The influence of the growing season and the following dry season on the hardseeedness of subterranean clover in different environments

1965 ◽  
Vol 16 (3) ◽  
pp. 277 ◽  
Author(s):  
BN Quinlivan
Keyword(s):  
Surface Temperature ◽  
Critical Factor ◽  
Subterranean Clover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Temperature Fluctuations ◽  
Growing Season ◽  
Growing Period ◽  
Hard Seeds ◽  
Soil Surface Temperature

The length of the growing period in the spring months appears to be a critical factor in the development of hardseededness in subterranean clover (Trifolium subterraneum L.). Environments with relatively long spring growing periods cause a higher proportion of hard seeds to form at field maturity, and increase the resistance which these hard seeds are capable of offering to the softening effects of the following summer environment. During the dry summer period the rate of softening of hard seeds is determined, not only by the previous growing season but also by the summer environment itself. Hot summer environments with wide soil surface temperature fluctuations are conducive to a relatively rapid rate of softening. Grazing or removal of the dry topgrowth from a pasture during the summer increases the daily soil surface temperature fluctuations, and results in the hard seeds softening at an increased rate. Differences in the overall environment manifest themselves in terms of site and seasonal variation in the proportion of hard seeds which survive beyond the opening of the following growing season. The scope for variation is wide, and this has agronomic significance from the aspect of long-term persistence of the species.

Effect of burial on the softening of hard seeds of subterranean clover

1984 ◽  
Vol 35 (2) ◽  
pp. 201 ◽  
Author(s):  
GB Taylor
Keyword(s):  
Subterranean Clover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Temperature Fluctuations ◽  
The Other ◽  
Soil Tillage ◽  
Microbial Decomposition ◽  
Buried Seeds ◽  
Hard Seeds ◽  
Depth Of Burial

Burrs of eight varieties of subterranean clover (Trifolium subterraneum L.), which had experienced one summer at the soil surface, were placed on the soil surface and at depths of 2, 6 and 10 cm in the soil. The numbers of residual hard seeds were determined after 1, 2 and 3 years. The effects of laboratory treatment at a diurnally fluctuating temperature of 60/15�C on the softening of buried seeds and of seeds stored in the laboratory for 1 and 3 years were determined. Rate of seed softening in all varieties decreased with increasing depth of burial, apparently because the soil insulated the seeds from high soil surface temperatures. Few seeds of the varieties Northam and Geraldton softened during 3 years of burial at 6 or 10 cm; while, at the other extreme, few seeds of Yarloop survived 3 years at any depth. Some evidence was found for microbial decomposition of hard seeds in the field. Seeds softened more readily at 60/15�C (in the laboratory) as the preceding periods of either laboratory storage or field burial increased. Such storage or burial experiences have a preconditioning effect on hard seeds, making them more amenable to softening once they are subjected to wide diurnal temperature fluctuations. The results indicate that soil tillage associated with cropping should build up a useful soil seed reserve of the harder seeded varieties.

The relationship between temperature fluctuations and the softening of hard seeds of some legume species

1966 ◽  
Vol 17 (5) ◽  
pp. 625 ◽  
Author(s):  
BJ Quinlivan
Keyword(s):  
Critical Factor ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Temperature Fluctuations ◽  
Maximum Temperature ◽  
Hard Seeds ◽  
Maximum Temperatures ◽  
The Relationship ◽  
Fluctuating Temperatures ◽  
Main Factor

Hard seeds of subterranean clover (Trifolium subterraneum L.) of the Geraldton and Bacchus Marsh strains, and of West Australian blue lupin (Lupinus varius L.), were subjected to various daily fluctuating temperatures within the normal summer environmental range (15–75°C). The main factor determining the rate of softening of the hard seeds was the maxinlum temperature of the fluctuation. Provided the temperature changed by some 15°C , the amplitude of the fluctuation did not appear to be a critical factor. The softening of hard seeds of any particular species did not commence until the amplitude of the temperature fluctuation, or the maximum temperature, reached a certain level, which in turn varied with the species. Beyond this level the rate of softening increased with increasing fluctuations to a point where the rate became very rapid, and thereafter wider fluctuations or higher maximum temperatures did not give significant increases.

