Annual clovers (Trifolium spp.) have different reproductive strategies to achieve persistence in Mediterranean-type climates

2005 ◽  
Vol 56 (1) ◽  
pp. 33 ◽  
Author(s):  
Hayley C. Norman ◽  
Philip S. Cocks ◽  
Nick W. Galwey
Keyword(s):  
Reproductive Strategies ◽  
Principal Component ◽  
Reproductive Traits ◽  
Farming Systems ◽  
High Fecundity ◽  
Risk Of Failure ◽  
Ley Farming ◽  
Collection Sites ◽  
Ley Farming Systems

The aim of this work was to determine whether different species of annual clover (Trifolium spp.), obtained from the same environment, have different reproductive strategies (combinations of reproductive traits) to achieve ecological success. A better understanding of the traits that improve persistence should allow agronomists to narrow the selection criteria for new clover cultivars for ley-farming systems in southern Australia. Seeds of 18 annual clover species were obtained from 3 Australian and 6 Mediterranean sites and were subsequently grown in a common garden in Western Australia. Reproductive traits, including time of flowering, weight per seed, fecundity, pollen to ovule ratio, and pattern of seed softening, were observed. Accessions of different clover species from the same site of collection had different reproductive strategies. Across a range of collection sites, accessions of the same species demonstrated the same broad reproductive strategy; however, some traits, e.g. the timing of flowering, varied within species across collection sites. Principal component analysis suggested that there are 3 broad reproductive strategies demonstrated by these clover species. At one extreme were the relatively large-seeded clovers (T. subterraneum, T. clypeatum, and T. stellatum). The associated cost of these large seeds is reduced fecundity. The large-seeded clovers do not have high long-term hardseededness (the predominant form of seed dormancy in clovers). The relatively small-seeded clovers were all characterised by high fecundity. Many of the small-seeded clovers have high levels of long-term hardseededness, which allow the risk of failure to be spread across seasons (T. spumosum, T. hirtum, T. lappaceum, T. angustifolium, and T. tomentosum). Some of the small-seeded clovers (T. glomeratum, T. nigrescens, T. campestre, T. cernuum, and T. suffocatum) are generalists, producing as many seeds as possible in each season, with very little hardseededness. There are several possible explanations for the apparent success of such different reproductive strategies among clover accessions of different species at the same site. A plant may achieve the same goal by trading one reproductive trait for another. For example, it may either produce many small seeds to spread the risk of failure or produce fewer large seeds with an inherent competitive advantage. Alternatively, temporal and spatial variation may favour clovers with a number of different reproductive strategies. It is likely that a mixture of species with different reproductive strategies will maximise production and persistence of legume-based pastures in ley-farming systems.

Effect of pasture management on the contributions of fixed N to the N economy of ley-farming systems

1998 ◽  
Vol 49 (3) ◽  
pp. 459 ◽  
Author(s):  
M. B. Peoples ◽  
R. R. Gault ◽  
G. J. Scammell ◽  
B. S. Dear ◽  
J. Virgona ◽  
...  
Keyword(s):  
N2 Fixation ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Farming Systems ◽  
Grass Species ◽  
Pasture Management ◽  
Mineral N ◽  
South Wales ◽  
Ley Farming ◽  
Ley Farming Systems

The effects of different management regimes on N2 fixation by subterranean clover (Trifolium subterraneum) in annual pastures and lucerne (Medicago sativa) in perennial-based pastures were examined in 5 experiments and 55 commercial paddocks, in which the pastures were grown in phased rotation with crops. The objectives were to quantify the inputs of fixed N2 and to determine ways of increasing nitrogen (N) inputs into ley-farming systems of southern New South Wales and north-eastern Victoria. Estimates of annual amounts of N2 fixed, based on above-ground herbage production in grazed pastures, ranged from 5 to 238 kg N/ha for subterranean clover and from 47 to 167 kg N/ha for lucerne. Legume reliance upon N2 fixation for growth (Pfix) was high (>65%) in most annual and perennial pastures examined. The levels of Pfix were generally unaffected by management treatments. As a consequence the amounts of N2 fixed were predominantly regulated by the legume content and herbage yield of pastures rather than by any marked differences in the ability of the legume to fix N. When all experimental results were combined with on-farm measurements of N2 fixation, the data indicated that lucerne and subterranean clover fixed 22-25 kg N for every tonne of legume dry matter produced. Management inputs to annual pastures which improved the productivity of subterranean clover and the amounts of N2 fixed included applications of superphosphate and the removal of grass species with herbicide, although the response to these treatments was not consistent across all sites in all years. Potential inputs from N2 fixation were high in annual pastures, and improved management during a good clover season enhanced the levels of mineral N detected in the soil profile (0-200 cm) the following autumn by 100-200 kg N/ha. However, year-to-year variability in annual pasture productivity and clover content resulted in large fluctuations in amounts of N2 fixed. Perennial pastures containing lucerne provided consistently greater annual herbage production, had more stable legume contents, and fixed on average 90-150% more N2 than neighbouring subterranean clover-based pastures. Even during the 1994 drought when annual pastures failed, lucerne still managed to fix >70 kg N/ha. It is proposed that lucerne-based pastures could represent a more reliable means of improving soil fertility for subsequent crops than annual pastures.

