A century of subclover: Lessons for sustainable intensification from a historical review of innovations in subterranean clover seed production

2022 ◽  
pp. 305-339
Author(s):  
W.M. Moss ◽  
P.G.H. Nichols ◽  
K.J. Foster ◽  
M.H. Ryan ◽  
W. Erskine ◽  
...  
2021 ◽  
Vol 72 (3) ◽  
pp. 223
Author(s):  
Wesley M. Moss ◽  
Andrew L. Guzzomi ◽  
Kevin J. Foster ◽  
Megan H. Ryan ◽  
Phillip G. H. Nichols

Subterranean clover (Trifolium subterraneum L.) is Australia’s most widely sown annual pasture legume. Its widespread use as a pasture plant requires a well-functioning seed production industry, and Australia is the only significant producer of subterranean clover seed globally. However, the sustainability of this industry is under threat due to its reliance on ageing harvest equipment and the resultant environmental impacts. In order to evaluate seed harvesting practices, technology, and issues, we report on case studies, workshops, and a survey of seed producers across southern Australia. The Horwood Bagshaw Clover Harvester, designed in the 1950s, remains the most popular subterranean clover seed harvester. We discuss its use and modifications, and document several contemporary issues facing the seed production industry. Issues are primarily soil erosion and degradation; the expensive, slow and labour-intensive harvest process; and poor reliability and maintainability of harvesters that are now at least 30 years old. We conclude the root cause of these issues is the suction harvest technology utilised by the Horwood Bagshaw Clover Harvester. Analysis of the current harvest system is provided to support the development of new approaches to harvest subterranean clover seeds.


2001 ◽  
Vol 52 (10) ◽  
pp. 973 ◽  
Author(s):  
B. S. Dear ◽  
J. M. Virgona ◽  
G. A. Sandral ◽  
A. D. Swan ◽  
B. A. Orchard

Seed production of subterranean clover (Trifolium subterraneum L.) in mixtures with lovegrass (Eragrostis curvula (Schrader) Nees cv. Consol), cocksfoot (Dactylis glomerata L. cv. Currie), phalaris (Phalaris aquatica L. cv. Sirolan), danthonia (Austrodanthonia richardsonii (Cashm.) H.P. Linder, cv. Taranna), and lucerne (Medicago sativa L. cv. Aquarius) was compared with pure and degraded (invaded by annual volunteers) annual subterranean clover pasture at 2 sites (Junee and Kamarah) in the southern wheatbelt of New South Wales. Seed yields, clover seedlings in winter, and the change in the proportion of 3 subterranean clover cultivars (Dalkeith, Seaton Park, Goulburn) when grown with and without perennials were assessed. The effect of thinning the perennials to 10 plants/m2 on clover seed set was examined at the drier site. Seed production of subterranean clover in the mixtures was depressed by up to 50% compared with the pure and degraded annual swards. Initial clover seed poduction in the mixtures was at least 60 kg/ha even in the drought year at the wetter site (Junee), and >85 kg/ha at Kamarah, the drier site (seedling establishment at Kamarah failed in the drought year). Clover seed reserves in the following 2 years progressively increased to >300 kg/ha in the perennial swards at Junee but were <100 kg/ha by the end of the third year at Kamarah. In comparison, seed reserves in the pure clover and degraded annual swards were >650 kg/ha at Junee and >350 kg/ha at Kamarah. Reducing perennial density to 10 plants/m2 at the drier site increased clover seed yield about 3-fold in the first year compared with unthinned perennial swards. The increased seed yield was due to increased numbers of burrs set and increased seeds per burr and, in all perennial pasture treatments except lucerne, increased seed size. Clover seedling regeneration in 3rd and 4th year after sowing was substantially lower in the perennial-based mixtures than annual plots, with a significant (P < 0.05) positive correlation at both sites between clover seedling regeneration and seed bank size (1996, r2 = 0.46–0.64; 1997, r2 = 0.64–0.85). Following false breaks in early autumn, clover seedling populations were substantially higher in the pure and degraded clover treatments than in most perennial treatments. The proportion of the 3 cultivars present in the seed bank at the end of the pasture phase differed between sites but the sward type only influenced the proportion at the drier site. At the medium rainfall site, the later maturing cultivar Goulburn constituted 27–54% of the seed bank and the early flowering Dalkeith 25–46%, with unsown cultivars being insignificant ( <1%). At the low rainfall site, Dalkeith was the major component (33–52%) of the seed bank but the background population of unsown cultivars constituted 11–48%, the lowest proportion being in swards without a perennial component. The proportion of Goulburn was highest (23%) in the pure sward and lowest (10%) in lucerne and phalaris. It was concluded that subterranean clover could form relatively stable mixtures with perennials in medium rainfall environments, with clover populations increasing with time. In lower rainfall environments, clover seedling populations in perennial swards may be low due to reduced seed set and decreased seedling survival following early autumn rains. In these environments earlier maturing, hard-seeded cultivars are more likely to persist in mixtures and there is more potential for unsown cultivars to constitute a greater proportion of the sward. Decreasing perennial density offers scope for improving clover seed set and survival in these environments.


