Selection of perennial grasses as a component of legume-based pastures on light-textured soils in the dry tropics of Queensland

1994 ◽  
Vol 34 (3) ◽  
pp. 355 ◽  
Author(s):  
TJ Hall ◽  
RW Walker
Keyword(s):  
Native Species ◽  
Perennial Grass ◽  
Genetic Material ◽  
Grazing Pressure ◽  
Perennial Grasses ◽  
Wet Season ◽  
Environmental Evaluation ◽  
Seasonally Dry ◽  
Dry Tropics ◽  
Andropogon Gayanus

Adaptation indices for introduced perennial grasses were derived for a site in the seasonally dry tropics of North Queensland to determine the suitability of grasses as a component of sown legume pastures. Grasses are required to replace native species that are intolerant of the heavy grazing pressure imposed on these legume-based pastures. Agronomic, production, morphological, and reproductive data on 143 accessions of 20 perennial grass genera were compared from 1983 to 1987. The grasses were grown in rows in a grazed Seca and Verano stylo pasture. The seed production potential of 40 Digitaria accessions grown in swards under irrigation was also assessed. The stoloniferous species Bothriochloa pertusa, Digitaria milanjiana, D. taatalensis, B. insculpta, and Urochloa mosamhicensis had the highest adaptation indices under continuous grazing. Digitaria accessions with the ability to produce appreciable viable seed were identified. Andropogon gayanus, a tussock species, had the highest yield and most spread in the first 2 years in the absence of wet season grazing. The potential of B. pertusa and D. milanjiana for stabilising legume pastures has been identified, and the need for wet season grazing management of tussock species has been shown. The range of genetic material in D. milanjiana requires further environmental evaluation.

The growth of Urochloa accessions in grazed swards with Stylosanthes near Townsville, north Queensland

1985 ◽  
Vol 25 (1) ◽  
pp. 61 ◽  
Author(s):  
JG McIvor
Keyword(s):  
Perennial Grass ◽  
Grazing Pressure ◽  
First Year ◽  
Wet Season ◽  
Low Level ◽  
Seasonally Dry ◽  
Stylosanthes Hamata ◽  
Annual Grasses ◽  
Tropical Areas ◽  
High Yields

Six Urochloa accessions (U. mosambicensis cv. Nixon, CPI 46876, CPI 47 167 and U. oligotricha CPI45607, CPI47122, CPI 47 124) were grown with Stylosanthes hamata cv. Verano and S. scabra cv. Seca in individually fenced, fertilized swards near Townsville, Queensland, for 5 years. The swards were grazed by single steers for 2 days at 6-weekly intervals (equivalent to a stocking rate of 1 steedha). Two grazing regimes were used: grazing throughout the year (high grazing pressure); and grazing during the dry season only (low grazing pressure). There was good establishment of Verano but Seca and all Urochloa accessions established poorly. In subsequent years there were few U. oligotricha seedlings but there were substantial numbers of U. mosambicensis seedlings. Most seedlings died during their first year and in the final year of the study the number of perennial Urochloa plants ranged from 1 /m2 (CPI 47 122) to 1 7/m2 (CPI 46876). Yield and proportion of Urochloa were low during the first year but later increased for the U. mosambicensis accessions, particularly CPI 46876, which out-yielded all other accessions in the final 3 years. High yields of Urochloa were associated with low yields of Verano and annual grasses. High grazing pressure reduced the total pasture yield. Verano was always a major component, especially at high grazing pressure. The proportion of Seca increased from an initial low level but then declined again to a very low level. There was very little native perennial grass at high grazing pressure. The proportion of grass in the swards was highest at the start of the wet season and then declined; in contrast, the proportion of legume increased during the wet season. The value of Urochloa species in seasonally dry tropical areas and their management in pastures are discussed.

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.

Diet selection by cattle grazing Stylosanthes-grass pastures in the seasonally dry tropics: effect of year, season, stylo species and botanical composition

1996 ◽  
Vol 36 (7) ◽  
pp. 781 ◽  
Author(s):  
DB Coates
Keyword(s):  
Cattle Grazing ◽  
Diet Selection ◽  
Dry Season ◽  
Major Influence ◽  
Botanical Composition ◽  
Wet Season ◽  
Seasonally Dry ◽  
Dietary Preference ◽  
Dry Tropics ◽  
Opportunity For Selection

