Phosphorus status of subterranean clover: a rapid and simple leaf test

1982 ◽  
Vol 22 (119) ◽  
pp. 428 ◽  
Author(s):  
D Bouma ◽  
EJ Dowling
Keyword(s):  
Total Phosphorus ◽  
Field Experiments ◽  
Relative Yield ◽  
Subterranean Clover ◽  
Critical Value ◽  
Sand Culture ◽  
Molybdenum Blue ◽  
Phosphorus Status ◽  
Extractable Phosphorus ◽  
Phosphorus Levels

A simple and rapid method is presented for the assessment of the phosphorus status of subterranean clover. The method rests on extracting fresh leaf tissue (400 mg) with five drops 10 N H2SO4 and measuring phosphorus in the filtered extract by a molybdenum blue colour method, visually or calorimetrically. No special skills or equipment are required and the method is therefore potentially suitable for use by advisers and farmers. Two standard blue colours would be sufficient for a visual separation between non-deficient, moderately deficient or severely deficient plants. The method was tested in early spring with leaf samples obtained from two field experiments (five phosphorus levels), a sand culture experiment, and a pot experiment with phosphorus deficient soil (five phosphorus levels in each). Close relations were obtained between relative yields (yields as a percentage of the maximum in each experiment) and extractable phosphorus (R2 = 0.93). The curve fitted to the relation had a clearly defined inflexion point, indicating a critical value of 150 ppm extractable phosphorus at 90% of the fitted asymptote for relative yield. The relation for total phosphorus and yields was not as close (R2=0.77) and the critical value not clearly defined. Extractable phosphorus was closely related to total phosphorus below the critical value for extractable phosphorus, but not above this value. Likely physiological are discussed.

Field evaluation of a leaf test for assessment of the phosphorus status of subterranean clover and for prediction of its response to phosphorus

1985 ◽  
Vol 25 (2) ◽  
pp. 331 ◽  
Author(s):  
EJ Dowling ◽  
D Bouma
Keyword(s):  
Field Experiments ◽  
Relative Yield ◽  
Leaf Tissue ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Field Evaluation ◽  
Close Relation ◽  
Critical Value ◽  
Late Winter ◽  
Phosphorus Status

A series of field experiments (5 phosphorus levels x 6 replicates) on the southern Tablelands of New South Wales was used, firstly, to confirm the suitability of a modified test for inorganic phosphorus (Pi) concentrations in fresh clover (Trifolium subterraneum) leaves as an index of the current phosphorus status of subterranean clover-based pastures; and, secondly, to evaluate the usefulness of Pi as a predictor of responses to phosphorus applications. A close relation (R2 = 0.910) was found between Pi in healthy green leaf tissue sampled in winter and field responses to phosphorus measured at the same time. The fitted curve had a critical value of 154 ppm Pi at 90% of the fitted asymptote for relative yield. Close relations were also found between total herbage yield measured over the season and Pi in leaf tissue sampled in late autumn and early winter (R2 = 0.896) and in leaves sampled in late winter and early spring (R2= 0.877). Critical values were 160 and 153 ppm Pi respectively. The relation was less close for the third sampling (seed set and flowering, R2= 0.809) and the critical value had declined to 118 ppm Pi. It is concluded that Pi determined in clover leaf samples provides a simple measure of the current phosphorus status of subterranean clover-based pasture, and of its likely response to phosphorus. A critical value of 150 ppm Pi is confirmed for assessing the current phosphorus status, and is also proposed for predictive purposes. The method described for the estimation of Pi is a further simplification of the method presented previously. It is also more rapid and achieves a saving of 80-90% in chemicals. The correlation coefficient for the straight line relationship between the two methods was 0.956 (68 observations).

Effect of topdressed phosphorus fertilizer on established white clover based pastures in south-east Queensland. 1. Prediction of yield responses using soil tests

1979 ◽  
Vol 19 (99) ◽  
pp. 454 ◽  
Author(s):  
GE Rayment ◽  
RC Bruce
Keyword(s):  
White Clover ◽  
Field Experiments ◽  
Soil Phosphorus ◽  
Relative Yield ◽  
Pasture Production ◽  
Phosphorus Status ◽  
Empirical Tests ◽  
Yield Responses ◽  
Phosphorus Levels ◽  
Term Field

