Comparing the potassium requirements of five pasture species

2006 ◽  
Vol 46 (5) ◽  
pp. 659 ◽  
Author(s):  
R. F. Brennan ◽  
M. D. A. Bolland

Potassium (K) deficiency is now common in sandy soils of south-western Australia and the K requirements of most pasture species grown in rotation with crops in the region are not known. In a glasshouse experiment using a K deficient yellow sand, we compared the K requirements of 5 pasture species now commonly grown in the region: French serradella (Ornithopus sativus Brot.) cv. Cadiz, yellow serradella (Ornithopus compressus Brot.) cv. Santorini, balansa clover [Trifolium balansae, classified as T. michelianum Savi var. balansae (Boiss)] cv. Paradana, 2 subterranean clover (Trifolium subterraneum L.) cultivars, cv. Seaton Park (subspecies subterraneum) and cv. Trikkala (subspecies yanninicum), and annual ryegrass (Lolium rigidum Gaud) cv. Wimmera. After 56 days of growth, above-ground growth was harvested and analysed for total K. Mitscherlich curves were fitted to yield of dried shoots, K concentration and K content (K concentration multiplied by yield) of the shoots. These fitted curves were used to determine the amount of K required to produce 75% of the maximum yield of dried shoots, K required to attain a K concentration in dried shoots of 25 g/kg, and K required to achieve a K content in dried shoots of 250 mg K/pot. Annual ryegrass and yellow serradella more effectively used indigenous soil K and applied K to produce dried shoots than the other species and cultivars, with the other species and cultivars requiring about 55% more applied K to produce 75% of the maximum shoot yield. The K content in dried shoots estimated the total K taken up from the soil, and annual ryegrass took up least K from soil, but it required least applied K to produce 75% of the maximum shoot yield, indicating it used the K it took up very effectively to produce shoots. Yellow serradella took up most K and, after annual ryegrass, it needed least applied K to produce the target yield of dried shoots. After yellow serradella, subterranean clover cv. Trikkala took up most K from soil, but it required nearly the most applied K to produce the target shoot yield so it was inefficient at using K taken up to produce the shoots. For all the other species and cultivars, K requirement was similar as assessed by yield or K content data. The critical concentration of K required for 90% maximum yield of dried shoots was about (g K/kg) 24 for balansa clover, 23 for both subterranean clover cultivars, 21 for yellow and French serradella, and 15 for annual ryegrass.


1994 ◽  
Vol 34 (4) ◽  
pp. 469 ◽  
Author(s):  
A Pinkerton ◽  
PJ Randall

Critical concentrations of potassium (K) for the diagnosis of K deficiency were derived for tissues of balansa clover (Trifolium balansae) cv. Paradana, murex medic (Medicago murex) cv. Zodiac, and subterranean clover (T. subterraneum) cv. Karridale. The legumes were grown for 2 seasons at 2 sites to which 7 rates of K fertiliser were applied in each season. Symptoms of K deficiency appeared on leaves of plants at both sites, where <50 kg K/ha had been applied. Diagnostic indices were obtained for K in the dry matter (DM) of blades and petioles of youngest open leaves (YOL) and of whole shoots, and for K in petiolar sap of the YOL. In all species, critical K concentrations in dry matter were initially high but decreased steadily as the season progressed. Critical values were highest for YOL petioles, and simllar for YOL blades and for whole shoots, with good discrimination between deficient and adequately supplied plants for K concentrations in these tissues. Critical concentrations (%) of K in DM of YOL laminae of balansa clover declined from 4.00 in May to 0.70 in November, of YOL petioles from 5.80 in May to 1.40 in October, and of whole shoots from 2.48 in July to 0.68 in November, while critical K concentration (�g/mL) in the YOL petiole sap declined from 1000 in May to 384 in November. The decline in critical K concentration (%) in DM of YOL laminae of murex medic was from 2.75 in May to 1.12 in September, of YOL petioles from 5.58 in May to 1.57 in September, and of whole shoots from 1.57 in July to 0.70 in November. Critical K concentrations (�g/mL) in murex medic petiole sap fell from 1000 in May to 471 in September. The decline in critical K concentrations in DM was related to date and was unaffected by rainfall before sampling, temperature, or sodium concentrations. Critical concentrations in DM of subterranean clover were similar to those in the literature for other cultivars. Critical concentrations in balansa clover agreed with those derived previously from glasshouse experiments. The test for K in petiolar sap was less satisfactory: the decline in critical concentration in sap was less consistent than that in DM, and the critical values for subterranean clover did not agree with published results.