Commercial experience in developing ley farming systems for the Katherine-Darwin region, Northern Territory

1996 ◽  
Vol 36 (8) ◽  
pp. 1059 ◽  
Author(s):  
TP Price ◽  
F O'Gara ◽  
ESC Smith ◽  
R Pitkethley ◽  
P Hausler
Keyword(s):  
Crop Production ◽  
Systems Approach ◽  
Farming Systems ◽  
Northern Territory ◽  
Commercial Development ◽  
Plant Disease Control ◽  
Ley Farming ◽  
Control And Management ◽  
On Farm ◽  
Ley Farming Systems

This paper examines the past, present and likely future commercial development and adoption of ley farming systems in the Katherine-Darwin region(about 12-14�S, 131-132�E, elevation 30-1 10 m) of the Northern Territory. Producers' current practices, adaptations and the extent to which they have adopted a systems approach are reported. Advantages of ley farming and the constraints to its more rapid adoption are described. Also discussed are aspects of crop, cattle and hay production; weed, insect and plant disease control, and management; on-farm demonstrations and the economics of crop production, from the producer's perspective, in the context of ley farming.

Operational aspects of ley farming systems in the semi-arid tropics of northern Australia: a review

1996 ◽  
Vol 36 (8) ◽  
pp. 1025 ◽  
Author(s):  
SJ Yeates ◽  
DG Abrecht ◽  
TP Price ◽  
WS Mollah ◽  
P Hausler
Keyword(s):  
Seed Quality ◽  
Critical Time ◽  
Farming Systems ◽  
Northern Territory ◽  
No Tillage ◽  
Transition Management ◽  
Ley Farming ◽  
Semi Arid ◽  
Operational Aspects ◽  
Ley Farming Systems

The ley farming systems proposed for the Australian semi-arid tropics involve rotating an annual pasture (usually legume) with crops sown using no-tillage. These systems were developed to overcome many of the climatic constraints that beset previous attempts at cropping in the region. However, difficulties in the timing of farm operations also contributed to past failures. No analysis of the operational aspects of ley farming had been made; this was the objective of this paper. During the transition between wet and dry seasons rainfall is extremely variable. These periods were shown to be the most critical time for operations in ley farming systems. During the dry-wet transition, management of ley pastures is very difficult because pastures must provide grazing for livestock as well as sufficient soil cover for timely sowing of a following crop. Legume pastures have reduced grazing value at this time due to spoilage by early rain. Similarly, during the wet-dry transition annual pastures must be allowed to set seed at a time when crops are yet to be harvested and stubbles are not available for grazing. It was suggested that including separate paddocks of perennial pasture could reduce the demand on annual pastures during the seasonal transitions. A limited number of days to sow a crop combined with severe yield penalties for late sowing restrict the area that can be sown in any season. Sowing opportunities were determined for 3 locations in the Northern Territory. No-tillage was shown to increase the potential number of sowing days. However, the time available to apply glyphosate before sowing using no-tillage was confined to the morning due to risk of afternoon rainshowers reducing efficacy. The number of seasons where a particular crop or cultivar could not be sown was independent of the method of tillage. The wet-dry transition was shown to be important for harvest operations. Our analysis of 3 sites in the Northern Territory suggests that for mungbean and sorghum, later maturity combined with prompt harvest will reduce the risk of poor seed quality due to weathering and could permit earlier sowing. However, for sorghum, an economic assessment of these practices required research that can quantify the interaction between sowing date, time-to-maturity and grain yield.