2012 ◽  
Vol 63 (9) ◽  
pp. 902 ◽  
Author(s):  
D. M. Peck ◽  
N. Habili ◽  
R. M. Nair ◽  
J. W. Randles ◽  
C. T. de Koning ◽  
...  

In the mid 2000s subterranean clover (Trifolium subterraneum) seed producers in South Australia reported symptoms of a red-leaf disease in fields with reduced seed yields. The red-leaf symptoms resembled those caused by several clover-infecting viruses. A set of molecular diagnostic tools were developed for the following viruses which are known to infect subterranean clover: Alfalfa mosaic virus; Bean leafroll virus (BLRV); Beet western yellows virus; Bean yellow mosaic virus; Cucumber mosaic virus; Pea seed-borne mosaic virus; Soybean dwarf virus and Subterranean clover stunt virus. Surveys of subterranean clover seed production fields in 2008 in the south-east of South Australia and western Victoria identified Bean leafroll virus, Alfalfa mosaic virus and Cucumber mosaic virus as present, with BLRV the most widespread. Surveys of pasture seed production fields and pasture evaluation trials in 2009 confirmed that BLRV was widespread. This result will allow seed producers to determine whether control measures directed against BLRV will overcome their seed losses. Bluegreen aphid (Acyrthosiphon kondoi) was implicated as a potential vector of BLRV because it was observed to be colonising lucerne plants adjacent to subterranean clover seed production paddocks with BLRV, and in a glasshouse trial it transmitted BLRV from an infected lucerne plant to subterranean clover in a persistent manner.


Author(s):  
S. Ates ◽  
H.E. Brown ◽  
R.J. Lucas ◽  
M.C. Smith ◽  
G.R. Edwards

Liveweight gain of ewes and lambs and subterranean clover reproduction were measured in tall fescuesubterranean clover pastures on a dry, stony soil stocked at 10 (low) and 20 (high) ewes and their twin lambs/ha over 46 days in spring 2005. Lambs grew at 374 g/day at the low stocking rate and 307 g/day at the high stocking rate, meaning final liveweight was 3.1 kg higher at the low stocking rate. However, lamb liveweight gain/ha/ day was greater at the high (12.3 kg/ha/day) than the low (7.5 kg/ha/day) stocking rate. Ewes gained 2.2 kg at the low stocking rate and lost 4.9 kg at the high stocking rate, with most liveweight loss occurring in the second half of the grazing period when moisture stress restricted subterranean clover growth. There were 62% fewer burrs/ m2 at the high than the low stocking rate. For both stocking rates, inadequate seed production resulted in inadequate seedling numbers in the following autumn (285 and 223 seedlings/m2 at low and high stocking rate, respectively). The results show high lamb liveweight gains can be obtained on subterranean clover pastures, but, in a drier than average spring, selective grazing of the clover may result in poor subterranean clover seed production and reduced seedling numbers in the following the autumn. Keywords: liveweight gain, seed production, sheep grazing, stocking rate, subterranean clover, tall fescue


