Waite Agricultural Research Institute Research Articles

THE TURNOVER OF SOIL ORGANIC MATTER IN SOME OF THE ROTHAMSTED CLASSICAL EXPERIMENTS

Rothamsted Experimental Station, Harpenden, Herts. AL5 2JQ, England Received for publication January 4, 1977 1At present Hannaford Research Fellow, Waite Agricultural Research Institute, Adelaide, South Australia 5064.

Trends in wheat yields and soil organic carbon in the Permanent Rotation Trial at the Waite Agricultural Research Institute, South Australia

The Permanent Rotation Trial at the Waite Agricultural Research Institute in South Australia was established on a red-brown earth in 1925, with predominately cereal-long fallow rotations on 34 adjacent plots. The trial was upgraded in 1948 to include a greater proportion of pasture leys in the rotations and currently contains 11 treatments. The trial is unreplicated; however, each phase of a sequence is represented each year. Seven of the original rotations have remained in an unbroken sequence since 1925: continuous wheat (W), wheat-fallow (WF), wheat-peas (WPe), wheat-pasture-fallow (WPaF), wheatoats- fallow (WOF), wheat-barley-peas (WBPe), wheat-oats-pasture-fallow (WOPaF). For the 11 rotations, soil organic carbon (SOC) in the top 10 cm declined from 2.75% in 1925 to a mean value of 1.56% in 1993. One plot, which had reverted to permanent pasture in 1950, showed the smallest decline with an SOC content of 2.46% in 1993. The greatest declines in SOC were in the 4 original rotations that included fallow phases in the sequence (mean value of 1.22%). In the WF rotation the SOC content had declined from 2.75 to 1.04% during 68 years of cropping. Associated yield decreases showed that the treatment could not sustain production. Soil organic C declined linearly with increasing frequency of fallows and decreasing frequency of pasture in the rotations. Average grain yields (1925-93) in the 7 original sequences ranged from 2.64 t/ha in WOPaF to 0.89 t/ha in the continuous W plot. The linear decline in yields for WBPe, WPaF, WPe, and WOF treatments indicate a convergence in the 1990s under current management, with an average yield of 1.54 t/ha in 1993 and average SOC in the top 10 cm of 1.32%. We hypothesise that the gradual increase in grain yields from the continuous W plot since the 1960s is the result of a gradual build-up of light fraction organic material, which assists in the maintainence of structure and nutrient availability.

Structural amelioration of a South Australian red-brown earth using calcium and organic amendments

The ability of wheat straw, gypsum and agricultural lime to ameliorate the unstable structural condition of a degraded red-brown earth located at the Waite Agricultural Research Institute, South Australia, was investigated in a field experiment lasting 5 years. Wheat straw was added at rates of 0, 5 and 10 t ha-1 y-1, and gypsum and agricultural lime were added at rates of 3.4 and 2.0 t ha-1 y-1 respectively. Most of the measurements were taken on samples collected after three and four consecutive years of treatment applications, but some were taken one year after the fifth and final application of the treatments. The amount of water-stable macroaggregation in the top 10 cm increased with increasing rate of wheat straw application. Addition of agricultural lime incorporated with straw temporarily increased macroaggregate stability to a greater extent than was observed with either amendment alone. The proportion of the soil surface occupied by macropores was also increased significantly by addition of agricultural lime, and this was attributed to a stimulation of biological activity in the soil due to the increased soil pH. Density fractionation of the soil suggested the turnover of the added wheat straw in the lime-treated soil was greater than in the gypsum-treated and control soils. Addition of gypsum decreased the content of mechanically dispersible clay by modifying the electrolyte concentration and composition, but was unable to completely resist the dispersive tendencies created by the decomposing organic residues. The high rates of wheat straw incorporated in the top 10 cm caused significant dispersion in the top 20 cm, which was thought to have mobilized clay particles causing them to move downward, resulting in pore blockage and the consequent lowering of hydraulic conductivity in the zone immediately below.

