Bunch spear grass dominance in burnt pastures in South-Eastern Queensland

1957 ◽  
Vol 8 (4) ◽  
pp. 325 ◽  
Author(s):  
NH Shaw
Keyword(s):  
Ground Cover ◽  
Botanical Composition ◽  
Bare Ground ◽  
Heteropogon Contortus ◽  
South Eastern ◽  
Main Effect ◽  
Native Pasture ◽  
Present Distribution

The results are reported of a study of the effect of annual burning, in the absence of grazing, on the botanical composition of a native pasture in south-eastern Queensland. The main effect of burning was to give dominance of Heteropogon contortus (L.) Beauv. ex R. & S. This appeared to be due to three main causes: established plants were resistant to fire; fire favoured the germination of seed; and fire reduced the basal ground cover of other species. The effects on other species and on the proportion of bare ground are reported. The significance of the results in relation to the present distribution of H. contortus-dominant pastures is discussed.

Superphosphate and stocking rate effects on a native pasture oversown with Stylosanthes humilis in central coastal Queensland. 1. Pasture production

1978 ◽  
Vol 18 (95) ◽  
pp. 788 ◽  
Author(s):  
NH Shaw
Keyword(s):  
Soil Phosphorus ◽  
Total Yield ◽  
Botanical Composition ◽  
Stocking Rate ◽  
Pasture Production ◽  
Average Percentage ◽  
Heteropogon Contortus ◽  
Native Pasture ◽  
Nitrogen Concentrations ◽  
Stocking Rates

Changes in the yield, botanical composition and chemical composition of a native pasture (Heteropogon contortus dominant) oversown with S. humilis (T.S.) were measured in a grazing experiment from 1966 to 1973. The 24 treatments were factorial combinations of two sowing methods for T.S. (ground sowing into spaced cultivated strips, or aerial sowing), three levels of molybdenized superphosphate (F0 = nil ; F1 = 125 kg ha-1 annually; F2 = 250 kg ha-1 annually plus an extra 250 kg ha-1 initially) and four stocking rates. Stocking rates were gradually increased during the experiment and for the last three years overlapping ranges were used for the three fertilizer levels; the overall range was then from 0.55 to 1.65 beasts ha 1 T.S. establishment by ground sowing was much more reliable than from aerial sowing, giving twice the average percentage frequency, and this proportion was maintained over years. High fertilizer improved establishment and the best legume stands were in the high fertilizer high stocking rate treatments. Total presentation yield of pasture was increased by fertilizer and reduced by high stocking rates. Over the last two years the means for March, adjusted by regression to the overall average stocking rate of 0.98 beasts ha-1, were 31 20,4020 and 5370 kg ha-1 for F0, F1 and F2 respectively, but these yields were reduced by ca 25 per cent for an increase of 0.5 beasts ha-1. H. contortus remained dominant and its mean contribution to total yield increased from 48 per cent in 1969 to 67 per cent in 1973. This proportion was reduced by 12.8 per cent over the range from 0.55 to 1.65 beasts ha-1, but high fertilizer had the opposite effect so that differences between the extremes low stocked F0 and high stocked F2 were small. The DM percentage yield of T.S. was strongly increased by fertilizer, and, most importantly, also by high stocking rates in the presence of fertilizer. Values for F0 treatments remained below 10 per cent, but in the final year values for F1 and F2 at the highest stocking rates were 36 and 27 per cent, respectively. Despite these large changes in T.S., there was overall stability of botanical composition. Phosphorus and nitrogen concentrations in T.S. and H. contortus were increased by superphosphate but there was an overall decline in potassium concentration. Soil phosphorus levels were greatly increased

Influence of soil type on Heteropogon contortus-Bothriochloa bladhii dominant native pasture in south-eastern Queensland

1988 ◽  
Vol 28 (5) ◽  
pp. 587
Author(s):  
DG Cooksley ◽  
KL Butler ◽  
JH Prinsen ◽  
CJ Paton
Keyword(s):  
Soil Type ◽  
Dry Matter ◽  
Major Effect ◽  
Nutrient Concentrations ◽  
Major Influence ◽  
Root Yield ◽  
Limited Effect ◽  
Heteropogon Contortus ◽  
South Eastern ◽  
Native Pasture

