Effect of application of bauxite residue (red mud) to very sandy soils on subterranean clover yield and P response

Soil Research ◽  
2001 ◽  
Vol 39 (5) ◽  
pp. 979 ◽  
Author(s):  
R. N. Summers ◽  
M. D. A. Bolland ◽  
M. F. Clarke
Keyword(s):  
Soil Ph ◽  
Red Mud ◽  
Close Contact ◽  
Bauxite Residue ◽  
Maximum Yield ◽  
Sandy Soils ◽  
Subterranean Clover ◽  
Yield Response ◽  
Lime Treatment ◽  
Pasture Production

Bauxite residue (red mud) is the byproduct from treatment of crushed bauxite with caustic soda to produce alumina. When dried the residue is alkaline and has a high capacity to retain phosphorus (P). The residue is added to pastures on acidic sandy soils to increase the capacity of the soils to retain P so as to reduce leaching of P into waterways and so reduce eutrophication of the waterways. This paper examines how red mud influences the effectiveness of P from single superphosphate for producing subterranean clover (Trifolium subterraneum) dry herbage, in the year of application and in the years after application (residual value). Red mud was applied at 0, 2, 5, 10, 20, and 40 t/ha and the P was applied at 0, 5, 10, 20, 40, 80, and 160 kg P/ha. In the year of application and the year after application of red mud, dry matter yields were doubled on the soil treated with 20 t/ha of red mud compared with the untreated control. Improvements in production were initially greater in the red mud treatments than in the lime treatment (2 t lime/ha). Red mud increased the maximum yield plateau for P applied in current and previous years. When P was applied to freshly applied red mud, more P needed to be applied to produce the same yield as the amount of red mud applied increased. Red mud increased soil pH, and the increases in yield are attributed to removing low soil pH as a constraint to pasture production. This initial need for higher amounts of fertiliser P when increasing amounts of red mud were applied may be due to increased P sorption caused by increased precipitation of applied P when the fertiliser was in close contact with the freshly alkaline red mud. When P was freshly applied to red mud that had been applied to the soil 12 months ago, yield response and P content increased. This was attributed to the reduction in sorption of P due to red mud being neutralised by the soil and because sorption of P already present in the soil reduced the capacity of the red mud to sorb freshly applied fertiliser P. Residues of P in the soil and pH were also increased with application of red mud. In the years after application of red mud and lime, relative to P applied to nil red mud and nil lime treatment, the effectiveness of fertiliser P applied to the red mud and lime treatments increased. This was so as determined using plant yield, P concentration in plant tissue, and soil P test.

Effects of phosphorus fertiliser and rate of stocking on the seasonal pasture production of perennial ryegrass-subterranean clover pasture

1998 ◽  
Vol 49 (2) ◽  
pp. 233 ◽  
Author(s):  
J. W. D. Cayley ◽  
M. C. Hannah ◽  
G. A. Kearney ◽  
S. G. Clark
Keyword(s):  
Growth Rate ◽  
Maximum Yield ◽  
Subterranean Clover ◽  
Grazing Pressure ◽  
Yield Response ◽  
Potential Yield ◽  
Constant Growth Rate ◽  
Single Superphosphate ◽  
Pasture Production ◽  
Stocking Rates

