Bragg soybeans grown on a southern coastal plain soil

Determinate soybean (Glycine max) has been characterized by very few detailed nutrient partitioning studies. Knowledge of the variation in nutrient concentrations with plant part, nodal position, and plant age is needed for a better understanding of plant function. The information will benefit soybean nutrient modeling and diagnostic interpretation of plant analysis. In this study, ‘Bragg’ soybean were grown on an Aquic Paleudult soil (Series Goldsboro loamy sand). Plants were sampled at 10 to 14‐day intervals beginning 44 days after planting (July 7) until harvest. Maximum observed K concentrations were 5.27, 5.05, 2.88, and 2.99% for stem internodes, petioles (+ branches), leaf blades, and pods, respectively. Maximum observed Ca concentrations were 1.05, 1.98, 2.48, and 1.47% for the same respective plant parts. Maximum observed Mg concentrations were 0.63, 0.81, 0.65, and 0.58% for the same respective plant parts. Nodal and temporal mean concentrations of K and Ca generally varied considerably due to plant age and nodal position, respectively, in all plant parts. Mean concentrations of Mg were largely unaffected by either plant age or nodal position. Peak concentrations of Ca and Mg are generally associated with upper nodal positions. As new nodes are initiated, the expanding tissue represents an identifiable sink for K. Of importance in plant analysis is the observation that mean concentrations of elements in all four plant parts can vary by two fold or more depending upon plant age and nodal composition of the sample.     

In vivo anti-influenza virus activity of an immunomodulatory acidic polysaccharide isolated from Cordyceps militaris grown on germinated soybeans

An acidic polysaccharide (APS) was isolated from the extract of Cordyceps militaris grown on germinated soybeans. Analyses of sugar composition indicated that APS consisted of d-galactose, L-arabinose, D-xylose, L-rhamnose, and D-galacturonic acid. On the basis of the result of methylation analysis, APS was considered to be mainly composed of Araf-(1-->, -->5)-Araf-(1-->, -->4)-Galp-(1--> and -->4)-GalAp-(1--> residues. When the polysaccharide was intranasally administered, it decreased virus titers in the bronchoalveolar lavage fluid and the lung of mice infected with influenza A virus and increased survival rate. Furthermore, APS increased TNF-alpha and IFN-gamma levels in mice when compared with those of untreated mice. APS enhanced nitric oxide (NO) production and induced iNOS mRNA and protein expressions in RAW 264.7 murine macrophage cells. The induction of mRNA expression of cytokines including IL-1beta, IL-6, IL-10, and TNF-alpha was also observed. These results demonstrated that APS might have beneficial therapeutic effects on influenza A virus infection at least in part by modulation of the immune function of macrophages.     

Influence of temporary flooding at three growth stages on soybeans grown on a clayey soil

Abstract

Knowledge of crop response to temporary waterlogging is important in the development of effective water management practices. A field study was conducted to determine the response of soybean [Glvcine max. (L.) Merr] grown on a poorly drained, clayey soil to temporary flooding at three growth stages. The four treatments were soybean flooded for seven consecutive days at either VI, V4 or R2 growth stages at a flood height of 0.03 m above the soil surface and a well‐watered control. Flooding for seven consecutive days wetted but did not saturate the lower parts of the soil profile. This was attributed to the swelling by the montmorillonitic clay and subsequent sealing of the soil near the surface. In general, Eh and ODR decreased gradually during the flood, but increased as the soil dried upon removal of the flood. Canopy heights and dry weights of the flooded soybeans were dependent on plant growth stage at flooding and time of measurement but were lower than the control. When flooded at the VI or V4 growth stages, concentrations of N and K in the above‐ground plants were lower than the control after the flood. Three weeks after the flood was removed higher concentrations of these elements were found. When flooded at R2, concentrations of N and K were lower than in the control. Few differences were found in the plant concentrations of Ca, Mg, Mn, Fe, Al, and Na in the plant due to the flood, but by the end of the growing season, concentrations of Mn, Fe and Al were higher in the R2 flooded soybeans than in the other treatments. Seed yield response of the soybeans depended upon plant growth stage at flooding. The soybeans were particularly sensitive to the seven days of continuous flood at the R2 growth stage. Values of relative seed yield were 88, 83, and 44 % of the well watered‐control for the VI, V4 and R2 growth stages, respectively. Differences in seed yield were found with cultivar and with cultivar?flood treatment.     

