Establishment of introduced grasses at different stages of pasture development: effects of seedbed

1981 ◽  
Vol 21 (111) ◽  
pp. 417 ◽  
Author(s):  
JG McIvor ◽  
CJ Gardener
Keyword(s):  
Plant Competition ◽  
Thick Layer ◽  
Soil Surface ◽  
Perennial Grasses ◽  
Wet Season ◽  
Stylosanthes Hamata ◽  
Native Grassland ◽  
Successful Establishment ◽  
Chloris Gayana ◽  
Seedbed Preparation

The seedbed preparation necessary for the successful establishment of five promising perennial grasses for the dry tropics was studied on two pastures - native grassland and a pasture dominated by Stylosanthes hamata cv. Verano - near Townsville, in northern Queensland. Seed of Cenchrus ciliaris cv. Biloela, Chloris gayana cv. Callide, Chrysopogon sp. CPI 5221 3, Digitaria milanjiana CPI 5981 4 and Urochloa mosambicensis CPI 46876 was sown into the two pastures, which had been left untreated, sprayed with herbicide, burnt, or burnt and cultivated. S. hamata cv. Verano was also sown on the native grassland plots. Sowings were made at the start of the growing season in successive years. Germination of all lines was adequate except where a thick layer of green and dead herbage physically separated the seed from the soil surface; this happened on the native pasture plots that were untreated or herbicide treated. However, there was high plant mortality in the first month after sowing except where plant competition had been reduced or removed by cultivation or spraying. After this period, most plants survived to the end of the wet season in both pasture types. This pattern of change in plant numbers resulted in good establishment on the cultivated seedbeds, some establishment on the herbicide-treated plots and little or no establishment on the control and burnt plots. Of the five grasses, U. mosambicensis had the best establishment and Chrysopogon sp. and D. milanjiana the worst. None seem likely to survive when sown into living grassland. We therefore conclude that the use of these introduced species will be largely restricted to completely cleared and cultivated land.

Competition among seedlings of perennial grasses, subterranean clover, white clover, and annual ryegrass in replacement series mixtures

2000 ◽  
Vol 51 (3) ◽  
pp. 377 ◽  
Author(s):  
G. M. Lodge
Keyword(s):  
White Clover ◽  
Plant Competition ◽  
Perennial Grass ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Perennial Grasses ◽  
Maximum Likelihood Estimates ◽  
Annual Ryegrass ◽  
Replacement Series ◽  
Successful Establishment

Seedlings of 3 perennial grasses, Danthonia linkii Kunthcv. Bunderra, D. richardsonii Cashmore cv. Taranna(wallaby grasses), and Phalaris aquatica L. cv. Sirosa,were each grown in replacement series mixtures with seedlings ofTrifolium repens L. (white clover),Trifolium subterraneum L. var. brachycalycinum (Katzn.et Morley) Zorahy & Heller cv. Clare (subterraneanclover), and Lolium rigidum L. (annual ryegrass). Plantswere sown 5 cm apart in boxes (45 by 29 by 20 cm) at a density of 307plants/m2. Maximum likelihood estimates were usedto derive parameters of a non-linear competition model using the dry matterweights of perennial grasses and competitors at 3 harvests, approximately 168,216, and 271 days after sowing. Intra-plant competition was examined inmonocultures of each species, grown at plant spacings of 2, 5, and 8 cm apartwith plants harvested at the above times.Competition occurred in all perennial grass–competitor mixtures, exceptin those of each perennial grass with white clover and thephalaris–subterranean clover mixture (Harvest 1) and those withD. richardsonii and phalaris grown with white clover(Harvest 2). For D. richardsonii (Harvests 1 and 2) andD. linkii (Harvest 1 only) grown with white clover andthe phalaris–subterranean clover (Harvest 1), the two species in themixture were not competing. In the phalaris–white clover mixture, eachspecies was equally competitive (Harvests 1 and 2). These differences incompetition and aggressiveness reflected differences in individual plantweights in monocultures where there was an effect (P < 0.05) of species ondry matter weight per box, but no significant effect of plant spacing.These data indicated that for successful establishment,D. richardsonii and D. linkiishould not be sown in swards with either subterranean clover or white clover,or where populations of annual ryegrass seedlings are likely to be high.Phalaris was more compatible with both white clover and subterranean clover,but aggressively competed with by annual ryegrass.