The dietary preference of cattle grazing Stylosanthes-based pastures in the seasonally dry tropics of North Queensland was studied using faecal carbon ratios (S13C) to determine grass-legume proportions. Estimates were made at monthly intervals for several years in 1 experiment to determine the effect of year, season and botanical composition on dietary stylo proportions. In another experiment, the effect of stylo cultivars (Verano and Seca) on dietary preference was monitored for 17 months. Where pastures provided ample opportunity for selection, cattle showed a strong preference for grass in the early wet season and in the late dry season. The proportion of stylo in the diet increased during the wet season and reached peak proportions (as high as 80%) in the late wet season or early dry season. Dietary stylo proportions decreased as pastures dried off and as the stylo shed leaf or became more stemmy. The length of the wet season and the amount and distribution of rainfall had a major influence on the seasonal pattern of diet selection. Stylo rarely fell below 20% in the diet. On an annual basis, stylo accounted for about 45% of the diet which was appreciably higher than the proportion of stylo in the pasture. Dietary stylo proportions were higher on Seca-based pasture than on Verano-based pasture. The avoidance of stylo in the early wet season was less pronounced with Seca compared with Verano. Later in the season Seca was the dominant dietary component for a much longer period than Verano. The effect of botanical composition on dietary grass-legume proportions varied between and within years. Correlations between grass-legume proportions in the pasture and in the diet were highest in the late dry season and early wet season when preference for grass was strongest. At the end of the wet season when cattle preferred stylo, dietary stylo was not related to pasture stylo content except in a drought year. Averaged over the full year, dietary stylo content was significantly correlated with pasture stylo content in all years and the correlation was highest in a drought year when there was a high level of utilisation and less opportunity for selection. A simple model relating dietary stylo to pasture stylo was developed and is discussed.

The Influence of Recent Grazing Pressure and Landscape Position on Grass Recruitment in a Semi-Arid Woodland of Eastern Australia.

1996 ◽  
Vol 18 (1) ◽  
pp. 3 ◽  
Author(s):  
VJ Anderson ◽  
KC Hodgkinson ◽  
AC Grice
Keyword(s):  
Seedling Emergence ◽  
Perennial Grass ◽  
Soil Surface ◽  
Grazing Pressure ◽  
Perennial Grasses ◽  
Run Off ◽  
Eastern Australia ◽  
Annual Grasses ◽  
History Of ◽  
Semi Arid

This study examined the effects of previous grazing pressure, position in the landscape and apparent seed trapping capability of soil surface micro-sites on recruitment of the perennial grass Monachather paradoxa (mulga oats) in a semi-arid woodland. Seedling emergence was counted on small plots which had been kept moist for one month. The plots were on bare ground, or at grass tussocks, or at log mounds, sited in the run-off, interception and run-on zones of paddocks that had been grazed for six years at 0.3 and 0.8 sheep equivalent/ha. Few naturally occurring perennial grass seedlings emerged on any of the sites. The level of previous grazing pressure influenced the recruitment of grasses from natural sources as well as from seed of M. paradoxa broadcast on the soil surface; significantly more grass seedlings recruited in paddocks stocked at 0.3 than at 0.8 sheep/ha. Emergence of the sown grass did not differ significantly between the three zones in the landscape, but trends in the data suggest the interception zone may have been the most favourable. Recruitment from in situ grass seed was highest in the mulga grove (run-on) zone. Most seedlings of the sown grass emerged around the bases of existing perennial grass tussocks, but recruitment of volunteer perennial and annual grasses was more evenly distributed between the mulga log-mounds and perennial grass tussocks. It is concluded that very low levels of readily germinable seed of perennial grasses remained in the soil at the end of the drought and that areas with a history of high grazing pressure have less probability of grass recruitment when suitable rain occurs.

The economics of temperate pasture systems on the central and southern Tablelands of New South Wales

2001 ◽  
Vol 23 (2) ◽  
pp. 159 ◽  
Author(s):  
D. T. Vere ◽  
R. E. Jones ◽  
M. H. Campbell
Keyword(s):  
Native Species ◽  
Programming Model ◽  
New South ◽  
Perennial Grass ◽  
New South Wales ◽  
Perennial Grasses ◽  
Economic Returns ◽  
High Quality ◽  
South Wales ◽  
The Individual

Pastures are the basis of most forms of agricultural production on the New South Wales central and southern tablelands. Pastures occupy the bulk of the region's landmass and pasture-based livestock production annually contributes more than three-quarters of the regional gross value of rural production. Throughout the region, there is substantial variation in pasture composition, ranging from high quality introduced perennial grasses and legumes to pastures comprising mainly low quality native species. This paper examines the economics of the main categories of temperate pastures over a range of soil fertility-rainfall environments on the south-eastern tablelands areas of New South Wales. Using a linear programming model and discounted development budgets, the results demonstrate the strong influence of the environment on the economics of the individual pasture systems. The highest economic returns in both the short and longer-terms were to the introduced perennial grass pastures in most of the environments. Pastures based on introduced legumes and the high quality native species also generated sound economic returns, although there are recognised problems with the persistence of the legume pastures. Over time, the returns to the better quality native pastures compare favourably with the introduced legumes and are better suited to acidic soils than the perennial grasses. Low quality native species produced relatively poor economic returns in all environments and unfortunately, are the main pasture type in the region's less favourable environments.