Rhizosphere microbiota assemblage associated with wild and cultivated soybeans grown in three types of soil suspensions

Soil microbial community composition is determined by the soil type and the plant species. By sequencing the V3-V4 region of the bacterial 16S rRNA gene amplicons, the current study assessed the bacterial community assemblage in rhizosphere and bulks soils of wild (Glycine soja) and cultivated (Glycine max) soybeans grown in the suspensions of three important soil types in China, including black, red and soda-saline-alkali soils. The alpha-diversity of the bacterial community in the rhizosphere was significantly higher than that of the bulk soils suggesting that bulk soil lacks plant nurturing effect under the current study conditions. Black and red soils were enriched with nitrifying and nitrogen-fixing bacteria but the soda-saline-alkali soil suspension had more denitrifying bacteria, which may reflect agronomic unsuitability of the latter. We also observed a high abundance of Bradyrhizobium and Pseudomonas, enriched cellulolytic bacteria, as well as a highly connected molecular ecological network in the G. soja rhizosphere soil. Taken all, the current study suggest that wild soybeans may have evolved to recruit beneficial microbes in its rhizosphere that can promote nutrients requisition, biostasis and disease-resistance, therefore ecologically more resilient than cultivated soybeans.     

Bragg soybeans grown on a southern coastal plain soil IV. Seasonal changes in nodal N and P concentrations

Determinate soybean [Glycine max (L.) Merr.] has been characterized by few detailed nitrogen and phosphorous partitioning studies. Knowledge of the variation in N and P concentrations with plant part, nodal position, and plant age is needed for a better understanding of plant functions. In this field study, ‘Bragg’ soybean was grown on an Aquic Paleudult soil (series Goldsboro loamy sand). Plants were sampled at 10 to 14 day intervals beginning 44 days after planting (July 7) until harvest. Maximum observed N concentrations were 3.1, 2.8, 5.8, and 5.4% for stem internodes, petioles (+branches), leaf blades, and pods, respectively. Maximum observed P concentrations were 0.34, 0.48, 0.78, and 0.52 for the same respective plant parts. Nodal and temporal mean N and P concentrations varied considerably with plant age and nodal position in all plant parts. These data show that mean N and P concentrations in all four plant parts can vary several fold, depending upon plant age and nodal position for the sample. This suggests caution should be exercised in tissue sampling and interpretation of plant analysis. Concentrations of N and P generally decreased with time for stem internode, petioles (+branches), and leaf blades, but increased with time for pods. Except for N concentration in stem internodes, which increases with internode number, the N and P concentrations remain nearly constant throughout the growing season. The relationships provide insight for developing accurate plant models depicting N and P concentrations and translocations over time and among plant parts in determinate soybean.     

Effect of crop residue biochar on soil acidity amelioration in strongly acidic tea garden soils

Strongly acidic soil (e.g. pH < 5.0) is detrimental to tea productivity and quality. Wheat, rice and peanut biochar produced at low temperature (max 300 °C) and differing in alkalinity content were incorporated into Xuan‐cheng (Ultisol; initial pH_{soil/water = 1/2.5} 4.12) and Ying‐tan soil (Ultisol; initial pH _{soil/water = 1/2.5} 4.75) at 10 and 20 g/kg (w/w) to quantify their liming effect and evaluate their effectiveness for acidity amelioration of tea garden soils. After a 65‐day incubation at 25 °C, biochar application significantly (P < 0.05) increased soil pH and exchangeable cations and reduced Al saturation of both tea soils. Association of H⁺ ions with biochar and decarboxylation processes was likely to be the main factor neutralizing soil acidity. Further, biochar application reduced acidity production from the N cycle. Significant (P < 0.05) increases in exchangeable cations and reductions in exchangeable acidity and Al saturation were observed as the rate of biochar increased, but there were no further effects on soil pH. The lack of change in soil pH at the higher biochar rate may be due to the displacement of exchangeable acidity and the high buffering capacity of biochar, thereby retarding a further liming effect. Hence, a significant linear correlation between reduced exchangeable acidity and alkalinity balance was found in biochar‐amended soils (P < 0.05). Low‐temperature biochar of crop residues is suggested as a potential amendment to ameliorate acidic tea garden soils.     