2007 ◽  
Vol 58 (4) ◽  
pp. 359 ◽  
Author(s):  
R. F. Brennan ◽  
M. D. A. Bolland

Most sandy soils used for cropping in south-western Australia are now deficient in potassium (K) due to removal of K from soil in hay and grain, and profitable grain yield responses to applied fertiliser K are commonly obtained for spring wheat (Triticum aestivum L.) and canola (oilseed rape, Brassica napus L.). However, there are only limited data comparing the K requirements of these 2 species in the region. In a glasshouse experiment we compared the K requirements of wheat (cv. Westonia), conventional canola cv. Outback (cultivars of canola not produced by classical breeding techniques to be tolerant of specific herbicides), triazine-tolerant (TT) canola cvv. Pinnacle and Surpass 501, and imidazolinone-tolerant (IT) canola cv. Surpass 603. The following measures were used: yield of 54-day-old dried shoots and seed (grain) without added K, applied K required to produce 90% of the maximum yield of shoots and grain, K required to attain a K concentration in shoots of 30 g/kg, and K required to achieve a K content in shoots (K concentration multiplied by yield) of 40 mg/pot. We also determined for each species and cultivar the concentration of K in dried shoots that was related to 90% of the maximum grain yield, to estimate critical concentration in shoots below which K deficiency was likely to reduce grain production. All 4 canola cultivars produced similar results. Both canola and wheat produced negligible shoot yields and no grain when no K was applied. For each species and cultivar the amount of applied K required to produce 90% of the maximum yield was similar for shoots and grain, and was ~121 mg K/pot for the 4 canola cultivars and 102 mg K/pot for wheat, so ~19% more K was required for canola than for wheat. For each amount of K applied, the concentration of K in shoots was greater for canola than for wheat. The amount of applied K required to attain a K concentration of 30 g K/kg in shoots was ~96 mg K/pot for canola and 142 mg K/pot for wheat, so ~48% more K was required by wheat than by canola. The amount of K applied required to achieve a K content of 40 mg K/pot in shoots was ~46 mg K/pot for canola and 53 mg K/pot for wheat, so ~13% more applied K was required by wheat than by canola. The data suggest that canola roots were better able to obtain K from soil than wheat roots, but wheat used the K taken up more effectively than canola to produce shoots and grain. The concentration of K in dried shoots of 54-day-old plants that was related to 90% of the maximum dried shoot yield or grain was ~32 g/kg for canola and ~23 g/kg for wheat.



2000 ◽  
Vol 51 (3) ◽  
pp. 377 ◽  
Author(s):  
G. M. Lodge

Seedlings of 3 perennial grasses, Danthonia linkii Kunthcv. Bunderra, D. richardsonii Cashmore cv. Taranna(wallaby grasses), and Phalaris aquatica L. cv. Sirosa,were each grown in replacement series mixtures with seedlings ofTrifolium repens L. (white clover),Trifolium subterraneum L. var. brachycalycinum (Katzn.et Morley) Zorahy & Heller cv. Clare (subterraneanclover), and Lolium rigidum L. (annual ryegrass). Plantswere sown 5 cm apart in boxes (45 by 29 by 20 cm) at a density of 307plants/m2. Maximum likelihood estimates were usedto derive parameters of a non-linear competition model using the dry matterweights of perennial grasses and competitors at 3 harvests, approximately 168,216, and 271 days after sowing. Intra-plant competition was examined inmonocultures of each species, grown at plant spacings of 2, 5, and 8 cm apartwith plants harvested at the above times.Competition occurred in all perennial grass–competitor mixtures, exceptin those of each perennial grass with white clover and thephalaris–subterranean clover mixture (Harvest 1) and those withD. richardsonii and phalaris grown with white clover(Harvest 2). For D. richardsonii (Harvests 1 and 2) andD. linkii (Harvest 1 only) grown with white clover andthe phalaris–subterranean clover (Harvest 1), the two species in themixture were not competing. In the phalaris–white clover mixture, eachspecies was equally competitive (Harvests 1 and 2). These differences incompetition and aggressiveness reflected differences in individual plantweights in monocultures where there was an effect (P < 0.05) of species ondry matter weight per box, but no significant effect of plant spacing.These data indicated that for successful establishment,D. richardsonii and D. linkiishould not be sown in swards with either subterranean clover or white clover,or where populations of annual ryegrass seedlings are likely to be high.Phalaris was more compatible with both white clover and subterranean clover,but aggressively competed with by annual ryegrass.



