Transformation in soil and turnover to wheat of nitrogen from components of grazed pasture in the south of Western Australia

1997 ◽  
Vol 48 (7) ◽  
pp. 1033 ◽  
Author(s):  
R. B. Thompson ◽  
I. R. P. Fillery
Keyword(s):  
N Uptake ◽  
Subterranean Clover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
N Mineralisation ◽  
Leaching Losses ◽  
Grazed Pasture ◽  
Application Rates ◽  
Wind Blow ◽  
Western Australian

Nitrogen (N) mineralisation from mature subterranean clover (Trifolium subterraneum L.) shoots and roots and from sheep urine and faeces, and N uptake by wheat from the shoots, urine, and faeces, were determined with 15 N in a field study in the Western Australian wheatbelt. Treatments were applied to the soil surface of confined micro-plots in autumn and incorporated into soil immediately before wheat was sown in winter. Mature subterranean clover shoots containing 18 kg N/ha were applied to the soil surface, and root material containing 17 kg N/ha was mixed into soil. 15N-labelled urine and faeces were obtained from housed sheep fed 15N-labelled wheat straw and grain. Urine was applied at the rates of 151 and 301 kg N/ha, and faeces was added at the rate of 47 kg N/ha. There was a loss of 14% of shoot 15N in the 2 months this residue was on the soil surface, although very little mineralisation occurred. On the assumption that wind-blow caused the initial loss of 15N, 28% of shoot N mineralised in 6 months following incorporation of shoot residues into soil, and crop recovery was 11% of the 15N applied. N mineralisation from the mature roots was 26% in 6 months. NH3 volatilisation from urine, estimated by difference, was 25% for high urine (0·517 mL/cm2) and 33% for low urine (0·258 mL/cm2) application rates, the loss occurring in the first 2 weeks. Wheat uptake was 23% of the high urine 15N and 22% of the low urine 15N. Leaching losses from unplanted micro-plots were approximately 25-30% of urine 15N. In contrast, leaching losses from planted micro-plots were estimated to be approximately 10% of urine 15N. Approximately 30% of faecal N was mineralised and recovery of faeces N by wheat was 1% of applied 15N. The relative contributions of these components to N turnover in the ley pasture wheat rotation are discussed. It is concluded that assessments of the potential turnover of N in pastures to cropping phases need to consider the low rates of N mineralisation of above-ground herbage, the potential for supply of N from the total root system, the effect of grazing on NH3volatilisation, and consequent loss of N fixed by legumes.

Mineralisation of nitrogen contained in mature subterranean clover, capeweed and annual ryegrass, and subsequent nitrogen use by wheat in dryland farming systems in southern Australia

Soil Research ◽  
2002 ◽  
Vol 40 (2) ◽  
pp. 299 ◽  
Author(s):  
R. B. Thompson ◽  
I. R. P. Fillery
Keyword(s):  
N Uptake ◽  
Subterranean Clover ◽  
Soil Surface ◽  
Farming Systems ◽  
Experimental Period ◽  
Field Studies ◽  
Climatic Conditions ◽  
N Mineralisation ◽  
Annual Ryegrass ◽  
Intact Roots