Comparison of 15N natural abundance and difference methods for estimating N2 fixation of soybeans grown in a tropical soil

Abstract

A study was carried out to compare the difference or N-yield method with the ¹⁵N natural abundance method for the estimation of the fractional contribution of biological N₂ fixation in the different plant parts of nodulating and non-nodulating isolines of soybeans. The results indicated that the δ¹⁵N values of most plant parts of soybeans were significantly lower (p<0.05) in the nodulating than in the non-nodulating isoline. However, in the case of the root+nodule component, the δ¹⁵N value was higher in the nodulating than in the non-nodulating isoline possibly due to isotopic discrimination of ¹⁵N over ¹⁴N which may have occurred in the nodules. Inoculation of soybeans with the Bradyrhizobium japonicum strain CB 1809 increased significantly (p<0.05) the δ¹⁵N value of the root+nodule component implying that the effectiveness of the soybean-rhizobium symbiosis had increased by inoculation.

Percentage of plant N derived from atmospheric N₂ fixation (%Ndfa) estimated by the ¹⁵N natural abundance method was highly correlated (r=0.762, p<0.01) with that by the difference or N-yield method and the differences between the two methods were not statistically significant. The agreement between the two methods was closer at maturity than at the early reproductive stage.

The %Ndfa obtained by the difference method ranged from 48.4 to 92.6% whereas the %Ndfa obtained by the ¹⁵N natural abundance method ranged from 43.2 to 92.4% in the different plant parts. Based on the ¹⁵N natural abundance method, approximately 15% of the N in pod, shoot, grain, and shell was derived from the soil but in the case of stover, this fraction was about 55%.     

Bragg soybeans grown on a southern coastal plain soil III. Seasonal changes in nodal Fe,Zn, and Mn concentrations

Determinate soybean [Glyclne max (L.) Merr.] has been characterized by few detailed micronutrlent partitioning studies. Knowledge of the variation in mlcronutrient concentrations with plant part, nodal position, and plant age is needed for a better understanding of plant functions. In this field study, ‘Bragg’ soybean were grown on an Aquic Paleudult soil (Series Goldsboro loamy sand). Plants were sampled at 10–14 day intervals beginning 44 days after planting (July 7) until harvest. Maximum observed Fe concentrations were 152, 276, 259, and 191 ppm for stem internodes, petioles (+ branches), leaf blades, and pods, respectively. Maximum observed Zn concentrations were 118, 91, 95, and 112 ppm for the same respective plant parts. Maximum observed Mn concentrations were 41, 73, 134, and 63 ppm for the same respective plant parts. Nodal and temporal mean concentra tlons of Fe, Zn, and Mn generally varied considerably due to plant age and nodal position, respectively, in all plant parts. These data document that for plant analysis, mean concentrations of elements in all four plant parts can vary by several fold depending upon plant age and nodal composition of the sample. Regression equations and associated response surfaces will be extremely useful in the development of accurate plant growth models which describe Fe, Zn, and Mn concentrations and translocations among parts of determinate soybean.     

