Sulphur immobilization and availability in soils assessed using isotope dilution

Increasing recognition of S deficiency in soils has raised the need for understanding processes governing S cycling and availability in soils. However, the quantification of the two main processes of S cycling, i.e. mineralization and immobilization, remains difficult as these processes occur simultaneously. A modified isotope ³⁵SO₄ dilution technique was developed and used to measure the effect of sulphate (SO₄) fertilization on S mineralization and immobilization in planted (pot experiment with ryegrass (Lolium multiflorum L.)) and unplanted soils (incubation). The immobilization and mineralization of S was calculated from the dynamics of stable and labelled S in soil KH₂PO₄ extracts containing an anion exchange membrane that concentrates SO₄ and mainly excludes other S species. The mathematical analysis of the isotope dilution data differs from methods proposed earlier. The radiolabile S in unplanted soil (E value) and in ryegrass (L value) were used as a measure of total available S in soils. Sulphate immobilization rate significantly declined during incubation. Sulphate application reduced gross mineralization but surprisingly reduced SO₄ immobilization. The E value significantly increased during the incubation in all soils as a result of gross mineralization, e.g. from 3.8 mg S kg⁻¹ at day 0 to 11.5 mg S kg⁻¹ at day 43 in the sandy soil with no sulphate addition. A full recovery in the E value of S added in (+S) treatments was achieved. Similarly, radiolabile S in the above-ground ryegrass biomass (L value) increased with S addition, with a full recovery of added S. The E and L values nearly fit a 1:1 line suggesting identical S dynamics in a planted and unplanted soil. The method proposed has operational advantages compared to methods used earlier.     

Sulphur mineralisation in some New Zealand soils

Summary An open incubation technique was used to measure S mineralisation in a range of New Zealand soils. For most of the soils studied, the release of S as sulphate was curvilinear with time, and during a 10-week incubation, the amounts of S mineralised ranged from less than 3 g S g^-1 soil to more than 26 g S g^-1 soil. The best predictor of mineralised S appeared to be the amount of C-bonded S in the soil (explaining 59% of the variation in mineralised S between soils). Examination of the soils after incubation also revealed that the bulk of the mineralised S was derived from the C-bonded S pool. Hydriodic acid-reducible forms of organic S appeared to make little contribution to mineralised S.Attempts were made to predict total potentially mineralisable S (S _o) from incubation data using an exponential equation and a reciprocal-plot technique. However, the dependence of estimated values of S _o on the length and temperature of incubation cast doubts on the validity of this approach.     

Sulphur distribution and metabolism in waterlogged peat

About 90% of total S in a peat profile from a valley mire was associated with organic matter, and in the anaerobic zone, most of the remaining S could be distilled as H₂S (steam-volatile H₂S). [³⁵S]SO^2?₄ was rapidly incorporated into both organic and steam-volatile H₂S pools, with preferential labelling of organic matter at the surface of the peat (? 10 cm depth) and of steam-volatile H₂S at greater depth (? 10 cm depth). Less than 2% of the steam-volatile H₂S could be accounted for as H₂S in solution in the pore water, and evidence suggesting FeS as the source of this fraction is presented. Less than 2% of the total S in the profile was present as FeS₂ or S°, and S₂O^2?₃ and S₄O^2?₆ could not be detected. Measurements of total S content of the peat and estimates of the age of the deposit indicate a rate of S accumulation of 4.76–6.06 g S m^?2yr^?1. The results are discussed in the context of the mechanisms of S transformations and uptake by other mire systems.     

Sulphur in air and soil

Natural S supplies are insufficient for high crop yields. The S brought down by rain is limited, even in industrial areas, and much of it is lost in drainage. Additional supplies are needed either as fertilizers or as SO₂, which vegetation readily absorbs. The margin between the minimum SO₂ concentration for full growth and the concentration at which damage occurs is wide enough for distribution via the air, without deleterious effects, of such S as is available from the combustion of fuels.     

Sulphur Mineralization and Carbon,Nitrogen, and Sulphur Relationships in Some Alfisols of India

Abstract

The amount of sulphur (S), nitrogen (N), and organic carbon (C) in different layers of soils from some Alfisols varied considerably with location. The amount of S extracted by different extractants as a percentage of the total S was in the order of organic (3.5%)>0.05 (N) NH₄OAc+0.25 (N) HOAc (1.9%)>0.1 (N) H₃PO₄ (1.8%)>0.025 (N) CaCl₂ (1.8%)>0.03 (N) NaH₂PO₄ (1.7%)>0.001 (N) HCl (0.6%). In all the soil series SO₄ ^2?‐S mineralization decreased up to the second week after incubation, followed by a slight increase up to the fourth week, a subsequent decline up to the sixth week, and a slight increase up to the eighth week. The C:N, C:S, N:S, and C:N:S ratios averaged 9.4:1, 63.7:1, 6.9:1, and 94:10:2.08, respectively.     

