COMPARATIVE STUDY OF DIFFERENT SALTS (SODIUM CHLORIDE,SODIUM SULFATE,POTASSIUM CHLORIDE,AND POTASSIUM SULFATE) ON GROWTH OF FORAGE SPECIES

Osmotic and specific ion effects are the most frequently mentioned mechanisms by which saline substance reduces plant growth. However, the relative importance of osmotic and specific ion effect on plant growth seems to vary depending on the salt tolerance of the plant under study. Tall wheatgrass (TW), perennial ryegrass (PR), African millet (AM) and Rhodesgrass (Rh) were grown in nutrient solution with sodium chloride (NaCl), sodium sulfate (Na₂SO₄), potassium chloride (KCl), and potassium sulfate (K₂SO₄) salinity up to electrical conductivity (EC) 27 dS m^?1. Growth of all plant species decreased significantly at high level (EC 27 dS m^?1) of NaCl and Na₂SO₄ salts. However, the growth of none of the plant species was affected significantly by KCl and K₂SO₄ at any level. Even leaf and shoot fresh weights were enhanced by K₂SO₄ in all plant species, except AM. Chlorine (Cl) was taken up in similar quantities from KCl and NaCl solutions and the content of the respective cations was similar to each other. Further sensitivity to sulfate and chloride was equal when sodium concentrations in shoots were equal, regardless of the anion composition of the media. The sodium (Na) concentration of the leaves of the plant species increased with increased NaCl and Na₂SO₄ levels in the nutrient solutions. The leaf Na concentration of TW was lower than that of the other plant species. However, the root Na concentration of TW was higher than that of the other plant species. Increased NaCl and Na₂SO₄ concentrations had a marked effect on leaf water potential of all plant species, and the TW showed higher leaf water potential at all levels of salts. Tall wheatgrass adjusted osmotically by accumulating electrolytes from the nutrient solution and by accumulation of glycinebetaine. Sodium was generally found more injurious than Chloride in all the four forage species. Salt tolerance could be ascribed as greater exclusion of Na ion.     

Comparison of some methods for determination of sulfate in soils

Abstract

Sulfate (SO₄ ^2‐) is present in soils as salts of various metals, and the different metals associated with sulfate may influence adsorption of SO₄ ^2‐by soils. The analytical method used for determination of SO₄ ^2‐could be affected by the type of metal associated with the SO₄ ^2‐. Four analytical methods based on different principles were evaluated for determination of SO₄ ^2‐in different metal salts and in soil extracts obtained with three extractants {0.1M lithium chloride (LiCl), 0.15% calcium chloride (CaCl₂), and 500 mg P/L as calcium phosphate [Ca(H₂PO₄)2]}. The analytical methods were: (i) a methylene blue (MB) colorimetric method after the reduction of SO₄ ^2‐to hyrogen sulfide (H₂S), (ii) an ion Chromatographie (IC) method, (iii) a turbidimetric (TD) method, and (iv) an indirect barium (Ba) atomic absorption spectrophotometric (SP) method. The recovery of SO₄ ^2‐associated with various mono‐, di‐, and tri‐valent metals was quantitative by the MB method. But, trivalent metals, such as aluminum (Al), indium (In), lanthanum (La), and scandium (IC), decreased the recovery of SO₄ ^2‐by the other three methods. The MB and IC methods gave similar values for SO₄ ^2‐in soils by using the three extractants. The TD and SP methods gave variable results and, in general, underestimated the amounts of SO₄ ^2‐in soils. Among the four methods, the MB and IC methods were the most accurate and precise.     

Simultaneous automated determination of chloride,nitrite, nitrate,and ammonia in water and wastewater

An automated system capable of simultaneous determination of chloride, nitrite, nitrate, and ammonia in about 2 ml of fresh water or wastewater is described. The four compounds are determined using modifications of established colorimetric procedures. Results can be reported at a true rate of five samples per hour with a relative standard deviation at optimum concentrations of less than 2%. Detection limits are 1 ppm Cl for chloride and 1, 5, and 5 ppb N for nitrite, nitrate, and ammonia, respectively. Sample pH adjustment is not required from 0.0002 N H₂SO₄ (pH 3.7) to 0.005 N NaOH (pH 11.2). Fresh water and wastewater samples were analyzed for nitrite and ammonia by the proposed procedure and by the manual sulfanilic-naphthylamine and nesslerization method. Analysis by the student t-test showed no significant difference between the paired sets of data (P > 0.5). When potable and wastewater samples were spiked with sodium chloride, potassium nitrate, sodium nitrite, and ammonium chloride and analyzed, average recoveries were 99 to 103%.     