Soil respiration in the seasonally dry tropics near Townsville, North-Queensland

Soil Research ◽  
1990 ◽  
Vol 28 (5) ◽  
pp. 737 ◽  
Author(s):  
JA Holt ◽  
MJ Hodgen ◽  
D Lamb
Keyword(s):  
Soil Respiration ◽  
Root Respiration ◽  
Respiratory Activity ◽  
Major Effect ◽  
Wet Season ◽  
Untreated Soil ◽  
Seasonally Dry ◽  
Respiration Rates ◽  
Dry Tropics ◽  
Total Soil Respiration

The contribution of root respiration to total soil respiration has been examined in an Australian tropical semi-arid woodland. Respiration rates were estimated by measuring CO2 released from untreated soil and from soil where roots had been severed and were extensively decomposed. The amount of C released as CO2 by soil respiration was estimated to be 3800 kg ha-1 year-1, and by root respiration to be 1500 kg C ha-l year-1. Soil moisture was found to have a major effect on soil respiration, with temperature being less significant. Consequently, most respiratory activity in the soil was confined to the relatively short wet season, with respiration rates being much lower during the dry season.

Limited impact of irrigation on the phenology of Brachychiton megaphyllus: a deciduous shrub that flowers while leafless during the tropical dry season

2015 ◽  
Vol 31 (5) ◽  
pp. 459-467 ◽  
Author(s):  
Patricia J. Bate ◽  
Donald C. Franklin
Keyword(s):  
Soil Moisture ◽  
Reproductive Activity ◽  
Dry Season ◽  
Reproductive Phenology ◽  
Wet Season ◽  
Canopy Development ◽  
Seasonally Dry ◽  
Dry Tropics ◽  
Tap Root ◽  
Leaf Flush

Abstract:A suite of woody plants inhabiting the seasonally dry tropics flower while leafless during the dry season, raising intriguing questions about the role of moisture limitation in shaping their phenology. Brachychiton megaphyllus is one such species, a shrub of open forests and savannas in northern Australia. We documented leaf and reproductive phenology of 14 shrubs, and irrigated a further 15, to determine if soil moisture affected leafiness and reproductive activity. Brachychiton megaphyllus showed first flower buds shortly after the cessation of wet-season rains, and budded and flowered throughout the dry season. In some plants, leaf flush occurred prior to the first rains. Rates of fruit set and maturity were very low. Irrigation did not significantly influence leaf shoot or subsequent canopy development. Contrary to expectation, irrigation decreased the production of buds and flowers though it had no impact on the production of fruit, a response for which we suggest a number of hypotheses. Phenological responses to irrigation may have been limited because B. megaphyllus responds primarily to cues other than soil moisture and is buffered against seasonal drought by a large tap root. This suggests mechanisms by which flowering while leafless may occur in a range of species.

Changes in the Quantitative Floristics in Some Astrebla Spp. (Mitchell Grass) Communities in South-Western Queensland in Relation to Trends in Seasonal Rainfall

1981 ◽  
Vol 29 (5) ◽  
pp. 533 ◽  
Author(s):  
DM Orr
Keyword(s):  
Relative Abundance ◽  
Perennial Grass ◽  
Grazing Pressure ◽  
Perennial Grasses ◽  
Seasonal Rainfall ◽  
Individual Species ◽  
Botanical Composition ◽  
Basal Cover ◽  
Wide Range ◽  
Annual Grasses

Seasonal changes in the quantitative floristics at a wide range of Astrebla grassland sites in south-western Queensland were monitored between 1972 and 1980 with a wheel point apparatus. Changes in the floristics were measured in terms of both relative abundance and basal cover. A large increase in the relative abundance of perennial grasses, particularly Aristida latifolia, Astrebla spp. and Dichanthium sericeum, occurred between 1972 and 1976. This increase was at the expense of annual grasses and forbs which declined in both relative abundance and number of genera present. The relative abundance of perennial grasses declined between 1978 and 1980 and this was associated with a large increase in the forbs such as Daucus glochidiatus and Plantago spp., particularly at southern sites. The contribution of annual grasses to botanical composition remained low throughout the period. Total basal cover differed between years although these differences were not significant. As perennial grass, particularly Astrebla spp., was the major vegetation component of total basal cover, changes in the latter were associated mainly with changes in the basal cover of Astrebla spp. Changes in the contribution of individual species to total basal cover were related to changes in the relative abundance of those species. Changes in botanical composition in Astrebla grassland may be influenced more by trends in seasonal rainfall than by grazing pressure.