Ecogeochemical investigation,Kola peninsula: Sulphur and trace element content in snow

The Central Kola Expedition and the Geological Surveys of Norway and Finland have undertaken a multi-media investigation of eight catchments situated in Russia (Zapoljarniy, Monchegorsk, Kirovsk, Kurka), Norway (Skjellbekken) and Finland (Kirakka, Naruska, Pallas) to determine the environmental impact of local industrial pollution. Results of analysis of snow samples collected in March/April 1994 are presented for both filtered meltwater and filter residues. Many heavy metals (As, Cd, Co, Cr, Cu, Mo, Ni, Pb, V and Zn), as well as S, Al and Fe, are unusually enriched in both phases in the Russian catchments, primarily in Monchegorsk and/or Zapoljamiy. Typically, some elements are found mostly in the meltwater phase (e.g. Na, S, Sr, Zn), others in the filter residues (e.g. Cr, Fe, Mo, Ni). Cu and Ni are well correlated, both in meltwater and in filter residue, and the ratio of Cu to Ni can be useful in identifying pollution sources. Snow is a well-suited medium for fingerprinting environmental pollution sources. Estimates of deposition from snow meltwater only, will be seriously underestimated for many elements.     

Sulfur uptake and translocation in maize (zea mays) grown in a high pH soil treated with elemental sulfur

A glasshouse experiment was conducted to elucidate the influence of elemental sulfur (S) application rates (0, 0.5, 1.0, and 2.0 g S kg^?1 soil) on the release and uptake of S at 0, 20, and 40 days after incubation. Results showed that there was a progressive upward trend in maize leaves, stem, and root S content with application of elemental S. However, maize production followed a nonlinear model. Plants grown in untreated soils suffer from S deficiency and addition of elemental S at a rate of 0.5 g S kg^?1 soil alleviated S deficiency. The decrease in maize performance due to the highest S application rate was not related to S toxicity. The greatest leave, stem, and root productions were obtained at S concentrations of 0.41, 0.58, and 0.2%, respectively. Overall, application of elemental S at a rate of 0.5 g S kg^?1 soil is recommended for maize performance improvement.     

中国农业中硫的消费现状、问题与发展趋势

近年来,施用硫肥效果显著的报道逐渐增多,硫对农业生产的重要性被广泛认可。基于农业部统计数据、农户调查和行业统计数据,对农业生产中硫的输入状况与硫肥消费特征的分析表明,中国硫肥消费存在很大盲目性。过于集中在过磷酸钙的生产或施用地区,缺乏整体的科学引导;各种作物的单位面积硫输入量有较大差异;与各自适宜的推荐量相比,水稻、小麦和玉米的硫输入量偏高,油菜和棉花的硫输入量偏低,而豆类的硫输入量严重不足。为引导含硫肥料合理消费,需要启动全国尺度土壤硫肥力和硫肥技术研究,跟踪环境硫的状况,科学预测农业硫需求,稳定传统含硫肥料的投入并研发新的硫肥产品,以满足局部地区作物的需求。     

Influence of sulfur on growth and nutrient composition of soft red winter wheat

Sulfur (S) deficiencies in soft red winter wheat (Triticum aestivum L.) result in reduced yields and inferior grain quality. Diagnosis of S deficiency has been unreliable since soil testing does not accurately measure available soil S, and tissue S concentration varies with plant age. In order to establish more reliable guidelines for determining S deficiency in winter wheat we used nutrient solution culture to provide uniform conditions for determining the effect of tissue S content on dry matter accumulation and nutrient uptake. The critical level of S for 90% of maximum growth in winter wheat seedlings (Feekes scale 1 with 5 leaves) was calculated at 1.4 g kg^‐1 using a modified Mitscherlich model. Root growth was less sensitive to low S levels than top growth which may reduce the effect of S deficiency in the field. Concentrations of N, Mg, Fe, and Cu in the plant tissue increased with increased S concentration. An N/S ratio of greater than 22 was associated with reduced growth. Our results suggest that if care is taken in standardizing the plant age when sampling early diagnosis of S deficiency could be based on total S analysis.     