Amatoxin poisoning following ingestion of the mushroom Lepiota helviola. Report of two cases with hepatotoxicity: C. Lloyd, J. White, S. Downes, R. Willing, C. Baggoley, S. Pond and R. Coles (Flinders Medical Centre, Bedford Park SA 5042; State Toxinology Services, Adelaide Children's Hospital, North Adelaide SA 5006; Princess Alexandria Hospital, Woolloongabba Qld 4102; Waite Agricultural Research Institute, Urrbrae SA 5064,

Amatoxin poisoning following ingestion of the mushroom Lepiota helviola. Report of two cases with hepatotoxicity: C. Lloyd, J. White, S. Downes, R. Willing, C. Baggoley, S. Pond and R. Coles (Flinders Medical Centre, Bedford Park SA 5042; State Toxinology Services, Adelaide Children's Hospital, North Adelaide SA 5006; Princess Alexandria Hospital, Woolloongabba Qld 4102; Waite Agricultural Research Institute, Urrbrae SA 5064,

The growth and yield of uniculm and tillered barley over a range of sowing rates

The growth and yield of two lines of uniculm barley, WID-103 and WID-105, were compared over a range of sowing rates (50-400 kg/ha) with the commercial varieties Galleon and Schooner. The experiments were conducted at Strathalbyn, S.A., in 1986, 1987 and 1988 and at the Waite Agricultural Research Institute in 1987. A third tillered variety, Clipper, was included in the comparison in 1988. Over the three years plant populations measured early in the season ranged from 39/m2 to 709/m2, and grain yields from 97 to 41 1 g/m2. Dry matter production at ear emergence increased with greater plant density, and both the tillered varieties and the uniculm lines showed similar responses to higher sowing rates. At maturity, dry matter production of the tillered barleys was greater than or equal to that of the uniculms and the harvest indices (HIs) of the two types were similar. Consequently, grain yields of the tillered types were greater than or equal to the yields of the uniculms. Over the four experiments the tillered varieties had a 6% higher yield. The number of ears/m2 was the yield component most affected by plant density in both the tillered and uniculm barleys. The uniculm lines had more spikelets/ear, but tended to set fewer grains/spikelet and produce smaller kernels. The experiments failed to demonstrate any advantage of the uniculm habit to the grain yield of barley. These results differ from previous experiments that showed that a uniculm line, WID-101, had a higher yield than the tillered variety Clipper. It is suggested that the uniculm habit per se was not the cause of this higher yield, but its higher HI resulted in it outyielding Clipper. Current varieties, however, have HIs similar to the uniculm lines and yield equally to or more than the uniculm barleys examined. To further improve the grain yield of uniculm barley, greater dry matter production is necessary as the HIs of these lines are already high.

Book Review - Rhynchosporium secalis. A Keyword Index to the Literature. by C.C. Ryan, B.G. Clare and R.P. Cook. Waite Agricultural Research Institute, University of Adelaide. 1987. 197pp.

Book Review - Rhynchosporium secalis. A Keyword Index to the Literature. by C.C. Ryan, B.G. Clare and R.P. Cook. Waite Agricultural Research Institute, University of Adelaide. 1987. 197pp.

Solute Accumulation by Grape Pericarp Cells

Findlay, N., Oliver, K. J., Nii, N. and Coombe, B. G. 1987. Solute accumulation by grape pericarp cells. IV. Perfusion of pericarp apoplast via the pedicel and evidence for xylem malfunction in ripening berries.—J. exp. Bot. 38: 668-679. 14C-labelled sucrose was applied to freshly-cut pedicels of excised unripe and ripening grape berries and let perfuse for different periods; skin and flesh tissues were then extracted and the radioactivity partitioned and measured. Accumulation of radioactivity in a compartmented fraction was greatest in the skin of unripe berries at the stage when sugar accumulation in vivo was slow. Total radioactivity of parts of berries showed that activity spread rapidly throughout when the berry was unripe but slowed once ripening commenced. The perfusion of eosin from pedicels was also rapid in unripe berries but in ripe berries it was blocked beyond the pedicel at the outer edge of the 'brush' where the pericarp is aerenchymatous and tanniniferous. The failure of movement through the vascular bundles beyond the brush could not be associated with the development of tyloses in tracheary elements; it appeared to be associated with stretched tracheids in the network of dorsal vascular bundles evidenced by irregularities in the spacing of wall thickenings and breaks in the bounding membranes. This physical disruption of the tracheary elements of the vascular bundles occurred when the berry expands suddenly, about a week after the inception of rapid sugar accumulation. The different rates of perfusion limit the utility of the pedicel route for studies of compartmentation and metabolism in grape berries at different developmental stages. Nevertheless, the rapid compart mentation of radioactivity after pedicel perfusion of unripe skin with 14C-labelled sucrose discounts the hypothesis that the slow rate in skin in situ is due to an apoplastic inhibitor. Key words—Grape berry, accumulation, xylem malfunction. Correspondence to: Department of Plant Physiology, Waite Agricultural Research Institute, University of Adelaide, Glen Osmond, South Australia.

