The critical concentration of manganese in field-grown wheat

1985 ◽  
Vol 36 (2) ◽  
pp. 145 ◽  
Author(s):  
RD Graham ◽  
WJ Davies ◽  
JS Ascher
Keyword(s):  
Field Experiments ◽  
Critical Level ◽  
Critical Concentration ◽  
Optimal Growth ◽  
Mn Deficiency ◽  
Unreliable Method ◽  
Chlorophyll A Fluorescence Transients ◽  
Yield Responses ◽  
Fluorescence Transients ◽  
Wheat Tissues

The critical concentration of manganese (Mn) in wheat tissues for optimal growth was determined from field experiments. In the youngest emerged blade showing a ligule (YEB), the critical concentration was 11 � 1 8g g-1 (DW). The critical concentrations for older blades and whole tops were: next leaf below YEB, 13 � 1 8g g-1 DW; older leaves, 16 � 1 8g g-1 DW; whole tops, 12 � 1 8g g-1 DW. The older blades were less sensitive determinants of the growth response and are not recommended tissues for analysis. Diagnosis using whole tops was less sensitive than with YEB, but analysis of whole tops may give an integrated picture of Mn deficiency where availability varies rapidly with time. The critical concentration of 11 � 1 8g g-1 in the YEB for growth is also the critical level for the appearance in that leaf of normal chlorophyll a fluorescence transients. The Fo/Fv ratio, a parameter of the leaf fluorescence transients, correlated well with the Mn concentration in the leaf and may prove suitable for the diagnosis of Mn deficiency in field-grown wheat. The critical level of Mn was the same for two genotypes differing in their ability to tolerate Mn deficiency in the soil. Grain yield responses and other relevant data collected over three years are presented. Analysis of grain was shown to be an unreliable method of diagnosing an earlier Mn deficiency in the crop.

Soil and tissue tests to predict pasture yield responses to applications of potassium fertiliser in high-rainfall areas of south-western Australia

2002 ◽  
Vol 42 (2) ◽  
pp. 149 ◽  
Author(s):  
M. D. A. Bolland ◽  
W. J. Cox ◽  
B. J. Codling
Keyword(s):  
Western Australia ◽  
Field Experiments ◽  
Relative Yield ◽  
Subterranean Clover ◽  
Test Method ◽  
Yield Response ◽  
Soil Test ◽  
Test Procedures ◽  
Pasture Production ◽  
Yield Responses

Dairy and beef pastures in the high (>800 mm annual average) rainfall areas of south-western Australia, based on subterranean clover (Trifolium subterraneum) and annual ryegrass (Lolium rigidum), grow on acidic to neutral deep (>40 cm) sands, up to 40 cm sand over loam or clay, or where loam or clay occur at the surface. Potassium deficiency is common, particularly for the sandy soils, requiring regular applications of fertiliser potassium for profitable pasture production. A large study was undertaken to assess 6 soil-test procedures, and tissue testing of dried herbage, as predictors of when fertiliser potassium was required for these pastures. The 100 field experiments, each conducted for 1 year, measured dried-herbage production separately for clover and ryegrass in response to applied fertiliser potassium (potassium chloride). Significant (P<0.05) increases in yield to applied potassium (yield response) were obtained in 42 experiments for clover and 6 experiments for ryegrass, indicating that grass roots were more able to access potassium from the soil than clover roots. When percentage of the maximum (relative) yield was related to soil-test potassium values for the top 10 cm of soil, the best relationships were obtained for the exchangeable (1 mol/L NH4Cl) and Colwell (0.5 mol/L NaHCO3-extracted) soil-test procedures for potassium. Both procedures accounted for about 42% of the variation for clover, 15% for ryegrass, and 32% for clover + grass. The Colwell procedure for the top 10 cm of soil is now the standard soil-test method for potassium used in Western Australia. No increases in clover yields to applied potassium were obtained for Colwell potassium at >100 mg/kg soil. There was always a clover-yield increase to applied potassium for Colwell potassium at <30 mg/kg soil. Corresponding potassium concentrations for ryegrass were >50 and <30 mg/kg soil. At potassium concentrations 30–100 mg/kg soil for clover and 30–50 mg/kg soil for ryegrass, the Colwell procedure did not reliably predict yield response, because from nil to large yield responses to applied potassium occurred. The Colwell procedure appears to extract the most labile potassium in the soil, including soluble potassium in soil solution and potassium balancing negative charge sites on soil constituents. In some soils, Colwell potassium was low indicating deficiency, yet plant roots may have accessed potassum deeper in the soil profile. Where the Colwell procedure does not reliably predict soil potassium status, tissue testing may help. The relationship between relative yield and tissue-test potassium varied markedly for different harvests in each year of the experiments, and for different experiments. For clover, the concentration of potassium in dried herbage that was related to 90% of the maximum, potassium non-limiting yield (critical potassium) was at the concentration of about 15 g/kg dried herbage for plants up to 8 weeks old, and at <10 g/kg dried herbage for plants older than 10–12 weeks. For ryegrass, there were insufficient data to provide reliable estimates of critical potassium.

