%. DMS-S was mainly oxidized to sulfate (SO42-) in the landfill cover soils. In the landfill cover soils, DMS could inhibit the expression of bacteria and decrease the abundances of pmoA and mmoX genes, while it could prompt the expression of pmoA and mmoX genes. γ-Proteobacteria methanotrophs including Methylocaldum, Methylobacter, Crenothrix and unclassified Methylococcaceae and α-Proteobacteria methanotrophs Methylocystis dominated in assimilating CH4 in the landfill cover soils. Of them, Methylobacter and Crenothrix had strong tolerance to DMS or DMS could promote the growth and activity of Methylobacter and Crenothrix, while Methylocaldum had weak tolerance to DMS and showed an inhibitory effect. Metagenomic analyses showed that methanotrophs had the genes of methanethiol oxidation and could metabolize CH4 and methanethiol simultaneously in the landfill cover soils. These findings suggested that methanotrophs might metabolize sulfur compounds in the landfill cover soils, which may provide the potential application in engineering for co-removal of CH4 and sulfur compounds.