Net nitrogen (N) mineralisation in soil and N uptake by wheat from mature shoots and roots of subterranean clover, capeweed, and annual ryegrass, and from clover burrs were assessed with 15N-labelled plant material in 2 field studies, using confined micro-plots. In the first study, shoot residues of the 3 species (150 g DM/m2) were placed on the soil surface, and roots of the 3 species (75 g DM/m2) were mixed into 0–10 cm soil. The treatments were applied in March 1991. The shoot residues were incorporated into soil in early June 1991. Net 15N mineralisation from the clover, capeweed, and ryegrass shoots during the 8-month experimental period was estimated to be, respectively, 15%, 12%, and 12%, and for the corresponding roots was 10%, 7%, and 6%. Negligible net mineralisation of 15N occurred during the 2.5 months that the shoot residues were on the soil surface. Crop 15N recoveries in wheat, at maturity, in November 1991 were 9%, 7%, and 7%, respectively, of that applied in the clover, capeweed, and ryegrass shoot residues. The respective crop recoveries from the root residues were 6%, 5%, and 3%. Less than 5% of N taken up by wheat was obtained from shoot or root residues. In a second similar study, 15N-labelled subterranean clover shoots (200 g DM/m2) and burrs (75 g DM/m2) were applied in December 1992; 3% of 15N in the clover shoots was net mineralised during the 5 months they were on the soil surface. Crop recoveries of 15N in October 1993, at the time of wheat anthesis, from the clover shoots and burrs were, respectively, 14% and 17% of applied 15N. The results of these field studies suggest that mature shoot residues and the associated intact roots (recoverable by wet-sieving), and clover burrs, make only a small direct contribution to the N response of cereals immediately following ley pasture in southern Australia. They also indicate that, under Mediterranean climatic conditions, generally very little net N mineralisation occurs from mature shoot residues until the shoots are incorporated into soil. pasture, shoots, roots, 15N, rotation, cereals, burr.

Response of defoliated swards of subterranean clover and yellow serradella to superphosphate applications

1991 ◽  
Vol 31 (6) ◽  
pp. 777
Author(s):  
MDA Bolland
Keyword(s):  
Field Experiment ◽  
Sandy Soil ◽  
Dry Matter ◽  
Maximum Yield ◽  
Subterranean Clover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Herbage Yield ◽  
Ornithopus Compressus ◽  
The Relationship

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.

Effect of perennial pasture species on surface soil moisture and early growth and survival of subterranean clover (Trifolium subterraneum L.) seedlings

1997 ◽  
Vol 48 (5) ◽  
pp. 683 ◽  
Author(s):  
B. S. Dear ◽  
P. S. Cocks
Keyword(s):  
Mineral Soil ◽  
Subterranean Clover ◽  
Late Summer ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Annual Grass ◽  
Growth And Survival ◽  
Eastern Australia ◽  
Standing Dead ◽  
Clover Seed

Subterranean clover seedling numbers and growth in swards containing 1 of 5 perennial pasture species [phalaris (Phalaris aquatica) cv. Sirolan, cocksfoot (Dactylis glomerata) cv. Currie, lucerne (Medicago sativa) cv. Aquarius, wallaby grass (Danthonia richardsonii) cv. Taranna, and lovegrass (Eragrostis curvula) cv. Consol] were compared with those in typical annual pastures and pure clover swards in the wheatbelt of eastern Australia. Presence of a perennial species or the volunteer annual grass (Eragrostis cilianensis) increased the rate of drying of the soil surface (0–5 cm) after late February and May rain, compared with subterranean clover swards. Perennials differed in the rate they dried the soil surface, with the more summer-active lucerne and consul lovegrass drying the profile more rapidly than phalaris. The amount of water in the surface 5 cm, 6 days after the rainfall event on 27–28 February, was strongly negatively correlated (r = –0·75, P < 0·01) with the amount of green perennial biomass, but not related to standing dead material or surface residues. Where perennials were present, a smaller proportion (2–4%) of the clover seed pool produced seedlings in response to late summer rain, compared with pure clover swards (18%). A higher proportion of the seed pool produced seedlings (19–36%) following rain in late autumn but there was no difference between species. The more summer-active perennials (cocksfoot, danthonia, and lucerne) markedly depressed the survival of emerged clover seedlings following both germinations. Of the seedlings that emerged in early March, the proportion remaining by 29 March was 57% in phalaris, 21% in lucerne, 13% in danthonia, and 1% in cocksfoot, compared with a 78% increase in seedlings in pure subterranean clover swards. By 15 May, all perennials had <2 clover seedlings/m2 surviving, compared with 37 in the annual pasture and 964 plants/m2 in pure subterranean clover. Following the May germination, the highest proportion of emerged seedlings surviving until 29 May was in the phalaris swards (40%) and least in the cocksfoot and danthonia swards (2–4%). Presence of a perennial or annual grass decreased (P < 0·05) relative water content of clover seedlings on 15 March from 74% in pure clover swards, to 48% in annual pasture, 34% in phalaris, and 29% in lucerne swards. Clover seedlings growing in pure subterranean swards on 15 March (17 days after germinating rain) were 4 times larger than those in lucerne and twice as large as those in either phalaris or annual pasture. Seed size did not differ between treatments, but available mineral soil nitrogen was significantly higher (P < 0·001) in pure subterranean clover swards (32 mg N/g) compared with perennials (3–13 mg N/g). Strategies such as heavy grazing in late summer to reduce green biomass of the perennials or sowing the perennials at lower densities may reduce the adverse effects that perennials have on subterranean clover seedlings in these drier environments.