Interactive effects of sodium chloride,sodium sulfate,calcium sulfate,and calcium chloride on snapbean growth,photosynthesis, and ion uptake

Excessive sodium (Na) accumulation in soil, which can be a problem for production agriculture in arid and semiarid regions, may be ameliorated by calcium (Ca). The mechanisms of Ca amelioration of Na stress in plants have received much more attention than has the effect of the anion of the Ca salt. Our objective was to determine the relative effects of the chloride (Cl^‐) and sulfate (SO₄ ^2‐) anions on Ca amelioration of Na stress. We exposed Phaseolus vulgaris L., cv. Contender seedlings growing in 1‐L styrofoam pots under greenhouse conditions to sodum chloride (NaCl) or sodium sulfate (Na₂SO₄) at concentrations of 0, 15, 30, 45, and 60 mmol/L combined with either 15 and 30 mmol/L of calcium sulfate (CaSO₄) or calcium chloride (CaCl₂). Plants in each styrofoam pot were irrigated with 300 mL of salt solution (leaching fraction = 0.25) every fourth day for four weeks. Increasing Na concentration decreased shoot dry weight, number and weight of pods, and number of nodules. The photo‐ synthesis rate was affected by all levels and types of Na salts. Calcium sulfate treatments ameliorated Na‐induced salinity in snapbeans more than did comparable CaCl₂ treatments. The thermodynamic activity of Ca, Na, and Cl was linearly related to the tissue content of each ion.     

The generation of aerosols by binary homogeneous nucleation

The rates of nucleation of liquid aerosols from the gaseous mixtures H₂SO₄ + H₂O and HNO₃ + H₂O at 25°C for various relative humidities (10 to 100%) and various activities of acid vapor are calculated using the Flood-Neumann-Döring-Reiss-Doyle theory of binary homogeneous nucleation. The activities of acid vapor needed for nucleation are 25 to 300 times smaller for H₂SO₄ + H₂O than for HNO₃ + H₂O. This is due to the much larger free energy of mixing in the liquid phase for H₂SO₄ + H₂O. Conversion from activities to actual pressures leads to concentrations of HNO₃ which are much too high to be found under normal atmospheric conditions. On the other hand, the concentrations of H₂SO₄ vapor needed to nucleate droplets in the H₂SO₄ + H₂O system are in the range 4(10^?5) to 1.3 (10^?2) ppm, a concentration which can result from photo-oxidation of SO₂ in the atmosphere. Calculations are made of the growth curves for H₂SO₄ + H₂O droplets (radius vs composition) at various relative humidities from the critical size radius up to a 1000 Å radius, corresponding to nuclei large enough to serve as condensation centers for heterogeneous nucleation. The limitations of binary homogeneous nucleation theory at extremely low concentrations of one of the components are discussed and it is shown that this theory becomes inapplicable if the actual vapor pressure of one component is below 10^?6 torr.     

Accumulation and partitioning of biomass and soluble carbohydrates in maize seedlings as affected by source of nitrogen,nitrogen concentration,and cultivar 1

Abstract

Seedlings of four maize hybrids were grown hydroponically to investigate the impact of different N sources (Ca(NO₃)₂, (NH₄)₂SO₄ and a 1:1 mixture of both) on (i) production and partitioning of root and shoot dry matter, (ii) concentration of soluble carbohydrates in roots and shoots and their partitioning to these plant parts, (iii) concentration of starch in the shoot, and (iv) N uptake. During the main phase of the experiments (duration 14d), the plants were grown in a greenhouse at 25/22°C day/night temperatures and a photoperiod of 16h. Nitrogen was supplied at three concentrations (2.8, 28, and 280 ppm). The root‐zone pH was 6.5. Under the lowest N supply, the N sources produced similar root and shoot dry matters. At the highest N level (280 ppm), NO₃‐fed plants were superior. In contrast, the mixture of NH₄ and NO₃ ^? was optimum at 28 ppm. More or less pronounced N form by N concentration interactions were also found in the concentration and distribution of soluble carbohydrates and in all remaing traits. There were almost statistically significant cultivar by N form interactions in shoot dry matter (P = 0.07) and total dry matter (P = 0.06), indicating the existence of considerable genotypic variation in sensivity to NH₄‐N.     