The response of pastures based on Lolium perenne L. and Trifolium subterraneum L. to single superphosphate was assessed at Hamilton, Victoria, by measuring the growth of pastures during winter, spring, and summer over 7 years from 1979 to 1987. The seasons were defined by the pattern of pasture production, rather than by calendar months. Winter was the period of constant growth rate following the autumn rain; spring was the period of accelerating growth rate until growth rate changed abruptly following the onset of dry summer weather. Pastures were grazed with sheep at a low, medium, or high grazing pressure, corresponding generally to stocking rates of 10, 14, or 18 sheep/ha. At each level of grazing pressure, single superphosphate was applied at 5 rates from 1979 to 1982; the highest rate, expressed as elemental phosphorus (P), was reduced from 100 to 40 kg/ha during this time. In addition there was an unfertilised treatment. In 1984, fertiliser was applied at 6 rates from 4 to 40 kg P/ha. No fertiliser was applied in the remaining years, including 1983. Pasture production was measured from 1979 to 1982 and from 1985 to 1987. Total pasture dry matter (DM) accumulation per year at the highest stocking rate was less than the other treatments in 4 of the years. Averaged over all years and fertiliser treatments, the annual net production was 10·1, 10·1, and 9·0 t DM/ha (P < 0·05) for plots grazed at low, medium, and high stocking rates, respectively. The amount of fertiliser required to reach a given proportion of maximum yield response did not vary between winter and spring in any year, but the greater potential yield in spring (P < 0 ·001) meant that as more fertiliser was applied, the disparity between pasture grown in winter and pasture grown in spring increased. Differences in this disparity between extreme levels of P ranged from 1·4 t DM/ha in a drought to about 7 t DM/ha in a good season. The implications for managing farms when pastures are fertilised at higher rates than currently practised by district farmers are that systems of animal production with a requirement for plentiful good quality pasture in spring, such as ewes lambing in spring, should be used. The benefit of spring lambing over autumn lambing was supported when the 2 systems were compared over 26 years using the GrassGro decision support system. Well fertilised pasture systems will also allow more scope for conserving pasture as hay or silage, and increase opportunities for diversification in the farming enterprise, such as spring-growing crops.

Bauxite residue (red mud) improves pasture growth on sandy soils in Western Australia

Soil Research ◽  
1996 ◽  
Vol 34 (4) ◽  
pp. 569 ◽  
Author(s):  
RN Summers ◽  
NR Guise ◽  
DD Smirk ◽  
KJ Summers
Keyword(s):  
Heavy Metals ◽  
Calcium Carbonate ◽  
Sodium Carbonate ◽  
Soil Ph ◽  
Red Mud ◽  
Sandy Soils ◽  
Subterranean Clover ◽  
Rooting Depth ◽  
Manganese Sulfate ◽  
Crushed Limestone

Red mud is a finely crushed, iron-rich, alkaline residue, obtained by digesting bauxite with caustic soda to remove the alumina. The remnant alkalinity of red mud is equivalent to 11% pure calcium carbonate. Phosphorus leaching from infertile sandy soils has resulted in eutrophication of estuaries and has caused algal blooms. Red mud has been shown to reduce leaching of phosphorus from sandy soil. This research was undertaken to determine the effect of red mud on pasture growth and uptake of heavy metals. Red mud, either untreated or treated with gypsum, was applied at rates of 0, 10, 20, 40, and 80 t/ha to a subterranean clover and ryegrass hay paddock. There were 3 replicates of each treatment and a completely randomised design was used. The experimental design was 5 rates of red mud x 2 untreated and treated with gypsum x 3 replicates, resulting in 30 plots. Plant growth, and nutrient and heavy metal composition of the plant tops, were measured. An application of 40 t/ha of red mud increased hay (mainly subterranean clover and ryegrass) production by 24% and increased soil pH in the top 10 cm by 1.0 unit from 3.5 (1 : 5 soil : 0.1 M CaCl2). The increase in production was probably because of the liming effect of the remnant alkali in the red mud, which may have potential as a replacement for crushed limestone. Sodium carbonate, the predominant alkali in red mud, is more soluble than calcium carbonate from crushed limestone and has the potential to change the pH of the soil more rapidly. The soil was top-dressed with red mud, without disturbing the existing pasture, resulting in changes to the pasture production and nutrient composition consistent with a change in soil pH throughout the rooting depth. If crushed limestone is not mixed into the soil it may take many years to increase the pH of the soil; however, this mixing results in extra cost from re-seeding and an initial depression in yield. Although much more red mud is needed than lime, the cost is comparable when the haulage distance is less than about 30 km. In previous trials, at red mud application rates > 500 t/ha, gypsum was mixed into the red mud to reduce salinity and pH. At these rates, the red mud had overwhelmed the buffering capacity of the soil. The gypsum reduced the pH by changing the sodium carbonate in the red mud to calcium carbonate, thus changing the pH from > 10 to about 8.5. However, amendment of the red mud with gypsum when applied at rates < 80 t/ha proved unnecessary in this experiment, probably because the proportion of soil was sufficient to alter the pH of the red mud. When red mud is applied to acidic infertile sands, manganese application as manganese sulfate may be necessary, because the rise in pH may rapidly induce manganese deficiency in plants. Care should be taken to monitor other nutrients which have their availability for plants affected by pH (e.g. copper, zinc, and molybdenum). Red mud did not elevate the concentrations of heavy metals in the soil, hay, or fresh plant tissue.