Comparing different sources of sulfur for high-rainfall pastures insouth-western Australia

2003 ◽  
Vol 43 (10) ◽  
pp. 1221 ◽  
Author(s):  
M. D. A. Bolland ◽  
J. S. Yeates ◽  
M. F. Clarke
Keyword(s):  
Western Australia ◽  
Field Experiments ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Residual Value ◽  
Single Superphosphate ◽  
Pasture Production ◽  
Leaching Losses ◽  
S Deficiency ◽  
Different Sources

The dry herbage yield increase (response) of subterranean clover (Trifolium subterraneum L.)-based pasture (>85% clover) to applications of different sources of sulfur (S) was compared in 7 field experiments on very sandy soils in the > 650 mm annual average rainfall areas of south-western Australia where S deficiency of clover is common when pastures grow rapidly during spring (August–November). The sources compared were single superphosphate, finely grained and coarsely grained gypsum from deposits in south-western Australia, and elemental S. All sources were broadcast (topdressed) once only onto each plot, 3 weeks after pasture emerged at the start of the first growing season. In each subsequent year, fresh fertiliser-S as single superphosphate was applied 3 weeks after pasture emerged to nil-S plots previously not treated with S since the start of the experiment. This was to determine the residual value of sources applied at the start of the experiment in each subsequent year relative to superphosphate freshly-applied in each subsequent year. In addition, superphosphate was also applied 6, 12 and 16 weeks after emergence of pasture in each year, using nil-S plots not previously treated with S since the start of the experiment. Pasture responses to applied S are usually larger after mid-August, so applying S later may match plant demand increasing the effectiveness of S for pasture production and may also reduce leaching losses of the applied S.At the same site, yield increases to applied S varied greatly, from 0 to 300%, at different harvests in the same or different years. These variations in yield responses to applied S are attributed to the net effect of mineralisation of different amounts of S from soil organic matter, dissolution of S from fertilisers, and different amounts of leaching losses of S from soil by rainfall. Within each year at each site, yield increases were mostly larger in spring (September–November) than in autumn (June–August). In the year of application, single superphosphate was equally or more effective than the other sources. In years when large responses to S occurred, applying single superphosphate later in the year was more effective than applying single superphosphate 3 weeks after pasture emerged (standard practice), so within each year the most recently applied single superphosphate treatment was the most effective S source. All sources generally had negligible residual value, so S needed to be applied each year to ensure S deficiency did not reduce pasture production.

A Method for obtaining Samples of the Population of Collembola (Symphypleona) in Pastures

1933 ◽  
Vol 24 (3) ◽  
pp. 351-352 ◽  
Author(s):  
J. Davidson ◽  
D. C. Swan
Keyword(s):  
Moisture Content ◽  
Total Population ◽  
Surface Soil ◽  
Relative Proportion ◽  
Subterranean Clover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Food Plants ◽  
Simple Method ◽  
Factors Affecting

In our investigations on Smynthurus viridis, L., a study has been made of the population of this species, in an area of lucerne, at intervals of three and four days throughout the season.The density of the population of the species in a favourable pasture is markedly affected by the relative abundance of certain food-plants, especially leguminous species and particularly clovers such as subterranean clover (Trifolium subterraneum) and lucerne (Medicago sativa).The activity of the insect is intimately associated with the moisture of its environment, and the moisture content of the surface soil is one of the most important factors affecting the environmental conditions.Considering the habits of the insect, it was felt that the sweeping method would not give a reliable record of the total population in a given area of pasture. A sample obtained by sweeping with a net does not include individuals on or near to the surface of the soil. The relative proportion of individuals situated on or near the soil surface and those situated further up the plants varies considerably from time to time, according to the meteorological conditions, the growth of the herbage and the moisture content of the surface soil. It was necessary therefore to devise a simple method by means of which a more accurate record of the total population in a given area could be obtained.

