Techniques for estimating plant basal area and assessing the herbage mass of some native perennial grasses.

1981 ◽  
Vol 3 (1) ◽  
pp. 83 ◽  
Author(s):  
GM Lodge ◽  
JA Taylor ◽  
RDB Whalley
Keyword(s):  
Plant Density ◽  
Unit Area ◽  
Basal Area ◽  
Ground Level ◽  
Field Studies ◽  
Fertilizer Application ◽  
Perennial Grasses ◽  
Individual Species ◽  
Laboratory Studies ◽  
Plant Parts

Techniques for using grid and unmarked transparent perspex overlays to estimate the area of tufted native perennial grasses were investigated in field and laboratory studies. Basal area was overestimated by using an unmarked overlay to trace the periphery of actual or atificial plant bases at ground level; this was caused by the amount of airspace included in the estimate. The compression of hand-held tufts reduced the airspace and improved the estimate of plant basal area. In the laboratory studies, the estimation by eye of filled cells in a transparent grid overlay was accurate over a range of areas from 0.02 to 10.39 cm2, although it required considerable operator training. Changes in herbage mass occur as a result of change in the number of plants per unit area (plant density), the basal area of individual plants or the plant mass per unit of basal area of individual plants. Field studies were undertaken at two sites to collect data on each of these components of herbage mass and to investigate whether or not such information could be used to estimate the herbage mass of individual species in a pasture. The relationship between the mass per unit basal area of certain plant parts would appear to have some potential for use in studies of the seasonal changes in various plant components, such as green leaf and stem. This relationship could be used to examine the response of some species to fertilizer application, grazing and defoliation and hence the process of change in species composition with management. Estimates of the herbage mass per unit area of individual native perennial grasses calculated from plant density, plant basal area and mass per unit of basal area data compared favourably with estimates of total herbage mass of individual species obtained from clipped quadrats. Suggested techniques for collecting data in the field and the time involved in sampling are discussed.

Effects of continuous grazing and seasonal closures on the performance and persistence of some sown temperate perennial grasses, North-West Slopes New South Wales

2002 ◽  
Vol 42 (4) ◽  
pp. 431 ◽  
Author(s):  
G. M. Lodge
Keyword(s):  
Festuca Arundinacea ◽  
Perennial Grass ◽  
Basal Area ◽  
Trifolium Subterraneum ◽  
Perennial Grasses ◽  
Individual Species ◽  
North West ◽  
Basal Cover ◽  
Crown Density ◽  
Plant Frequency

A split-plot experiment was sown at Tamworth in 1992 to examine the effects of continuous sheep grazing and seasonal closures (autumn, spring, spring + autumn, and summer + winter) on the herbage mass, plant frequency and basal cover of 5 perennial grasses, when sown as monocultures or with a perennial (Trifolium repens cv. Haifa) or annual legume (Trifolium subterraneum var. subterraneum cv. Seaton Park). Plant basal area and crown density data were also collected. The perennial grasses were Phalaris aquatica cv. Sirosa, Festuca arundinacea, cv.� Demeter, Lolium perenne cv. Kangaroo Valley, Austrodanthonia richardsonii (syn. Danthonia richardsonii) cv.�Taranna, and A. bipartita (syn. D. linkii) cv. Bunderra. There was no significant effect of legume presence on the herbage mass or persistence of the perennial grasses. The only treatment that had a significant effect (P< 0.05) on either herbage mass, plant frequency or basal cover data was the grazing treatment × perennial grass interaction in each of the years 1993-98, except for herbage mass in December 1993 and basal cover in October 1998. In all of the grazing treatments examined, Kangaroo Valley ryegrass failed to persist after spring 1994; Demeter fescue had failed by spring 1997 and Sirosa phalaris by spring 1998. Six years after sowing the only temperate grass cultivars that were persisting in all grazing treatments were the native perennials, Taranna and Bunderra. Hence, the data represent the entire stand life from sowing to eventual failure for the 3 introduced cultivars. While grazing treatment effects within years for individual species were significant, overall grazing had little effect on the rate of decline in herbage mass and persistence of Kangaroo Valley, Demeter and Sirosa. By 1998, grazing treatment had no significant effect on the herbage mass and basal cover of Taranna and Bunderra, but their plant frequencies were lowest in the spring rest and summer + winter rest treatments.