The movement of fluids and substances in the testis.

Three aspects of the control of movements of fluids and substances into, out of and inside the testis are discussed: the tubular barrier, the interstitial extracellular fluid and the testicular blood vessels. The functional basis for the tubular barrier is twofold; there are significant differences in the concentration of many substances inside and outside the tubules and marker substances enter or leave the tubular fluid at widely different rates, depending on lipid solubility and the presence of specific carrier systems. The anatomical basis for this barrier appears to be the specialized junctions between adjacent pairs of Sertoli cells. The barrier develops only at puberty, as the first cells undergo meiosis, but the development may not be as sudden as previously believed. The barrier breaks down after efferent duct ligation when spermatogenesis is disrupted. Techniques for measuring the volume, the turnover rate, the composition and fate of the interstitial extracellular fluid are described, and the unsatisfactory features of the presently available techniques for collecting this fluid for analysis are emphasized. There is a relationship between the fluid in the testis and lymph from vessels in the spermatic cord and lymph may be important for the transport of hormones to the general circulation in some circumstances and to other organs close to the testis. The testicular blood vessels display certain unusual features, a very high susceptibility to the toxic effects of cadmium salts, a high level of alkaline phosphatase activity in all endothelial cells but only after puberty and a high level of gamma-glutamyl transpeptidase in the endothelial cells of the arterioles and the testicular artery. These same cells are the site for a specific transport system for leucine and phenylalanine, with kinetic characteristics similar to the system in brain. Flow of blood may limit hormone secretion by the aspermatogenic testis, but diffusion limitation may also be important under some circumstances. A fuller understanding of the ways in which substances move around in the testis, particularly how they cross the endothelial cell layer or penetrate into the tubules, will be important for a better appreciation of testicular function.

Stem nitrate nitrogen and yield of wheat in a permanent rotation experiment

The growth of wheat on the permanent rotation experiment at the Waite Agricultural Research Institute was examined over two seasons. Measurements of stem nitrate nitrogen concentration were used to assess the effect of nitrogen on yield for treatments which can also affect the availability of water and the severity of pests and diseases. High nitrate nitrogen was positively correlated with yield in a wet year, but its importance changed between years and was determined by rotation and environmental conditions. On average the sequence oats-oats for grazing-fallow-wheat had the highest nitrate nitrogen and the highest long-term mean yield, even though it had no apparent nitrogen input. Rotations which included grass-clover phases can be more severely infested by pests and diseases, and the wheat less able to respond to favourable nitrogen supply than rotations which included fallow or a non-host crop.

Comments on Recent Work with Critical Point Dried Soils

Journal of Soil ScienceVolume 32, Issue 1 p. 161-162 Comments on Recent Work with Critical Point Dried Soils R. S. Murray, R. S. Murray Director's Research Unit, Waite Agricultural Research Institute, The University of Adelaide, Glen Osmond, 5064 South AustraliaSearch for more papers by this authorJ. P. Quirk, J. P. Quirk Director's Research Unit, Waite Agricultural Research Institute, The University of Adelaide, Glen Osmond, 5064 South AustraliaSearch for more papers by this author R. S. Murray, R. S. Murray Director's Research Unit, Waite Agricultural Research Institute, The University of Adelaide, Glen Osmond, 5064 South AustraliaSearch for more papers by this authorJ. P. Quirk, J. P. Quirk Director's Research Unit, Waite Agricultural Research Institute, The University of Adelaide, Glen Osmond, 5064 South AustraliaSearch for more papers by this author First published: March 1981 https://doi.org/10.1111/j.1365-2389.1981.tb01694.xCitations: 3AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume32, Issue1March 1981Pages 161-162 RelatedInformation

Stable isotope studies on the oxidation of ammonia to hydroxylamine by nitrosomonas europaea