Spatial Distribution and Management Zones for Sulphur and Micronutrients in Shiwalik Himalayan Region of India

Agricultural land degradation due to nutrient deficiencies is a threat to agricultural sustainability. As nutrients availability is influenced by soil heterogeneity, climatic conditions and anthropogenic activities; hence, delineation of nutrient management zones (MZs) based on spatial variability could be an effective management option at regional scale. Thus, the present study was carried out to delineate MZs in the Shiwalik Himalayan region of India by capturing spatial variability of soil properties and secondary and micronutrients status because of the emerging nutrient deficiencies. For the study, a total of 2575 geo‐referenced representative surface (0–15 cm depth) soil samples were collected from the study region covering an area of 53,483 km². The soils were analysed for pH, electrical conductivity, soil organic carbon, available sulphur (S) and micronutrients (Zn, Fe, Cu, Mn, B and Mo) concentrations. There was a wide variation in soil properties with coefficient of variation values of 14 (for pH) to 86% for available Mo. Geostatistical analysis revealed spherical, Gaussian, exponential, stable, circular and K‐Bessel best‐fit models for soil properties. Most of the soil properties were having moderate spatial dependence except soil pH and S (strong spatial dependence) and Zn (weak spatial dependence). About 49%, 10%, 2%, 13%, 11%, 12% and 8% area of the study region were found to be deficient (including acute and marginal deficiency) in S, Zn, Fe, Cu, Mn, B and Mo, respectively. The principal component analysis and fuzzy c‐mean clustering were performed to develop the MZs. Four principal components with eigenvalues greater than 1 and accounting 65·4% of total variance were retained for further analysis. On the basis of fuzzy performance index and normalized classification entropy, four potential MZs were identified. Analysis of variance confirmed the heterogeneity in most of the studied soil properties among the MZs. The study indicated that the methodology of delineating MZs can be effectively used in site‐specific S and micronutrients management in the Shiwalik Himalayan region of India. Copyright © 2016 John Wiley & Sons, Ltd.     

Sulphur Balances and Dynamics in Three Forested Catchments in Sweden

The deposition of sulphyr (S) has decreased considerably during the last decade and is now at levels below those recorded in the middle of the 1950s in Sweden. However, the sulphate concentrations in surface waters have not decreased to the extent that could be expected from the decreased S deposition. Catchment studies have shown a net S output, indicating a soil-derived S source besides the atmospheric S input. This study was performed in three small, forested catchments in southern and central Sweden, that are part of the national, integrated monitoring program for forests. The aim was to assess S levels and fluxes in and between the different compartments of the ecosystems in order to trace the possible sources of excess S in runoff. The sulphate concentrations in soil water indicate that the excess S originates from mineralization and oxidation of organically bound S in humus and peat, as well as from desorption of sulphate from Fe and Al oxohydroxides in the B-horizon. The latter process will quickly respond to changes in S deposition, while the former probably is independent of S deposition in a short time perspective. This will have implications for the modelling of recovery from soil and surface water acidification.     

Sulfur nutrition requirements of peach trees

Changes in fertilizer and pesticide formulations plus success in reducing sulfur (S) emissions to the air from industrial operations have reduced the availability of S to peach trees in some locations. Peach (Prunus persica L. Batsch) trees on highly leached acid sands have shown responses to S fertilization. The levels of total S required for S sufficiency is important to determine fertilizer needs. The 100 ppm SO₄‐S requirement offered by some sources has been misinterpreted. Greenhouse experiments with Nemaguard, Lovell, Montclar and Nemared rootstock seedlings resulted in the establishment of levels representing S deficiency and sufficiency. The foliage and growth rates of rootstock seedlings in this experiment showed severe deficiency symptoms at 550–990 μg S g^‐1 DW. Sufficiency was achieved at 1400–2500 μg S g^‐1 DW.     

Sulphur transformations in soils using sulphur-35 labelling

Mineralization and immobilization of sulphur in two soils was studied by means of incubation experiments involving the labelling of soil with radioactive ³⁵S. The results obtained were consistent with the concept of a continuous, concurrent mineralization and immobilization cycle taking place involving a relatively small proportion (3–6%) of the soil organic S pool. Addition of glucose to the soil increased both the amounts of S mineralized or immobilized and the apparent size of the actively cycling organic S fraction. HI-reducible forms of soil S appeared to be the predominant forms of organic S involved in the S transformations.Re-incubation of the soils after leaching and drying caused a considerable amount of fresh sulphate mineralization to take place. The original actively cycling organic S pool initially contributed an extremely high proportion (40–70%) of the freshly mineralized sulphate. However, as the re-incubation proceeded, a much greater proportion of the soil organic S became involved in S transformations.     