Growth, seed production and effect of defoliation in an early flowering perennial grass, Alloteropsis semialata (Poaceae), on Cape York Peninsula, Australia

2001 ◽  
Vol 49 (6) ◽  
pp. 735 ◽  
Author(s):  
Gabriel M. Crowley ◽  
Stephen T. Garnett
Keyword(s):  
Plant Growth ◽  
Seed Production ◽  
Perennial Grass ◽  
Soil Surface ◽  
Plant Size ◽  
Perennial Grasses ◽  
Wet Season ◽  
Cape York ◽  
Seed Dynamics

Alloteropsis semialata (R.Br.) A.Hitchc. is one of the first perennial grasses in monsoonal Australia to produce seed at the start of the wet season. Patterns of growth and seed production and seed dynamics of Alloteropsis semialata were examined in this study, along with the effects of partial defoliation. Growth of Alloteropsis semialata tussocks started with the first pre-wet-season rains, and was then interrupted during a period with little rain. Growth ceased before the end of the wet season, indicating that factors other than moisture availability were limiting. Seeds of Alloteropsis semialata were germinable on production, but did not remain viable or persist on the soil surface through the dry season. Most seeds and young seedlings were harvested and no seedlings were recruited. Inflorescence production increased with plant size. Moderate defoliation in the early wet season had no impact on plant growth, but reduced inflorescence and seed production for at least 2 years. Absence of a seed bank and early wet-season flowering mean that Alloteropsis semialata is likely to be sensitive to long-term over-grazing.

scholarly journals Biophysical Effects of Evapotranspiration on Steppe Areas: A Case Study in Naâma Region (Algeria)

2021 ◽  
Author(s):  
Abdelkrim Benaradj ◽  
Hafidha Boucherit ◽  
Abdelkader Bouderbala ◽  
Okkacha Hasnaoui
Keyword(s):  
Mediterranean Climate ◽  
Potential Evapotranspiration ◽  
Thick Layer ◽  
Soil Surface ◽  
Cold Season ◽  
Perennial Grasses ◽  
Herbaceous Plants ◽  
Humid Climate ◽  
Water Losses ◽  
Steppe Vegetation

The Algerian steppe is of great interest in terms of vegetation, mainly in the Naâma region. This steppe vegetation is generally composed of annual and perennial grasses and other herbaceous plants, as well as, bushes and small trees. It is characterized by an arid Mediterranean climate where the average annual precipitation (100 to 250 mm) is insufficient to ensure the maintenance of the vegetation, in which the potential evaporation always exceeds the precipitations. This aridity has strong hydrological effect and edaphic implications from which it is inseparable. Water losses are great than gains due to the evaporation and transpiration from plants (evapotranspiration). The wind moves soils for one location to another, and causes a strong evapotranspiration of the plants, which is explained by a strong chronic water deficit of climatic origin of these compared to the potential evapotranspiration, opposed to a humid climate. Evapotranspiration is certainly closely linked to climate factors (solar radiation, temperature, wind, etc.), but it also depends on the natural environment of the studied region. Potential evapotranspiration (PET) data estimated from Thornthwaite’s method for the three stations (Mécheria, Naâma and Ainsefra). The average annual value of potential evapotranspiration is of the order of 807 mm in Mécheria, of 795 mm in Naâma de and in Ainsefra of 847 mm. It is more than 3 times greater than the value of the rainfall received. This propels it globally in the aridity of the region and from which the water balance of plants is in deficit. The potential evapotranspiration of vegetation in arid areas is very important due to high temperature and sunshine. During the cold season, precipitation covers the needs of the potential evapotranspiration and allows the formation of the useful reserve from which the emergence of vegetation. From the month of April there is an exhaustion of the useful reserve which results of progressive deficit of vegetation. Faced with this phenomenon of evatranspiration, the steppe vegetation of the region then invests in “survival” by reducing the phenomena of evapotranspiration, photosynthetic leaf surfaces, in times of drought. These ecophysiological relationships can largely explain the adaptation of steppe species (low woody and herbaceous plants) to the arid Mediterranean climate. Mechanisms and diverse modalities were allowing them to effectively resist for this phenomenon. The adaptation of the steppe vegetation by the presence of a root system with vertical or horizontal growth or both and seems to depend on the environmental conditions, and by the reduction of the surface of transpiration, and by the fall or the rolling up of the leaves, and by a seasonal reduction of transpiration surface of the plant to reduce water losses during the dry season (more than 6 months) of the year.. Some xerophytes produce “rain roots” below the soil surface, following light precipitation or during dew formation. Other persistent sclerophyllous species by which decreases transpiration by the hardness of the leaves often coated with a thick layer of wax or cutin.