Preliminary assessment of bladder clover (Trifolium spumosum L.) as an annual legume for ley farming systems in southern Australia

2012 ◽  
Vol 63 (6) ◽  
pp. 582 ◽  
Author(s):  
Angelo Loi ◽  
Brad J. Nutt ◽  
John G. Howieson ◽  
Ron. J. Yates ◽  
Hayley C. Norman
Keyword(s):  
New Species ◽  
Agronomic Traits ◽  
Farming Systems ◽  
Summer Rainfall ◽  
General Hypothesis ◽  
Mixed Crop ◽  
Ley Farming ◽  
Feeding Value ◽  
Annual Medicago ◽  
Ley Farming Systems

Trifolium spumosum L. (bladder clover) is an aerial seeding annual legume that is adapted to fine-textured soils throughout the Mediterranean Basin. This article is the first of two papers that describe the process of domestication of T. spumosum as a new species to commercial agriculture. This paper describes a broad range of investigations into the ecology, agronomy and rhizobiology of this new species. Through a series of five experiments, we have tested the general hypothesis that T. spumosum accessions demonstrate a range of sought-after agronomic traits and offer an alternative to annual Medicago spp. for ley farming systems in the medium to low rainfall areas of the mixed crop/livestock zone of southern Australia. T. spumosum presents seeds at the top of the canopy in heads that do not readily shatter, so seed can be harvested using conventional cereal harvesters instead of the specialist suction equipment required for harvest of seed from annual T. subterraneum and Medicago spp. T. spumosum was found to be relatively fecund and had high levels of biomass production in comparison to the other annual legumes that were tested. The species also demonstrated high levels of within-season hardseededness (remaining hard in summer and softening in autumn) so seedbanks would be protected from summer rainfall events. In addition, T. spumosum showed high levels of between-season dormancy, which allows the species to carry a seedbank through a cropping phase or series of poor seasons. A herbicide experiment showed that clover species varied in tolerances, with T. spumosum the least sensitive of all of the legumes tested to Flumetsulam. A cross-inoculation experiment to measure symbiotic effectiveness revealed that WSM1325 (current clover strain) surpasses WSM409 (previous strain) in its relationship with the annual clovers of contemporary interest, while being highly effective at nitrogen fixation with T. spumosum. The results of this study and an associated investigation into feeding value indicate that T. spumosum offers a productive alternative to annual Medicago spp. on fine-textured soils. Of the T. spumosum accessions tested, the most promising has been released under the cultivar name of AGWEST Bartolo.

scholarly journals The Return of Large Carnivores and Extensive Farming Systems: A Review of Stakeholders’ Perception at an EU Level

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1735
Author(s):  
Marcello Franchini ◽  
Mirco Corazzin ◽  
Stefano Bovolenta ◽  
Stefano Filacorda
Keyword(s):  
Negative Attitude ◽  
Farming Systems ◽  
Large Carnivores ◽  
Direct Experience ◽  
Large Carnivore ◽  
Degree Of Acceptance ◽  
Extensive Farming ◽  
Over Time ◽  
The Eu

Conflicts between large carnivores and human activities undermine both the maintenance of livestock practices as well as the conservation of carnivores across Europe. Because large carnivore management is driven by a common EU policy, the purpose of this research was to assess stakeholders’ perception towards bears and wolves at an EU level. We conducted a systematic search and subsequent analysis of 40 peer-reviewed studies collected from 1990 to September 2020 within Member States of the EU. Rural inhabitants and hunters exhibited the most negative attitude compared to urban inhabitants and conservationists, whose attitude was more positive. We showed that direct experience with predators as a consequence of ongoing re-colonization may have affected the degree of acceptance of certain categories and that the long-term coexistence between humans and carnivores does not necessarily imply increased tolerance. To encourage coexistence, we recommend monitoring changes in attitudes over time relative to carnivore population dynamics.