Isoflavone composition and antioxidant capacity of modified-lipoxygenase soybeans grown in Maryland

Maryland-grown soybean lines modified for low lipoxygenase-1 (LOX-1) content and a traditional nonmodified cultivar were analyzed for fatty acid composition, total phenolic content (TPC), isoflavone composition, relative DPPH? scavenging capacity (RDSC), and hydroxyl radical scavenging capacity (HOSC). Soybean lines included black, brown, and yellow soybeans. TPC of all soybean lines ranged from 2.84 to 4.74 mg gallic acid equiv (GAE)/g flour. Total isoflavones were between 2.78 and 8.66 μmol/g flour. RDSC of all lines was between 0.48 and 14.62 μmol Trolox equiv (TE)/g flour, and HOSC ranged from 53.57 to 135.52 μmol TE/g flour. Some modified-LOX genotypes demonstrated antioxidant capacity and/or isoflavone content similar to or higher than those of the nonmodified cultivar (P < 0.05). Black soybeans demonstrated higher TPC and RDSC than most yellow soybean lines, although they did not have higher isoflavone content. The results demonstrate that modification of the LOX trait did not necessarily alter the antioxidant capacity or chemical composition of the experimental soybean lines when compared with a nonmodified cultivar. These soybean lines may be studied further for nutraceutical properties and use in functional foods.     

Detection of aluminium tolerance plasmids and microbial diversity in the rhizosphere of plants grown in acidic volcanic soil

The rhizosphere is considered as a hot-spot for gene exchange among bacteria in terrestrial ecosystems. Chilean volcanic soils are characterized by low pH and high concentrations of aluminium (Al) in the soil solution, thus Al tolerance could be important for the survival of microorganisms in these soils; loss of genes encoding for Al tolerance may affect competitiveness particularly in the rhizosphere where competition is strong. The occurrence of Al-tolerance plasmids was investigated in the rhizospheres of pasture and crop plants growing in acidic volcanic soils from southern Chile. Al tolerance plasmids were captured by biparental mating. Two types of Al tolerance plasmids could be distinguished, based on their endonuclease restriction pattern. One plasmid of each group (denoted as pRPA21 and pOPA21) was selected for further studies. The plasmids showed a high stability in presence and absence of Al. Additionally, microbial community composition in the rhizosphere soils was assessed by denaturing gradient gel electrophoresis (DGGE). Sequencing of DGGE bands revealed among others, members of the bacterial phylum Gemmatimonadetes and archaeal phylum Crenarchaeota. The present study shows that the rhizosphere of pasture and crop plants growing in Chilean volcanic soil harbors genetic mobile elements which could play a role in the adaptation of bacterial populations to environmental stressors, such as Al-toxicity.     

Leaching and efficiency of six organic zinc fertilizers applied to navy bean crop grown in a weakly acidic soil of Spain

Zinc contamination of groundwater from fertilizers applied to pulse crops is a potential problem, but the use of different types of organic chelates can minimize the contamination potential while still adequately feeding the crops. The objective of this study was to compare the leaching, distribution in fractions and availability, and relative effectiveness of Zn from six organic Zn fertilizers (zinc-ethylenediaminetetraacetate- N-2-hydroxyethylethylenediaminetriacetate (Zn-EDTA-HEDTA), Zn-HEDTA, zinc- S, S'-ethylenediaminedisuccinate (Zn- S, S-EDDS), zinc-polyhydroxyphenylcarboxylate, Zn-EDTA, and zinc-ethylenediaminedi(2-hydroxy-5-sulfophenylacetate) (Zn-EDDHSA)) applied to a navy bean ( Phaseolus vulgaris, L.) crop cultivated by applying different Zn levels, in a weakly acidic soil under greenhouse conditions. Zinc soil behavior was evaluated by diethylenetriaminepentaacetic acid-triethanolamine (DTPA-TEA), DTPA-ammonium bicarbonate (DTPA-AB), Mehlich-3, and BaCl 2 extractions and sequential fractionation. In all the fertilizer treatments, the percentage of labile Zn that remained in the soil was high with respect to the quantity of Zn applied, with values respectively ranging from 42 to 80% for Zn-EDDHSA and Zn-EDTA sources. A positive correlation with a high level of significance existed between the micronutrient concentration in the navy bean crop (total and soluble) and labile Zn fractions, available Zn, and easily leachable Zn ( r ranged from 0.89 to 0.95, P < 0.0001). The relatively high quantity of total Zn leached by applying Zn-EDTA and Zn-S,S-EDDS sources (11.9 and 6.0%, respectively, for the rate 10 mg of Zn kg(-1) of soil) poses a potential pollution risk for neighboring waters. It would seem recommendable to apply Zn-HEDTA or Zn-EDDHSA sources, even applied at the low rate (5 mg of Zn kg(-1) of soil), because they produced available Zn concentrations in the soil that were above the critical concentration and also produced high Zn concentrations in plants (139 and 106 mg of Zn kg(-1) of dry matter, respectively).     