FEBS LettersVolume 106, Issue 2 p. 401-404 Full-length articleFree Access Stable isotope studies on the oxidation of ammonia to hydroxylamine by nitrosomonas europaea R.D. Dua, R.D. Dua Agricultural Biochemistry Department, Waite Agricultural Research Institute, University of Adelaide, Glen Osmond, SA 5064, Australia Present address: Chemistry Department, Indian Institute of Technology, New Delhi, 110029, India Search for more papers by this authorBasant Bhandari, Basant Bhandari Agricultural Biochemistry Department, Waite Agricultural Research Institute, University of Adelaide, Glen Osmond, SA 5064, AustraliaSearch for more papers by this authorD.J.D. Nicholas, D.J.D. Nicholas Agricultural Biochemistry Department, Waite Agricultural Research Institute, University of Adelaide, Glen Osmond, SA 5064, Australia To whom reprint requests should be addressed Search for more papers by this author R.D. Dua, R.D. Dua Agricultural Biochemistry Department, Waite Agricultural Research Institute, University of Adelaide, Glen Osmond, SA 5064, Australia Present address: Chemistry Department, Indian Institute of Technology, New Delhi, 110029, India Search for more papers by this authorBasant Bhandari, Basant Bhandari Agricultural Biochemistry Department, Waite Agricultural Research Institute, University of Adelaide, Glen Osmond, SA 5064, AustraliaSearch for more papers by this authorD.J.D. Nicholas, D.J.D. Nicholas Agricultural Biochemistry Department, Waite Agricultural Research Institute, University of Adelaide, Glen Osmond, SA 5064, Australia To whom reprint requests should be addressed Search for more papers by this author First published: October 15, 1979 https://doi.org/10.1016/0014-5793(79)80541-4Citations: 50 AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume106, Issue2October 15, 1979Pages 401-404 ReferencesRelatedInformation

Pedigree investigation using biochemical markers: the wheat cultivar Gabo

Biochemical tests for characterizing genotype were used to investigate the pedigree of the important Australian wheat Gabo. Although its registered pedigreeis (Bobin Selection x Gaza) x Bobin Selection, there have been suggestions that the recurring parent is Gular, not Bobin. Phenol reactions (grain and glume) and electrophoresis/isoelectric focusing patterns (gliadins) were obtained for a number of different accessions of Gabo, Gaza, Bobin and Gular. Gabo and Gaza samples were uniform; Bobin and Gular samples were not. The characteristics of most Bobin and Gular samples were inconsistent with their being a parent of Gabo. The results indicated that a sample called 'Bobin Selection W39' was the parent used in the cross with Gaza to produce Gabo, and that this selection was probably not Bobin, but a sample of Gular similar to that accessioned as 634 at the Waite Agricultural Research Institute.

Patent protection of microorganisms with special reference to ferrous‐iron and sulfur oxidizing bacteria

Biotechnology and BioengineeringVolume 17, Issue 12 p. 1853-1857 Communications to the EditorFree Access Patent protection of microorganisms with special reference to ferrous-iron and sulfur oxidizing bacteria O. H. Tuovinen, O. H. Tuovinen Dept. of Agricultural Biochemistry, Waite Agricultural Research Institute, The University of Adelaide, Glen Osmond, South Australia 5064Search for more papers by this authorD. J. D. Nicholas, D. J. D. Nicholas Dept. of Agricultural Biochemistry, Waite Agricultural Research Institute, The University of Adelaide, Glen Osmond, South Australia 5064Search for more papers by this author O. H. Tuovinen, O. H. Tuovinen Dept. of Agricultural Biochemistry, Waite Agricultural Research Institute, The University of Adelaide, Glen Osmond, South Australia 5064Search for more papers by this authorD. J. D. Nicholas, D. J. D. Nicholas Dept. of Agricultural Biochemistry, Waite Agricultural Research Institute, The University of Adelaide, Glen Osmond, South Australia 5064Search for more papers by this author First published: December 1975 https://doi.org/10.1002/bit.260171217Citations: 2AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL References 1 C. T. Taylor and Z. A. Silberston, The Economic Impact of the Patent System. A Study of the British Experience, Cambridge University Press, London, 1973. 2 J. W. Whittenburg, Advan. Appl. Microbiol., 13, 383 (1970). 3 H. G. Gyllenberg, Postepy Hig. Med. Dosw., 26, 423 (1972). 4 J. W. Baxter, World Patent Law and Practice, Sweet and Maxwell, London, 1973. 5 C. W. Hesseltine and W. C. Haynes, Prog. Ind. Microbiol., 12, 1 (1973). 6 L. G. Silvestri and D. Gottlieb, Global Impacts Appl. Microbiol., 1, 109 (1964). Citing Literature Volume17, Issue12December 1975Pages 1853-1857 ReferencesRelatedInformation

Electrofocusing of grain proteins from wheat genotypes.