Sulphur Forms in Open and Afforested Areas of Two Scottish Peatlands

Sulphur forms were determined at twopeatland sites in Scotland, each having both open bogvegetation and afforested areas. Afforestationactivity (including initial ploughing and, in onecase, active drainage) had a significant effect onpeat physical characteristics, depending on the depthsampled, but had less influence on S chemistry. Therewas no significant difference in mean total Sconcentration (mean of 0.24% over the upper 100 cmpeat) between the two sites or between the afforestedand open areas. Organic S was dominant withapproximately 64% of the total S being C-bonded S and27% ester sulphate S. Reduced inorganic forms (acidvolatile S, elemental S and Cr-reducible S) accountedfor approximately 8% of the total S. On average, onlyhalf of the Cr-reducible S could be accounted for bypyrite S as determined by analysis of the Fe; theremainder was considered to be an organic S fraction.The presence of both S-oxidizing thiobacilli andsulphate-reducing bacteria were indicative of anactive oxidation/reduction cycle that resulted in theaccumulation of S at or below the mean water table.The results are discussed in terms of S retention and alkalinity generation in peatlands.     

Sulphur mineralization and release of soluble organic sulphur from camp and non-camp soils of grazed pastures receiving long-term superphosphate applications

Summary Topsoils (0–75 mm) from four soil types with different sulphate retention capacities were collected from stock camp and non-camp (main grazing area) sites of grazed pastures in New Zealand which had been annually fertilized with superphosphate for more than 15 years. These soils were analysed for different S fractions and incubated at 30°C for 10 weeks using an open incubation technique in order to assess the extent of S mineralization and the release of soluble soil organic S from camp and non-camp soils during incubation. The soils were preleached with 0.01 M KCl, followed by 0.04 M Ca(H₂PO₄)₂ before being incubated. Pre-incubation leachates and weekly 0.01 M KCl leachates were analysed for mineralized S (i.e., hydriodic acid-reducible S) and total S. Soluble organic S was estimated as the difference between these two S fractions. Results obtained show higher cumulative amounts of all three S fractions in leachates over a 10-week incubation period in camp than in non-camp soils, suggesting that higher mineralization occurred in camp soils. Cumulative amounts of mineralized S from camp and non-camp soils showed a linear relationship with duration of incubation (R ²0.985^***), while the cumulative release of soluble organic S followed a quadratic relationship (R ²0.975^***). A significant proportion (14.6%–40.8%) of total S release in KCl leachates was soluble organic S, indcating that organic S should be taken into account when assessing S mineralization. Mineralized S and soluble organic S were best correlated with 0.01 M CaCl₂-extractable soil inorganic S (R ²=0.767^***) and 0.04 M Ca(H₂PO₄)₂-extractable soil inorganic S(R ²=0.823^***), respectively. Soil sulphate retention capacity was found to influence amounts of mineralized S and soluble organic S, and thus periodic leaching with KCl to remove mineralized S from soils may not adequately reflect the extent of soil S mineralization in high sulphate-retentive soils. In low (<10%) sulphateretentive soils, increasing the superphosphate applications from 188 to 376 kg ha^–1 year^–1 increased S mineralization but not amounts of C-bonded and hydriodic acid-reducible soil S fractions.     

Effect of sulfur rate,application method,and source on yield and mineral content of corn

Abstract

Corn (Zea mays L.) grown on sandy Coastal Plain soils may be subject to sulfur (S) deficiency due to the low levels of available S in the soil. The diagnosis of S deficiency in the field is sometimes ambiguous since mineralization of soil organic matter or root growth into the subsoil may supply adequate S to the crop. Yield response to S fertilizers has been more frequent since incidental additions of S to the soil by air pollution and fertilizer applications have been reduced. This study was conducted to identify S deficiency in corn grown on sandy Coastal Plain soils and to determine the effects of S source, rate and method of application on grain yield. Irrigated corn was grown on Norfolk loamy sand and Tifton loamy sand near Leesburg and Moultrie, Georgia, respectively in 1987. Grain yields were increased with addition of 11 kg S ha^‐1 compared to the check treatment. Increased rates of S up to 88 kg ha^‐1 did not increase grain yields above the 11 kg ha^‐1 rate. There was no difference between banded or broadcast application of (NH₄)₂SO₄ or between elemental S and (NH₄)₂SO₄ as S sources. Earleaf S concentrations of 1.6 g kg^‐1 and extractable soil S concentrations of 4.0 to 8.7 mg kg^‐1 were associated with S deficiency. Visual symtoms of S deficiency were observed in the check treatments throughout the growing season at both experimental sites. The results indicate that visual symptoms and tissue analysis can be used to identify S deficiency. Extractable soil S may be useful in determining the possible response to S fertilizer especially if the subsoil is sampled.     