Controlling manganese deficiency in sugarbeet with foliar sprays

1991 ◽  
Vol 116 (3) ◽  
pp. 351-358 ◽  
Author(s):  
P. J. Last ◽  
K. M. R. Bean
Keyword(s):  
Field Experiments ◽  
Early Summer ◽  
The Other ◽  
Manganese Deficiency ◽  
Manganese Sulphate ◽  
Mn Deficiency ◽  
Deficiency Symptoms ◽  
Foliar Sprays ◽  
Mn Concentrations

SUMMARYField experiments in 1987 and 1988 on peaty-loam, Mn-deficient soils of the Adventurers series in Cambridgeshire, UK, tested the response of sugarbeet to three forms of manganese fertilizer supplied as foliar sprays. The influence of a wetter and an adjuvant on manganese absorption and growth was also investigated.Cutonic and chelated forms of Mn, when applied at standard rates, were inefficient at increasing Mn concentrations in plants and alleviating deficiency symptoms during early summer. Mn concentrations in foliage increased rapidly after spraying with manganese sulphate, and most of the deficiency symptoms disappeared. These benefits were usually enhanced when manganese sulphate sprays were used with an adjuvant.Averaged over both years, yield without Mn was 8·83 t sugar/ha; the largest yield, 9·56 t/ha, was obtained with manganese sulphate plus adjuvant. Smaller benefits were obtained with the other forms of Mn. The adjuvant, when used with chelated Mn, appeared to depress sugar yields in both years. The likelihood of reducing the number of sprays required to control Mn deficiency on Fen soils was improved by using an adjuvant with manganous sulphate sprays.

Plant-available manganese in bauxite residue sand amended with compost and residue mud

Soil Research ◽  
2012 ◽  
Vol 50 (5) ◽  
pp. 416 ◽  
Author(s):  
Chitdeshwari Thiyagarajan ◽  
R. W. Bell ◽  
J. Anderson ◽  
I. R. Phillips
Keyword(s):  
Calcium Carbonate ◽  
Critical Level ◽  
Bauxite Residue ◽  
Surface Adsorption ◽  
Organic Amendments ◽  
Effective Strategy ◽  
Alkaline Ph ◽  
Mn Deficiency ◽  
Exchangeable Fraction ◽  
Mn Concentrations

Manganese (Mn) deficiency has been a constraint for revegetation on bauxite residue sand and there is still no effective strategy to remedy this problem. The effect of addition of organic amendments (piggery waste, biosolids, and commercial compost) and mineral amendments (unamended, seawater-neutralised residue mud, and carbonated bauxite residue mud) on Mn forms and availability in residue sand was studied. Incubation of residue sand with organic amendments (applied at rates of 0, 10, and 50 t/ha) over a 30-day period found little change in DTPA-extractable Mn concentrations, which remained below the critical level of 1 mg/kg. The DTPA-extractable Mn concentrations were comparable to those in the exchangeable fraction (DTPA-Mn = 0.931 × Exch-Mn + 0.358, r2 = 0.84) and, therefore, may provide an estimation of plant-available Mn. The highest Mn concentrations were consistently associated with the carbonate fraction, suggesting that Mn was either retained by surface adsorption reactions and/or co-precipitated with calcium carbonate. The addition of residue mud amendments generally reduced DTPA-extractable Mn, probably through adsorption by hydrous Fe and Al oxides. Leaching did not cause significant (P > 0.05) movement of Mn in residue sand columns, possibly due to the alkaline pH and specific adsorption reactions. Given the difficulty of increasing plant-available Mn by organic amendments, residue mud additions, leaching, and/or fertilisers, overcoming Mn deficiency in vegetation on bauxite residue sand may depend on using Mn-efficient species that are able to efficiently extract Mn associated with carbonate and Fe/Al oxyhydroxide fractions.

Yield responses of oats and alfalfa to common hemp-nettle (Galeopsis tetrahit) interference

1991 ◽  
Vol 71 (1) ◽  
pp. 141-147 ◽  
Author(s):  
Anne Légère ◽  
Jean-Marc Deschênes
Keyword(s):  
Field Experiments ◽  
First Year ◽  
Weed Competition ◽  
Yield Losses ◽  
Weed Interference ◽  
Medicago Sativa L ◽  
Lower Height ◽  
Carry Over ◽  
Yield Responses ◽  
Early Harvest

