Studies of Central Australian Semidesert Rangelands. I. Range Condition and the Biomass Dynamics of the Herbage Layer and Litter.

1981 ◽  
Vol 29 (2) ◽  
pp. 219 ◽  
Author(s):  
MH Friedel
Keyword(s):  
Botanical Composition ◽  
Production Rates ◽  
Decomposition Rates ◽  
Litter Biomass ◽  
Range Condition ◽  
Standing Biomass ◽  
Average Rainfall ◽  
Biomass Dynamics ◽  
Condition Assessments ◽  
Herbage Layer

Following a sequence of years of above-average rainfall, standing biomass, rates of production and quantities of litter were high in the ground storey of three central Australian rangeland plant communities. Standing biomass was of the order of 4000 kg ha-1 in Astrebla grasslands, 2600 kg ha-1 in open woodlands and 1300 kg ha-1 in Acacia shrublands, and litter biomass was c. 1300 kg ha-1, 1600 kg ha-1 and 4000 kg ha-1 respectively. Levels of biomass and production rates were comparable with those of some semiarid and temperate sown pastures in average seasons, but they appeared to have reached their natural limit. Total standing biomass, production rates, species diversity, litter biomass and decomposition rates were not correlated with range condition assessments of the experimental sites. Species frequency was the only characteristic measured which was related to range condition other than botanical composition, the basis of site selection.

Studies of Central Australian Semidesert Rangelands. II. Range Condition and the Nutrient Dynamics of the Herbage Layer, Litter and Soil.

1981 ◽  
Vol 29 (2) ◽  
pp. 233 ◽  
Author(s):  
MH Friedel
Keyword(s):  
Plant Communities ◽  
Arid Regions ◽  
Nutrient Dynamics ◽  
Plant Parts ◽  
Range Condition ◽  
Positive Correlations ◽  
Nitrogen Phosphorus ◽  
Herbage Layer ◽  
Phosphorus Levels ◽  
Different Soils

The levels and turnover of nitrogen, phosphorus and sulfur in the herbage layer: litter and soil of three central Australian plant communities were investigated, following several years of above-average rainfall, and the possibility of a relationship between nutrient levels and range condition assessment was examined. There were only a few positive correlations between range condition and phosphorus levels, and they were not associated with the susceptibility of different soils to erosional losses. There were no positive correlations between range condition and the levels of either nitrogen or sulfur. The herbage and litter layers together, of the three plant communities, contained 30-72 kg ha-1 of total nitrogen, 4 kg ha-1 of total phosphorus and 4-7 kg ha-1 of total sulfur. These quantities were comparable to those of arid regions in other parts of the world, but the levels of nitrogen, phosphorus and sulfur in soils, estimated by incubation or extraction to be available to plants, were comparatively low. Incubated nitrogen in the 0-10 cm depth of soils was 9-14 ppm and extractable phosphorus was 3-1 1 ppm. The 0-4 cm depth of soil contained 0.5-3 ppm extractable sulfur, and concentrations decreased with depth. Total soil nitrogen was lower than that in other arid regions whereas the amount of organic carbon in soil was comparable, so that C:N was relatively high. Substantial withdrawal of nutrients from senescing plant parts and rapid cycling of nutrients through litter appeared to be responsible for maintaining the level of nutrients in the herbage layer.

Rangeland condition in relation to environmental variables, grazing intensity and livestock owners' perceptions in semi-arid rangeland in western Iran

2010 ◽  
Vol 32 (4) ◽  
pp. 367 ◽  
Author(s):  
M. Faramarzi ◽  
S. Kesting ◽  
J. Isselstein ◽  
N. Wrage
Keyword(s):  
Environmental Variables ◽  
Management Practices ◽  
Grazing Intensity ◽  
Bare Soil ◽  
Grazing Pressure ◽  
Botanical Composition ◽  
Western Iran ◽  
Range Condition ◽  
Rangeland Condition ◽  
Semi Arid

Rangeland condition has often been assessed in relation to either botanical, edaphic, environmental or management factors. In this investigation, we analysed the interaction of soil and topographic variables, management and range condition against the background of a sociological survey of livestock owners in western Iran to better understand the main influencing factors of rangeland quality in the area. In four grazing areas in Kermanshah differing in grazing pressure, environmental variables and livestock owners’ perceptions on range condition, investigations of botanical composition, soil and topographic variables were carried out on 43 main plots. To evaluate range condition, four factors were considered, namely litter frequency, herbage palatability, amount of biomass, and percentage of bare soil. A questionnaire was used to obtain information about management practices, the perception of livestock owners on range condition and suggested solutions to problems in the different grazing areas. The range condition scores showed that the condition of the sites was either fair or poor. Of the soil and topographic factors, only north-facing aspect explained part of the variation in range condition scores. High grazing intensity was associated with poor range condition. To improve the rangeland condition, measures influencing water availability and a reduction of grazing pressure seem to be more relevant in the study area than fertilisation or seeding.