Genetic variability in Seaton Park subterranean clover

1985 ◽  
Vol 36 (1) ◽  
pp. 43 ◽  
Author(s):  
RC Rossiter ◽  
WJ Collins ◽  
Y Haynes
Keyword(s):  
Genetic Variability ◽  
South Australia ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Golf Course ◽  
Low Frequencies ◽  
Predominant Genotype ◽  
Isozyme Patterns ◽  
Commercial Strain ◽  
Western Australian

Single plants of subterranean clover (Trifolium subterraneum) were grown from seed of 13 commercial Seaton Park seed samples and of five pastures sown to Seaton Park at least 8 years previously. Most populations had several variants of Seaton Park, though the predominant genotype was that usually considered to be the Seaton Park strain - herein differentiated as Western Australian Seaton Park (W.A.S.Pk). The original Seaton Park - from the Royal Adelaide Golf Course in South Australia - differed slightly but clearly in several characters, including some seed isozyme patterns, from W.A.S.Pk. It was present in half of the populations, but at low frequencies (1-6% of the total). One genotype (strain S) comprised 20% or more of the populations from three commercial seed samples; it contained significant levels of the oestrogenic isoflavone formononetin. The origin of W.A.S.Pk remains unclear. The present commercial strain (cv. Seaton Park) is being re-built, based on W.A.S.Pk alone.

Effect of tillage practices on the fate of hard seeds of subterranean clover in a ley farming system

1985 ◽  
Vol 25 (3) ◽  
pp. 568 ◽  
Author(s):  
GB Taylor
Keyword(s):  
Subterranean Clover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Farming System ◽  
Conventional Tillage ◽  
No Tillage ◽  
Minimum Tillage ◽  
Tillage Practices ◽  
Tillage Treatment ◽  
Clover Seed

In a rotation of 1 year pasture/l year crop, a subterranean clover (Trifolium subterraneum cv. Daliak) pasture was either left untilled or subjected to minimum or conventional tillage. One set of tillage treatments was imposed in each ofthree crop years while another set of treatments was imposed in only the first crop year. Regenerating clover plants were prevented from setting seed. In the first crop, 44% of the clover seeds were buried below 2 cm of soil by minimum tillage; this proportion was 65% in the conventional tillage treatment. In the first pasture regeneration year, seedling densities were highest in the no-tillage treatment. Conversely, there were more residual seeds in the tilled treatments and, in the second and third pasture regeneration years, this led to higher seedling densities than in the no-tillage treatment. The effects of tillage were more marked in the conventional than in the minimum-tillage treatment. Clover establishment was improved by repeat tillage operations which returned some of the buried seeds closer to the soil surface. Although more seedlings overall were obtained from the no-tillage treatment, the disadvantage of fewer seedlings in the tilled treatments was offset by the spread of seedling establishment over a number of pasture years. This spread, which would be more marked with harder-seeded cultivars, could be desirable in environments in which clover seed production is unreliable.

Mass rearing Halotydeus destructor (Tucker) (Acari : Penthaleidae) for use in summer screening of Trifolium subterraneum (L.) for mite resistance

1997 ◽  
Vol 37 (3) ◽  
pp. 343 ◽  
Author(s):  
D. J. Thackray ◽  
T. J. Ridsdill-Smith ◽  
D. J. Gillespie
Keyword(s):  
Subterranean Clover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Mass Rearing ◽  
Screening Tests ◽  
Common Vetch ◽  
Halotydeus Destructor ◽  
Natural Pasture ◽  
Redlegged Earth Mite ◽  
First Time