Effects of prolonged exposure of Oryzopsis hymenoides to SO2

Oryzopsis hymenoides, a desert grass, was exposed to low concentrationsof SO₂ ranging from 0.03 to 1.00 ppm for six week fumigation periods. Deleterious effects were noted only at atmospheric SO₂ concentrations of 0.13 ppm and above. These effects included necrotic lesions and reduced net primary productivity. At concentrations below 0.13 ppm, the SO₂ appeared to have a beneficial effect on productivity. The deleterious effects noted at the higher concentrations have ecological implications if pollutant sources are located in desert environments.     

Evaluation of the Nutrients Variability in Sap of Different Petiole Samples in Tomato Plant

The aim of this trial was to study the variability of anions and cations concentrations in the different petiole samples: young leaves (YL), mature leaves (ML) and aged leaves (AL). The experimental design consisted of four blocks and four plants per block being each plant one replication. In each plant, petiole samples were collected at 135 days after transplanting (DAT) to determine chloride, nitrate-nitrogen, phosphate-phosphorus, sulfate-sulfur, sodium, potassium, calcium, and magnesium (Cl^?, NO₃^–N, H₂PO₄^–P, SO₄^2–S, Na^+, K⁺, Ca²⁺ and Mg²⁺) concentrations. Our results showed that the selection of sample petiole in the tomato crop did not modify the Ca²⁺, Cl^?, SO₄^2–S and Na⁺ concentrations, while NO₃^–N, K⁺, Mg²⁺ and H₂PO₄^–P concentrations showed a great variability due to the selection of the sample petiole, therefore it is necessary to be careful with the sample selection.     

Indirect determination of micrograms of sulfate by barium absorption spectroscopy

Abstract

The indirect procedure for sulfate determination by Ba absorption spectroscopy was modified so that low concentrations of SO₄ in small volumes of solutions could be determined rapidly and precisely. Major modifications consisted of seeding the sample with BaSO₄, precipitating in ethanol solutions to lower BaSO₄ solubility, and determining Ba in a N₂O‐acetylene flame using the absorption mode.

The results showed: complete SO₄ precipitation as BaSO₄ after 15 min of shaking, little or no effect from solution Al on SO₄ determination, quantitative recovery of SO₄ from 0.01 M Ca(H₂PO₄)₂ soil extracts, and greater precision of SO₄ measurement with indirect method than with turbidimetric method.     

Effects of cold storage on anion,ammonium, and total nitrogen concentrations in soil water

Abstract

Researchers frequently must store water samples >24 h after collection until chemical analyses can be accomplished. Samples are commonly stored in darkness at near‐freezing temperatures until analysis, but effects of this storage method on soil water chemistry are not well‐documented. Soil water samples were collected from eastern hemlock [Tsuga canadensis (L.) Carriere] stands and analyzed initially and over time to determine if nitrate (NC₃ ^‐), chloride (Cl^‐), sulfate (SO₄ ^2‐), ammonium (NH₄ ⁺), and/or total nitrogen (TN) concentrations changed when samples were stored in darkness at 2–4°C. Subsamples were analyzed <24 h after collection and reanalyzed five times in a 12 to 24 wk period following sample collection. Nitrate concentrations remained stable for at least one wk and were only slightly lower than initial concentrations after 3–16 wk of storage. Chloride and SO₄ ^2‐ remained stable for 16 wk, while TN remained stable for 8 wk and decreased slightly after 24 wk. Most NH₄ ⁺ concentrations were below the limit of quantification, but concentrations of samples with quantifiable NH₄ ⁺ decreased in the first week of storage. Overall, cold storage in darkness was effective for preserving NO₃ ^‐, Cl^‐, SO₄ ^2‐, and TN concentrations in soil water, but NH₄ ⁺ analyses should probably be performed as soon as possible after sample collection.     