The action of temperature fluctuations on hard seeds of subterranean clover

1971 ◽  
Vol 11 (51) ◽  
pp. 440 ◽  
Author(s):  
MW Hagon
Keyword(s):  
No Reduction ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Temperature Fluctuations ◽  
Specific Region ◽  
Daily Temperature ◽  
Laboratory Conditions ◽  
Hard Seeds ◽  
Cycle Lengths ◽  
Daily Temperature Fluctuations

Burrs of three cultivars of subterranean clover (Trifolium subterraneum) were placed in soil in a cold frame at Canberra so that they were subjected to daily temperature fluctuations of the order of 20-54�C. After three months and eight months the proportion of permeable seeds was significantly increased. Such seeds were conductive to water at one specific region of the testa-the strophiole. In a further experiment, under laboratory conditions, hard seeds were subjected to temperature fluctuations of 23-60�C with cycle lengths varying from 15 minutes to 1 hour. There was no reduction in the percentage of hard seeds except in two trials when that portion of each cycle at 60�C was greater than 45 minutes.

Effect of depth of burial on the longevity of hard seeds of subterranean clover and annual medics

1988 ◽  
Vol 28 (1) ◽  
pp. 77 ◽  
Author(s):  
GB Taylor ◽  
MA Ewing
Keyword(s):  
Subterranean Clover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Barrel Medic ◽  
Hard Seeds ◽  
Burr Medic ◽  
Seed Reserves ◽  
Annual Medics ◽  
Depth Of Burial ◽  
Tillage Operations

Burrs of 3 cultivars of subterranean clover (Trifolium subterraneum) and 1 cultivar each of burr medic (Medicago polymorpha) and barrel medic (M. truncatula), which had experienced 1 summer at the soil surface, were placed on the soil surface and at depths of 2, 6 and 10 cm in the soil. The numbers of residual hard seeds were determined each year for up to 4 years. There was a marked reduction in the rate of seed softening in all 3 clover cultivars with increasing depth of burial. Whereas <20% of the seeds of the hardest seeded clover cultivar, Nungarin, survived 3 years at the soil surface, there was no significant decline in seed numbers during 4 years of burial at 10 cm. Even with cv. Geraldton, in which only 5% of seeds remained after 1 year of placement at the soil surface, 75% of seeds survived 4 years of burial at 10 cm. Hard seeds of both medic varieties were considerably more resilient than clover seeds at the soil surface, particularly during the first summer following seed set. However, burial had much less effect on their longevity, with no significant effect of burial to 2 cm in either medic, or of burial to 6 cm in the case of barrel medic. These results support earlier findings which showed that tillage operations associated with crop establishment which result in the burial of substantial proportions of subterranean clover seeds can lead to useful soil seed reserves. The much lesser effect of burial on seed softening of the medics, compared with subterranean clover, suggests that tillage operations will be less advantageous to medic persistence in leys.

Effects of extended (4-12 years) burial on seed softening in subterranean clover and annual medics

1996 ◽  
Vol 36 (2) ◽  
pp. 145 ◽  
Author(s):  
GB Taylor ◽  
MA Ewing
Keyword(s):  
Subterranean Clover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Razor Blade ◽  
Barrel Medic ◽  
Hard Seeds ◽  
Soil Temperatures ◽  
Burr Medic ◽  
Annual Medics ◽  
Softening Process