Improvement in soil structure resulting from sown pastures on degraded areas in the dry savanna woodlands of northern Australia

Soil Research ◽  
1983 ◽  
Vol 21 (1) ◽  
pp. 83 ◽  
Author(s):  
BJ Bridge ◽  
JJ Mott ◽  
WH Winter ◽  
RJ Hartigan
Keyword(s):  
Soil Structure ◽  
Surface Soil ◽  
Northern Australia ◽  
Wet Season ◽  
Stylosanthes Hamata ◽  
Native Grassland ◽  
Townsville Stylo ◽  
Stocking Rates ◽  
High Infiltration

The structure of the surface soil under pastures sown on a former Themada australis native grassland and on degraded areas in the red earths of northern Australia was examined micromorphologically. Heavily grazed pastures containing the legumes Stylosanthes hamata cv. Verano and Alysicarpus vaginalis had more macropore space in the surface soil than arlightly grazed native grassland, while pastures containing S. humilis (Townsville stylo) had as little macropore space as degraded areas. Macropore space in a S. hamata pasture increased between the third and fourth wet seasons after establishment. Where macropore space was high, infiltration measurements showed that sorptivities were as high as those in the native grassland. Where macropore space was low, sorptivities were as low as those in degraded areas. However, all sown pastures showed low hydraulic conductivities equivalent to those in the degraded areas, and this was attributed to trampling during the wet season under the higher stocking rates involved. The improvement and maintenance of soil structure in the S. hamata and A. vaginalis pastures, together with their high sorptivities, indicates that they are stable in the long term.

Survival and growth of perennial halophytes on saltland in a Mediterranean environment is affected by depth to watertable in summer as well as subsoil salinity

2013 ◽  
Vol 64 (2) ◽  
pp. 123 ◽  
Author(s):  
E. G. Barrett-Lennard ◽  
Sarita Jane Bennett ◽  
M. Altman
Keyword(s):  
Shallow Groundwater ◽  
Soil Surface ◽  
Perennial Grasses ◽  
Good Survival ◽  
Dryland Salinity ◽  
Rhodes Grass ◽  
Small Leaf ◽  
Chloris Gayana ◽  
Survival And Growth ◽  
Chloris Gayana Kunth

Farmers need methods for assessing the capability of saltland for productive use based on characteristics that are readily measurable at the paddock scale. We conducted experiments on saltland transects with gradients of salinity and depth to watertable at three sites in south-western Australia. Each was planted with five perennial species with at least some salt tolerance: samphire (Tecticornia mellaria K.A.Sheph.), river saltbush (Atriplex amnicola Paul G.Wilson), small leaf bluebush (Maireana brevifolia (R.Br.) Paul G.Wilson), saltwater couch (Paspalum vaginatum Sw.), and Rhodes grass (Chloris gayana Kunth). Survival and growth of species was related to depth to watertable in summer and average subsoil (0.25–0.50 m depth) electrical conductivity of the saturation extract (ECe). It has been hypothesised that plant zonation on land affected by dryland salinity is affected by the level of salinity and waterlogging on sites. While plant survival ≥60% could be associated with particular ranges of depth to watertable and soil salinity, our data suggest that the most important factor affecting survival and growth was the presence of shallow groundwater in summer. The range of depths to watertable in summer associated with ‘good survival’ (≥60%) was 0.7–1.0 m with samphire, 0.7–1.6 m with saltwater couch, 0.8–1.5 m with Rhodes grass, 0.7–2.4 m with river saltbush, and 0.9–2.4 m with small leaf bluebush. The subsoil ECe (95% confidence interval) associated with ‘good survival’ was 5–14 dS/m for Rhodes grass, 6–11 dS/m for small leaf bluebush, 7–11 dS/m for river saltbush, 6–16 dS/m for saltwater couch, and 27–65 dS/m for samphire. Growth of the perennial grasses was strongly affected by the presence of a shallow watertable in summer; the size of saltwater couch and Rhodes grass increased many-fold as watertable depths decreased from ~1.3 to 0.9 m from the soil surface.

