scholarly journals Tree seedling establishment among C4 grasses

2016 ◽  
Author(s):  
Edmund C February ◽  
Joel R Lewis
Keyword(s):  
Species Composition ◽  
Plant Height ◽  
Root Length ◽  
Canopy Cover ◽  
Perennial Grasses ◽  
Rooting Depth ◽  
Grass Species ◽  
Tree Seedlings ◽  
Panicum Maximum ◽  
Perennial Species

The coexistence of leguminous trees and C4 grasses in African savanna remains poorly understood. Trees are able to establish among grasses despite grasses being competitively superior for below ground resources. Here we test the hypothesis that trees are only able to establish when grass biomass has been reduced. We do this at four locations in Limpopo Province South Africa where we locate young seedlings of Senegalia nigrescens. Where we found seedlings we determine grass species composition as well as grass percentage canopy cover, height above ground, and root length. We also make determinations of grass characteristics at two locations where we found no seedlings. For seedlings we determine rooting depth, plant height and stem diameter. To confirm that these are indeed young seedlings, less than a year old, we compare root length and plant height with that of seedlings germinated and grown for 77 days in a greenhouse. Our results show that where seedlings are present grasses are dominated by short-lived species such as Aristida congesta and Enneapogan cenchroides. These species are often found in disturbed soils and would increase with overgrazing. On those sites with no seedlings grass species composition is dominated by perennial species such as Panicum maximum, Panicum coloratum and Cenchrus ciliarus that would decrease with overgrazing and/or repeated burning. The perennial species have a 90-100% canopy cover while the short-lived species have a much lower canopy cover of less than 50%. Within 77 days of germinating tree seedlings are able to develop a root system that is deeper than the short-lived grasses but not deeper than the perennial grasses. These results demonstrate that tree seedlings are only able to establish among grasses if there are gaps in both grass canopy and root mass resulting from increased herbivory, frequent fire or extended drought.

scholarly journals Tree seedling establishment among C4 grasses

2016 ◽  
Author(s):  
Edmund C February ◽  
Joel R Lewis
Keyword(s):  
Species Composition ◽  
Plant Height ◽  
Root Length ◽  
Canopy Cover ◽  
Perennial Grasses ◽  
Rooting Depth ◽  
Grass Species ◽  
Tree Seedlings ◽  
Panicum Maximum ◽  
Perennial Species

The coexistence of leguminous trees and C4 grasses in African savanna remains poorly understood. Trees are able to establish among grasses despite grasses being competitively superior for below ground resources. Here we test the hypothesis that trees are only able to establish when grass biomass has been reduced. We do this at four locations in Limpopo Province South Africa where we locate young seedlings of Senegalia nigrescens. Where we found seedlings we determine grass species composition as well as grass percentage canopy cover, height above ground, and root length. We also make determinations of grass characteristics at two locations where we found no seedlings. For seedlings we determine rooting depth, plant height and stem diameter. To confirm that these are indeed young seedlings, less than a year old, we compare root length and plant height with that of seedlings germinated and grown for 77 days in a greenhouse. Our results show that where seedlings are present grasses are dominated by short-lived species such as Aristida congesta and Enneapogan cenchroides. These species are often found in disturbed soils and would increase with overgrazing. On those sites with no seedlings grass species composition is dominated by perennial species such as Panicum maximum, Panicum coloratum and Cenchrus ciliarus that would decrease with overgrazing and/or repeated burning. The perennial species have a 90-100% canopy cover while the short-lived species have a much lower canopy cover of less than 50%. Within 77 days of germinating tree seedlings are able to develop a root system that is deeper than the short-lived grasses but not deeper than the perennial grasses. These results demonstrate that tree seedlings are only able to establish among grasses if there are gaps in both grass canopy and root mass resulting from increased herbivory, frequent fire or extended drought.