Grazing management of natureal pastures at Trangie, NSW

1956 ◽  
Vol 7 (4) ◽  
pp. 233 ◽  
Author(s):  
EF Biddiscombe ◽  
RJ Hutchings ◽  
G Edgar ◽  
EG Cuthbertson
Keyword(s):  
Body Weight ◽  
Plant Density ◽  
Basal Area ◽  
Body Weight Loss ◽  
Perennial Grasses ◽  
Growth Stages ◽  
Natural Pasture ◽  
Continuous Grazing ◽  
Average Rainfall ◽  
Fleece Weight

Results of a 5-year grazing experiment on Stipa-Chlaris natural pasture are presented. Treatments were three rates of stocking each tested with continuous grazing, autumn deferment, and spring deferment. These were studied in relation to: (a) body weight and wool production of Merino wethers; (b) available feed; (c) density and basal area of the perennial grasses. Lighter stocking (one sheep/2 ac) showed little superiority in production per animal under the generally favourable rainfall conditions. There was only one interval of acute feed shortage in which heavier stocking (one sheep/ac) caused extreme body-weight loss and lower fleece weight. The spelling treatments gave no advantage over continuous grazing, either to sheep or to pasture. Effect of stocking rate on perennial grasses mainly depended upon the amount of rainfall received during certain growth stages of the species, e.g. the winter vegetative growth of Stipa, and the March-April maturation of Chloris and Digitaria. Generally, lighter stocking was favourable to plant density and basal area in seasons of average or below average rainfall; heavier stocking was best in wet seasons. Probable reasons for these relationships are discussed.

scholarly journals Native Perennial Grasses in Highway Medians: Pre- and Postplant Techniques for Establishment in a Mediterranean Climate

2008 ◽  
Vol 1 (4) ◽  
pp. 368-375
Author(s):  
Stephen L. Young ◽  
Victor P. Claassen
Keyword(s):  
Plant Density ◽  
Perennial Grass ◽  
Field Studies ◽  
Perennial Grasses ◽  
Species Selection ◽  
Grass Species ◽  
Native Plant ◽  
Grass Establishment ◽  
Grass Growth ◽  
Native Perennial Grass

AbstractWithin highway rights-of-way, native perennial grasses provide desirable services to support natural and human constructed ecosystems. However, native perennial grass establishment in annual grass dominated roadsides of semiarid and Mediterranean climates of the western United States requires specific cultural and chemical management treatments to control weeds. In 2004, field studies were conducted in Sacramento Valley, California to determine the effect of herbicide, disc cultivation, and species selection on native perennial grass establishment and annual weed persistence. Perennial grass species mixes common to drier and wetter upland areas in northern California were drill seeded at two sites (I-5 North and I-5 South) that had been burned in 2003 and received weed control (i.e., herbicide, cultivation, mowing) in spring 2004. Herbicides were the most important treatments for native perennial grass establishment and weed reduction. Native perennial grass species persistence was largely unaffected by cultivation or native plant accessions at these sites. Native perennial grass density increased at I-5 North in the second year of growth (2006) resulting in a plant density totaled across all herbicide regimes of 3.9 plants m−1 compared to 2.5 plants m−1 at I-5 South. Vigorous native perennial grass growth in the more fertile and less droughty soils of I-5 North helped to limit annual weeds through competition, which is anticipated to reduce the need for chemical and mechanical control in years following early establishment.

scholarly journals A stand-level multispecies growth model for Appalachian hardwoods

1989 ◽  
Vol 19 (4) ◽  
pp. 405-412 ◽  
Author(s):  
Ernest H. Bowling ◽  
Harold E. Burkhart ◽  
Thomas E. Burk ◽  
Donald E. Beck
Keyword(s):  
Unit Area ◽  
Basal Area ◽  
Species Group ◽  
Arithmetic Mean ◽  
Growth And Yield ◽  
Diameter Distribution ◽  
Individual Species ◽  
Yield Model ◽  
Recovery Method ◽  
Appalachian Hardwoods

A stand-level growth and yield model was developed to predict future diameter at breast height (dbh) distributions of thinned stands of mixed Appalachian hardwoods. The model allows prediction by species group and dbh class. Stand attributes (basal area per unit area, trees per unit area, minimum stand dbh, and arithmetic mean dbh) were projected through time for the whole stand and for individual species groups. Future dbh distributions were obtained using the three-parameter Weibull probability density function and a variation of the parameter recovery method. The recovery method used employed the first two noncentral moments of dbh (arithmetic mean dbh and quadratic mean dbh2) to generate Weibull parameters. Future dbh distributions were generated for the whole stand and every species group but one; the diameter distribution for the remaining species group was obtained by subtraction.