2019 ◽  
Vol 70 (9) ◽  
pp. 800
Author(s):  
John W. Piltz ◽  
Simon J. Flinn ◽  
Leslie A. Weston

Barley grass (Hordeum spp.) is a relatively short lived annual that provides high quality grazing early in the season, but its seed heads cause contamination of wool and carcasses, and may irritate the mouth, eyes and nose of sheep. Treatments were imposed on established subterranean clover (Trifolium subterraneum L.) annual pasture in the same plots for three consecutive years (2015 to 2017) to evaluate changes in barley grass content. Treatments included: grazing alone (G), herbicide followed by grazing (HG), or a forage conservation harvest in early October, late October or early November consistent with an early silage harvest (ES), late silage harvest (LS) or hay cut (H). Grazing plus herbicide markedly reduced (P &lt; 0.05) barley grass numbers compared with all other treatments, but increased (P &lt; 0.05) the growth of annual ryegrass (Lolium rigidum L.). ES reduced (P &lt; 0.05) barley grass and increased (P &lt; 0.05) subterranean clover compared with H, but broadleaf weed content benefitted by LS in contrast to either ES or H. Although herbicide application was the most effective method for barley grass control, forage harvest timing could be used to beneficially manipulate pasture composition.



1991 ◽  
Vol 31 (6) ◽  
pp. 777
Author(s):  
MDA Bolland

The effect of superphosphate applications (0, 25, 50, 75, 100 and 125 kg P/ha to the soil surface) on the dry matter (DM) herbage production of dense swards of subterranean clover (Trifolium subterraneum cv. Junee) and yellow serradella (Ornithopus compressus cv. Tauro) was measured in a field experiment on deep, sandy soil in south-western Australia. The swards were defoliated with a reel mower at weekly intervals from 88 to 158 days after sowing, to a height of 2 cm for the first 9 cuts, 4 cm for the tenth cut and 5 cm for the eleventh cut. Yellow serradella was more productive than subterranean clover. Consequently, for the relationship between yield and the level of phosphorus (P) applied, yellow serradella supported larger maximum yields and required less P than subterranean clover, to produce the same DM herbage yield. Maximum yields of yellow serradella were 12-40% larger. To produce 70% of the maximum yield for yellow serradella at each harvest, yellow serradella required about 50% less P than subterranean clover. However, when yields were expressed as a percentage of the maximum yield measured for each species at each harvest, the relationship between yield and the level of P applied was similar for both species, and they had similar P requirements.



1998 ◽  
Vol 49 (1) ◽  
pp. 53 ◽  
Author(s):  
C. Tang ◽  
L. Barton ◽  
C. Raphael

The capacity of subterranean clover (Trifolium subterraneum L. cv. Clare), medic (Medicago murex Willd. cv. Zodiac), serradella (Ornithopus sativus Brot. line SP1/13), biserrula (Biserrula pelecinus L. line Mor99), and woolly clover (Trifolium tomentosum L.) to acidify soil under N2 fixation was compared in a pot experiment using a poorly buffered sandy soil. The amount of acid produced per kg shoot dry matter (specific acid production) varied betweefin species and with growth stages, ranging from 44 to 128 cmol/kg shoot. Subterranean clover and serradella acidied soil to a greater extent than woolly clover and medic, whereas biserrula acidified soil least. Irrespective of pasture species and growth stage, specific acid production correlated well with concentrations of excess cations and calcium in shoots. Furthermore, total excess cation, ash alkalinity, and calcium in shoots were all good indicators of total acid production across all of the species.