Seventeen short-term field experiments were conducted over a five year period in south-east Queensland in which rates of up to 60 kg P ha-1 as monocalcium phosphate were topdressed onto established, previously grazed, grass-white clover (Trifolium repens) pastures, Increases (P < 0.05) in yields of white clover were obtained at seven sites, but concurrent increases in grass production occurred at only four sites. Higher total pasture production resulted at six of these sites. One quantitative (total) and two empirical (0.005 M H2SO4 and 0.5 M Na HCO3) estimates of phosphorus status in 0-10 cm soil samples, collected prior to topdressing treatments, were separately correlated with relative yield responses of white clover, grass and total pasture components. Although soil phosphorus levels by all methods were statistically intercorrelated (P < 0.01), acid-extractable and total phosphorus tests were generally unsuitable for predictive purposes, having low coefficients of determination for regressions and Cate-Nelson separations of responsive from non-responsive sites. Bicarbonate-extractable phosphorus proved the most suitable soil test. It accounted for 60 and 44% of the variance in relative yields of white clover and total pasture, respectively, but was poorly correlated with relative yields of grass. The suggested critical level of soil phosphorus (bicarbonate extraction) for white clover is 28 ppm P. For total pasture, responses are likely below 22, unlikely above 28 and uncertain between 22 and 28 ppm P, respectively. Percentage variance in relative yields already explained by both empirical tests was not significantly increased by inclusion of terms for pH and exchangeable calcium into the X variable.

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.

Comparison of the use of total phosphorus concentration and acetic acid soluble phosphorus concentration in petioles for assessing the phosphorus status of potato crops

1989 ◽  
Vol 29 (3) ◽  
pp. 433 ◽  
Author(s):  
NA Maier ◽  
KA Potocky-Pacay ◽  
CMJ Williams
Keyword(s):  
Acetic Acid ◽  
Total Phosphorus ◽  
Relative Yield ◽  
Coefficient Of Determination ◽  
Phosphorus Concentration ◽  
Concentration Data ◽  
Total Phosphorus Concentration ◽  
Soluble Phosphorus ◽  
Phosphorus Status ◽  
Potato Crops

We studied the effect of rate of applied phosphorus on total phosphorus concentration (17 sites) and acetic acid soluble phosphorus concentration (12 sites) in petioles of youngest fully expanded leaves of potatoes (cvv. Kennebec, Coliban and Exton) when their largest tubers were 5-10 mm long. We showed that the internal requirements for phosphorus are similar for the cvv. Kennebec and Coliban. Taken over all sites, mean total phosphorus concentrations and acetic acid soluble phosphorus concentrations ranged from 0.22 to 0.84% and 0.10 to 0.63%, respectively depending on phosphorus supply. For each site a coefficient of determination (r2) was calculated based on the mean total phosphorus concentration versus acetic acid soluble phosphorus concentration data for all treatments. The r2 values varied from 0.969 (site 14) to 0.997 (site 17). On the pooled data for all sites, the Cate-Nelson separation and the Mitscherlich and Smith-Dolby bent-hyperbola models were used to investigate the correlations between relative yield [(mean treatment yields/maximum treatment yie1d)x 100] and total phosphorus concentration (n = 16 1, 17 sites) and acetic acid soluble phosphorus concentration (n = 112, 12 sites) and to calculate the critical values. Depending on the model fitted the critical total phosphorus concentrations varied from 0.41 (r2 = 0.62) to 0.53% (r2 = 0.72). The critical acetic acid soluble phosphorus concentrations varied from 0.29 (r2 = 0.62) to 0.52% (r2 = 0.72). Critical concentration ranges of 0.41-0-53% for total phosphorus and 0.29-0.52% for acetic acid soluble phosphorus have been proposed to assist in the assessment of the phosphorus status of irrigated potato crops in South Australia. Based on sensitivity, reproducibility and sharpness of the transition zone between adequacy and deficiency we found no advantage in determining acetic acid soluble phosphorus concentration rather than total phosphorus concentration to assess the phosphorus status of potato plants.

Phosphorus toxicity in Subterranean clover and oats grown on Muchea sand, and the modifying effects of lime and nitrate-nitrogen

1952 ◽  
Vol 3 (3) ◽  
pp. 227 ◽  
Author(s):  
RC Rossiter
Keyword(s):  
Total Phosphorus ◽  
Nitrate Nitrogen ◽  
Subterranean Clover ◽  
Nitrogen Supply ◽  
Toxic Effects ◽  
Short Supply ◽  
Beneficial Effects ◽  
Sodium Calcium ◽  
Phosphorus Toxicity ◽  
Phosphorus Levels

Phosphorus supplied as mono-sodium phosphate depressed the growth of subterranean clover and oats grown on Muchea sand in pot culture. In both plants the detrimental effects appeared at phosphorus levels equivalent to about 2-4 cwt. per acre superphosphate, provided both nitrogen and lime were in very short supply. Adequate nitrogen, as sodium nitrate, invariably overcame the toxic effects of phosphorus within the range of levels examined. With the clover, nodulation was usually poor, but some evidence is presented in which "heavy" inoculation with Rhizobium markedly increased nodulation and alleviated the toxic effects. Nodule numbers in the clover were increased by addition of lime and in most instances the beneficial effects resulted from enhanced nitrogen supply. Lime was advantageous to the growth of oats, also, wherever applied nitrogen was low. Possible explanations of this are suggested. Phosphorus toxicity symptoms are described for both plants and the relation to percentage total phosphorus in the leaves is discussed. Figures in excess of 1.4 per cent. and 3 per cent. total phosphorus were found in affected leaves of subterranean clover and oats respectively. Identical symptoms were observed in clover with the mono- and dibasic phosphates of sodium, calcium, and potassium.