Correlations between environmental factors, the biomass of exotic annual grasses and the frequency of native perennial grasses

2006 ◽  
Vol 54 (7) ◽  
pp. 655 ◽  
Author(s):  
Tanja I. Lenz ◽  
José M. Facelli
Keyword(s):  
Species Composition ◽  
Soil Fertility ◽  
Perennial Grass ◽  
Perennial Grasses ◽  
Annual Rainfall ◽  
Grass Species ◽  
Soil Factors ◽  
Annual Grasses ◽  
Exotic Annual Grasses ◽  
Native Perennial Grass

The species composition of temperate grasslands in the mid-north of South Australia has been radically altered from a system dominated by native perennial grasses to a system dominated by Mediterranean annual grasses. This study investigated the importance of chemical and physical soil characteristics, topographical features and climatic variables on the abundance of native and exotic grass species in nine ungrazed grasslands. Overall, climatic and other abiotic factors were highly variable. In addition, past management practices and original species composition are generally unknown, leading to further unexplained variation in the data. On a large spatial scale (among sites), the abundance of exotic annual grasses was positively correlated with mean annual rainfall, and on any scale, with finer soil textures and higher soil organic carbon levels. The most abundant annual grass, Avena barbata (Pott ex Link), was generally associated with soil factors denoting higher soil fertility. The abundance of native perennial grass species was not correlated with any environmental variables at any scale. The various native perennial grass species did not show clear associations with soil factors, although they tended to be associated with factors denoting lower soil fertility. However, at small spatial scales (within some sites) and among sites, the abundances of exotic annual and native perennial grasses were strongly negatively correlated. The results suggest that at the present time, rainfall and soil properties are important variables determining the abundance of annual grasses. The driving variables for the abundance of perennial grasses are less clear. They may be controlled by other factors or extreme rainfall events, which were not surveyed. In addition, they are likely to be controlled by competitive interactions with the annual grasses.

The response to moisture and defoliation stresses, and traits for resilience of perennial grasses on the Northern Tablelands of New South Wales, Australia

2003 ◽  
Vol 54 (9) ◽  
pp. 903 ◽  
Author(s):  
S. P. Boschma ◽  
M. J. Hill ◽  
J. M. Scott ◽  
G. G. Rapp
Keyword(s):  
Festuca Arundinacea ◽  
Plant Biomass ◽  
Nitrogen Concentration ◽  
Perennial Grass ◽  
Basal Area ◽  
Perennial Grasses ◽  
Rooting Depth ◽  
Grass Species ◽  
Severe Drought ◽  
Moderate Drought

A field experiment was conducted to study the effects of defoliation and moisture stresses on perennial pasture grasses and to identify traits associated with their resilience. The experiment, conducted near Armidale on the Northern Tablelands of NSW, studied 4 introduced perennial grass species (Phalaris aquatica, Festuca arundinacea, Dactylis glomerata, and Lolium perenne) and 2 native grass species (Microlaena stipoides and Austrodanthonia richardsonii) subjected to 3 moisture regimes (non-stress moisture, moderate drought, and severe drought) and 2 defoliation intensities (severe and moderate). Basal area, herbage mass, phenological growth stage, nitrogen concentration, root mass, and rooting depth were compared over 2 independent 6-month periods: spring–summer (1 September 1994–28 February 1995) and summer–autumn (1 December 1994–31 May 1995). Multiple regression was used to determine which traits were important for determining plant resilience.The differences between species and their respective responses were evident in the traits measured. In general, basal area tended to increase over summer and show little change during autumn. Severe defoliation stimulated plant growth, resulting in higher harvested herbage mass than from those moderately defoliated. Reproductive development was suppressed by severe drought and reduced by moderate drought. Severe defoliation suppressed flowering of Dactylis and Lolium at both drought intensities, compared with moderate defoliation. Phalaris, Festuca, and Austrodanthonia were the deepest rooting species during spring–summer, and Dactylis the shallowest. All species had similar rooting depths during summer–autumn, with those under severe and moderate drought having the deepest and shallowest rooting, respectively.Carbohydrate reserves and basal area were important traits for determining plant resilience during spring–summer. During summer–autumn, maintaining basal area and plant biomass through moderate grazing was important for resilience.

Agronomic potential of native grass species on the Northern Tablelands of New South Wales. II. Nutritive value

1988 ◽  
Vol 39 (3) ◽  
pp. 425 ◽  
Author(s):  
KA Archer ◽  
GG Robinson
Keyword(s):  
White Clover ◽  
Festuca Arundinacea ◽  
Native Species ◽  
Nutritive Value ◽  
Perennial Grasses ◽  
Grass Species ◽  
Native Grasses ◽  
Perennial Species ◽  
Green Leaves

