Competitive growth of capeweed (Arctotheca calendula) and some annual pasture species

1973 ◽  
Vol 13 (61) ◽  
pp. 185 ◽  
Author(s):  
JG McIvor ◽  
DF Smith

A comparison of the relative growth rates (RGR) of plants of capeweed (Arctotheca calendula), subterranean clover (Trifolium subterraneum) and annual ryegrass (Lolium rigidum) under high soil fertility conditions showed capeweed to have a higher RGR in the early weeks of growth, offsetting the effect of smaller seed size. However, when grown in mixed swards with the clover, under conditions of high NPK and water availability, capeweed did not readily suppress clover growth. If the capeweed and clover began growth together, clover growth was reduced by associated capeweed only after twelve weeks of growth, and then only slightly. If the capeweed was established four weeks before the clover there was a marked reduction of clover growth at the harvest eight weeks after the clover was sown. The results suggest that 'smothering' of clover by capeweed through competition for light is unlikely in grazed pastures in southern Australia.


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 < 0.05) barley grass numbers compared with all other treatments, but increased (P < 0.05) the growth of annual ryegrass (Lolium rigidum L.). ES reduced (P < 0.05) barley grass and increased (P < 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.



2006 ◽  
Vol 46 (5) ◽  
pp. 627 ◽  
Author(s):  
B. S. Dear ◽  
A. Hodge ◽  
D. Lemerle ◽  
J. E. Pratley ◽  
B. A. Orchard ◽  
...  

Annual legumes sown as short-term forage crops are an important non-chemical option for the control of herbicide-resistant annual ryegrass (Lolium rigidum L.). The relative ability of 5 annual forage legume species (Trifolium subterraneum L., T. michelianum Savi., T. alexandrinum L., Medicago murex Wild and Vicia benghalensis L.) to suppress annual ryegrass seedlings was examined in a glasshouse study. The experiment investigated the importance of legume species, seed size and seeding rate in influencing the relative competitiveness of the legumes. Balansa clover (T. michelianum) and berseem clover (T. alexandrinum), the smallest seeded of the legume species, were the most effective of the 5 legume species, when compared at equivalent seeding rates, at reducing ryegrass biomass. Legume leaf area and biomass were the 2 factors measured that were most closely associated with depressing ryegrass biomass and were themselves most influenced by legume species and seeding rate. Balansa clover and vetch (V. benghalensis) were the most effective at restricting the amount of light penetrating to 50% of the height of the canopy over a range of seeding rates. The study showed that the competitiveness of forage break crops can be optimised by maximising legume biomass through selecting small-seeded legume species with high relative growth rates and dense canopies and by increasing the seeding rate where seed costs are low.



1957 ◽  
Vol 8 (1) ◽  
pp. 1 ◽  
Author(s):  
JN Black

Three strains of subterranean clover (Bacchus Marsh, Clare, and Mount Barker) were grown in pot culture at the Waite Agricultural Research Institute; for each strain, seed of four widely separated sizes mere sown. Dry weight a t any one time in the early vegetative stage was linearly related to embryo weight, but was independent of strain. Hence differences in early growth noted under uniform environmental conditions between strains are the result not of differing relative growth rates, but of differences in the size distribution within the seed populations; evidence is presented suggesting that there may well be little difference in the size distribution of seed of Bacchus Marsh and Mt. Barker, but that Clare contains a higher proportion of large seed, and thus as a strain would be expected to give greater early production. Leaf area per plant was also linearly related to embryo weight but independent of strain; but for a common embryo weight, Clare was found to have fewer leaves than the other two strains. Examination of the areas of successive leaves showed that the maintenance of similar total leaf areas depended on a balance of rate of leaf production and size of individual leaves; in relation to Bacchus Marsh and Mt. Barker, Clare has fewer but large1 leaves.



1975 ◽  
Vol 15 (76) ◽  
pp. 631 ◽  
Author(s):  
DR Kemp

The feasibility of using subterranean clover (Trifolium subterraneum) rather than oats (Avena spp.) or annual ryegrass (Lolium rigidum) as a low cost winter forage crop was studied over three years at Taree (lat 32�S) on the subtropical east coast of Australia. When sown in early autumn, with sufficient moisture, subterranean clover yields during the winter were equal to oats liberally supplied with nitrogen, though initial yields from oats were greater over the first two months from sowing. Subterranean clover and ryegrass yields were similar during winter when sown in early autumn. In a dry year, the best results were obtained from sowing subterranean clover in mid autumn. Late autumn or early winter sowings of subterranean clover were unsatisfactory. It was concluded that sowing subterranean clover at high rates (30 kg ha-1) in early autumn provides a suitable low cost, alternative, winter forage crop.



1973 ◽  
Vol 13 (61) ◽  
pp. 178 ◽  
Author(s):  
JG McIvor ◽  
DF Smith

The comparative production from pure and mixed swards of capeweed (Arctotheca calendula), subterranean clover (Trifolium subterraneum), and annual ryegrass (Lolium rigidum) grown in containers was measured over a 12-week period. Densities of one to 64 plants dm-2, and clipping frequencies of two- and four-weekly intervals and no defoliation were combined factorially. Plant survival decreased as density rose for all swards. More frequent defoliation increased the survival of capeweed and clover in mixed swards and capeweed in pure swards. In both pure and mixed swards, capeweed produced the most herbage at low densities, but this advantage was not maintained at the highest density in undefoliated swards when ryegrass was the most productive. Increased defoliation reduced root weights. The treatments only affected the root : shoot ratios of capeweed grown at high densities-clipping at four-week intervals gave higher ratios. In the mixed swards, capeweed content declined and clover and ryegrass content increased as density was increased. Capeweed content was little altered by defoliation, but subterranean clover increased and ryegrass decreased with more frequent defoliation.