Effects of phosphorus and sulphur on dark respiration of subterranean clover leaves

1971 ◽  
Vol 22 (5) ◽  
pp. 723 ◽  
Author(s):  
D Bouma
Keyword(s):  
Dark Respiration ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
The Other ◽  
Phosphorus Level ◽  
Respiration Rates ◽  
Phosphorus Status ◽  
Whole Plants ◽  
Complete Solutions ◽  
Phosphorus Levels

Respiration rates in the dark (oxygen uptake) of leaves sampled from subterranean clover plants (Trifolium subterraneum L. cv. Mt Barker) increased with the phosphorus supply in the culture solutions in which the plants were grown. Over a period of 3 hr no differences were detected in respiration rates when leaves of these plants were placed in Warburg flasks containing complete solutions or solutions without phosphorus. However, when whole plants were transferred to complete and no-phosphorus solutions, the differences in respiration rates of leaves sampled from the two groups of plants depended on the phosphorus status of the plants at transfer. Leaves from plants raised at an adequate phosphorus level showed no differences over a period of 96 hr after transfer, but leaves from plants raised at suboptimal phosphorus levels before transfer to complete and no-phosphorus solutions showed significant differences in respiration rates as early as 18-19 hr after transfer. Similar results were obtained for leaves sampled from plants raised at different sulphur levels when transferred to complete solutions and to solutions without sulphur. However, these differences took longer to develop than in the phosphorus experiments. When phosphorus-deficient plants were transferred to complete solutions and to other solutions each without a different element, the respiration rates of the leaves sampled from the plants in the solutions without phosphorus were much lower than for the leaves of plants in the other solutions.

The physiological assessment of the nutrient status of plants. I. Preliminary experiments with phosphorus

1962 ◽  
Vol 13 (5) ◽  
pp. 791 ◽  
Author(s):  
D Bouma ◽  
EJ Dowling
Keyword(s):  
Leaf Area ◽  
Complete Solution ◽  
Subterranean Clover ◽  
Nutrient Status ◽  
Response Patterns ◽  
Simple Method ◽  
Subsequent Response ◽  
Low Phosphorus ◽  
Phosphorus Status ◽  
Phosphorus Levels

Subterranean clover plants of different phosphorus status, obtained from pastures or raised in the glass-house, were transferred to nutrient solutions. These included a complete solution, and others each lacking a different element. Subsequent response patterns were defined by leaf area changes. Plants raised at low phosphorus levels showed considerably smaller increases in leaf area in the solutions without phosphorus than in the other solutions. These differences were discernible as early as 2 days after transfer. There was little difference between the control treatments and treatments omitting elements other than phosphorus. Plants raised at a more adequate phosphorus level did not show differences between treatments till much later. The results are discussed, and their use as a basis for a simple method of determining the nutrient status of plants is indicated.

Tissue testing to assess the sulfur requirements of subterranean clover on very sandy soils in high rainfall areas of south-western Australia

2003 ◽  
Vol 43 (11) ◽  
pp. 1311 ◽  
Author(s):  
M. D. A. Bolland ◽  
J. S. Yeates ◽  
B. J. Codling ◽  
M. F. Clarke
Keyword(s):  
Western Australia ◽  
Field Experiments ◽  
Relative Yield ◽  
Subterranean Clover ◽  
Ground Level ◽  
Total N ◽  
High Rainfall ◽  
Significant Yield ◽  
Yield Responses ◽  
Ratio Range