Nitrate and phosphate recovery from anion exchange resins

Abstract

The recovery of nitrate and phosphate from two anion exchange resins was determined. A general purpose and nitrate‐selective resin were extracted with potassium chloride (KCl), acidified ammonium chloride (NH4C1), and sodium sulfate (Na₂SO₄). The recovery of both nitrate and phosphate were significantly affected by the choice of resin and extractant. The combination of Na₂SO₄ extractant and nitrate‐selective resin resulted in less than half as much nitrate recovery as any other combination of resin and extractant. Consequently, if it is important to recover nitrate from the resins, Na₂SO₄ should not be used. Greater quantities of phosphate were recovered from the nitrate selective resin with all extractants. However, phosphate recovery was not significantly affected by choice of extractant. More rigorous extraction was required for the nitrate‐selective resin to achieve a level of nitrate recovery comparable to the general purpose resin. The nitrate selectivity also resulted in less phosphate being adsorbed from solutions high in nitrate. Finally, new batches of resin should be tested because differences between them can be significant.     

QUARTZ PORPHYRY TREATMENT ALTERS IRRIGATION WATER CHEMISTRY,AFFECTING HYDROPONIC VEGETABLE PRODUCTION

This study focused on using quartz porphyry (QP) as a water treatment to improve hydroponic production of komatsuna (Brassica rapa L. nothovar; Japanese mustard spinach). We compared the chemistries of the control and QP-treated nutrient solutions and found that magnesium (Mg²⁺) and calcium (Ca²⁺) concentrations increased linearly up to day 21 following sowing in both conditions, then declined slightly. The QP treatment reduced sodium (Na⁺) and chloride (Cl^?) concentrations for the whole cultivation period. In both the control and QP-treated solutions, nitrate (NO^? ₃) and sulfate (SO^2? ₄) showed the same trend to a daily increase. In spite of these similarities, however, komatsuna production was better with the QP-treated nutrient solution compared to control. Treatment with QP during cultivation in August–September reduced the harmful effects of Na⁺, chloride (Cl^?), nitrite (NO^? ₂), and SO^2? ₄ by reducing concentrations of these ions, possibly leading to decreased salinity and toxicity effects in the plants. Mineral concentrations during October–November differed from those of August/September, resulting in variation among the different growth parameters for komatsuna.     

Shoot growth,plant tissue elemental composition,and soil salinity following irrigation of alfalfa and tall fescue with high‐sulfate waters 1

Groundwater contaminated with sulfate (SO₄ ^2‐) at concentrations higher than allowable for drinking water might still be usable for irrigation. Objectives were to determine the growth response and mineral uptake of two forage crops irrigated with waters containing SO₄ ^2‐ at concentrations ranging from 175 to 1743 mg/L, and with electrical conductivities (EC) ranging from 1.2 to 3.6 dS/m. Plants were grown for 12 weeks in 8‐L pots containing a calcareous sandy loam and were harvested at 4, 8, or 12 weeks for plant growth measurements and tissue analysis. Digested leaves, stems, and reproductive tissues were analyzed by inductively coupled plasma (ICP) spectroscopy at each harvest, as were saturated soil paste extracts. Shoot growth of tall fescue (Festuca arundinacea Schreb.) was not affected by irrigation water treatment, whereas shoot growth of alfalfa (Medicago sativa L.) was increased by a moderate level of soil solution SO₄ ^2‐ Sulfur (S), boron (B), magnesium (Mg), sodium (Na), and zinc (Zn) concentrations in shoot tissues of both species showed a tendency to increase with increasing SO₄ ^2‐ content of irrigation water. Shoot tissue concentration of molybdenum (Mo) increased with maturation in both species, while the concentrations of B, potassium (K), manganese (Mn), Na, and Zn decreased. Soil saturated paste extract concentrations of Mg and Na increased with irrigation water Mg and Na concentrations, while Ca and S concentrations in the soil solution became saturated at the higher irrigation water concentrations of these elements.     