The importance of plant density, plant basal area and plant mass per unit basal area as factors influencing the herbage mass of some native perennial grasses.

1982 ◽  
Vol 4 (2) ◽  
pp. 61 ◽  
Author(s):  
GM Lodge ◽  
AC Gleeson
Keyword(s):  
Plant Density ◽  
Basal Area ◽  
Perennial Grasses ◽  
Green Leaf ◽  
Relative Significance ◽  
Mass Estimate ◽  
Component Field ◽  
The Mean ◽  
The Individual ◽  
Green Stem

Four native perennial grasses, Aristida ramosa R.Br. (wire grass), Bothrioc.llloa macra (Steud) S.T. Blake (red grass), Spovo- bolus elongatus R.Br. (slender rats tail grass) and Stipa variabilis Hughes (corkscrew grass) were collected from 60 randomly allocated quadrats (0.16 m2) in a grazed unfertilized native pasture in November 1979. In each quadrat all plants of each species were counted, harvested individually and their basal areas were estimated. The mass of green leaf, green stem, dead herbage and total herbage of each species was estimated using the mean mass of the individual plants harvested in each of the quadrats. A method for determining the relative importance of the components of this herbage mass viz. plant density, basal area and mass per unit basal area is presented and these values are compared for each species. Plant density contributed significantly fP <0.05) to green leaf, green stem, dead and total herbage mass estimates of A. ramosa and S. elongatus; basal area to all herbage mass estimates of A. ramosa, S. elongatus and S. variabilis; and mass per unit basal area to all herbage mass estimates of A. ramosa and B. macra. The plant basal area of individual plants contributed signifi- cantly more (P <0.05) to the herbage mass estimate of S. vaviabilis and S, elongatus plants than did mass per unit basal area, whereas for B. rnacra mass per unit basal area was the significant (P < 0.05) component. Field procedures for estimating herbage mass and assessing the relative significance of its components are discussed and the extra time taken to collect plant density, plant basal area, and plant mass per unit basal area datais outlined.

Effects of nitrogen and phosphorus fertilizers and gypsum on a Danthonia caespitosa-Stipa variabilis grassland. 1. Response to fertilizer application over four successive years

1978 ◽  
Vol 18 (91) ◽  
pp. 253 ◽  
Author(s):  
GJ Tupper
Keyword(s):  
Summer Rainfall ◽  
Fertilizer Application ◽  
Perennial Grasses ◽  
Annual Rainfall ◽  
Individual Species ◽  
Forage Production ◽  
Nitrogen And Phosphorus ◽  
Eastern Australia ◽  
Phosphorus Fertilizers ◽  
Minimum Requirements

The effect of nitrogen and phosphorus fertilizers and gypsum was assessed over four years on a Danthonia caespitosa-Stipa variabilis grassland, growing on the semi-arid Riverine Plain in south-eastern Australia. Fertilizers were applied annually and gypsum once only. The treatments were combined factorially. Seasonal production of total dry matter and individual species, and nitrogen and phosphorus contents of the plant tops, were measured. Forage production increased in response to the additives in years in which the annual rainfall varied from well below to near average. They accentuated the normal pattern of a spring peak, but also gave lesser increases in production in winter and autumn. Summer production was not measured because of the absence of effective summer rainfall. Nitrogen and phosphorus fertilizers and gypsum all contributed to the increased production, and the combination of the three additives produced the greatest yield. Over all seasons the yield of grassland treated with nitrogen plus phosphorus plus gypsum averaged 250 per cent of the control, or approximately 1500 kg ha-1. The main contributors to increases in yield were D. caespitosa, S. variabilis, annual herbs, and legumes. The perennial grasses were particularly favoured by nitrogen fertilizer whereas the yield of legumes was suppressed. The yield of legumes increased greatly in response to phosphorus fertilizer. With the exception of two species, all plants which increased in yield are acceptable to sheep. Nitrogen and phosphorus contents were above the minimum requirements for domestic herbivores.