Direct seeding of black spruce in northwestern Ontario: Seedbed relationships

1994 ◽  
Vol 70 (2) ◽  
pp. 151-158 ◽  
Author(s):  
R. L. Fleming ◽  
D. S. Mossa
Keyword(s):  
Seedling Establishment ◽  
Black Spruce ◽  
Mineral Soil ◽  
Soil Surface ◽  
Direct Seeding ◽  
First Year ◽  
Strongly Correlated ◽  
Seedling Mortality ◽  
Northwestern Ontario ◽  
Seedbed Preparation

A series of spot seeding experiments was set out on coarse-textured upland sites in northwestern Ontario to investigate how black spruce (Picea mariana [Mill.] B.S.P.) seedling establishment and growth could be improved by site selection and seedbed preparation. Virtually all germination occurred within the first growing season. Annual seedling mortality rates were greatest during the first year, then declined steadily and stabilized at low levels (<10%) after the third year. The highest fifth-year establishment ratios (seedlings/viable seed sown) were found on seedbeds derived from materials near the mineral soil/humus interface. On wetter sites (i.e., higher Soil Moisture Regimes) the best seedbeds occurred closer to the soil surface. Mean fifth year establishment ratios for the best seedbeds were 0.032 on moderately fresh to fresh sites, 0.146 on very fresh to moderately moist sites, and 0.082 on moist to very moist sites. On adjacent lowland sites, slow-growing, compact Sphagnum mosses had a mean establishment ratio of 0.179. Mean fifth-year seedling heights on upland sites ranged from 12 to 14 cm, and were not strongly correlated with site or seedbed type. Key words: direct seeding, black spruce, seedbed, seedling establishment, site type and germination

Technologies of drop irrigation of young almond garden on terraces in foothland conditions of the Kyzylsu-Yuzhnaya river basin

2021 ◽  
Vol 0 (1) ◽  
pp. 12-15
Author(s):  
Daler Domullodzhanov
Keyword(s):  
River Basin ◽  
Drip Irrigation ◽  
Field Experiments ◽  
Soil Surface ◽  
Perennial Grasses ◽  
Minimum Amount ◽  
Almond Orchard

The article presents the results of field experiments on the study of the technology of drip irrigation of a young almond orchard on terraces with clear cover with tillage soil surface, with use of mulching and overseeding of perennial grasses. In the variant with mulching, the minimum amount of irrigation observed – 24, with the irrigation norm – 1904 litre per tree. In other cases, the number of irrigation events increases from 8 to 23, respectively, the irrigation norms are 1.39 and 2.06 times.

scholarly journals Spatial variability of shallow groundwater level in the Northern Kathmandu Valley

2018 ◽  
Vol 55 (1) ◽  
pp. 45-54
Author(s):  
Manish Shrestha ◽  
Naresh Kazi Tamrakar
Keyword(s):  
Groundwater Level ◽  
Shallow Groundwater ◽  
Soil Surface ◽  
Northern Region ◽  
Dry Season ◽  
Kathmandu Valley ◽  
Wet Season ◽  
Geological Material ◽  
Groundwater Levels ◽  
Shallow Groundwater Level