A comparison of two modified Kjeldahl digestion techniques for multi‐element plant analysis with conventional wet and dry ashing methods

Abstract

The efficiency of two modified Kjeldahl procedures (H₂SO₄‐H₂‐O₂‐Li₂SO₄‐Se and H₂SO₄‐Na₂SO₄) for digestion of plant tissue for analysis of P, K, Ca and Mg contents was compared with a conventional wet (HNO₃‐HClO₄) and a dry ashing procedure. Six plant tissues were chosen as test material: leaves of Malus pumila Mill., Medicago sativa L., Dactylis glomerata L., fruit and wood tissue of M. pumila and Nothofagus mensiesii Oerst. leaf litter. Apart from low P contents of M. pumila wood tissue by dry ashing, the mean P, K, Ca and Mg contents as determined after the four digestion procedures were in good agreement. Furthermore, the precision of the data for each element was generally quite similar for each of the digestion methods. The N contents determined by the two modified and a conventional Kjeldahl procedure (H₂SO₄‐K₂SO₄‐CuSO₄‐Se) also agreed closely.     

Evaluation of several methods for determining the potassium content in diverse plant materials

Abstract

Different plant analysis methods including varied incubation times with 0.5N and IN hydrochloric acid (HCl), diacid [nitric (HNO₃) and perchloric (HClO₄) acids], triacid [HNO₃, sulfuric acid (H₂SO₄) and HClO₄], H₂SO₄+hydrogen peroxide (H₂O₂) (Wolf method), and 0.5N and lN ammonium acetate (NH₄OAc) were evaluated for measuring the potassium (K) concentration in straw and grain samples of cereal, legumes, oilseed crops, and fruit‐tree leaves. The average K concentration in nine plant materials indicated that K extracted by 0.5N and lN HCl for 5 minutes, 1 hour, and 17 hours contact periods did not differ significantly. But the amount of K extracted by these acidic solutions gradually decreased during incubation, possibly due to reabsorption of released K by the plant material. The amount of K released in to the 0.5N HCl and IN HCl extractants was in close agreement with that obtained with the standard triacid method. The IN NH₄OAc extraction method slightly overestimated the K concentration in the materials compared to the other methods. Differences were observed among the methods in extracting K from different plant materials. In case of grain samples, the triacid method gave slightly higher values than that obtained by IN NH₄OAc extraction. The results suggest that the 0.5N HCl and lN NH₄OAc extraction methods can be used for the determination of K in plant tissues as these methods gave lower standard deviation and coefficient of variation values compared to the triacid method.     

Evaluation of calcium dihydrogen phosphate solution as an extractant for inorganic sulfate applied to soils

Abstract

To evaluate conventional calcium dihydrogen phospahte [Ca(H₂PO₄)₂] solution containing 500 mg P/L as an extractant for soluble plus adsorbed sulfate (SO₄), we added known amounts of SO₄ to 10 soil samples differed in clay mineral composition and extracted with Ca(H₂PO₄)₂ solution. The experimental results showed that the five successive extractions at a soihsolution ratio of 1:10 could quantitatively recover the added SO₄, and there was little effect of air‐drying the soils after addition of SO₄. Based upon these experimental results, we concluded that the Ca(H₂PO₄)₂ extraction is an excellent method for determining soluble plus adsorbed inorganic SO₄ in soils.     

Sulfur status of volcanic ash‐derived soils in Hawaii

Abstract

Several rainwater samples and 14 profiles of Hawaii's volcanic ash‐derived soils were analyzed for sulfur (S). Atmospheric deposition was an important S source at the coast (24 kg S/ha), but its contribution decreased with increasing distance from the sea (1 kg S/ha at 24‐km inland). The S concentration of rainwaters also decreased linearly with increasing rainfall.

Several thousand mg SO₄‐S/kg can be extracted from many volcanic ash‐derived soils of Hawaii, and it was often required at least four extractions [0.04 M Ca(H₂PO₄)₂, 1:10 soil to solution ratio] to completely desorb this SO₄. There was a close association of high SO₄ retention with high rainfall. This might have resulted from (1) the development of a solid phase with high SO₄ retention under intense weathering conditions, (2) more total SO₄ received by the soils from atmospheric deposition, and (3) past fertilization of sugarcane grown in high rainfall areas.

Low concentrations of soil solution SO₄‐S in relation to large amounts of P‐extractable SO₄ suggest that a S bearing mineral, such as basaluminite, may be controlling soil‐solution SO₄. Furthermore, SO₄ adsorption isotherms of these volcanic soils generally show a bi‐phasic property, and suggest that 40 to 80 mg SO₄‐S/kg is required to maintain 3 ‐ 6 mg SO₄‐S/L in the soil solution, a concentration range considered adequate for the growth of most crops.     