The role of plant mass, basal area and density in assessing the herbage mass response to fertility of some native perennial grasses.

1981 ◽  
Vol 3 (1) ◽  
pp. 92 ◽  
Author(s):  
GM Lodge
Keyword(s):  
Field Experiments ◽  
Plant Density ◽  
Basal Area ◽  
Perennial Grasses ◽  
Green Leaf ◽  
Density Data ◽  
Leaf Mass ◽  
Pot Culture

The effects of nitrogen (N) application and differing past fertilizer history on the ,preen leaf mass per plant, plant basal area, green leaf mass per unit of plant basal area and the plant density of some native perennial grasses were investigated in pot culture and field experiments. Data on each of these components of herbage mass were assessed, either individually or in combination with each other, as methods of evaluating the responsiveness of some native perennial grasses to increased fertility. Different mechanisms of increasing plant green leaf mass with applied N (pot culture) and superphosphate (field) were deter- mined in different species and these affected the relationship between green leaf mass anti basal area. Species such as Aristida ramosa and Bothriochloa macra increased their green leaf mass per unit of plant basal area but not their plant basal area. In the glasshouse the application of N significantly (P<0.05) increased the basal area of Chloris truncata, Eragrostis leptostachya, Dichanthium sericeum, Sporoholus elongatus, Danthonia linkii and Stipa variabilis. However, in the field long-term superphosphate application only significantly increased the basal area of C. truncata and D. linkii plants. In the field the mean densities of A. ramosa, D. sericeum and C. truncata plants growing at the unfertilized site were significantly higher than those at the fertilized site and the density of E. leptostachya plants was significantly higher (P<0.01) at the fertilized site. These data indicated that the use of either mass per plant, mass per unit basal area, plant basal area or plant density alone could bias the apparent responsiveness of some species to fertility. To accurately determine the effect of management on the herbage mass of individual native perennial grasses in the field either mass per plant and plant density data, or mass per unit basal area, basal area and plant density data should be combined.

scholarly journals Productivity of common Saint-John's wort (Hypericum perforatum L.) by using transplant reproduction method in the conditions of drip irrigation

2021 ◽  
pp. 153-161
Author(s):  
N. V. Pryvedenyuk ◽  
A. P. Shatkovskyi
Keyword(s):  
Drip Irrigation ◽  
Plant Density ◽  
Unit Area ◽  
Raw Materials ◽  
Fertilizer Application ◽  
First Year ◽  
St John’S Wort ◽  
St John's Wort ◽  
Second Year ◽  
Reproduction Method

The influence of plant nutrition area and mineral fertilizer rates on the productivity of St. John's wort (Hypericum perforatum L.) by using transplant reproduction method in the conditions of drip irrigation was studied. It was proved that the transplant method of cultivation of St. John's wort under drip irrigation is a very effective method of reproduction of this crop. Four variants of  planting density per unit area were studied: 42 thousand plants / ha (cultivation scheme 60x40 cm), 56 thousand plants / ha (60x30 cm), 83 thousand plants / ha (60x20 cm) and 167 thousand plants / ha (60x10 cm). Yield recording of raw materials (air-dry tops) was carried out in the phase of mass flowering. In the first year of vegetation this period was in the first decade of August, in the second year – in the second decade of June. It was found that the increase in the number of planted plants of St. John's wort per 1 ha contributed to the increased plantation productivity. When having a cultivation plant density of 42,000 plants / ha, the yield of dry grass in the first year of vegetation was 3,02 t / ha. Increasing the number of plants to 56 thousand plants / ha provided 3,26 t / ha of raw materials. The highest yield of dried St. John's wort – 3,76 t / ha in the first year of vegetation was obtained in the variant with the largest number of planted plants per unit area - 167 thousand plants / ha. In the second year of vegetation of St. John's wort in the variant with the lowest plant density of 42 thousand plants / ha, the yield was 3,65 t / ha. The most productive plantation of the second year of vegetation was in the variant with a plant density of 83 thousand plants / ha, where the yield of dry raw materials was 3,96 t / ha. A further increase in the number of plants per unit area led to a decrease in crop yields. The influence of four variants of the main application of mineral fertilizers on the productivity of St. John's wort was also studied: N0P0K0 (reference), N60P60K60, N120P120K120 and N180P180K180. It was found that with increasing fertilizer application rate, the yield of dry raw materials increased. The most favorable conditions for growth and development of plants of St. John's wort developed in the variant with the maximum rate of fertilizer application - N180P180K180, where the yield of dry raw materials in the first year was 3,31 t / ha, and in the second year – 4,15 t / ha, which exceeded the reference result (without fertilizers) by 0,61 t / ha and 0,84 t / ha, respectively.