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.



1983 ◽  
Vol 23 (121) ◽  
pp. 131 ◽  
Author(s):  
CR Stockdale

The seasonal distribution and variability of growth of three types of irrigated pastures were measured at Kyabram over a period of up to seven years. The pasture types studied were (1) paspalum (Paspalum dilatatum)-dominant perennial pasture, (2) ryegrass (Lolium perenne)/clover (Trifolium repens) perennial pasture, and (3) annual pasture based on subterranean clover (Trifolium subterraneum) and Wimmera ryegrass (Lolium rigidum). The influence of environmental factors on the year-to-year variability in monthly growth rates was also examined. Annual growth curves were constructed for each pasture type, and examination of the variability about each monthly mean indicated that the spring months, and October in particular, were the most variable months for pasture growth. Environmental factors were found to account for part of the year-to-year variation in pasture growth of paspalum pastures in August, September, October, November and April. Higher mean maximum temperatures significantly increased growth in September, October and April, with the greatest response occurring in October; hours of sunshine was the significant factor influencing growth in August and November. Annual pasture growth also responded to changes in mean maximum temperature or hours of sunshine in September and October. The comparative mean annual production of paspalum pasture, ryegrass/clover pasture and annual pasture was 18.3, 18.3 and 11.0 t DM/ha, respectively. These levels of production represented 1.1, 1.2 and 1.6% conversion of photosynthetically active radiation during the growing period of the three pasture types, respectively. These levels of productivity and the animal production that should result, suggest that the pasture productivity on many irrigated dairy farms is either very low or the pasture that is grown is inefficiently utilized. Because animal productivity depends on pasture productivity more than any other single factor, farmers should make improvement of pasture growth their major aim while having regard for the variability in growth that can result from variations in environmental factors.



2011 ◽  
Vol 62 (3) ◽  
pp. 236 ◽  
Author(s):  
S. A. Conning ◽  
M. Renton ◽  
M. H. Ryan ◽  
P. G. H. Nichols

Biserrula (Biserrula pelecinus L.) is a recently domesticated annual pasture legume developed for ley farming systems that have traditionally relied upon subterranean clover (Trifolium subterraneum L.). This study examined competitive interactions between biserrula and subterranean clover and the common broad-leaf weed capeweed (Arctotheca calendula L.) during seedling establishment and vegetative growth, in order to develop guidelines for successful legume pasture management. Two glasshouse experiments were conducted to investigate the allocation of biomass to roots and shoots in biserrula, capeweed, and subterranean clover and its relationship with competitive ability in the first 100 days after sowing. In Experiment 1, capeweed had a higher relative growth rate of shoots and roots than the two legumes and developed a more extensive root system. Experiment 2 consisted of growing binary mixtures of the three species at different densities. The effect of competition on the biomass of biserrula, capeweed, and subterranean clover was best modelled by a power–exponential model. Increasing capeweed densities suppressed the biomass production of both biserrula and subterranean clover, whereas capeweed biomass increased with increasing densities of subterranean clover. This study suggests that the competitive advantage of capeweed is mainly conferred during the seedling stage. It also suggests that biserrula and subterranean clover germinating at the same time can co-exist as a mixed sward, at least up until flowering, if biserrula density is high relative to subterranean clover.



1965 ◽  
Vol 18 (2) ◽  
pp. 295 ◽  
Author(s):  
AH Gibson

Nitrogen fixation by six varieties of Trifolium subterraneum L., each inoculated with a number of strains of Rhizobium trifolii, was examined over a range of root temperatures. Significant differences in the rate of nodule establishment and early nitrogen fixation were found between varieties, and between bacterial strains. In order to minimize the effect of such differences, relative nitrogen assimilation rates (RN) and relative growth rates (R w) were used to compare the different legume-bacteria associations.



1973 ◽  
Vol 13 (64) ◽  
pp. 549 ◽  
Author(s):  
RCG Smith ◽  
EF Biddiscombe ◽  
WR Stern

Newly sown pure swards of Wimmera ryegrass (Lolium rigidum) and subterranean clover (Trifolium subterraneum) were either grazed or spelled (deferred) for five weeks after emergence in autumn and then evaluated with young Merino wethers stocked at 10 sheep ha-1. Sheep on deferred pastures had higher intakes and liveweight than on plots continuously grazed. Spelling increased the availability of pasture for prehension due to a greater weight of herbage being offered and the more erect growth form. Under continuous grazing the animal productivity on clover was much lower than on ryegrass but following deferment, both species had similar productivity. The beneficial effects of spelling after emergence were manifest over the ensuing ten months by liveweight, fleeceweight and number of days of grazing. Spelling also increased seed reserves at the end of summer and the number of plants re-establishing at the beginning of the next growing season.



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