Summary. Controlled environment experiments were conducted to establish some of the requirements for successful mass rearing of Halotydeus destructor (redlegged earth mite). Numbers of mites reared on Vicia sativa (common vetch) cv. Blanchefleur grown alone or on a mixture of vetch with Trifolium subterraneum (subterranean clover) cv. Goulburn, were significantly higher than those on subterranean clover or Arctotheca calendula (capeweed) alone. Populations reared on vetch grown in a sandy soil were significantly higher than those reared on vetch grown in a loamy soil, pure sand or pure loam. Covering the soil surface with a natural pasture mulch increased mite numbers compared with leaving the soil bare or placing plant pots inside ventilated cages. Subsequent changes in rearing methodology produced enough mites to enable summer screening of subterranean clover lines for resistance to H. destructorfor the first time. Over 20 000 mites can be produced from vetch at one time for screening tests throughout the year.

Amelioration of soil compaction by a cover-crop for no-tillage lettuce production

1995 ◽  
Vol 46 (3) ◽  
pp. 553 ◽  
Author(s):  
RJ Stirzaker ◽  
I White
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
Sandy Loam ◽  
Subterranean Clover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Field Trials ◽  
Early Summer ◽  
No Tillage ◽  
Hot Weather

Excessive cultivation in many horticultural areas results in soil structural decline and poor utilization of water and nutrients. There are no reliable techniques for growing irrigated vegetables without cultivation. This work explores the hypothesis that a winter legume cover-crop can overcome the soil limitations of no-tillage and provide an alternative to excessive cultivation in the vegetable industry. We grew lettuce (Lactuca sativa) under no-tillage in field trials on a sandy loam soil following a bare winter fallow or a cover-crop of subterranean clover (Trifolium subterraneum), and compared this with cultivation by rotary hoe. The clover died naturally in early summer or was desiccated in the spring to form a mulch of at least 5 t ha-1 on the soil surface. The experiment was carried out over a 2.5 year period. The first crop was grown during hot weather and the soil in the no-tillage treatments was only moderately compacted. The yield of lettuce was similar in the no-tillage and cultivated treatments, and increased by about 30% when a mulch was added to each treatment. The soil was artificially compacted after the first crop. The second crop was grown 18 months later, during cooler spring weather, and following two further cover-crops. The yield of no-tillage lettuce was only 40% of that obtained with cultivation. Yield in the no-tillage treatment was doubled in two different ways: (1) by the addition of a surface mulch, and (2) through changes to soil structure stimulated by a cover-crop in the absence of a mulch. The experiments showed that a well-managed cover-crop can significantly ameliorate a compacted sandy soil by modifying soil temperature, soil strength, and by stimulating the formation of biopores.

Soil fertility changes in a red-brown earth under irrigated pastures. II. Changes in phosphorus

1966 ◽  
Vol 17 (3) ◽  
pp. 303 ◽  
Author(s):  
AJ Rixon
Keyword(s):  
Soluble Fraction ◽  
Organic Phosphorus ◽  
Subterranean Clover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Inorganic Phosphorus ◽  
Soil Horizon ◽  
Phosphorus Fraction ◽  
Organic Form ◽  
Wimmera Ryegrass

Changes in phosphorus applied as superphosphate to irrigated pastures on a red-brown earth were studied for a 4 year period commencing 1 year after the establishment of the pastures. The pastures consisted of Wimmera ryegrass (Lolium rigidum Gaud.), perennial ryegrass (L. perenne L.), subterranean clover (Trifolium subterraneum L.), and white clover (T. repens L.). Measurements of phosphorus fractions were made on the 0–3 in. soil horizon over this period and, for the final 2 years, on the organic matter layer (mat) which was present on the soil surface under all pastures. The mat was shown to be an important accumulation site for organic phosphorus, as well as for inorganic phosphorus which accumulates from interception of broadcast applications of superphosphate. Of the 155 lb phosphorus per acre added as fertilizer, 82–100% was accounted for principally as increases in the acetic acid-soluble fraction or as organic phosphorus. There were no significant changes in the inorganic phosphorus fraction soluble in sodium hydroxide. It was concluded that the amount of phosphorus converted to the organic form will determine the level for maintenance applications of phosphorus on the irrigated pastures.

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