The effect of burial of seeds of 3 cultivars of subterranean clover (Trifolium subterraneum) and 1 cultivar each of burr medic (Medicago polymorpha) and barrel medic (M. truncatula) that had experienced 1 summer at the soil surface was continued from 4 to up to 12 years. Seeds were situated at 2, 6 and 10 cm depth, as well as at the soil surface. Numbers of residual seeds were determined after each sampling occasion, the timing of which was varied between cultivars and depths of burial according to the progress of seed softening. The marked reduction in the rate of seed softening in all 3 clover cultivars with increasing depth of burial established during the first 4 years of the experiment was maintained. After 12 years, 37% of the Nungarin clover seeds that had been buried at 10 cm were still present as hard seeds. All residual hard seeds germinated readily after nicking with a razor blade. Seeds of both medic cultivars, that were slower to soften than the clovers at the soil surface, continued to show little effect of burial at 2 cm, or of burial to 6 cm in the case of Cyprus barrel medic. Species differences in response to seed burial are explained in terms of the effects of soil temperatures on the 2-stage seed softening process. The absence of an effect of shallow burial on the softening of medic seeds appears to be attributable to a lower optimum temperature for the first stage of seed softening than is the case for subterranean clover. Unfavourable temperatures for the final stage of seed softening can result in the accumulation of latent soft seeds, particularly in subterranean clover. These latent soft seeds will soften during the first summer/autumn after their return to close to the soil surface as a consequence of tillage. Whereas increased seed longevity as a consequence of burial in crop years can be advantageous in terms of legume persistence, particularly of clover, it can also be distinctly disadvantageous when it comes to cultivar replacement.

Variation in seed softening patterns and impact of seed production environment on hardseededness in early-maturing genotypes of subterranean clover

2006 ◽  
Vol 57 (1) ◽  
pp. 65 ◽  
Author(s):  
H. C. Norman ◽  
F. P. Smith ◽  
P. G. H. Nichols ◽  
P. Si ◽  
N. W. Galwey
Keyword(s):  
Seed Production ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Growing Season ◽  
Production Environment ◽  
Field Exposure ◽  
Hard Seed ◽  
Supplementary Irrigation ◽  
Hard Seeds ◽  
Early Maturing

This paper describes variation in the dynamics of seed softening (loss of impermeability) in 20 early-maturing genotypes, including 6 cultivars, of subterranean clover (Trifolium subterraneum L.). It reports the effect of 3 sites of seed production in south-western Australia on the pattern of softening in the first summer–autumn and on total softening over the subsequent 2 years. Seeds were softened at a single field location and in a diurnally fluctuating cabinet (60°C/15°C). There was significant variation among genotypes in the pattern of seed softening over the first 5 months after senescence. Cultivars Nungarin, Dwalganup, and Geraldton softened most rapidly in late February, whereas cultivars Dalkeith, Urana, and Izmir softened most rapidly in late March. The duration of field exposure required in order for 50% of the first season’s softening to occur ranged from 44 to 108 days among the 20 genotypes. Persistence of hard seeds into the second and third years also varied among genotypes. Of the cultivars, Nungarin and Izmir had the highest levels of residual hard seed after 30 months (5.3% and 3.9%, respectively), whereas Dalkeith had the lowest (0.9%). Site of seed production had a small but significant effect on both the pattern of softening in the first summer–autumn and the persistence of hard seeds in subsequent years. Seeds produced in a relatively high-rainfall site (768 mm of growing-season rainfall plus supplementary irrigation) had a slower rate of hard seed breakdown than those from either of 2 sites located in the wheatbelt (217 and 423 mm growing-season rainfall). Seed softening through exposure in the field and in a 60°C/15°C fluctuating-temperature cabinet was compared for all genotypes. The cabinet treatment was fairly successful in ranking genotypes for relative between-season hardseededness, although it underestimated total softening by an average of 16%. However, the cabinet treatment was a poor predictor of the within-season pattern of seed softening.

The effect of constant and fluctuating temperatures on the permeability of the hard seeds of some legume species

1961 ◽  
Vol 12 (6) ◽  
pp. 1009 ◽  
Author(s):  
BJ Quinlivan
Keyword(s):  
Constant Temperature ◽  
Temperature Fluctuation ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Temperature Fluctuations ◽  
Lupinus Luteus ◽  
Maximum Effect ◽  
Rate Of Increase ◽  
Hard Seeds ◽  
Temperature Ranges