Sulphur deposition and changes in Swedish lake chemistry 1988–1993

Acidification of surface waters in northern Europe due to anthropogenic sulphur (S) deposition has led to new emission restrictions based on Critical Loads (CL). There is likely to be considerable interest in documenting the effect resulting S deposition changes have on surface water quality. This paper will focus on how the chemistry of 134 reference lakes in Sweden has changed between 1988 and 1993 in response to a decline in S deposition. Only 10% of the reference lakes had significant declines in sulphate during the 5 year study period. A similar number of lakes had an increase in the acid neutralizing capacity (ANC), but few of those with an increase in ANC were also lakes with significant sulphate decreases. Since there is good evidence that S deposition decreases will eventually result in ANC increases, a five year period is probably too short for evaluating the S protocol in terms of changes in lake chemistry. It takes a number of years to equilibriate to new deposition levels, and weather patterns may also obscure longer term trends.     

Investigating the Provenance and Seasonal Variations in Sulphate Sulphur and Oxygen Isotopes of Central Roztocze River Water,SE Poland

The isotope composition of sulphur and oxygen were measured in water collected from the Central Roztocze (SE of Poland) rivers. The research focused mainly on the upper section of the Wieprz River, its confluences and springs and on two confluences of the Tanew River. The results proved that there are two sources of sulphate dissolved in water: the Cretaceous aquifer and soil within the catchment's area. Seasonal variation of the sulphate concentration together with sulphur and oxygen isotope composition was observed. The isotope composition of sulphate varied in water collected at the different locations of the same river. They are similar for sulphates in springs and rivers. The isotope composition of sulphate varied in water collected at the different locations of the same river. The δ³⁴S values of sulphates in the Wieprz River are the lowest (negative) in lower part of the river. It shows that the contribution of sulphate from spring water increases downstream. The low sulphate content and high δ³⁴S and δ¹⁸O value in sulphates was found downstream from dams. It may be the result of deficiency of oxygen in mud and the reduction in bacteria activity. The seasonal variations of the oxygen isotope composition in sulphate are significant in sulphates collected from rivers and from springs. They are caused by seasonal variations of the δ¹⁸O in water stored in the soil. The narrow range of the δ¹⁸O values for the sulphates extracted from springs at the same time means that the main source of sulphate in spring water are oxidising processes using the same source of oxygen in every location. The high sulphate content combined with the high δ³⁴S values of the sulphates in springs suggest, that the sulphates from Cretaceous aquifer were mixed with sulphates dissolved from the soil.     

Sulphur mineralization kinetics as influenced by soil properties

A 10-week laboratory study, using an open incubation technique, was carried out to determine net sulphur (S) mineralization potentials of soil samples obtained from some representative soils in Tuscany, Italy. The time-course of organic S mineralization in the soils was analyzed by fitting the experimental values to three kinetic models (first-order, first-order E, zero-order). The first-order model was found to be the most suitable because it provided the best fit to the experimental data and for its simplicity. Potentially mineralized S (S ₀) values ranged from a minimum of 13.6 to a maximum of 50.7 mg kg⁻¹ soil and the mineralization rate k varied from 0.111 to 0.615 week⁻¹. It was also positively related to organic C, N, and S, protease, arylsulphatase, and dehydrogenase activities. The mineralization rate did not show any significant relationship with soil properties.     

Photosynthesis and metabolic changes in leaves of rapeseed grown under long‐term sulfate deprivation 1

The effect of prolonged sulfur (S) deficiency on photosynthesis and S‐containing compounds in leaves of rapeseed (Brassica napus L.) plants, grown in nutrient solution, was studied under greenhouse conditions. The rate of photosynthetic activity and stomatal conductance of water and CO₂ in treated plants decreased significantly after 3 months of treatment. The total chlorophyll content decreased after one month of S deprivation, after which it remained constant. The total S. content and both the water‐soluble and non‐protein soluble S fractions in the leaves showed a marked decrease. Whereas, the total protein soluble S remained unaffected during the period of observation. In the treated plants, the content of two major S compounds, e.g., cysteine and glutathione, were as a result of deprivation, although in the control it showed a trend to increase. Sulfur deficiency also decreased appreciably the activity of ATP sulfurylase. After the three‐month period of S deprivation, this enzymatic activity was about four times lower than that in the control plants. The data reported in this paper suggested that plants grown under S deficiency were capable of adjusting their S metabolism to maintain a sufficient protein and glutathione synthesis by lowering their photosynthetic activity.