Tissue testing was studied in field experiments between 1979 and 1985 to predict when sulfur (S) fertiliser was required for pastures in high rainfall (>650 mm annual average) areas of south-western Australia. The pastures comprised about half subterranean clover and annual ryegrass (Lolium rigidum Gaud.), the major pasture species in the region. Tissue testing was done for each species, using: (i) whole shoots, the present method used by commercial laboratories in Western Australia; (ii) youngest open leaves (legumes, YOLs) or youngest expanded blades (grass, YEBs); (iii) old leaves and blades (leaves that were not YOLs or YEBs); and (iv) stems (left after removal of YOLs, YEBs, old leaves and blades). Dried tissue was measured for total S, sulfate S, the total nitrogen : total S ratio and the sulfate S : total S ratio. For each pasture species, tissue test values were related to yield of dried herbage of that species measured for plants cut at ground level. Fertiliser nitrogen was not applied in the experiments.Annual ryegrass showed no significant yield responses to applied fertiliser S for all harvests in all experiments. Subterranean clover showed significant yield responses for most harvests of all experiments. At each site in each year, yield responses to applied S tended to become larger as the growing season progressed. For subterranean clover critical S values related to 90% of the maximum (relative) yield varied for different harvests of the same experiment within and between years, and for different experiments in the same and different years. As determined from all data, critical S values were similar for all plant parts (whole shoots, YOLs, old tissue, stems), with no consistent, systematic trend with plant age, and were: total S, range 0.10–0.30% S, mean 0.23%; sulfate S, range 0.01–0.14%, mean 0.04%; total N : total S ratio, range 11–30, mean 19; sulfate S : total S ratio, range 0.01–0.48, mean 0.27. The exception was that total S was lower for clover stems, the range being 0.06–0.20%, and mean 0.13%. Therefore, % total S in clover shoots can continue to be used as an indicator of sulfur deficiency in subterranean clover in the region.

Assessment of the phosphorus and sulphur status of subterranean clover pastures. 1. Environmental factors and pasture responses

1969 ◽  
Vol 9 (38) ◽  
pp. 310 ◽  
Author(s):  
K Spencer ◽  
D Bouma ◽  
DV Moye ◽  
EJ Dowling
Keyword(s):  
Soil Ph ◽  
Field Experiments ◽  
Subterranean Clover ◽  
Strong Relationship ◽  
Phosphorus Addition ◽  
Pasture Production ◽  
Podzolic Soils ◽  
South Wales ◽  
Site Characteristics ◽  
Phosphorus Status

A series of 21 standardized field experiments was set out on established subterranean clover (Trifolium subterranem) pastures in south-eastern New South Wales in the autumn of 1963. Pasture growth at eleven of the 21 sites responded to phosphorus addition ; eight responded to sulphur addition. A dual deficiency existed at five sites. Seasonal pasture production was increased by up to 3,200 lb of dry matter an acre by phosphorus addition, and by up to 5,500 lb by sulphur addition. Clover was the component responsive to phosphorus and/or sulphur at most sites. To determine whether site characteristics can provide a basis for predicting the phosphorus or sulphur status of a pasture, several climatic and soil components of the environment were correlated with responses. Phosphorus status was not related to the rainfall, temperature or elevation at the site, nor to the kind of soil or soil pH. The more deficient pastures were younger, and, on the granitic soils only, present phosphorus status reflected the amount of superphosphate used in the past. Sulphur status was significantly related to rainfall for the podzolic soils only (r = 0.72) ; the driest sites tended to be the most sulphur deficient ones. Sulphur status showed a poor overall relationship with temperature, the trend being for the occurrence of more deficient soils at lower temperatures or higher elevations. Within the podzolic soils, the relationship with temperature was more definite (r = 0.69). There was no association with kind of soil or past superphosphate use, but there was a moderate to strong relationship (r = -0.78) with soil pH (the less acid, the more S deficient).

scholarly journals Yield Responses to Different N-P-K Levels, and Correlations With Foliar Analysis, in Sand-Culture Studies With Corn, Sugarcane, and Cotton

1969 ◽  
Vol 42 (3) ◽  
pp. 168-184
Author(s):  
J. A. Bonnet ◽  
A. R. Riera ◽  
J. Roldán
Keyword(s):  
Field Experiments ◽  
Sweet Corn ◽  
Relative Yield ◽  
Sand Culture ◽  
Available Phosphorus ◽  
Dent Corn ◽  
Yield Values ◽  
Phosphorus And Potassium ◽  
Major Nutrients ◽  
Yield Responses

The layout for 28 concrete pits is described herein where sand-culture and irrigation studies under cover have been carried in Puerto Rico since 1940 with certain crops: Sugarcane, beans, corn, sweetpotatoes, and cotton. The data for 10 experiments performed with sweet corn, dent corn, sugarcane, and cotton are reported. These data included N-P-K contents of the respective leaves at different crop ages and yields obtained by varying the N or P or K levels from deficient to sufficient values, but keeping other major and minor nutrients constant. These experiments were important in showing that foliar contents of the major nutrients at specific crop ages can be used to predict or correlate with relative yield values. These correlations are not generally obtained with phosphorous and potassium in field experiments because the initial available phosphorus and potassium contents of the soil are usually high.

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