Groundwater is the water which is present in pore spaces and in the fractures of the geological materials beneath earth surface. Water is incompressible substance and presence of small amount of water in geological material modifies the behavior of geological material under stresses. Determination of engineering behavior of the geological material is almost impossible skipping the role of water. The objective of this study was to map and evaluate shallow groundwater level of the northern Kathmandu Valley covering main rivers such as the Bagmati River, Bishnumati River, Dhobi Khola and the Manahara Khola. These rivers flow from the North to the South across the sand rich sediment zone. Static groundwater levels of 239 wells were measured from different locations of the study area in April/March 2017 (Dry Season) and in August 2017 (Wet Season). Shallow groundwater level was measured from soil surface to water level using well water depth logger (Qin and Li, 1998). The result showed that groundwater level ranged from 0.6 m to 12.5 m in dry season and 0.1 m to 13 m in wet season. The groundwater level increased by average of 34.68% (n = 235) as compared to that in dry season. Increase in the groundwater level suggests recharge of groundwater in wet season of the study area. The flow pattern of groundwater levels from the study shows flow of shallow groundwater towards the major rivers of that particular river watershed. As a consequence, seepage flow and piping erosion is likely along the riverbank slopes. Increase in recharge of groundwater during wet season exhibits that the northern region of the Kathmandu Valley is potential for groundwater recharge and can be used to manage water for the dry period.

scholarly journals Measurement of Soluble Arsenic in Soil of Bangladesh by Acid-alkali Sequential Extraction

2008 ◽  
Vol 1 (1) ◽  
pp. 92-107 ◽  
Author(s):  
Mohammad Shafiul Azam ◽  
Md. Shafiquzzaman ◽  
Iori Mishima ◽  
Jun Nakajima
Keyword(s):  
Sequential Extraction ◽  
Soil Phosphorus ◽  
Extraction Procedure ◽  
Soil Surface ◽  
Soil Samples ◽  
Wet Season ◽  
Arsenic Mobility ◽  
Reducing Conditions ◽  
Sequential Extraction Method ◽  
Core Soil

To measure easily soluble fraction of arsenic, a sequential extraction method by 0.1N HCl and 0.1N NaOH was used according to the soil phosphorus extraction procedure. The effects of reducing conditions on arsenic extraction were examined in incubation test. In high reducing conditions arsenic solubility was shown to be high and seemed to be controlled by dissolution of iron oxy-hydroxides. pH played a predominant role in determining the concentrations of soluble arsenic. Arsenic solubility could be possible at low or high pH conditions. Released arsenic in different pH and redox conditions showed that it is a part of acid extractable arsenic which is sorbed weakly on the soil surface and can be extracted during acid-alkali sequential extraction. Therefore, the method could be applicable to measure potential solubility of arsenic as a result of alteration in soil (e.g. redox, pH) and environmental factors. Sequential extraction results of the soil samples collected in dry and wet season suggested that acid-alkali extracted arsenic fractions of surface and core soil samples of paddy field were increased in wet season. They seemed to be moved with irrigation groundwater. Keywords: Acid-alkali extraction; Arsenic contamination; Soil arsenic mobility; Groundwater contamination; Paddy soil.  © 2009 JSR Publications. ISSN: 2070-0237(Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v1i1.1058  

scholarly journals Smog Nitrogen and the Rapid Acidification of Forest Soil, San Bernardino Mountains, Southern California

2007 ◽  
Vol 7 ◽  
pp. 175-180 ◽  
Author(s):  
Yvonne A. Wood ◽  
Mark Fenn ◽  
Thomas Meixner ◽  
Peter J. Shouse ◽  
Joan Breiner ◽  
...  
Keyword(s):  
Southern California ◽  
Mediterranean Climate ◽  
Rapid Change ◽  
Soil Surface ◽  
Atmospheric Nitrogen ◽  
Wet Season ◽  
San Bernardino Mountains ◽  
San Bernardino ◽  
Fog Deposition ◽  
Very High

We report the rapid acidification of forest soils in the San Bernardino Mountains of southern California. After 30 years, soil to a depth of 25 cm has decreased from a pH (measured in 0.01 M CaCl2) of 4.8 to 3.1. At the 50-cm depth, it has changed from a pH of 4.8 to 4.2. We attribute this rapid change in soil reactivity to very high rates of anthropogenic atmospheric nitrogen (N) added to the soil surface (72 kg ha–1 year–1) from wet, dry, and fog deposition under a Mediterranean climate. Our research suggests that a soil textural discontinuity, related to a buried ancient landsurface, contributes to this rapid acidification by controlling the spatial and temporal movement of precipitation into the landsurface. As a result, the depth to which dissolved anthropogenic N as nitrate (NO3) is leached early in the winter wet season is limited to within the top ~130 cm of soil where it accumulates and increases soil acidity.

Sign in / Sign up

Export Citation Format

Share Document