Composition and field distribution of the population of Rhizobium meliloti in root nodules of uninoculated field-grown alfalfa

Only four antibiotics (kanamycin, spectinomycin, ampicillin and novobiocin) of ten tested were capable of discriminating between root nodule isolates of Rhizobium meliloti obtained from uninoculated field-grown alfalfa (Medicago sativa L.). The 300 isolates in the collection were subdivided into seven groups based on their intrinsic antibiotic resistance characteristics with 204 and 55 isolates placed into two groups, C and F, respectively. Isolates from group C dominated the root nodule population on plants in eight of the nine quadrats analyzed. Furthermore they were one of the two dominant groups found in nodules formed on plants grown in a plant infection-soil dilution experiment and challenged with a composite soil sample from the field site. Antiserum raised to a group C isolate (No. 31) cross-agglutinated with 46 of 55 group C isolates to a titer identical with that of the parent antigen. There were no cross-reactions between isolates from any of the other six groups. Only 9 of 34 isolates from group F cross-agglutinated with antiserum raised to a group F isolate (No. 17). Thirty-three of 35 cross-agglutinating field isolates from group C had the same sodium dodecyl sulphate-polyacrylamide-gel electrophoretic protein-profile pattern as isolate No. 31 whereas non-agglutinating isolates from the same group had distinctly different protein profile patterns. The data suggest that intrinsic antibiotic resistance characteristics can be a useful complementary tool to be used in conjunction with other methods to identify and discriminate isolates of R. meliloti. It should not be used on its own as a strain identification method.     

Bragg soybeans grown on a southern coastal plains soil i. dry matter distribution,nodal growth analysis,and sample variability

Yields of soybean [Glycine max (L.) Merr.] are affected by the manner in which available resources are partitioned into component plant parts. Little is known about these partitioning processes and much of what has been reported describes indeterminate cultivars or comes from other than field studies. A field investigation was conducted, therefore, on a Goldsboro loamy sand (Aquic Paleudult) to characterize in detail the growth and development of a determinate soybean cultivar ‘Bragg’. Soybean were grown in well watered field plots in four replications from each of which 4 nested samples of 0.3 m² each were combined at each sampling. Leaf area, dry matter production, internode length, and sample variability were determined nodally at 10‐ to 14‐day intervals from 7 July to 17 October. Plant components at each node were separated into stems, leaf blades, pods, and petioles. Primary and secondary branches were combined in the petiole fraction.

Maximum above ground plant dry weight achieved was 1027 g/m² and maximum combined nodal dry weight was 92 g/m² (at node 8), both occurring at the R7 growth stage. Canopy dry weight distribution over time was unique for each plant part. Growth analyses showed that RGR, NAR, LAR, and LWR declined with plant age at a rate that could be described with either linear or exponential models. A maximum CGR of 16.24 g/m²/day occurred at mid‐podfill and declined thereafter due to maturity. Leaf area per node peaked between nodes 7 and 12, decreasing uniformly toward the top of the canopy. Maximum nodal LAI was 0.79 at node 7 on 31 August.