The effects of soil type on presentation dry matter yields and nutrient concentrations of a native pasture in south-eastern Queensland were investigated within a 160 ha area over 5 years. The soil types ranged from a shallow sand (Ug 2.12; Northcote 1971 classification) to deep self-mulching clays (Ug 5.15). Soil type had a major influence on above-ground yield (range 2700-8700 kg/ha), but a limited influence on root yield at 15 cm (range 3200-3800 kg/ha) and on nutrient concentrations of above-ground matter and of roots, (ranges for tops and roots: nitrogen 0.51-0.63 and 0.83-1.22%, phosphorus 0.09-0.14 and 0.08-0.10%, potassium 0.40-056 and 0.23-0.46%, and sulfur 0.05 and 0.05-0.06%). This suggests that soil type has only a limited effect on the liveweight gains per animal which can be attained on native pasture, but a major effect on sustainable stocking rate.

scholarly journals 115 Nitrogen fertilizer effects on above ground sward characteristics and beef heifer performance from native warm-season grass blends

2020 ◽  
Vol 98 (Supplement_2) ◽  
pp. 26-27
Author(s):  
Caroline Chappell ◽  
Landon Marks ◽  
Katie Mason ◽  
Mary K Mullenix ◽  
Sandra L Dillard ◽  
...  
Keyword(s):  
Nutritive Value ◽  
Warm Season ◽  
Ground Cover ◽  
Application Rate ◽  
Light Interception ◽  
Botanical Composition ◽  
Forage Production ◽  
Beef Heifers ◽  
Fertilizer Application Rate ◽  
Canopy Light Interception

Abstract A 2-yr study was conducted at Black Belt Research and Extension Center in Marion Junction, AL, to evaluate the effect of nitrogen (N) fertilizer application rate on forage production characteristics, nutritive value, and animal performance of beef heifers grazing a mixture of native warm-season grasses (NWSG) including big bluestem, little bluestem, and indiangrass. Six, two-hectare plots were randomly assigned to one of two treatments (0 or 67 kg N ha-1 applied in early April; n = 3 replications per treatment). Paddocks were continuously stocked with four weaned Angus × Simmental beef heifers (initial BW 288 ± 7 kg) from late May/early June through mid-to-late August during 2018 (73 grazing d) and 2019 (70 grazing d), respectively. Put-and-take cattle were used to manage forage to a target of 38 cm. Forage mass and canopy heights were collected every two weeks during the trial. Visual ground cover ratings, canopy light interception, and botanical composition were measured at the beginning and end of the trial in each year. Hand-plucked samples were collected every two weeks during the grazing trial to determine forage nutritional value. Data were analyzed using the PROC MIXED procedure in SAS 9.4, and differences were declared significant when P ≤ 0.05. Nitrogen fertilized NWSG had greater crude protein (P < 0.0001), sward heights (P = 0.0003), and canopy light interception at the beginning of the season (P = 0.0049) compared to non-fertilized paddocks. However, there were no differences (P ≥ 0.05) among N-fertility treatments for mean forage mass, heifer ADG, or BCS across the 2-yr study. Botanical composition data indicated that indiangrass decreased from 64% to 61% (P = 0.0022) and weed pressure increased from 11% to 15% (P = 0.0064) across the summer grazing season. Canopy light interception decreased by 51% from early June to August in fertilized NWSG and 26% in unfertilized paddocks, respectively. These data illustrate that NWSG systems may provide a viable grazing system in the summer months under reduced N inputs.

Beef production from native pastures sown to fine-stem stylo in the Burnett region of south-eastern Queensland

1979 ◽  
Vol 19 (97) ◽  
pp. 140 ◽  
Author(s):  
EJ Bowen ◽  
KG Rickert
Keyword(s):  
Stocking Rate ◽  
Management Options ◽  
North West ◽  
Heteropogon Contortus ◽  
South Eastern ◽  
Continuous Grazing ◽  
Weight Gains ◽  
The Mean ◽  
Native Pastures ◽  
Stocking Rates

