Survival and seasonal germination of seeds of Avena fatua and A. ludoviciana

1968 ◽  
Vol 19 (5) ◽  
pp. 721 ◽  
Author(s):  
PH Quail ◽  
OG Carter
Keyword(s):  
Soil Type ◽  
Dominant Species ◽  
First Year ◽  
Moisture Regime ◽  
Seed Type ◽  
Wild Oats ◽  
Eastern Australia ◽  
Buried Seed ◽  
Second Year ◽  
Better Than

The effects of soil type, temperature, and moisture on the survival and seasonal germination of seeds of A. fatua and A. ludoviciana, buried at five depths in the soil, were studied in a glasshouse experiment. Seeds of both species germinated only when mean weekly minimum temperatures were below 20°C and mean weekly maxima below 28°. A. fatua germinated better than A. ludoviciana in the 20–30° range and was therefore the dominant species in autumn germinations of wild oats. Both species germinated throughout winter. Only 30% of the seeds sown produced seedlings. Of these 90% emerged in the first year after seeding and the remainder in the second year. Only 2% of the seeds sown remained viable after 18 months. The depth at which the seeds were buried, seed type, soil type. and moisture regime all affected the survival of seeds and the percentage that produced seedlings. An explanation is offered for the dominance of A. ludoviciana in the northern wheat-belt of eastern Australia.

scholarly journals COMPARISON OF GUINEA GRASS-TROPICAL KUDZU, PARA GRASS, PANGOLA GRASS, AND ST. AUGUSTINE GRASS AS PASTURE CROPS IN THE YABUCOA VALLEY IN EASTERN PUERTO RICO

1969 ◽  
Vol 38 (2) ◽  
pp. 96-104
Author(s):  
L. Rivera-Brenes ◽  
J. I. Cabrera ◽  
L. F. Colón
Keyword(s):  
Puerto Rico ◽  
Carrying Capacity ◽  
Water Conservation ◽  
Coastal Region ◽  
Eastern Coast ◽  
First Year ◽  
Guinea Grass ◽  
Second Year ◽  
Main Station ◽  
Better Than

A grazing trial was carried out at Yabucoa, on the eastern coast of Puerto Rico to determine the usefulness for this purpose of several grasses and a grass-legume mixture. It followed the same pattern and procedure as those which had been performed previously at the Main Station Farm located in the northern humid section of the Island. In the trial, which lasted for 2 years, Pangola grass, Pará grass, St. Augustine grass, and a Guinea grass-tropical kudzu combination were compared as to carrying capacity and other characters to determine their pasture values. The carrying capacities of these grasses were as follows: Pangola, 1.12; Guinea-tropical kudzu, 1.42; St, Augustine, 1.23; and Para grass, 0.87 head per acre. The gross returns per acre for the first year were, $118, $137, $97, and $87, respectively. For the second year they were: $159, $179, $124, and $68, respectively. Besides the information obtained on the carrying capacity of the pastures, the results show that well-managed pastures are at least as profitable as many of the cash crops actually grown in the Island. This does not take into consideration additional soil- and water-conservation benefits which accrue from having the soil covered by a sod. Pangola and St. Augustine grasses are good pasture crops that can be used in the eastern coastal region satisfactorily. The Guinea-tropical kudzu mixture, however, is better than these grasses by themselves. The superiority of the legume-grass combination was again demonstrated by the results of this experiment. Pará grass was not well adapted for grazing in the light soil in which the experiment was planted.

Ecological segregation in a subterranean reptile assemblage in arid Australia

1989 ◽  
Vol 10 (3) ◽  
pp. 277-295 ◽  
Author(s):  
Klaus Henle
Keyword(s):  
National Park ◽  
Reproductive Effort ◽  
Arid Zone ◽  
Daily Maximum ◽  
First Year ◽  
Lizard Species ◽  
Eastern Australia ◽  
Food Size ◽  
Late Maturity ◽  
Second Year

AbstractThe organisation of the subterranean component of an arid zone reptile community was studies in Kinchega National Park (Eastern Australia) from September 1985 to May 1987. Three species of fossorial or semifossorial lizards and two species of snakes were found in Kinchega. All species were habitat generalists, but microhabitat, food size and food taxon clearly separated them. All species were primarily nocturnal although Lerista xanthura was occasionally active during the day. All three lizard species were active from September to May. Activity of Eremiascincus richardsonii and L. xanthura were significantly correlated with monthly mean daily maximum and minimum temperatures. The optimum temperature of L. punctatovittata was 28.8 °C in daytime retreats. Biomass ranged from 505-900 g/ha in E. richardsonii and from 968-1152 g/ha in L. punctatovittata. All three lizard species produced only one clutch per year. L. punctatovittata and E. richardsonii reached sexual maturity at the end of their second year, L. xanthura matured in its first year. The data show that subterranean lizard guilds have a different structure than diurnal and non-fossorial noctunal lizard assemblies. The data also indicate a correlation of late maturity and low reproductive effort in fossorial lizards.