Annals of the New York Academy of SciencesVolume 209, Issue 1 p. 154-162 ELECTROFOCUSING OF GRAIN PROTEINS FROM WHEAT GENOTYPES C. W. Wrigley, C. W. Wrigley C.S.I.R.O. Wheat Research Unit North Hyde, New South Wales 2113, AustraliaSearch for more papers by this authorK. W. Shepherd, K. W. Shepherd Waite Agricultural Research Institute Glen Osmond, South Australia 5064, AustraliaSearch for more papers by this author C. W. Wrigley, C. W. Wrigley C.S.I.R.O. Wheat Research Unit North Hyde, New South Wales 2113, AustraliaSearch for more papers by this authorK. W. Shepherd, K. W. Shepherd Waite Agricultural Research Institute Glen Osmond, South Australia 5064, AustraliaSearch for more papers by this author First published: June 1973 https://doi.org/10.1111/j.1749-6632.1973.tb47526.xCitations: 164AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume209, Issue1Isoelectric Focusing and IsotachophoresisJune 1973Pages 154-162 RelatedInformation

3-Hydroxy acid dehydrogenases in sheep tissues.

Research Article| April 01 1972 3-Hydroxy acid dehydrogenases in sheep tissues P P Koundakjian; P P Koundakjian 1Department of Agricultural Biochemistry, Waite Agricultural Research Institute, University of Adelaide, Glen Osmond, S. Austral. 5064, Australia Search for other works by this author on: This Site PubMed Google Scholar A M Snoswell A M Snoswell 1Department of Agricultural Biochemistry, Waite Agricultural Research Institute, University of Adelaide, Glen Osmond, S. Austral. 5064, Australia Search for other works by this author on: This Site PubMed Google Scholar Biochem J (1972) 127 (2): 449–452. https://doi.org/10.1042/bj1270449 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Cite Icon Cite Get Permissions Citation P P Koundakjian, A M Snoswell; 3-Hydroxy acid dehydrogenases in sheep tissues. Biochem J 1 April 1972; 127 (2): 449–452. doi: https://doi.org/10.1042/bj1270449 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsBiochemical Journal Search Advanced Search This content is only available as a PDF. © 1972 The Biochemical Society1972 Article PDF first page preview Close Modal You do not currently have access to this content.

Mutilation of the Imported Cabbageworm by the Parasite Apanteles rubecula12

In a laboratory experiment conducted at the Waite Agricultural Research Institute, University of Adelaide, 2- to 7-day-old larvae of the cabbage white butterfly, Pieris rapae (L.) (known in the United States as the imported cabbageworm) were exposed to the female hymenopterous parasite Apanteles rubecula Marsh. It was found that during the act of oviposition the smaller caterpillars were evidently killed by being mutilated by the parasite. As many as 70% of the 2-day-old larvae died, as compared with less than 10% of the 7-day-old larvae. This parasite apparently docs not consider age when it selects larvae in which to obi posit and is possibly responsible for a considerable number of the deaths that occur among small P. rapae in South Australia.

An evaluation of lucerne lines at the Waite Agricultural Research Institute, South Australia

One hundred and ten lines of lucerne from regions with Mediterranean and temperate climates have been grown in three spaced-plant trials. The collection represented a wide range of morphological variation from erect to prostrate types, and included wild creeping lucernes. Seasonal growth was compared with or without summer irrigation. Plants were cut or grazed at the frequency usually recommended for lucerne or twice as often. No line consistently yielded more total dry matter than the Australian cultivar, Hunter River, but some from the Mediterranean region yielded more in winter. Persistence was poor in the winter active Mediterranean lines, but good in Hunter River. Frequent cutting decreased persistence, and a six-month period of heavy and continuous grazing eliminated nearly all plants from most lines. Wild, spreading plants from the Mediterranean region showed the best persistence, and persisted well even under the continuous grazing, but their yields were very low. Lines from Spain and Portugal showed sufficient promise to become new cultivars, and they are under further test. Other lines have potential value when breeding for improved seasonal yield or persistence.