Distribution of dry weight among parts varied with plant age and node position. Maximum dry weights of stems (276 g/m²), petioles (253 g/m²), and leaves (263 g/m²) were found during mid‐podfill. During mid‐August, the dry weights of the stems, petioles, and leaves were similar and approximately 250 g/m². Stem dry weights had the lowest coefficients of variation of all plant fractions once maximum dry weight was achieved. Internode length varied along the stem with the maximum at node 12. By bloom, expansion of the internodes lower than 12 had ceased; expansion of the eight higher internodes ceased three weeks later. During vegetative growth, the ratio of stem internodal dry weight to internodal length had peak values at the lowest and highest internodes. During reproductive growth, the ratio decreased linearly with internode number. Coefficients of variation (CV) for the combined weight of plant parts, and for stems, petioles, leaves, and pods were relatively constant during the season and were 24.8, 23.4, 38.2, 25.5, and 26.8%, respectively. The CV's for the combined weight of plant parts were somewhat higher at the lowest and uppermost nodes. This variability resulted from the abscission of petioles and leaves in the lower nodes and the initiation of leaves, petioles, and pods in the upper nodes where rapid growth and development was occurring. Time from node initiation to achievement of lowest stable CV was determined for each node and plant part. Plant node position and morphological part with the lowest CV was identified for each sampling date (and growth stage).     

Antiallergic activity of novel isoflavone methyl-glycosides from Cordyceps militaris grown on germinated soybeans in antigen-stimulated mast cells

Isoflavones are known to possess immunomodulating and antiallergic activities. Previously we identified novel isoflavone methyl-glycosides (daidzein 7-O-β-d-glucoside 4″-O-methylate (CDGM), glycitein 7-O-β-D-glucoside 4″-O-methylate (CGLM), genistein 7-O-β-D-glucoside 4″-O-methylate (CGNMI) and genistein 4'-O-β-D-glucoside 4″-O-methylate (CGNMII)) from Cordyceps militaris grown on germinated soybeans (GSC). The biological activity of novel isoflavone methyl-glycosides, however, remains unknown. In this study, CGNMII showed the strongest inhibition of degranulation. Additionally, the release of interleukin (IL)-4 and tumor necrosis factor (TNF)-α was decreased by CGNMII in antigen-stimulated RBL-2H3 cells. To elucidate the antiallergic mechanism of CGNMII, we examined whether it affected levels of signaling molecules responsible for degranulation. The levels of activated Lyn, Syk, PLCγ1 and LAT proteins were reduced in CGNMII treated RBL-2H3 cells. CGNMII also inhibited the activation of AKT and ERK1/2 proteins. These results suggest that CGNMII might be used as a therapeutic agent for allergic diseases.     

Occurrence and nature of mixed infections in nodules of field-grown soybeans (Glycine max)

Summary Mixed infections of Bradyrhizobium japonicum strains in early and late nodules of four soybean cultivars were studied in a field soil. Nodule occupants were identified by immunofluorescence using serogroup specific antibodies prepared against B. japonicum strains USDA 110, USDA 123, and USDA 138. Double infection was determined directly by combined examination of the same microscopic field by fluorescence and phase contrast microscopy. Double strain occupancy was observed consistently, and its occurrence did not differ substantially in pouch, soil pot, and field experiments, ranging in incidence from 12% to 32%. No significant differences in the incidence or nature of double infection could be attributed to cultivar, seed inoculation, or plant maturity. Strains reactive to strain USDA 123-fluorescent antibody were dominant in both singly and doubly infected nodules irrespective of cultivar, plant age, or seed inoculation with strain USDA 110.Paper no. 15092 in the Scientific Journal Series of the Minnesota Agricultural Experiment Station, St. Paul     

Behavior of zinc from six organic fertilizers applied to a navy bean crop grown in a calcareous soil