Effects of various densities of hemp-nettle (Galeopsis tetrahit L.) on yields of oats (Avena sativa L.) and first year alfalfa (Medicago sativa L.) were investigated in field experiments. In both crops, emergence of hemp-nettle seedlings occurred after plot establishment such that final densities were generally greater than initial densities. Hemp-nettle plants within a stand were distributed normally over no more than seven 15-cm height classes. Very few plants were found in the lower height classes. Weight distribution according to the same height classes showed that average to tall individuals produced a large proportion of the weed biomass. Oat yields decreased as hemp-nettle density increased. In the density range of 28–248 hemp-nettle plants m−2, oat grain yield losses varied between 12 and 50%. Alfalfa was cut according to either a two-cut regime, or a three-cut regime which included an early harvest. Alfalfa yields decreased with increase in hemp-nettle density regardless of cutting regime, whereas effects of cutting regime on alfalfa yield varied with year of experiment. In each regime, timing of first harvest determined the duration of hemp-nettle interference and may have affected the degree of carry-over effects to later harvests. Key words: Hemp-nettle, Galeopsis tetrahit, weed competition, weed interference, crop losses

The use of chemical extractions and continuous cropping to measure the potassium status of soils

1978 ◽  
Vol 29 (6) ◽  
pp. 1247 ◽  
Author(s):  
AM Graley
Keyword(s):  
Nitric Acid ◽  
Critical Level ◽  
Potassium Uptake ◽  
Continuous Cropping ◽  
Exchangeable Potassium ◽  
Soil Potassium ◽  
Chemical Extractions ◽  
Plant Yields ◽  
Yield Responses ◽  
Soil Groups

Soil potassium, measured by simple chemical extractions, was compared with potassium availability assessed during continuous cropping of perennial ryegrass in pots, on 12 surface soils representing four Tasmanian soil groups. For three soil groups with mainly kaolinitic clay, potassium uptake by the plant (the main measure of potassium availability) was related to a decrease in the potassium extracted from the soil by boiling lM nitric acid during the experiment. The decrease in soil potassium extracted by repeated nitric acid digestions averaged 95% of the total potassium uptake. However, a large and rapid uptake from the illitic yellow podzolics was only partly assessable by chemical extractions. For all soils, much of the large amount of potassium taken up early was stored in the plant roots and transferred to the tops much later. Plant yields were related to exchangeable potassium only within soil groups; over most soils they were related to nitric acid-soluble potassium. Yield responses to added potassium usually occurred when exchangeable potassium became depleted to a critical level of 0.2–0.25 m-equiv./100 g or nitric acid-soluble potassium to 0.4–0.7 m-equiv./100 g. The critical level of potassium in ryegrass tops was 0.5–0.8%. On average nearly two-thirds of the potassium released from soils came from exchangeable sources. Potassium initially non-exchangeable was differentiated into quickly released 'intermediate' potassium and slowly released 'constant rate' potassium. Release of intermediate potassium predominated from the yellow podzolics and from one non-calcic brown soil with much randomly interstratified material in its clay.

scholarly journals RELAXATION IN EXTRACTED MUSCLE FIBERS

1954 ◽  
Vol 38 (2) ◽  
pp. 149-159 ◽  
Author(s):  
Emil Bozler
Keyword(s):  
Critical Level ◽  
Critical Concentration ◽  
Muscle Fibers ◽  
Complexing Agent ◽  
Tetraacetic Acid ◽  
Relaxation Factor ◽  
Low Concentrations ◽  
High Concentrations ◽  
Relaxing Effect ◽  
Subsequent Addition

1. Ethylenediamine tetraacetic acid (EDTA) in low concentrations imitates all the known effects of the relaxation factor ("Marsh factor"). In extracted muscle fibers which have contracted in a solution containing adenosinetriphosphate (ATP), the addition of EBTA causes relaxation, the subsequent addition of CaCl2, contraction. 2. In fibers which have been briefly immersed in 5 MM EDTA, ATP causes rapid relaxation if Mg is also present. These fibers have essentially the same properties as briefly extracted fibers. Brief immersion into a solution containing CaCl2 restores at once the original condition. It is concluded that EDTA produces its action by firmly combining with bound Ca, thereby inactivating it. 3. In relaxed muscle fibers not only Ca, but also lowering the concentration of Mg below a critical level, causes contraction. In such fibers Mg in the lowest effective concentrations increases contraction, but the effect reverses above a certain concentration. 4. At 0° Mg in the presence of ATP has a relaxing effect without the relaxation factor. 5. The results indicate that Mg has two distinct effects in the presence of ATP. It causes contraction at low concentrations, but above a critical concentration its relaxing action prevails. The last of these effects is blocked by bound Ca. If the latter is inactivated by EDTA, Mg in sufficiently high concentrations causes relaxation. The action of the relaxation factor can similarly be explained by assuming that it acts as a complexing agent which inactivates bound Ca. 6. Previous evidence that the relaxed state depends on the formation of an enzymatically inactive ATP-protein complex was confirmed. It was found that PP in low concentrations strongly increases the relaxing effect of ATP in briefly extracted fibers.

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