At Gayndah, south-eastern Queensland, a native Heteropogon contortus pasture, sown to fine-stem stylo (Stylosanthes guianensis var. intermedia), and invaded by red natal grass (Rhynchelytrum repens), was grazed by weaner steers from June 1 in three treatments : heavy and light put-and-take grazing for five years from 1971, and set-stocked at 1.37 animals ha-1 for two years from 1974. Weight gains in the put-and-take treatments were not significantly different. The mean annual liveweight gain was 167 kg animal-1 at a mean equivalent stocking rate of 1.47 animals ha-1. Over the same period unsown native pasture, cleared of timber, gave a gain of 62 kg animal-1 at 0.62 animals ha-1. In all seasons except summer, weight gains declined linearly with stocking rate and in 1972-73, with a mean equivalent stocking rate of 2.66 animals ha-1, the annual gain was almost halved. When equivalent stocking rates were 0.9, 0.9, 1.8 and 1.2 animals ha-1 in winter, spring, summer and autumn, the respective gains were 4, 73, 65 and 45 kg animal-1. The set-stocked treatment had a mean annual gain of 147 kg animal-1. At another site 116 km north-west of Gayndah, two paddocks of Heteropogon contortus and fine-stem stylo were set-stocked with weaners over four years. One paddock had four applications of superphosphate of 250 kg ha-1. The mean annual liveweight gains were significantly different, being 154 and 143 kg animal-1 in the fertilized and unfertilized paddocks at mean stocking rates of 0.83 and 0.74 animals ha-1, respectively. In a grazing protection experiment the density of fine-stem stylo declined exponentially with an accumulation of pasture dry matter in spring and summer. Heavy continuous grazing, an annual hay cut and an accidental fire all increased the density of fine-stem stylo. Management options to maintain the density of fine-stem stylo and the relative importance of the legume and grass to animal production are discussed.

scholarly journals Urban inland wintertime N<sub>2</sub>O<sub>5</sub> and ClNO<sub>2</sub> influenced by snow-covered ground, air turbulence, and precipitation

2021 ◽  
Author(s):  
Kathryn D. Kulju ◽  
Stephen M. McNamara ◽  
Qianjie Chen ◽  
Jacinta Edebeli ◽  
Jose D. Fuentes ◽  
...  
Keyword(s):  
Ground Cover ◽  
Atmospheric Particulate Matter ◽  
Ionization Mass ◽  
Bare Ground ◽  
Near Surface ◽  
Dinitrogen Pentoxide ◽  
Nitryl Chloride ◽  
Air Turbulence ◽  
Chlorine Radicals ◽  
Wet Scavenging

Abstract. The atmospheric multiphase reaction of dinitrogen pentoxide (N2O5) with chloride-containing aerosol particles produces nitryl chloride (ClNO2), which has been observed across the globe. The photolysis of ClNO2 produces chlorine radicals and nitrogen dioxide (NO2), which alter pollutant fates and air quality. However, the effects of local meteorology on near-surface ClNO2 production are not yet well understood, as most observational and modeling studies focus on periods of clear conditions. During a field campaign in Kalamazoo, Michigan from January–February 2018, N2O5 and ClNO2 were measured using chemical ionization mass spectrometry, with simultaneous measurements of atmospheric particulate matter and meteorological parameters. We examine the impacts of atmospheric turbulence, precipitation (snow, rain) and fog, and ground cover (snow-covered and bare ground) on the abundances of ClNO2 and N2O5. N2O5 mole ratios were lowest during periods of lower turbulence and were not statistically significantly different between snow-covered and bare ground. In contrast, ClNO2 mole ratios were highest, on average, over snow-covered ground, due to saline snowpack ClNO2 production. Both N2O5 and ClNO2 mole ratios were lowest, on average, during rainfall and fog because of scavenging, with N2O5 scavenging by fog droplets likely contributing to observed increased particulate nitrate concentrations. These observations, specifically those during active precipitation and with snow-covered ground, highlight important processes, including N2O5 and ClNO2 wet scavenging, fog nitrate production, and snowpack ClNO2 production, that govern the variability in observed atmospheric chlorine and nitrogen chemistry and are missed when considering only clear conditions.

scholarly journals Effects of cover crops on beetle assemblages in tea plantations

2021 ◽  
Author(s):  
Li-Lin Chen ◽  
Gabor Pozsgai ◽  
Xiang-Yu Li ◽  
Lei Li ◽  
Gadi V.P. Reddy ◽  
...  
Keyword(s):  
Species Richness ◽  
Pest Management ◽  
Cover Crops ◽  
Ground Cover ◽  
Paspalum Notatum ◽  
Bare Ground ◽  
Tea Plantations ◽  
Beetle Assemblages ◽  
Potential Benefits ◽  
Species Richness And Abundance