1990 ◽  
Vol 41 (4) ◽  
pp. 669 ◽  
Author(s):  
Z Hochman ◽  
GJ Osborne ◽  
PA Taylor ◽  
B Cullis

In a field study on four sites, soil acidity, root rot (Phytophthora clandestina), and soil phosphorus were identified as causes of 'subterranean clover decline'. Liming increased herbage and seed production at four sites, with a tendency for lime to increase herbage yields in autumn (22%) and winter (15%) but not in spring. The presence of ryegrass with clover increased total herbage yields, and reduced clover seed production, but there was no interaction with liming. Losses caused by root rot associated with P. clandestina were quantified for the first time in New South Wales. Root rot reduced survival of seedlings as well as herbage production in autumn and/or winter at three of the four sites. In the presence of the disease, lime did not improve root health or seedling survival. On two sites with high aluminium saturation of exchangeable cations (> 17%) and high phosphorus sorption index values, subterranean clover growth responded to high levels of P fertilizer. On one site, where lime increased the soil pH to above 5.5, the P sorption index was temporarily increased, and this was associated with a temporary adverse effect on herbage yields. Some possible mechanisms underlying the seasonality of lime responses are proposed and the practical implications of our findings are discussed.


1968 ◽  
Vol 8 (30) ◽  
pp. 46
Author(s):  
IH Cameron ◽  
AA McGowan

Eight cultivars of subterranean clover (Trifolium subterraneum L.)-Yarloop, Burnley, Bacchus Marsh, Nangeela, Clare, Portugal, Chiltern Valley, and Mt. Barker-were compared in mowing experiments at the Rutherglen Research Station in north-eastern Victoria. All eight had similar total annual yields of dry matter, but all except Chiltern Valley outyielded Mt. Barker (the common district cultivar) in most winters. Yarloop, Burnley, and Bacchus Marsh grew best in winter. Of these, Burnley has most promise, being apparently more persistent than Bacchus Marsh, and having lower oestrogenic potency than Yarloop. There was no difference in greasy wool production from wethers run at five to the acre on Mt. Barker or Bacchus Marsh pastures, despite higher pasture production on the latter. Hay was cut in two seasons ; after feeding equal amounts to each group of sheep, there was a surplus of 20 cwt an acre in favour of the Bacchus Marsh pasture. Clover seed production, winter pasture growth, and sheep liveweights also favoured Bacchus Marsh.


1973 ◽  
Vol 13 (65) ◽  
pp. 681 ◽  
Author(s):  
BJ Quinlivan ◽  
AC Devitt ◽  
CM Francis

In two experiments in successive years on a sandy soil in Western Australia, seed production of subterranean clover (Trifolium subterraneum) when sown as a commercial crop was greatly influenced by time of sowing, phosphate rates and seeding rate. Early (April) sowing, high phosphate (up to 600 kg ha-1) and higher seeding rates (up to 24 kg ha-1) all increased seed set but the major effect was that of earliness of sowing. Time of sowing interacted with phosphate rates, the time of sowing differences being only fully expressed at high phosphate rates. Artificial nitrogen applied had a significant effect on seed yield in one of the trial years.


1973 ◽  
Vol 13 (60) ◽  
pp. 56 ◽  
Author(s):  
AA McGowan ◽  
WA Williams

Subterranean clover (Trifolium subterraneum) was sown with barley (Hordeum vulgare) in autumn under a variety of management treatments. Clover seed production was increased when barley emergence was delayed by seed treatment with CCC or paraffin wax, or by delayed sowing, when barley seeding rates were reduced, or when barley was clipped in late winter. The main factor limiting growth of the undersown clover was competition for light, especially in late winter and early spring when light transmission through the barley crop dropped below 60 per cent. Despite a dry spring, interspecific competition for moisture evidently imposed very little restriction on clover growth and seed production. Competition for nitrogen may have occurred earlier in the season.


Crop Science ◽  
1994 ◽  
Vol 34 (5) ◽  
pp. 1330-1335 ◽  
Author(s):  
J. J. Steiner ◽  
J. P. Snelling

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