Seedbanks and seedling emergence of saffron thistle (Carthamus lanatus) in eastern Australian pastures

2002 ◽  
Vol 53 (12) ◽  
pp. 1327 ◽  
Author(s):  
B. S. Grace ◽  
A. W. Sheppard ◽  
R. D. B. Whalley ◽  
B. M. Sindel
Keyword(s):  
Weed Management ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
First Year ◽  
Seed Loss ◽  
Eastern Australia ◽  
Mesh Bags ◽  
Second Year ◽  
Number Of Seeds ◽  
Over Time

Weed management has often proved difficult because of persistent seedbanks that allow recruitment to occur for many years after the weed has otherwise been controlled. The number of seeds in seedbanks of Carthamus lanatus, a widespread and troublesome weed, has not been investigated. Little is known about longevity of its seedbanks in pastures of eastern Australia.The numbers of seeds in the soil and the rate of seed loss were investigated at 3 sites in eastern Australia. Seedbanks were found to be patchy, and they had mean densities between 815 and 2290 seeds/m2 after the main germination flush. These seedbanks decreased over time and between 11 and 15% of seeds remained in the soil after 2 years without further input. More seeds were lost in the first year than in the second year, and pasture cover did not affect the rate of seed loss.Seeds buried in mesh bags and exhumed regularly showed that dormancy was lost, induced, then lost again within the 2-year experiment. Maximum seed germinability coincided with peak germination times. The likelihood of a seed producing a seedling was reduced when seeds were sown at high density. C. lanatus seeds appear to be well adapted for persistence in eastern Australian pastures by maintaining a bank of seeds that generally germinate when conditions favour seedling survival.

Soundoff: Teach Geometry before Second-Year Algebra

1988 ◽  
Vol 81 (4) ◽  
pp. 236-298
Author(s):  
Beverly W. Nichols
Keyword(s):  
High School ◽  
Mathematics Education ◽  
Good Reason ◽  
First Year ◽  
School Program ◽  
Teachers And Students ◽  
Second Year ◽  
Traditional High School ◽  
Better Than ◽  
High School Program

For years we have debated whether geometry should come before or after second-year algebra in the traditional high school program. Teachers and students at my high school, with the support of the Mathematics Education Trust, have completed a threeyear study of this issue. I have good reason to claim that the traditional first-year algebra, geometry, second-year algebra sequence is better than the first-year algebra, secondyear algebra, geometry sequence.

Changes with time in the germination of buried scentless chamomile (Matricaria perforata Mérat) seeds

1995 ◽  
Vol 75 (1) ◽  
pp. 277-281 ◽  
Author(s):  
G. G. Bowes ◽  
A. G. Thomas ◽  
L. P. Lefkovitch
Keyword(s):  
Seed Bank ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Growing Season ◽  
Early Spring ◽  
First Year ◽  
Temperature Regimes ◽  
Buried Seed ◽  
Second Year ◽  
Persistent Seed Bank

Change with time in the germination of scentless chamomile (Matricaria perforata Mérat) seeds was investigated. Seeds were placed in nylon net bags, buried 7 cm deep in soil, exhumed at monthly intervals for 2 yr and allowed to germinate in temperature regimes of 10/2 °C, 20/5 °C, 25/10 °C and 35/20 °C (16/8 h), simulating temperatures found during early spring or late fall, spring or fall, summer and mid-summer on the soil surface, respectively. Exhumed and refrigerator-stored (2 °C) check seeds exhibited no yearly dormancy/nondormancy germination cycle, but mortality of buried seed increased to 36%, after 10 mo in contrast with that of the check seeds which remained low for two years. Light was required for germination during the first year but was not required for a portion of the seed during the second year. The retention of viability in buried seed explains the persistent seed bank and seedling emergence throughout the growing season when moisture and temperature are nonlimiting. Key words: Seed burial, germination, Matricaria perforata Mérat

scholarly journals SMS as a learning tool: an experimental study

2012 ◽  
Vol 20 (2) ◽  
pp. 33 ◽  
Author(s):  
Mar Gutiérrez-Colon Plana ◽  
Pere Gallardo Torrano ◽  
M. Elisa Grova
Keyword(s):  
Experimental Study ◽  
English Language ◽  
Research Question ◽  
Control Group ◽  
First Year ◽  
Support Tool ◽  
Research Questions ◽  
Second Year ◽  
The University ◽  
Better Than