Field amelioration of acidic soils in south-east Queensland. III. Relationships of maize yield response to lime and unamended soil properties

1998 ◽  
Vol 49 (4) ◽  
pp. 649 ◽  
Author(s):  
P. W. Moody ◽  
T. Dickson ◽  
R. L. Aitken
Keyword(s):  
Grain Yield ◽  
Soil Solution ◽  
Soil Ph ◽  
Maximum Yield ◽  
Maize Yield ◽  
Soil Types ◽  
Yield Response ◽  
Lime Treatment ◽  
Acidic Soils ◽  
Solution Ph

Maize (Zea mays) grain yield responses to rates of lime were measured at 19 sites onseveral soil types in south-east Queensland. At some sites, one rate of gypsum or phosphogypsum was also applied. Relative grain yield (100 mean yield of nil lime treatment/maximum yield) was correlated with each of soil pH (1 : 5 water and 1 : 5 0·01 M CaCl2), soil solution pH, exchangeable (1 M KCl) Al, exchangeable (1 M NH4Cl) Ca, Al saturation of the effective cation exchange capacity (ECEC), Ca saturation of the ECEC, and 0·01 M CaCl2 extractable Mn and Al. Across all soil types, Mitscherlich fits indicated that most of the variation in relative grain yield was accounted for by either Ca saturation (R2 = 0·62) or soil solution pH (R2 = 0·61), although soil pH(water) (R2 =0·53), Al saturation (R2 = 0·46), exchangeable Ca (R2 = 0·42), soil pH(CaCl2) (R2 = 0·40), and CaCl2-extractable Mn (R2 = 0·33) also accounted for significant (P < 0·05) amounts of variation. These results demonstrate that one or both of Al and Mn toxicities were having an impact on yieldat different sites. The contrast between the lack of responses to gypsum/phosphogypsum at mostlime responsive sites and the observation that Ca saturation was well correlated with relative grainyield suggested an ameliorating effect of Ca on Al toxicity. This effect was captured by an index,Al saturation/Ca saturation, which was well correlated with relative grain yield (R2 = 0·66 for a Mitscherlich fit). A step-up regression approach indicated that most variation in relative grain yield (RY) could beaccounted for by the following equation: The assessment of factors likely to limit yield on strongly acidic soils of the region will therefore needto include indices of Al and Mn toxicities as well as Ca status. Soil pH integrated the effects of these factors on yield, and as a single index, was shown to bean effective diagnostic tool. Relative grain yields of 90% were associated with pH values in the soil solution, 1 : 5 water and 1 : 5 0·01 M CaCl2 of 4·5, 5·2, and 4·4, respectively.

Corrigendum to: Effects of phosphorus fertiliser and rate of stocking on the seasonal pasture production of perennial ryegrass-subterranean clover pasture

2002 ◽  
Vol 53 (12) ◽  
pp. 1383
Author(s):  
J. W. D. Cayley ◽  
M. C. Hannah ◽  
G. A. Kearney ◽  
S. G. Clark
Keyword(s):  
Growth Rate ◽  
Maximum Yield ◽  
Subterranean Clover ◽  
Grazing Pressure ◽  
Yield Response ◽  
Potential Yield ◽  
Constant Growth Rate ◽  
Single Superphosphate ◽  
Pasture Production ◽  
Stocking Rates