The quality of three year-long green and three summer-growing, frost-susceptible perennial native grasses was compared with that of two introduced temperate perennial grasses and white clover (Trifolium repens L. cv. Haifa). Digestibility of white clover generally exceeded that of all grasses, except for the green leaves of the two introduced species, Festuca arundinacea Screb. cv. Demeter and Phalaris aquatica L. cv. Sirosa, during winter. The digestibility of the green leaves of most winter-green species increased during winter and decreased in summer, the extent of this being greater for the introduced grasses.The digestibility of fescue and phalaris was generally similar throughout the study and was mostly higher than that of the native grasses, but the quality of the green leaves of two year-long green native species, Danthonra linkii Kunth and Microlaena stipoides (Labill.) R.Br., approached that of the two introduced grasses. The quality of the summer perennial species was poor during winter owing to the presence of only dead leaves, but the green leaves of Bothriochloa macra (Steud) S. T. Blake retained high levels of digestibility during summer. Considerable variation in digestibility exists between individual plants of Poaseiberana Spreng, indicating that opportunities may exist for selection of highly productive lines from some native species.In pen-feeding studies, voluntary intake of most of the year-long green native grasses was similar to that of the introduced grasses, but intake of the summer perennial species tended to be lower.Results from this study indicate that the quality of native pastures and their potential for animal production will vary considerably according to species composition, season and the presence of white clover.

scholarly journals The influence of single-species crops and their grass mixes on the grass species composition

2018 ◽  
Vol 20 (89) ◽  
pp. 3-7
Author(s):  
L. К. Savchuk ◽  
I. V. Vyhovsky
Keyword(s):  
Species Composition ◽  
Growth And Development ◽  
Lolium Multiflorum ◽  
Single Species ◽  
Perennial Grasses ◽  
Cultivated Plants ◽  
Grass Species ◽  
Mineral Fertilizers ◽  
Main Task ◽  
Alfalfa Seed

When creating artificial phytocoenoses, the main task is to create optimal conditions for growth and development, in accordance with the needs of each type of cultivated plants, which would ensure the highest productivity of the group during the entire period of use of herbs and the production of high quality and cheap feed for public livestock breeding. In order to successfully solve the problem of regulating the composition of agrophytocenoses in scientific and practical buckling, it is important to know how the relations between plants in the process of their joint growth and development occurs, which changes take place in the botanical composition not only in species groups, but also in single-species crops of grasses on the eroded slope of steepness 6–7о on the basis of Rivne Institute of Agro-Industrial Production of the National Academy of Agricultural Sciences of Ukraine. The results of research showed that it is economically expedient to grow grass-legume grass mixtures with a longer period of productive longevity using the low nitrogen fertilizer rates, which contributes to the formation of phytocenosis, in which valuable species of cereal and perennial bean grasses (beetroot grass and alfalfa sowing). The positive effect on the species composition of the grass was slight mowing in the phase of tubing. The results of the research showed that for the production of grass-legume grass, the hay-grass-free use should be sown with grass mixtures, the following herbs were added to the composition: alfalfa sowed (4.4 million pounds per hectare) + long beetroot horned (4.4 million pounds per hectare) + bromus inermis (3.4 million pounds per hectare) + lolium perenne (3.4 million pounds per hectare) of conditioned seeds that affect the species composition of the grass during the growing season. On the basis of the conducted researches it was established that the analysis of the species composition of the herb shows that the quantitative correlation of the species varied over the years, mainly from the biological characteristics of herbs that were part of the grass mixture. The percentage of sown species of grasses has grown with the age of grass. The results of researches, which showed that in four component grass mixtures, in the fertilization of grass with complete mineral fertilizers in the norm N60P60K90, dominant legume perennial grasses – beetroot horn (25.0%), alfalfa seed (30.9%), and cereals – stokolos seamless (21.7%) and Lolium multiflorum (13.0%). In a small number, during the years of research, self-seedling appeared timothy bean (2.0%), non-infected cereals (4.0%) and herbs – 3.4%. During the years of research on varieties, which were planted with alfalfa seed and beetroot, bean herbs predominated. The percentage of hare cattle was 88.5%, alfalfa seeded 91.4%.

scholarly journals Changes in Herbaceous Species Composition in the Absence of Disturbance in aCenchrus biflorusRoxb. Invaded Area in Central Kalahari Game Reserve, Botswana

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Shimane W. Makhabu ◽  
Balisana Marotsi
Keyword(s):  
Species Composition ◽  
Human Activities ◽  
Grass Species ◽  
Herbaceous Species ◽  
High Tolerance ◽  
Perennial Species ◽  
The Third ◽  
Disturbed Areas ◽  
Game Reserve ◽  
Vegetation Characteristics