The objective of this study was to compare the mobility, leaching, availability, and relative effectiveness of Zn from Zn-polyhydroxyphenylcarboxilate (Zn-PHP), Zn-HEDTA (Zn-N-2-hydroxyethyl-ethylenediaminetriacetate), Zn-EDDHSA [Zn-ethylenediamine-di-(2-hydroxy-5-sulfophenylacetate)], Zn-EDTA (Zn-ethylenediaminetetraacetate), Zn-S,S-EDDS (Zn-ethylenediaminedisuccinate), and Zn-EDTA-HEDTA sources by applying different Zn rates (5 and 10 mg kg(-1)) to a calcareous soil under greenhouse conditions. A lysimeter experiment was carried out for 60 days and using navy bean (Phaseolus vulgaris L.) as an indicator plant. The Zn available to the plant and easily leachable Zn were determined in soil by different single extractions, while the distribution of Zn in the soil was assessed by sequential speciation. The utilization of applied Zn by the navy bean was greatest when the Zn treatments were Zn-EDTA, Zn-EDTA-HEDTA, Zn-HEDTA, and Zn-EDDHSA. Both total Zn in the plants and soluble Zn in the plant dry matter (extracted with 1 mM 2-morpholino-ethanesulfonic acid) were positive and significantly correlated with the following: the amounts of Zn extracted with the three single extractions used to estimate soil available Zn and the amounts of Zn in the water soluble plus exchangeable and organically complexed fractions. The Zn-HEDTA, Zn-EDDHSA, Zn-EDTA-HEDTA, Zn-S,S-EDDS, and Zn-EDTA sources significantly increased the mobility of micronutrients through the soil with respect to the control and Zn-PHP source. The maximum Zn concentration obtained in the leachate fractions was 65 mg L(-1) (13% of Zn applied) for the Zn-S,S-EDDS chelate applied at a rate of 10 mg Zn kg(-1) soil. In the course of the crop, the soil pH + pe parameter increased significantly with experimental time.     

Effect of liming and gypsum on soil chemistry,yield, and mineral composition of ryegrass grown in an acidic Andisol

Abstract

Changes in the chemistry of the acidic Chilean Andisols in response to various ameliorant treatments (gypsum, dolomitic, and calcitic limestone) and their effects on ryegrass (Lolium perenne) production were studied in laboratory incubation and greenhouse experiments. Dolomitic and calcitic limestone alone and in combination with gypsum increased pH significantly and, at the same time, decreased exchangeable aluminum (Al) concentration to low concentrations. Gypsum alone increased pH slightly and reduced Al concentration by 50%, but its effect on ryegrass yield was similar to calcitic and dolomitic limestone. The Al/calcium (Ca) ratio was not a good predictor of the Al toxicity for plant growth but the Al/sulfur (S) ratio in the soil showed a good relationship with dry matter yield. The Ca + magnesium (Mg) + potassium (K) content in shoots was highly correlated with dry matter yield.     

Corrosion of archaeological bronze artefacts in acidic soil

Corrosion of bronze in soil is a well-known phenomenon. In particular, archaeological artefacts which may remain in the soil for thousands of years are subject to severe corrosion. However, bronze objects excavated 50–100 years ago seem to be less corroded than those found today. Therefore, recent pollution of the soil is suspected to accelerate the corrosion. An interdisciplinary project has been started in Sweden to search for correlations between the degree of bronze corrosion, corrosion products, general archaeological and environmental conditions, and parameters characterizing the soil chemically.From three archaeological sites near Stockholm (Birka, Fresta, and Valsta), 33 bronze artefacts and related samples of soil have been investigated. All corrosion products and the metal core (if any) were analysed by SEM/EDS and XRD. Metal oxides, carbonates, sulphates, chlorides and phosphates have been identified. Each soil sample has been geologically classified, and a number of chemical analyses have been undertaken: pH in water and KCl, resistivity, loss on ignition, exchangeable acidity, chloride, phosphate, sulphur contents, acidsoluble cations extracted in two different ways, etc. About 8000 data have been compiled in an EXCEL data base. A statistical evaluation including multivariate modelling and analysis utilizing the SIMCA-S system, has been undertaken. The results so far obtained are only tentative but suggest that high concentrations of soot, sulphur or phosphate in the soil may have accelerated the corrosion of the investigated bronze objects. The influence of low pH values, though, is less clear.