The response of pastures based on Lolium perenne L. and Trifolium subterraneum L. to single superphosphate was assessed at Hamilton, Victoria, by measuring the growth of pastures during winter, spring, and summer over 7 years from 1979 to 1987. The seasons were defined by the pattern of pasture production, rather than by calendar months. Winter was the period of constant growth rate following the autumn rain; spring was the period of accelerating growth rate until growth rate changed abruptly following the onset of dry summer weather. Pastures were grazed with sheep at a low, medium, or high grazing pressure, corresponding generally to stocking rates of 10, 14, or 18 sheep/ha. At each level of grazing pressure, single superphosphate was applied at 5 rates from 1979 to 1982; the highest rate, expressed as elemental phosphorus (P), was reduced from 100 to 40 kg/ha during this time. In addition there was an unfertilised treatment. In 1984, fertiliser was applied at 6 rates from 4 to 40 kg P/ha. No fertiliser was applied in the remaining years, including 1983. Pasture production was measured from 1979 to 1982 and from 1985 to 1987. Total pasture dry matter (DM) accumulation per year at the highest stocking rate was less than the other treatments in 4 of the years. Averaged over all years and fertiliser treatments, the annual net production was 10·1, 10·1, and 9·0 t DM/ha (P < 0·05) for plots grazed at low, medium, and high stocking rates, respectively. The amount of fertiliser required to reach a given proportion of maximum yield response did not vary between winter and spring in any year, but the greater potential yield in spring (P < 0 ·001) meant that as more fertiliser was applied, the disparity between pasture grown in winter and pasture grown in spring increased. Differences in this disparity between extreme levels of P ranged from 1·4 t DM/ha in a drought to about 7 t DM/ha in a good season. The implications for managing farms when pastures are fertilised at higher rates than currently practised by district farmers are that systems of animal production with a requirement for plentiful good quality pasture in spring, such as ewes lambing in spring, should be used. The benefit of spring lambing over autumn lambing was supported when the 2 systems were compared over 26 years using the GrassGro decision support system. Well fertilised pasture systems will also allow more scope for conserving pasture as hay or silage, and increase opportunities for diversification in the farming enterprise, such as spring-growing crops.

Response of annual pastures to applications of limestone in the high rainfall areas of south-western Australia

2002 ◽  
Vol 42 (7) ◽  
pp. 925 ◽  
Author(s):  
M. D. A. Bolland ◽  
D. G. Allen ◽  
Z. Rengel
Keyword(s):  
Soil Ph ◽  
Western Australia ◽  
Field Experiments ◽  
Sandy Loam ◽  
Subterranean Clover ◽  
Italian Ryegrass ◽  
Yield Response ◽  
Pasture Production ◽  
High Rainfall ◽  
Yield Responses

The yield response of long-term pastures growing on acidified soil to applications of limestone (0, 2.5, 5.0, 7.5 and 10.0 t/ha with adequate magnesium fertiliser, and 0 and 5 t/ha with no magnesium fertiliser) was measured in 5 field experiments on different representative soils of the high rainfall areas of south-western Australia. After application, limestone was incorporated 1 cm deep in 3 experiments, 3 cm deep in 1 experiment, and 7 cm in another experiment. The pastures comprised subterranean clover (Trifolium subterraneum), and annual and Italian ryegrass (Lolium rigidum and L. multiflorum), the dominant species found in intensively grazed dairy and beef pastures of the region. Yields were measured when ryegrass plants had 3 leaves per tiller, which is when pastures in the region are grazed to maximise utilisation by cattle.Subsoil acidity was a problem at 4 of the 5 sites, and was so severe at 1 site that, despite having the lowest soil pH to 50 cm depth, there was no yield response to limestone incorporated to 3 cm deep. Applications of fertiliser magnesium had no significant effect on pasture production, soil pH, aluminium and manganese, or concentration of magnesium in dried herbage in any of the 5 experiments. Increasing amounts of limestone consistently: (i) increased soil pH, by between 1–2 pH units in the top 5 cm of soil, and 0.5–1.0 of a pH unit in the 5–10 cm soil profile; and (ii) decreased, by up to 84–98%, the amount of exchangeable aluminium in the 0–5 and 5–10 cm soil profiles. During 3 years (1998–2000) there were: (i) no yield responses to limestone for a total of 9 assessments on a sand, or 11 assessments on a sandy gravel; (ii) 2 significant (P<0.05) yield responses to limestone, from a total of 8 assessments on a loamy clay and from 9 assessments on a loam; (iii) 9 significant yield responses from a total of 13 assessments on a sandy loam (2 from 5 assessments in 1998, 3 from 4 assessments in 1999, and all 4 assessments in 2000). The sandy loam had the largest amount of exchangeable aluminium in the top 5 cm of soil [about 1.6 cmol(+)/kg, accounting for 35% of the exchangeable cations]. Increasing limestone applications did not induce deficiency or toxicity of any nutrient elements in subterranean clover or ryegrass dried herbage and, for dried herbage of bulk samples of both species, had no effect on dry matter digestibility, metabolisable energy and concentration of crude protein.