Diet composition of cattle grazing Stylosanthes - grass pastures in the seasonally dry tropics: the effect of phosphorus as fertiliser or supplement

1998 ◽  
Vol 38 (1) ◽  
pp. 7 ◽  
Author(s):  
D. B. Coates ◽  
R. P. Le Feuvre
Keyword(s):  
Diet Composition ◽  
Isotope Analysis ◽  
Cattle Grazing ◽  
Diet Selection ◽  
Wet Season ◽  
Seasonally Dry ◽  
Stylosanthes Hamata ◽  
Dry Tropics ◽  
Extractable P ◽  
Induced Changes

Summary. The effect of phosphorus (P) on diet selection in cattle grazing pastures based on Stylosanthes hamata cv. Verano andS. scabra cv. Seca in the seasonally dry tropics was studied in 3 grazing trials on soils with inherently low P status ( 5 µg/g bicarbonate-extractable P). The contribution of Stylosanthes (stylo) to diets was estimated at regular intervals (approximately monthly) using carbon isotope analysis of faeces. Feeding P supplement increased the proportion of stylo in the diet but the effect was seasonal and variable, being most pronounced during the late wet and early dry seasons when dietary stylo proportions are usually highest. The results indicated that P supplement influenced diet selection through its effect on dietary P status such that cattle with a deficiency of dietary P select a lower proportion of stylo than those with higher P intakes. The effect of fertiliser P on dietary stylo content was also variable. The dominant effect was via fertiliser-induced changes in pasture botanical composition. Higher stylo proportions in the diet of heifers grazing unfertilised pasture compared with those grazing fertilised pasture were associated with increasing stylo dominance in unfertilised pastures as opposed to grass dominance in fertilised pastures. At the same time there was evidence of a fertiliser treatment effect that was consistent with dietary P status influencing diet composition. In the grass-dominant pastures, unsupplemented cattle on low P pasture selected less stylo than those grazing pastures of higher P status due to more frequent fertilising but there was no difference where P supplement was fed. A strong seasonal preference for grass early in the wet season, reinforced by a generally reduced preference for stylo in cattle with diets deficient in P, probably hastened the development of stylo dominance in unfertilised pasture where P supplement was not fed.

Integrating Herbicide Use and Perennial Grass Revegetation to Suppress Weeds in Noncrop Areas

2010 ◽  
Vol 3 (1) ◽  
pp. 81-92 ◽  
Author(s):  
Rob G. Wilson ◽  
Steve B. Orloff ◽  
Donald L. Lancaster ◽  
Donald W. Kirby ◽  
Harry L. Carlson
Keyword(s):  
Weed Control ◽  
Native Species ◽  
Perennial Grass ◽  
Perennial Grasses ◽  
Grass Species ◽  
Grass Cover ◽  
Weed Cover ◽  
Grass Establishment ◽  
Herbicide Use ◽  
The Impact

AbstractNoncropland such as levees, roadsides, field borders, fencerows, and wildlife areas are vulnerable to weed invasion. Many sites have undergone frequent human disturbance, such as manipulation from surrounding land uses, and lack competitive, desirable vegetation. This study addressed the importance of revegetation in an integrated weed management program including revegetation for noncrop areas. The study evaluated 14 cool-season perennial grasses (seven native species and eight introduced species) for their establishment, vigor, and ability to suppress weeds. It also evaluated the impact of herbicides on weed control and grass establishment. Treatments were applied at three noncrop sites in Northeast California that were heavily infested with weeds. Chemical weed control during the year of seeding and the following year was critical for perennial grass establishment. Weed cover was greater than 50% whereas average seeded grass cover was less than 6% in untreated plots at all sites 2 yr after seeding. In contrast, average seeded grass cover at all sites was 22 to 31% 2 yr after seeding for treatments where herbicide use resulted in wide-spectrum weed control and grass safety. Increasing perennial grass cover decreased total weed cover across perennial grass species 1and 2 yr after seeding. Individual grass species' cover differed among sites. Two introduced grasses (tall wheatgrass and crested wheatgrass) and three native grasses (western wheatgrass, bluebunch wheatgrass, and thickspike wheatgrass) showed broad adaptation and had > 20% cover at all sites 2 yr after seeding. In herbicide-treated plots, these grasses reduced total weed cover by 43 to 98% compared to unseeded plots 2 yr after seeding.

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