<p>The aim of this experimental study was to find out the potential of using mobile phones in teaching English as a foreign language, specifically the use of SMS as a support tool in the EFL class. The research questions formulated were: (1) Is using SMS messages via a mobile phone an effective tool in terms of motivation and engagement? (2) What type of mini-lessons do subjects think are better to be sent via SMS in terms of effectiveness, engagement, and usefulness for their learning purposes? (3) What is the appropriate timing for the activities to be sent? (4) Did students who participated in the project perform better than the control group? This experimental study lasted two academic years. As this was a preliminary study of the viability of the SMS methodology, it was conducted with a small group of students (n=13) from the English Degree at the University Rovira i Virgili (Tarragona, Spain). During the first year we designed various types of activities and sent them though a period of 15 weeks. The aim of this first part was to answer the research questions 1 to 3. The second year, a new set of exercises was created. This time, the aim was to gather data to be able to answer the fourth research question. Both qualitative data (from the first year) and quantitative data (from the second year) were analysed. We can conclude that the subjects have found this experience engaging. The subjects preferred receiving short, direct exercises which could be answered immediately. They preferred receiving the SMS in the afternoon or evening and the results show that this methodology enhances the retrieval of memorized English language rules. The results of this study were presented at the EuroCALL 2011 conference in Nottingham and are the result of a research project funded by the Institut de Ciències de l'Educació (Universitat Rovira i Virgili).</p>

scholarly journals Solving the maths problem in chemistry: The impact of a pre-university maths summer school

2011 ◽  
pp. 58-62
Author(s):  
D E Shallcross ◽  
N L Allan ◽  
K L Shallcross ◽  
S J Croker ◽  
D M Smith ◽  
...  
Keyword(s):  
Summer School ◽  
First Year ◽  
Physical Sciences ◽  
Mathematical Skills ◽  
University Mathematics ◽  
Second Year ◽  
And Mathematics ◽  
The Uk ◽  
The Impact ◽  
Better Than

Mathematical skills beyond that taught at GCSE level (under 16 in UK) are required to pursue a physical sciences degree in the UK. However, many departments are unable to recruit sufficient students who have both the physical science and Mathematics qualification at A-level (post-16). Therefore, students are admitted with GCSE Mathematics and are taught the mathematical skills during the degree course. In this paper we investigate the impact of running a pre-university mathematics summer school for students about to start a physical sciences degree who have GCSE Mathematics as their highest mathematics qualification. The students are tracked through their first two years of a UK chemistry degree. It is shown that they perform significantly better than similarly qualified students in first year physical chemistry and second year theoretical chemistry units. Reasons for these results are presented.

scholarly journals Use of the agricultural practice of pasture termination in reducing soil N2O emissions in high-rainfall cropping systems of south-eastern Australia

Soil Research ◽  
2016 ◽  
Vol 54 (5) ◽  
pp. 585 ◽  
Author(s):  
Oxana N. Belyaeva ◽  
Sally J. Officer ◽  
Roger D. Armstrong ◽  
Rob H. Harris ◽  
Ashley Wallace ◽  
...  
Keyword(s):  
Cropping Systems ◽  
Pore Space ◽  
N2o Emission ◽  
First Year ◽  
N2o Emissions ◽  
Agricultural Practice ◽  
Fallow Period ◽  
High Rainfall ◽  
Eastern Australia ◽  
Second Year