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.

Effect of soil pH and crop sequence on the response of wheat (Triticum aestivum) to phosphorus fertiliser

2015 ◽  
Vol 66 (1) ◽  
pp. 23 ◽  
Author(s):  
Craig Scanlan ◽  
Ross Brennan ◽  
Gavin A. Sarre
Keyword(s):  
Grain Yield ◽  
Soil Ph ◽  
Response Curve ◽  
Crop Production ◽  
Yield Potential ◽  
Yield Response ◽  
Lime Treatment ◽  
South West ◽  
Extractable P ◽  
Crop Sequence

Changes in soil fertility following long periods of crop production in the south-west of Western Australia (WA) may have implications for phosphorus (P) fertiliser recommendations for wheat production. When the sandy soils of the region were first cleared for agricultural production, they were typically marginally acidic to neutral, with soil extractable-P levels inadequate for crop production. Recent surveys have shown that 87% of soils in south-west WA exceed the critical soil extractable-P level required for 90% of maximum grain yield, and ~70% of soils have a surface-soil pHCa <5.5. There has also been a shift towards a high frequency of wheat in the crop sequence. We conducted a field experiment to begin to quantify the importance of the interactions between soil pH and crop sequence on wheat response to P fertiliser. For grain yield, the magnitude of the response was greatest for rate of P applied, followed by lime treatment and then crop sequence. There were no interactions between these treatments. Our analysis of the grain-yield response to rates of P fertiliser showed no significant difference between the shape of the grain-yield response curve for treatments with and without lime. However, we did find a significant interaction between lime treatment and rate of P fertiliser applied for shoot P concentration and that soil P was more plant-available in the +lime than the –lime treatment. There is justification for making realistic adjustments to yield potential based on soil pH or crop sequence, although further work is required to determine whether the shape of the grain-yield response curve varies with these two factors.

Comparison of the phosphate requirements of burr medic and yellow serradella with subterranean clover in the low rainfall wheatbelt of Western Australia

1992 ◽  
Vol 32 (8) ◽  
pp. 1077 ◽  
Author(s):  
BH Paynter
Keyword(s):  
Seed Production ◽  
Western Australia ◽  
Maximum Yield ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Yield Response ◽  
Absolute Maximum ◽  
Absolute Yield ◽  
Burr Medic ◽  
Internal Efficiency

Burr medic (Medicago polymorpha) and yellow serradella (Ornithopus compressus) were compared with subterranean clover (Trifolium subterraneum) in their response to freshly topdressed phosphate in the low rainfall wheatbelt of Western Australia. Species were compared on the amount of applied phosphorus (P) required for 90% maximum yield and the ratio of their curvature coefficients from the Mitscherlich relationship between P applied and absolute yield. On marginally acidic, medium-textured soils, burr medic had a higher external shoot requirement for applied P than subterranean clover. Relative differences between the species were affected by season, initial concentration of bicarbonate-extractable P in the soil (0-10 cm), and timing of plant harvest during the growing season. Burr medic generally achieved a higher absolute maximum yield at each harvest, a larger absolute yield response, and a larger percentage response to applied P than subterranean clover. There was no difference between burr medic and subterranean clover with respect to the internal efficiency of P use for shoot production. For seed production, the external requirements of burr medic and subterranean clover for applied P were similar according to the criterion of P required at 90% maximum yield, but burr medic had a higher requirement if curvature coefficient was the criterion for comparison. Burr medic also had a higher internal efficiency of P use for seed production than subterranean clover. On an acidic, light-textured soil, yellow serradella had a lower requirement for applied P than subterranean clover, according to both criteria for all harvests in 2 separate years.