1955 ◽  
Vol 6 (5) ◽  
pp. 673 ◽  
Author(s):  
KD McLachlan

Subterranean clover (Trifolium subterraneum L.) was grown on 32 virgin soils in pot cultures, and the yield responses to phosphorus, sulphur, and molybdenum were determined for each soil. The soils were collected from a wide area in eastern Australia, extending from south-western Victoria to southern Queensland. Sulphur deficiency occurred almost as frequently as phosphorus deficiency. In fact, 75 per cent. of the soils were deficient in both phosphorus and sulphur. Thirty-one per cent. were deficient in all three elements. The effect of the interaction between the elements on the occurrence and intensity of the deficiencies is shown. Molybdenum responses were obtained only after the other deficiencies had been corrected. A deficiency in one of the elements is no indication of deficiency or sufficiency of either of the other two. There was no correlation between the occurrence or intensity of the deficiencies and the geological origin of the soil parent material, the climate of the regions from which the soils were collected, or such soil characters as colour, organic matter, and texture. Responses to phosphorus were less on the black earths than on the red or yellow podzolic soils; those on the red earths were intermediate. The intensity of sulphur deficiency increased, and the intensity of molybdenum deficiency decreased, with increasing soil pH.



2002 ◽  
Vol 42 (5) ◽  
pp. 565 ◽  
Author(s):  
R. F. Brennan

The residual value (RV) of molybdenum (Mo) for clover (Trifolium subterraneum L.) production was measured for an acidic sand when the fertiliser was spread over the soil surface (topdressed). The RV of Mo, as molybdenum trioxide, the most widely used Mo fertiliser in Western Australia, was measured using yield of dry herbage (DM), Mo concentration of DM, and Mo content of DM (yield of DM multiplied by the Mo concentration of DM). The RV of Mo fertiliser was measured in 1993 for fertiliser Mo applied once only to plots not treated with Mo before, either in 1993 (current Mo) or 1-10 years previously (previous Mo). Relative to the nil-Mo treatment, additions of Mo fertiliser increased DM yield by about 1.20 t/ha (20% DM increase) in October. When 80 or 320 g Mo/ha was applied, all yields were on the maximum yield plateau except for Mo applied 10 years previously. The yield for the 80 g Mo/ha treatment applied 10 years earlier decreased by about 15% relative to the other current and previous Mo treatments. However, as measured using Mo concentration and Mo content in DM, there was a continuous decline in the effectiveness of previous Mo relative to current Mo the longer the previous Mo was in contact with the soil. The decrease in RV was about the same as measured using Mo concentration or content in tissue. Molybdenum applied 5 years previously was about one-third as effective as current Mo for Mo content or Mo concentration of DM.



1968 ◽  
Vol 8 (35) ◽  
pp. 702 ◽  
Author(s):  
DF Smith

Mixed swards of barley grass (Hordeum leporinum) and subterranean clover (Trifolium subterraneum) of two densities were grown at two levels of nitrogen. Growth was started at two different times mid- April and mid-May-and at each time half the plots were subjected to moisture stress. The swards were harvested after nine weeks of growth. The survival of clover plants was reduced by an early start, moisture stress and nitrogen addition : much more so than barley grass. The root : shoot ratios of both species were calculated ; both showed some sensitivity to the time of break and moisture stress, and the grass was also affected by the other two factors. Total sward production and the ratios of clover to grass varied widely Grass daminance was favoured by moisture stress or a late break, and both of these factors tended to override the effect of higher soil nitrogen in determining clover-grass balance. Total sward production more dependent on density than any other factor, especially with the later start. Higher nitrogen was effective in boosting production only if the break was early and there was no moisture stress.



1967 ◽  
Vol 7 (24) ◽  
pp. 25 ◽  
Author(s):  
GB Taylor ◽  
RC Rossiter

Seed production and persistence of the Carnamah, Northam A, Dwalganup, and Geraldton strains of subterranean clover (Trifolium subterraneum L.) were examined in undefoliated swards in the wheatbelt of Western Australia. The early flowering characteristic of Carnamah was not always associated with higher seed yields. Only when there was a well-defined, early finish to the growing season, or when flowering was very much earlier in Carnamah (viz., following an early 'break' to the season), did this strain clearly outyield both Northam A and Geraldton. The seed yield of Dwalganup was generally inferior to that of the other strains. Factors affecting regeneration are discussed. Under low rainfall conditions, poorer germination-regulation of Carnamah, compared with Geraldton and Northam A, would be expected to result in poorer persistence unless offset by higher seed yields in the Carnamah strain.



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