AbstractBeetles are visible members of food webs in tea plantations, with high species richness and abundance. Many tea pests, as well as natural enemies, are members of this order, so a knowledge of how groundcovers affect beetles can aid pest management. We collected beetles in a replicated field experiment in the Wuyi Mountains, Fujian Province China. Tea was intercropped with Paspalum notatum or Chamaecrista rotundifolia, or rows were cleared to bare ground, or in the control they were left unmanaged to allow weeds to grow naturally. Sampling, done by sweep netting and vegetation beating, was conducted monthly, between May 2006 and April 2008, and Coleoptera abundance, biomass, species richness and assemblage structures were compared between groundcover treatments. Total beetle abundance and species richness were significantly higher in tea intercropped with C. rotundifolia and bare ground than in naturally grown weedy control. Whilst there was no difference between predator assemblages among treatments for any measure, herbivores were more abundant, weighed more, and were more diverse in C. rotundifolia treatments than in weedy control. Biomass and species richness were also greater in plots with P. notatum groundcover than those in weedy control. We found that beetle assemblages varied both seasonally and with ground cover treatment, but the potential pest control impact of more species-rich beetle assemblages was mixed, and further work is needed to gain information on trophic groups with potential benefits for use in non-insecticidal pest management.

Superphosphate and stocking rate effects on a native pasture oversown with Stylosanthes humilis in central coastal Queensland. 3. The balance of native species in the pasture

1978 ◽  
Vol 18 (95) ◽  
pp. 808 ◽  
Author(s):  
NH Shaw ◽  
MB Dale
Keyword(s):  
Native Species ◽  
Floristic Composition ◽  
Exchange Capacity ◽  
Response To Treatment ◽  
Data Sets ◽  
Heteropogon Contortus ◽  
Native Pasture ◽  
Total Exchange Capacity ◽  
Highly Correlated ◽  
Stocking Rates

The percentage frequency of all herbaceous species in a native pasture oversown with S. humilis (T.S.) was measured at the beginning and end of an eight-year grazing experiment. Treatments imposed were three levels of molybdenized superphosphate (nil; 125 kg ha-1 annually; 250 kg ha-1 annually plus an extra 250 kg ha-1 initially) in factorial combination with four stocking rates and two sowing methods for T.S. (ground sowing into spaced cultivated strips or aerial sowing). Stocking rates were gradually increased during the experiment and for the last three years overlapping ranges were used for the three fertilizer levels; the overall range was then from 0.55 to 1.65 beast ha-1. Treatments did not induce any major changes in the proportions of native species in the pasture. Heteropogon contortus remained dominant and its frequency increased in all treatments. Of the total of 113 species recorded, only 18 reached 10 per cent frequency in at least one paddock on one occasion. Several of these showed statistically significant changes in response to treatment, but their relative importance was not greatly changed. Examination of the results by principal co-ordinate and canonical analysis, showed that the first vectors of the two data sets were highly correlated, indicating that the major control on floristic composition was not changed by oversowing with T.S. or by the treatments imposed. Treatment effects dominated in the second and third vectors in the final year. The controlling vector was found to be highly correlated with soil calcium, potassium, total exchange capacity and organic carbon, but the basis for the correlations remains undetermined.

Demographic features and habitat preferences of southern pygmy mice (Baiomys musculus) in Colima, Mexico

2008 ◽  
Vol 86 (6) ◽  
pp. 507-524 ◽  
Author(s):  
Gary D. Schnell ◽  
Cassie J. Poindexter ◽  
Cornelio Sánchez-Hernández ◽  
María de Lourdes Romero-Almaraz ◽  
Michael L. Kennedy ◽  
...  
Keyword(s):  
Logistic Regression ◽  
Small Mammals ◽  
Woody Plants ◽  
Environmental Variables ◽  
Dead Wood ◽  
Habitat Preferences ◽  
Ground Cover ◽  
Bare Ground ◽  
Open Canopy ◽  
Demographic Features

In Colima, Mexico, we conducted 8-night mark–recapture grid studies of southern pygmy mice ( Baiomys musculus (Merriam, 1892)) in January 2003–2007 in dry deciduous and tropical moist forests. For 40 000 trap-nights, 436 individuals were captured 764 times (comprising 18.6% of small mammals). The male:female ratio was 1:1.37, 82.9% were adults, 51.4% of females were pregnant or lactating, and coastal animals, on average, were heavier than those inland. Females moved farther than males. Baiomys was on 17 of 25 grids (densities 1.82–106.24 individuals/ha). Moon illumination did not affect capture or recapture probabilities, but trap-night did (overall, probability increased 1.66%/night). Grids with Baiomys had less bare ground and a more open canopy. Capture sites had more grass, less dead wood and bare ground, a more open and lower canopy, and greater distance to trees. Logistic regression indicated coastal capture sites had more forbs, grasses, and woody plants, and thicker vegetation at 1 m height with trees being relatively distant. Variables differed somewhat for northern sites, and the equation for all grids included 10 of 14 environmental variables. Baiomys frequented edge of an unimproved road traversing one grid. Baiomys musculus, widespread in Colima, exhibited preference for habitats with relatively dense ground cover and at least a partially open canopy.