Wether bioassay of annual pasture legumes. I. Oestrogenic activity in Medicago tribuloides Desr. var. Cyprus* relative to four strains of Trifolium subterraneum L.

The grazing of pasture swards of Cyprus barrel medic and of four strains of subterranean clover resulted in increases of wether teat length similar to those produced by injections of a synthetic oestrogen, diethylstilboestrol. Oestrogenic activity of the medic, as measured by increase in wether teat length, was less than that of the Yarloop and Dwalganup strains of subterranean clover, but similar to that of the Mt. Barker strain. Coumestrol appears to be the principal oestrogenic substance in the medic. The coumestrol contents of Cyprus and commercial barrel medics were similar but varied at different localities. The low coumestrol content of the subterranean clovers suggests that it is not an important oestrogen in this species. ____________________ *Cyprus barrel medic. During the joint FAO–CSIRO collecting expedition in 1950–1951, J. F. Miles collected barrel medic, C.P.J. 13914, in Cyprus, and portion of the seed was passed to D. Symon at the Waite Agricultural Research Institute, Adelaide. A programme, commenced in 1950, to extend the legume belt into the lower rainfall districts of Western Australia, indicated the need for an earlier-flowering medic, and Symon suggested testing the Cyprus introductjon. Encouraging results from sward tnals conducted by the Institute of Agriculture, University of Western Australia, resulted in a programme of seed increase and large-scale commercial production of the Cyprus strain. The Cyprus strain flowers 4 weeks earlier than the commercial and 5 weeks before M. tr ibuloides 173, and is proving a very satisfactory legume on a wide range of soils in Western Australia.

Electron‐Microscopy of acid‐degraded Starch Granules

Starch - StärkeVolume 15, Issue 3 p. 85-92 Article Electron-Microscopy of acid-degraded Starch Granules M. S. Buttrose Ph.D., M. S. Buttrose Ph.D. Department of Plant Physiology, Waite Agricultural Research Institute, University of Adelaide, Adelaide (South Australia)Search for more papers by this author M. S. Buttrose Ph.D., M. S. Buttrose Ph.D. Department of Plant Physiology, Waite Agricultural Research Institute, University of Adelaide, Adelaide (South Australia)Search for more papers by this author First published: 1963 https://doi.org/10.1002/star.19630150304Citations: 35AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume15, Issue31963Pages 85-92 RelatedInformation

The role of time of emergence in determining the growth of individual plants in swards of subterranean clover (Trifolium subterraneum L.)

An experiment was carried out which enabled a separate assessment to be made of the influence of, firstly, pre-emergence growth rate, and secondly, the competitive environment at emergence on the subsequent growth of individual plants of subterranean clover. Swards of the Bacchus Marsh variety were grown in large seed boxes at the Waite Agricultural Research Institute, Adelaide. Four different sowing treatments were applied whereby the sowing of alternate plants in a checkerboard grid was delayed by 0, 2, 4, and 8 days. Emergence date and final dry weight were recorded individually for each plant in the experimental swards. There was considerable overlap in emergence times between the earlier and the later-sown plants. Consequently by a comparison of the separate regressions for earlier and later-sown plants of yield per plant on day of emergence for each treatment, it could be demonstrated that plants with very different pre-emergence growth rates but emerging on the same day in the same sward, and hence into the same competitive environment, gave essentially the same subsequent growth. In other words, in the absence of differential competitive effects, there was no detectable influence of pre-emergence growth rate on subsequent growth. On the other hand, the final dry weights of individual plants were very strongly related to day of emergence. A delay in emergence of 5 days brought about a reduction in final yield of about 50%, and a delay of 8 or 9 days of at least 75%. In view of the negligible influence of pre-emergence growth rate, per se, this reduction is attributable solely to the increased severity of competition from plants already emerged. In spite of the wide variation in emergence patterns, the total yields of all swards were very similar, indicating an almost complete compensation between plants in the utilization of available growth factors.