Single and coastal superphosphates are equally effective as sulfur fertilisers for subterranean clover on very sandy soils in high rainfall areas of south-western Australia

2003 ◽  
Vol 43 (9) ◽  
pp. 1117
Author(s):  
M. D. A. Bolland ◽  
J. S. Yeates ◽  
M. F. Clarke
Keyword(s):  
Western Australia ◽  
Field Experiments ◽  
Maximum Yield ◽  
Sandy Soils ◽  
Subterranean Clover ◽  
Water Soluble ◽  
Single Superphosphate ◽  
Suitable Alternative ◽  
High Rainfall ◽  
Coastal Superphosphate

To reduce leaching of phosphorus (P) from fertilised pastures to shallow estuaries in the high rainfall (>800 mm annual average) areas of south-western Australia, and to supply extra sulfur (S) for subterranean clover (Trifolium subterraneum L.) in pasture, 'coastal superphosphate' was developed as a possible alternative P and S fertiliser to single superphosphate. Coastal superphosphate is made by adding phosphate rock and elemental S to single superphosphate as it comes out of the den before granulation. It has about 3 times more sulfur (S) and one-third the water-soluble P content than single superphosphate. Four long-term (5-year) field experiments were conducted in south-western Australia to compare the effectiveness of single and coastal superphosphate as S fertilisers for subterranean clover pasture grown on very sandy soils that are frequently S deficient after July each year due to leaching of S from soil. Seven different amounts of S were applied as fertiliser annually. Fertiliser effectiveness was assessed from clover herbage yield and S concentration in dried herbage. Fertiliser nitrogen was not applied in these experiments as this was the normal practice for pastures in the region when the research was conducted.Both coastal and single superphosphates were equally effective per unit of applied S for producing dried clover herbage and increasing S concentration in herbage. Previous research on very sandy soils in the region had shown that coastal superphosphate was equally or more effective per unit of applied P for production of subterranean clover herbage. It is, therefore, concluded that coastal superphosphate is a suitable alternative S and P fertiliser for clover pastures on very sandy soils in the region. The concentration of S in dried clover herbage that was related to 90% of the maximum yield (critical S) was about 0.20–0.35% S during August (before flowering) and 0.15–0.20% S during October (after flowering).

The control of molybdenum deficiency in subterranean clover by pre-soaking the seed in sodium molybdate solution

1951 ◽  
Vol 2 (3) ◽  
pp. 295 ◽  
Author(s):  
CM Donald ◽  
D Spencer
Keyword(s):  
Nitrogen Content ◽  
Maximum Yield ◽  
Sodium Molybdate ◽  
Subterranean Clover ◽  
Normal Growth ◽  
Direct Application ◽  
Yield Response ◽  
Test Plant ◽  
Cent Sodium ◽  
Pot Culture

Pre-soaking seed in a sodium molybdate solution was compared with the direct application of sodium molybdate to the soil as a means of preventing deficiency of molybdenum. Subterranean clover, which was used as the test plant, was grown in a molybdenum deficient soil in pot culture for this study. Pre-soaking in 0.1 per cent. or 1 per cent. sodium molybdate was fully effective in promoting normal growth. The soil and seed treatments were equally effective in promoting yield response at all levels of application examined. At levels of application in excess of the requirements for maximum yield, pre-soaking gave a higher molybdenum content of the tops than did equivalent soil applications. At all levels of application, pre-soaking gave a higher nitrogen content than that resulting from the soil application of molybdenum.

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