Conversion of long-term pasture to cropping was investigated for its effects on nitrous oxide (N2O) emissions in a 2-year field experiment in the high-rainfall zone of south-western Victoria. Early termination (pasture terminated 6 months before sowing) followed by winter (ETw) and spring (ETs) crops and late termination (pasture terminated 1 month before sowing) followed by a winter crop (LTw) were compared with continuous, mown pasture (MP). Emissions of N2O were measured with an automated gas sampling and analysing system. Emissions from MP were the lowest throughout the study, resulting in annual losses of 0.13kg N2O-N ha–1 in the first and the second years of the experiment. N2O-N loss was 0.6kgha–1 from treatments without fallow in both years (LTw in 2013 and ETs in 2014). In the first year, annual losses from previous fallow in ETw and ETs plots were 7.1 and 3.6kg N2O-N ha–1, respectively. Higher annual N2O losses from treatments with fallow periods continued in the second year of the study and were 2.0 and 1.3kg N2O-N ha–1 from ETw and LTw treatments, respectively. High emissions were associated with N mineralisation and the accumulation of NO3-N in the soil during the extensive fallow period after early pasture termination or wheat harvest. Soil water content was a key factor influencing the temporal fluctuations in N2O emissions. Low emissions occurred when water-filled pore space was <30%, whereas high emissions occurred when it was >65%, suggesting that denitrification was the major source of N2O emission. Crop grain yield was not affected by the duration of fallow (and therefore timing of pasture termination) in the first year, but was lower (P<0.05) in the treatment without fallow in the second year. Terminating pasture late rather than early, thus reducing the length of the fallow period, is a practical way of reducing N2O emissions from mixed pasture–cropping systems.

scholarly journals Hatay İli Yonca Üretim Alanlarında Bulunan Böcek Faunasının Tespiti ve Bazı Türlerin Popülasyon Yoğunlukları

2018 ◽  
Vol 6 (3) ◽  
pp. 352 ◽  
Author(s):  
Kamuran Kaya
Keyword(s):  
Natural Enemies ◽  
Natural Enemy ◽  
Dominant Species ◽  
First Year ◽  
Population Densities ◽  
Insect Fauna ◽  
Lygus Rugulipennis ◽  
Beneficial Insect ◽  
Second Year ◽  
Sweep Net

The current study was conducted to determine insect fauna and population densities of some phytophagous and beneficial insect species at two different alfalfa fields in Narlıca district of Hatay province, Turkey in 2009-2010. In the first year biweekly, and in the second year weekly samplings were carried out by 25 sweep-net samplings taken by walking in diagonal directions. Aphids, thrips and gallery flies were also sampled by counting of 30 alfalfa stalks in every 8-10 steps in each of the sampling fields. As a result, 53 phytophagous species belonging to 14 families of five orders and 30 natural enemy species including 20 predators and 10 parasitoids belonging to nine families of six orders were obtained. With 19 species, Cicadellidae has been the largest number of species-containing family and Asymmetrasca descedens and Empoasca decipiens were the most intensively species in this family. In addition, Lygus rugulipennis was the most dominant species among all phytophagous species obtained. It has been found that populations of all pests species were affected by mowing the alfalfa, and show a decline. Predators were predominant among detected natural enemies, and their populations were persistent in the alfalfa fields despite approximately 7-8 mowing per year.

Effects of environmental variables on the competition between inoculum strains and naturalized populations of Rhizobium trifolii for nodulation of Trifolium subterraneum L. and on rhizobia persistence in the soil

1982 ◽  
Vol 33 (5) ◽  
pp. 803 ◽  
Author(s):  
J Brockwell ◽  
RR Gault ◽  
M Zorin ◽  
MJ Roberts
Keyword(s):  
Plant Growth ◽  
Soil Ph ◽  
Environmental Variables ◽  
Trifolium Subterraneum ◽  
Climatic Conditions ◽  
Cumulative Effects ◽  
First Year ◽  
Rhizobium Trifolii ◽  
Eastern Australia ◽  
Second Year

Experiments were conducted at six field sites in south-eastern Australia with three cultivars of Trifolium subterraneum L, inoculated with diverse strains of Rhizobium trifolii. The various locations provided different edaphic and climatic conditions for plant growth, and naturalized populations of R. trifolii provided competition in forming nodules for the inoculum strains. Success of the inocula in forming nodules in the first year was used as an index of competitiveness, and success in the second year as an index of persistence. Inoculum strains formed a majority of nodules in the first year but fewer in the second. Inocula generally persisted better at those sites which had smaller populations of naturalized rhizobia. Competitiveness and persistence did not appear to be related characteristics, although some strains were superior to others especially in terms of persistence. Values for strain persistence tended to be similar at locations where the Mt Barker cultivar was grown, indicating an effect of host on the expression of this character. Significant effects of soil texture, soil pH, or growth temperature (individually) on the relative competitiveness and persistence of the inoculum strains could not be measured, although the cumulative effects of these (and other) environmental variables may have been substantial. The inoculum strains could be assembled into groups according to strong relationships of nodulating performance at each harvest. Within these distinct groups, the nodulation behaviour of the strains relative to each other remained approximately constant, irrespective of the absolute levels of competitiveness or persistence, the location of the experiment, or the year of the harvest.

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