The response to season, exclosure, and distance from water of three central Australian pasture types grazed by cattle.

1982 ◽  
Vol 4 (1) ◽  
pp. 5 ◽  
Author(s):  
BD Foran ◽  
G Bastin ◽  
E Remenga ◽  
KW Hyde
Keyword(s):  
Beef Cattle ◽  
Plant Species ◽  
Dry Matter ◽  
Plant Density ◽  
Matter Production ◽  
Drought Conditions ◽  
Average Rainfall ◽  
Species Groups ◽  
Experimental Treatments ◽  
Herbage Layer

Three central Australian pasture types grazed by beef cattle were exdosed for eleven years, and detailed plant measure- ments made over the last seven years. The exclosed land extended out 3.2 km from permanent watering points. Rainfall during this period (1968-1979) varied from well above average for three years to near drought conditions. The series of above average rainfall years had a @eater influence on yield, density and cover of the herbage layer than the experimental treatments of exclosure and distance from water. Dry matter production varied from 217 kg ha-1 to 2377 kg ha-1. Overall, plant density and cover were generally not affected by treatments, although some plant species and species groups were affected. Grazing should continue at present stocking levels and under similar management on the studied landscapes, as no dele terious effects have been found during the study period.

The dynamics of a Mitchell grass (Astrebla spp.) rangeland on the Barkly Tableland, Northern Territory.

1984 ◽  
Vol 6 (2) ◽  
pp. 92 ◽  
Author(s):  
BD Foran ◽  
G Bastin
Keyword(s):  
Water Treatment ◽  
Northern Territory ◽  
Seasonal Effect ◽  
Basal Cover ◽  
Standing Biomass ◽  
Average Rainfall ◽  
Total Plant

The response of an area of Astrebla grassland at Helen Springs Station on the Barkly Tableland to the treatments of exclosure and distance from water were studied from 1974 to 1979. The seasonal effect produced by a number of above average rainfall years was greater than the effects of exclosure and distance from water. The total standing biomass varied from 940 kg hdl in 1974 to 2258 kg ha-' in 1979. Both Aristida latifolia and Astrebla pectinata increased in standing biomass and basal cover while the annual Iseilema vaginiflorunz decreased. Apparent responses of some species to the distance from water treatment were explained by local vegetation patterning within a seemingly uniform grassland. Regression relationships were developed that related basal cover to both species and total plant standing biomass.

Formation of botanical composition of clover cereal and alfalfa cereal crops agrophytocenoses depending on sowing method

2020 ◽  
pp. 160-168
Author(s):  
I. Senyk
Keyword(s):  
Festuca Arundinacea ◽  
Global Climate ◽  
Phleum Pratense ◽  
Grass Species ◽  
Cereal Crops ◽  
Forest Steppe ◽  
Botanical Composition ◽  
Cross Sectional ◽  
Row Crops ◽  
Adverse Weather