A-nine year study was carried out to investigate changes in herbaceous species composition in an area invaded byCenchrus biflorusRoxb, an exotic invader grass species. The study ensued termination of livestock and human activities in the area when residents of the area were relocated to another area. Vegetation characteristics from the disturbed sites (previous occupied areas) and undisturbed sites (previously unoccupied areas) were determined. The results show thatC. biflorushas high tolerance to disturbance. It comprised the larger proportion of grasses in disturbed sites at the inception of the study. However, it decreased in abundance with time in disturbed areas and was absent in the undisturbed areas, suggesting that its ability to invade undisturbed sites is limited. Perennial species successfully reestablished on the third year after termination of disturbance. The study reveals thatC. biflorusinvasion in the Kalahari ecosystem can be controlled by termination of disturbances.

Film coating of seeds with Bacillus cereus RS87 spores for early plant growth enhancement

2008 ◽  
Vol 54 (10) ◽  
pp. 861-867 ◽  
Author(s):  
Kanchalee Jetiyanon ◽  
Sakchai Wittaya-Areekul ◽  
Pinyupa Plianbangchang
Keyword(s):  
Plant Growth ◽  
Bacillus Cereus ◽  
Plant Height ◽  
Root Length ◽  
Film Coating ◽  
Field Trials ◽  
Growth Enhancement ◽  
Vegetative Cells ◽  
Plant Growth Promoting ◽  
Growth Promoting

The plant growth-promoting rhizobacterium Bacillus cereus RS87 was previously reported to promote plant growth in various crops in both greenhouse and field trials. To apply as a plant growth promoting agent with practical use, it is essential to ease the burden of routine preparation of a fresh suspension of strain RS87 in laboratory. The objectives of this study were to investigate the feasibility of film-coating seeds with B. cereus RS87 spores for early plant growth enhancement and to reveal the indoleacetic acid (IAA) production released from strain RS87. The experiment consisted of the following 5 treatments: nontreated seeds, water-soaked seeds, film-coated seeds, seeds soaked with vegetative cells of strain RS87, and film-coated seeds with strain RS87 spores. Three experiments were conducted separately to assess seed emergence, root length, and plant height. Results showed that both vegetative cells and spores of strain RS87 significantly promoted (P ≤ 0.05) seed emergence, root length and plant height over the control treatments. The strain RS87 also produced IAA. In conclusion, the film coating of seeds with spores of B. cereus RS87 demonstrated early plant growth enhancement as well as seeds using their vegetative cells. IAA released from strain RS87 would be one of the mechanisms for plant growth enhancement.

GROWTH RESPONSE OF BEHA GRASS (Brachiaria humidicola) FERTILIZED WITH GOAT MANURE

2021 ◽  
Vol 2 (3) ◽  
Author(s):  
Budiman Budiman ◽  
Natsir Sandiah ◽  
La Malesi
Keyword(s):  
Plant Height ◽  
Root Length ◽  
New Production ◽  
Brachiaria Humidicola ◽  
Randomized Design ◽  
Length Data ◽  
Number Of Leaves ◽  
Completely Randomized Design ◽  
Goat Manure ◽  
Difference Test

This study aimed to determine the best dosage of goat manure as a natural fertilizer on Beha grass(Brachiaria humidicola). This study used 64 poles of Beha grass grown in polybags divided into 16plots, and it used a completely randomized design (CRD) to analyze the data. This study consist of 4treatments that is P0 (0 ton/ha of goat manure), P1 (10 ton/ha of goat manure), P2 (15 ton/ha of goatmanure), and P3 (20 ton/ha of goat manure). This study's variables were plant height, number of leaves,numbers of tillers, new production, and root length. Data analysis used ANOVA variance continued withreal honest difference test. The result of this study showed that averages of plant height (cm) wereP0=26, P1=50.5, P2=51.5, and P3=52.75. Averages of the number of leaves were P0=22, P1=110,P2=160, and P3=185. Averages of numbers of tillers were P0=7, P1=25, P2=37, and P3=38. Averages ofnew production (g) were P0=17.75, P1=123.5, P2=178, and P3=192.25. Averages of root length (cm)were P0=37.8, P1=39.5, P2=41.775, and P3=49.5. Fertilization with natural fertilizer from goat manurehas a genuine effect (P<0.01) on the growth of Beha grass. The best dosage of fertilization with goatmanure was 15 ton/ha.