Ameliorative Effect of Hydro Gel Substrate on Growth,Inorganic Ions,Proline, and Nitrate Contents of Bean under Salinity Stress

The effect of varying hydrogel (0, 0.5, and 1.0% w/w) supply on some agro-physiological properties, such as dry matter, nutrient contents, chlorophyll contents, proline content, and ionic balance of bean plants in different salt sources and stress due to doses were investigated. Plants were treated with eight salt sources [sodium chloride (NaCl), sodium sulfate (Na₂SO₄), calcium chloride (CaCl₂), calcium sulfate (CaSO₄), potassium chloride (KCl), potassium sulfate (K₂SO₄), magnesium chloride (MgCl₂), magnesium sulfate (MgSO₄)] and four concentrations (0, 30, 60, and 120 mM doses) for 60 days in a growth media. Salt type, doses, and hydrogel (HG) affected the soil electrical conductivity. Soil salinity affected the parameters considered, and changed the nutrient balance of plants. High salt concentration caused substantial reduction in plant growth. Different salt concentrations negatively affected plant dry weight. The highest decrease of plant root dry weight was obtained with NaCl application followed by Na₂SO₄, CaCl₂, CaSO_4, MgCl₂, MgSO₄, KCl, and K₂SO₄, and similarly NaCl, Na₂SO₄, CaCl₂, CaSO_4, KCl, K₂SO₄, MgCl₂, and MgSO₄ in root dry weight. Total chlorophyll and nitrate contents of plants decreased with increasing salt doses, and the lowest value was obtained for NaCl application. Proline contents of plants were increased with increasing salt doses, and the highest value was obtained with the NaCl application. The effects of salt concentrations in nitrogen (N), potassium (K), and phosphorus (P) content of plants were significant. The presence of salt in the growth medium induced an important decrease the macro nutrient of the root and shoot part of plant such as N, P, K, calcium (Ca), and magnesium (Mg) content, but the N and P content of root and shoot part of the plant were increased with increasing of the HG application doses. The highest N and P increases were obtained with the 1.0 HG application for all salt types for both the root and shoots of plants. The HG added to saline soil significantly improved the variables affected by high salinity and also increased plant N and P, reduced soil electricity conductivity, nitrate, proline, and electrolyte leakage of plants, enhanced plant root and shoot dry weight by allowing nutrients and water to release to the plant as needed. The results suggested that HG has great potential for use in alleviating salinity stress on plant growth and growth parameters in saline soils of arid and semi-arid areas. This HG appears to be highly effective for use as a soil conditioner in vegetable growing, to improve crop tolerance and growth in saline conditions. It is intended to confirm the results of these studies by field trials.     

Response of corn to plowed‐down and disked‐in Zn as zinc sulfate

Abstract

A field investigation was conducted to compare the efficacy of plowed‐down and disked‐in Zn as ZnSO₄.H₂O in correcting Zn deficiency of corn (Zea mays L.). The soil, Buchanan fine sandy loam, was nearneutral in pH and contained 0.7 ppm of EDTA‐extractable Zn and 1.4 ppm of dilute HCl‐H₂SO₄ extractable P. Application of 6.72 kg Zn/ha as ZnSO₄.H₂O corrected Zn deficiency of corn plants on the soil. Corn grain yields and Zn concentrations in tissue samples indicated that the plowed‐down and disked‐in Zn were about equally effective in correcting Zn deficiency where the level of Zn application was 6.72 kg/ha.     

Polymers act as nitrogen carriers to fertilize greenhouse and field grown lettuce

Abstract

Two concentration levels for each of two polymer gels (polyacrylate and vinyl alcohol acrylic acid) were incorporated with urea, ammonium sulfate [(NH₄)₂SO₄], and potassium nitrate (KNO₃) fertilizer solutions and used as nitrogen (N) carriers to fertilize lettuce grown in a greenhouse and field study. Of the initial 1290 mg N applied, gel treatments contained up to 70 mg N after 43 days. The vinyl alcohol polymers retained significantly larger quantities of NO₃‐N from the (NH₄)₂SO₄ and KNO₃‐N sources than from the urea source. The N concentration in each gel treatment was an important factor and dependent on the polymer and fertilizer source. Both gels performed better when incorporated with (NH4)₂SO₄ and KNO₃ than with urea.