Soil temperatures and seed burial in relation to the performance of Heteropogon contortus and Themeda australis in burnt native woodland pastures in Eastern Queensland

1969 ◽  
Vol 17 (2) ◽  
pp. 269 ◽  
Author(s):  
JC Tothill
Keyword(s):  
Ground Cover ◽  
Ground Level ◽  
Maximum Temperature ◽  
Seed Burial ◽  
Ambient Temperatures ◽  
Seasonally Dry ◽  
Heteropogon Contortus ◽  
Average Maximum ◽  
Soil Temperatures ◽  
Native Pastures

The factors underlying the increasing dominance of Heteropogon contortus (bunch or black spear grass) as a result of regularly burning native pastures in eastern Queensland have been investigated. In the subtropical environment of this experiment the removal of ground cover by burning or other means significantly increased the average maximum temperature of the surface soil. Burning favoured the germination of buried H. contortus seed at a time when ambient temperatures were too low for this to occur in unburnt situations. In late seasons and in the seasonally dry tropics insufficient soil moisture would tend to limit growth and germination until ambient temperatures are high, in which case the burning effect would be less pronounced. The efficient seed burial mechanism of H. contortus places it at an establishment advantage over other commonly associated species such as blue grasses (Bothriochloa, Dichanthium) and others whose seeds remain largely in the surface litter. Fire destroys much of this litter, the microhabitat for seed germination at ground level, and some of the weaker perennial plants. The implications of these results in relation to the increased dominance of either H. contortus or Themeda australis (kangaroo grass) are discussed.

Steer gains, pasture yield and pasture composition on native pasture and on native pasture oversown with Indian couch (Bothriochloa pertusa) at three stocking rates

1997 ◽  
Vol 37 (7) ◽  
pp. 755 ◽  
Author(s):  
R. J. Jones
Keyword(s):  
Perennial Grasses ◽  
Grass Species ◽  
Stocking Rate ◽  
Pasture Grass ◽  
Pasture Production ◽  
Heteropogon Contortus ◽  
Native Pasture ◽  
Unit Increase ◽  
Stocking Rates ◽  
Pasture Yield

Summary. Pasture production and steer liveweight gain were compared on native pasture (Bothriochloa decipiens, Heteropogon contortus, Themeda triandra and Chrysopogon fallax) and on native pasture oversown with Indian couch or Indian bluegrass (Bothriochloa pertusa). This grass was not a planned introduction to the area but is spreading in Central and North Queensland and its value as a pasture species is questioned by graziers. There were 3 nominal stocking rates of 0.3, 0.6 and 0.9 steers/ha. Each paddock was stocked with 3 steers of stratified ages. The experiment was sown in March 1988 and terminated in June 1993. The experiment, sited 50 km south of Townsville in eucalypt woodland on a solodic-solodised-solonetz soil, was sown in March 1988 and terminated in June 1993. Increases in stocking rate resulted in a linear decline in both pasture yield (by 3–5 t/unit increase in stocking rate) and steer gains (by more than 100 kg/unit increase in stocking rate). Differences between pastures were apparent only at the medium and high stocking rates where, over time, Indian couch gave higher pasture yields and steer gains. Younger steers gained far more weight than older steers. Mean gains over 3 years were weaners 125 kg/year, yearlings 93 kg/year and 2-year-old steers 46 kg/year. Native pasture remained fairly stable botanically at the low stocking rate, but the tufted perennial grass species declined at both the medium and high stocking rates. Sowing Indian couch hastened the botanical changes due to stocking rate, and it became the dominant species at these higher stocking rates. At the low stocking rate, the contribution of Indian couch declined from initial values indicating that this is not an invasive species in the area at a low stocking rate. Contribution of Indian couch to pasture yield was linearly related to stocking rate. Nutritional quality of the Indian couch was similar to the other native perennial grasses though calcium concentration was higher. Increased steer gains were related to higher yield on Indian couch pastures at the higher stocking rates rather than to improved quality. Maximum liveweight gain/ha was achieved at about 0.6 steers/ha. Stocking at 0.9 steers/ha was not sustainable. Even at the low stocking rate, steers would need to spend about 2.8 years on the pastures after weaning to reach 500 kg liveweight. It was concluded that B. pertusa is a useful pasture grass in this environment giving steer gains equal to, or higher than, the gains from the native pasture which it replaced.

Sign in / Sign up

Export Citation Format

Share Document