The germinable soil seedbank of Eucalyptus victrix grassy woodlands at Roy Hill station, Pilbara district, Western Australia

2004 ◽  
Vol 26 (1) ◽  
pp. 17 ◽  
Author(s):  
R. A. Graham ◽  
S. K. Florentine ◽  
J. E. D. Fox ◽  
T. M. Luong
Keyword(s):  
Species Composition ◽  
Western Australia ◽  
Perennial Grass ◽  
Summer Rainfall ◽  
Distribution Patterns ◽  
Grass Species ◽  
Surface Areas ◽  
Hill Station ◽  
Soil Seedbank ◽  
Germinable Seed

The paper reports soil seedbank species composition, of Eucalyptus victrix grassy woodlands, of the upper Fortescue River in the Pilbara District, Western Australia. In this study, our objectives were to investigate germinable soil seedbanks and species composition in response to three simulated seasons, using emergence. Variation in seed density from three depths was tested. Four field sites were sampled. Thirty samples were collected in late spring, after seed rain and before summer rainfall. From each sample spot, three soil depths (surface, 1–5, and 6–10 cm) were segregated from beneath surface areas of 100 cm2. Samples were later incubated in a glasshouse to simulate three different seasonal conditions (autumn, winter and spring). Germinating seedlings were recorded on emergence and grown until identified. Forty-one species germinated, comprising 11 grasses (7 annuals and 4 perennials), 25 annual herbs and 5 perennial herbs. Distribution patterns of germinable seed in both the important annual grass Eragrostis japonica and the perennial Eragrostis setifolia (a preferred cattle fodder species), suggest that seedbank accumulation differs among species and between sites. In part, this may be associated with the absence of grazing. Species with most total germinable seed were E. japonica (Poaceae; 603/m2), and the annual herbs Calotis multicaulis (Asteraceae; 346/m2), and Mimulus gracilis (Scrophulariaceae; 168/m2). Perennial grass seed was sparse. Spring simulation gave most germination (1059), followed by autumn (892) and winter (376) sets. Greatest species diversity was produced from the spring simulation (33 species), followed by autumn (26), and winter (22). Of the total germination, 92% came from 17 species that were represented in all three simulations. Of the 1227 grass seedlings counted, most were recruited from the surface soil (735), followed by the 5 (310) and 10 (182) cm depths. Marginally more grass seedlings germinated from the spring simulation (558) than the autumn set (523). Only 11.9% of grass germinants came from the winter simulation. All grass species recruited from the soil seedbanks had a C4 photosynthetic pathway. Except for Cenchrus ciliaris all grass species are native to Australia. Of the four sites sampled, one fenced to exclude cattle five years earlier had significantly more germination than the three unfenced sites. Seedbank sampling produced several new records for plants in the areas sampled.

scholarly journals Recovery of Trichostrongylus colubriformis infective larvae from three grass species contaminated in the autumn

2012 ◽  
Vol 21 (4) ◽  
pp. 372-378 ◽  
Author(s):  
Raquel Abdallah da Rocha ◽  
Patrizia Ana Bricarello ◽  
Gilberto Pedroso da Rocha ◽  
Alessandro Francisco Talamini do Amarante
Keyword(s):  
Dry Matter ◽  
Cynodon Dactylon ◽  
Larval Survival ◽  
Grass Species ◽  
Panicum Maximum ◽  
Free Living ◽  
Trichostrongylus Colubriformis ◽  
Brachiaria Decumbens ◽  
Infective Larvae ◽  
Experimental Plots

This experiment aimed to assess the recovery of infective larvae (L3) of Trichostrongylus colubriformis from Brachiaria decumbens cv. Australiana, Cynodon dactylon cv. Coast-cross and Panicum maximum cv. Aruana. The experimental module comprised six plots, with two plots per herbage species. Larval survival was assessed from autumn to winter, under the effect of two herbage-paring heights (5 and 30 cm). TThe paring was carried out immediately before contamination with faces containing T. colubriformis eggs. The feces and herbage were collected at one, two, four, eight, 12 and 16 weeks after feces had been deposited in the experimental plots. In general, larvae were recovered from both herbage and feces until the 16th week. The longer persistence of these larvae in the environment was probably due to warmer temperatures. The number of L3 recovered from the pasture was not influenced by the height of plants, except for Brachiaria and Aruana herbage in the fourth week. Regarding the concentrations of larvae per kg of dry matter (L3/kg DM), recovery was higher from low pasture in all three herbage species. During the autumn, the development and survival of the T. colubriformis free-living stages were not affected by the different herbage species.

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