scholarly journals Myopic Savings Behaviour of Future Polish Pensioners

Risks ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 36
Author(s):  
Sonia Buchholtz ◽  
Jan Gąska ◽  
Marek Góra
Keyword(s):  
Logistic Models ◽  
Principal Component ◽  
Social Institutions ◽  
Health Seeking ◽  
Future Health ◽  
Policy Makers ◽  
Second Best ◽  
External Assistance ◽  
Old Age Poverty

Low saving rates combined with low effective retirement age herald old-age poverty. This paper examines the preferred strategies of future Polish pensioners in order to sustain the standard of living in the future. A two-step approach is used: as a first-best strategy, we explore determinants of supplementary saving with binary logistic models; as a second-best strategy, we examine alternative options with principal component analysis. Future retirees rarely accumulate long-term savings, do not use dedicated instruments, and they start to save additionally far too late. Savings are concentrated in wealthier and better educated groups. Such myopia is governed by their political stance and not by awareness of dire prospects. Second-best strategies are based on optimistic assumptions about future health (seeking for additional jobs), on the assumed generosity of acquaintances or social institutions (relying on external assistance), or on rebelling. Given the increasing political power of elder generations, balancing the interests of workers and retirees will be an increasingly difficult task for policy makers.

Adaptation of Medicago rigidula to a cereal–pasture rotation in north-west Syria

1986 ◽  
Vol 107 (1) ◽  
pp. 179-186 ◽  
Author(s):  
A. M. Abd El-Moneim ◽  
P. S. Cocks
Keyword(s):  
North Africa ◽  
Farming System ◽  
Livestock Production ◽  
Grazing Management ◽  
North West ◽  
Selection Programme ◽  
Ley Farming ◽  
Medicago Rigidula ◽  
Subsequent Regeneration

SUMMARYThe ley-farming system (integrated cereal and livestock production in which cerealsrotate with self-regenerating pastures) is considered to be of great potential benefit to north Africa and west Asia. In the colder parts of this region (of which north Syria is typical) its application is limited by poor adaptation of commercial medic cultivars (mainly Medicago truncatula and M. littoralis). An extended selection programme hag identified M. rigidula as adapted to the soils and climate of the region but nothing is known of its adaptation to the ley-farming system itself.An experiment which included 23 selections of M. rigidula and one each of M. rotata and M. noeana was conducted over 3 years during which herbage production, seed yield, and the fate of seeds were observed during the 1st year when pastures were established, the 2nd year when wheat was sown, and the 3rd year when the pasture regenerated. Of the 400–800 kg seed/ha produced in the 1st year an average of 87% remained in the soil in spring of the 3rd year. The weight of seed regenerating in the 3rd year varied from 30 to nearly 170 kg/ha, and herbage production, especially in winter, depended heavily on the number of regenerating seedlings. The most productive regenerating pastures produced nearly 2 t/ha of dried herbage by 1 January, and more than 6 t/ha for the whole growing season.The results showed that there was sufficient residual and newly produced seed at the end of the 3rd year to be sure that subsequent regeneration would result in similar herbage yields in the 5th year, and that the pasture was assured of long-term persistence. The significance of this for livestock production is discussed, and it is concluded that the results should encourage further investigation of grazing management and socioeconomic factors seen as constraints to introducing the ley-farming system to north Syria.

Reliability Parameters Forecasting for Transmission Lines Based on Principal Component Regression

2013 ◽  
Vol 291-294 ◽  
pp. 2381-2386 ◽  
Author(s):  
Wen Xia Liu ◽  
Ji Kai Xu ◽  
Hong Yuan Jiang ◽  
Yong Tao Shen
Keyword(s):  
Principal Component Analysis ◽  
Transmission Lines ◽  
Principal Component Regression ◽  
Principal Component ◽  
Forecasting Accuracy ◽  
Factors Affecting ◽  
Reliability Parameters ◽  
Impacting Factors ◽  
Simulation Results

It is the foundation for evaluating the reliability of transmission lines to obtain and analyze the original reliability parameters. However, these parameters depend on long- term statistic and calculation. In the case of lacking such parameters in a new project , this paper proposes a method of Principal Component Analysis to obtain the principal component of the impacting factors ,in which various factors affecting reliability parameters are taken into account. Through this method, we can use PCR to obtain the failure rate of the unknown transmission lines on the base of the known credible lines’ rates. The simulation results show that the proposed approach possesses higher forecasting accuracy and provides references for the power system dispatching departments and transmission lines maintenance departments.

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