Floristic composition and pasture condition of Aristida/Bothriochloa pastures in central Queensland. II. Soil and pasture condition interactions

2015 ◽  
Vol 37 (2) ◽  
pp. 217
Author(s):  
R. G. Silcock ◽  
T. J. Hall ◽  
P. G. Filet ◽  
A. M. Kelly ◽  
D. Osten ◽  
...  
Keyword(s):  
Soil Type ◽  
Plant Density ◽  
Surface Condition ◽  
Good Condition ◽  
Basal Area ◽  
Ground Cover ◽  
Perennial Grasses ◽  
Tree Cover ◽  
Themeda Triandra ◽  
Heteropogon Contortus

Sustainable management of native pastures requires an understanding of what the bounds of pasture composition, cover and soil surface condition are for healthy pastoral landscapes to persist. A survey of 107 Aristida/Bothriochloa pasture sites in inland central Queensland was conducted. The sites were chosen for their current diversity of tree cover, apparent pasture condition and soil type to assist in setting more objective bounds on condition ‘states’ in such pastures. Assessors’ estimates of pasture condition were strongly correlated with herbage mass (r = 0.57) and projected ground cover (r = 0. 58), and moderately correlated with pasture crown cover (r = 0.35) and tree basal area (r = 0.32). Pasture condition was not correlated with pasture plant density or the frequency of simple guilds of pasture species. The soil type of Aristida/Bothriochloa pasture communities was generally hard-setting, low in cryptogam cover but moderately covered with litter and projected ground cover (30–50%). There was no correlation between projected ground cover of pasture and estimated ground-level cover of plant crowns. Tree basal area was correlated with broad categories of soil type, probably because greater tree clearing has occurred on the more fertile, heavy-textured clay soils. Of the main perennial grasses, some showed strong soil preferences, for example Tripogon loliiformis for hard-setting soils and Dichanthium sericeum for clays. Common species, such as Chrysopogon fallax and Heteropogon contortus, had no strong soil preference. Wiregrasses (Aristida spp.) tended to be uncommon at both ends of the estimated pasture condition scale whereas H. contortus was far more common in pastures in good condition. Sedges (Cyperaceae) were common on all soil types and for all pasture condition ratings. Plants identified as increaser species were Tragus australianus, daisies (Asteraceae) and potentially toxic herbaceous legumes such as Indigofera spp. and Crotalaria spp. Pasture condition could not be reliably predicted based on the abundance of a single species or taxon but there may be scope for using integrated data for four to five ecologically contrasting plants such as Themeda triandra with daisies, T. loliiformis and flannel weeds (Malvaceae).

Land Condition in the Tropical Tallgrass Pasture Lands. 1. Effects on Herbage Production.

1995 ◽  
Vol 17 (1) ◽  
pp. 69 ◽  
Author(s):  
John G. Mcivor ◽  
Andrew J. Ash ◽  
Garry D. Cook
Keyword(s):  
Basal Area ◽  
Nutrient Status ◽  
Condition Index ◽  
Perennial Grasses ◽  
Individual Species ◽  
Growing Seasons ◽  
North East ◽  
Linear Relationships ◽  
Run Off ◽  
Land Condition

A quantitative condition index based on vegetation (botanical composition and basal area of perennial grasses) and soil characteristics (erodibility, nutrient status and availability, partitioning of rainfall into infiltration and run-off) was developed for tropical tallgrass pastures near Charters Towers (north-east Queensland) and Katherine (Northern Territory). Herbage growth and the responses of individual species at 10 sites over two growing seasons were related to the index. At all sites there were significant linear relationships between herbage growth and condition index although the values differed between sites. Annual grasses increased and most perennial grasses decreased as condition declined but Bothriochloa pertusa and Bothriochloa ewartiana were most abundant at intermediate condition levels. The response of Chrysopogon fallax varied widely between sites. The lower herbage production on poor condition sites will result in lower carrying capacity.

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