Botanical composition of grasses is one of the most important indicators the biological value and quality of the obtained hay and pasture forage, the longevity of hayfi elds and pastures depend on. The issue of changing the botanical composition of agrophytocenoses is especially important in the context of global climate change, which in recent decades is also manifested in the territory of Ukraine, as it is possible to establish the most adapted species of legumes and cereals to adverse weather conditions and to identify eff ective technological methods of managing these processes for maximum conservation economically valuable species in the herbage. The purpose of the research is to establish the infl uence of diff erent ways of sowing of clover and alfalfa cereal crops agrophytocenoses on the formation of their botanical composition. Field studies have established diff erent eff ects of conventional in-line, cross-section and cross-sectional methods of sowing on the formation of botanical composition of grass mixtures of clover meadow (Trifolium pratense) varieties Sparta and Pavlyna with timothy meadow (Phleum pratense) and fenugreek multifl oral (Lolium multifl orum) and of agrophytocenoses of alfalfa of Sinyukha and Seraphima sowing varieties with reed fire (Festuca arundinacea Schreb) and middle wheatgrass (Elytrigia intermedia). For the average of four years of life of clover and alfalfa cereal crops agrophytocenoses, the highest proportion of legume component was observed with split-cross sowing – 51.6 % for Sparta, 53.1 % for Pavlyna, 60.3 % for Seraphima and 61.6 % for the Sinyukha variety. In the fourth year of life (the third year of use) of sowed leguminous-cereals agrophytocenoses, the preservation of the legume component was 14.6–15.5 % in clover-cereals grass mixtures with the Sparta variety and 16.0–16.8 % with the Pavlyna variety. In alfalfa grasslands, these indicators were 54.0–55.1 % with Seraphim and 55.0–56.2 % with Sinyukha. Among the studied varieties of clover meadow and alfalfa sowing proved better in the conditions of the Forest Steppe of western Pavlyna and Sinyukha. Cross-sectional and divided cross-sectional sowing of legumes and cereals mixtures proved to be better compared to conventional row crops in terms of conservation of economically valuable grass species. Key words: agrophytocenosis, botanical composition, clover meadow, alfalfa sowing, sowing methods.

VARIATION OF CORTISOL METABOLISM AS A CONTRIBUTING FACTOR TO DISCREPANCIES IN THE MEASUREMENT OF CORTISOL PRODUCTION RATE

1972 ◽  
Vol 70 (1) ◽  
pp. 89-96 ◽  
Author(s):  
M. J. Levell
Keyword(s):  
Production Rate ◽  
Isotope Dilution ◽  
Normal Subjects ◽  
Contributory Factor ◽  
Morning Dose ◽  
Production Rates ◽  
Evening Dose ◽  
Cortisol Metabolism

ABSTRACT Five normal subjects were given [14C] cortisol in the morning and [3H] cortisol in the evening, in both cases by mouth. The excretion of radioactivity in tetrahydrocortisol (THF) and tetrahydrocortisone (THE) was measured by a modified form of reverse isotope dilution. In 2 subjects, the ratio of isotopic THF/isotopic THE was higher after the evening dose than after the morning dose. In 1 subject the ratio decreased. In 2 subjects it did not change. Cortisol production rates calculated from THF were usually higher than those calculated from THE. The observed variations of metabolism were only a contributory factor to these discrepancies.

Plant diversity and species richness of Ljubljana marsh grasslands under the influence of different cutting and fertilizing regimes

2009 ◽  
Vol 57 (2) ◽  
pp. 197-203 ◽  
Author(s):  
T. Sinkovč
Keyword(s):  
Species Richness ◽  
Plant Diversity ◽  
Grassland Management ◽  
Botanical Composition ◽  
Significant Negative Effect ◽  
Negative Effect ◽  
Cutting Regimes ◽  
N Rates ◽  
Exploitation Intensity ◽  
Plot Design

The botanical composition of grasslands determines the agronomic and natural values of swards. Good grassland management usually improves herbage value, but on the other hand it frequently decreases the plant diversity and species richness in the swards. In 1999 a field trial in a split-plot design with four replicates was therefore established on the Arrhenatherion type of vegetation in Ljubljana marsh meadows in order to investigate this relationship. Cutting regimes (2 cuts — with normal and delayed first cut, 3 cuts and 4 cuts per year) were allocated to the main plots and fertiliser treatments (zero fertiliser — control, PK and NPK with 2 or 3 N rates) were allocated to the sub-plots. The results at the 1 st cutting in the 5 th trial year were as follows: Fertilising either with PK or NPK had no significant negative effect on plant diversity in any of the cutting regimes. In most treatments the plant number even increased slightly compared to the control. On average, 20 species were listed on both unfertilised and fertilised swards. At this low to moderate level of exploitation intensity, the increased number of cuts had no significant negative effect on plant diversity either (19 species at 2 cuts vs. 20 species at 3 or 4 cuts). PK fertilisation increased the proportion of legumes in the herbage in the case of 2 or 3 cuts. The proportion of grasses in the herbage increased in all the fertilisation treatments with an increased numbers of cuts. Fertiliser treatment considerably reduced the proportion of marsh horsetail ( Equisetum palustre ) in the herbage of the meadows. This effect was even more pronounced at higher cut numbers. The proportion of Equisetum palustre in the herbage was the highest in the unfertilised sward with 2 cuts (26.4 %) and the lowest in the NPK-fertilised sward with 4 cuts (1.4%).

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