Hard seeds of Lupinus digitatus Forsk., Lupinus luteus L., Medicago tribuloides Desr., and Trifolium subterraneum L. (Mt. Barker, Dwalganup, and Geraldton strains) were subjected to constant temperatures of 60 and 140°F, and to fluctuating temperature ranges of 60–115°F, 60–140°, and 60–165°, for a period of 5 months. The temperature fluctuation treatments were set to follow patterns similar to those experienced on the soil surface during the summer months in the agricultural districts of Western Australia. Increased permeability, i.e. an increase in the percentage of seeds permeable to water, took place under all temperature conditions. The lowest increase occurred at a constant temperature of 60°F. A constant temperature of 140° gave a relatively higher increase. All three temperature fluctuation treatments increased the permeability as compared with the constant temperatures, with maximum effect at a range of 60-140°F. Increasing the range to 60–165° did not increase the permeability. With the exception of L. digitatus all species subjected to temperature fluctuations showed a rapid increase in permeability over the first 2 or 3 months. Beyond this point the rate of increase was very slow. The permeability or softening pattern followed by L. digitatus was almost the direct opposite to that of the other species. Of the three strains of T. subterraneum, Mt.. Barker showed the highest increase in permeability under temperature fluctuations and Geraldton the least.

Using soil surface temperature to assess soil evaporation in a drip irrigated vineyard

2013 ◽  
Vol 116 ◽  
pp. 128-141 ◽  
Author(s):  
B.L. Kerridge ◽  
J.W. Hornbuckle ◽  
E.W. Christen ◽  
R.D. Faulkner
Keyword(s):  
Surface Temperature ◽  
Soil Surface ◽  
Soil Evaporation ◽  
Soil Surface Temperature

scholarly journals Determination of the united quality latent index of adaptability (UQLIA) and contribution of some environmental parameters to it for Deschampsia antarctica populations, Galindez island (Maritime Antarctic) season 2017/2018

2019 ◽  
Vol 16 (2) ◽  
pp. 190-202
Author(s):  
I. Y. Parnikoza ◽  
N. Y. Miryuta ◽  
V. Y. Ivanets ◽  
E. O. Dykyi
Keyword(s):  
Surface Temperature ◽  
Pairwise Comparison ◽  
Environmental Parameters ◽  
Soil Surface ◽  
Deschampsia Antarctica ◽  
Near Surface ◽  
Soil Surface Temperature ◽  
Experimental Populations ◽  
The Individual

The purpose of our work has been to determine the indicator of complex adaptability — the United Quality Latent Index of Adaptability (UQLIA) for the experimental populations of Deschampsia antarctica É. Desv. and study the contribution to it of some environmental factors such as the near soil surface temperature and organogens content. Materials and methods. The determination of UQLIA was based on a pairwise comparison of the differences between investigated parameters of populations by mathematical regression techniques. The soil surface temperature was measured by loggers installed near plants in each locus during April 2017 – April 2018. Results and conclusions. Temperature fluctuations were described during December 2017 – February 2018 for twelve experimental populations of D. antarctica and one control fragment of moss turf subformation from Galindez Island. Significant variations in average daily near surface temperature were observed during the study period between populations, especially in December and January. The UQLIA of D. antarctica for this season was calculated on the basis of the projective cover, biometric indices of generative plants and the content of protective and reserve proteins in seeds for the eleven populations. The values of the United Soil Surface Temperature Influence Index (UTII) for the season summer months and the United Organogens Content in Soil Influence Index (UOCSII) have been calculated for the individual parameters of D. antarctica plants adaptability. The reliable contribution of UTII to ULIA has been shown for December and January, at the moment of the greatest variation of soil surface temperature. UOCSII provided a reliable contribution to the ULIA only in the amount of UTII. Keywords: Deschampsia antarctica, United Quality Latent Index of Adaptability (UQLIA), contribution of soil surface temperature and organogens content to complex adaptability.

scholarly journals Two-Dimensional Spectral Analysis of Soil Surface Temperature

Hilgardia ◽  
1988 ◽  
Vol 56 (3) ◽  
pp. 1-28 ◽  
Author(s):  
M. Bazza ◽  
R. H. Shumway ◽  
D. R. Nielsen
Keyword(s):  
Spectral Analysis ◽  
Surface Temperature ◽  
Soil Surface ◽  
Two Dimensional ◽  
Soil Surface Temperature
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