Seedling recruitment of native perennial grasses within existing swards

2011 ◽  
Vol 62 (7) ◽  
pp. 591 ◽  
Author(s):  
R. Thapa ◽  
D. R. Kemp ◽  
D. L. Michalk ◽  
W. B. Badgery ◽  
A. T. Simmons
Keyword(s):  
Plant Material ◽  
Field Experiments ◽  
Seedling Recruitment ◽  
Plant Cover ◽  
Perennial Grass ◽  
Soil Surface ◽  
Soil Disturbance ◽  
Perennial Grasses ◽  
Control Treatment ◽  
Bare Ground

Two field experiments, one each on Austrodanthonia spp. and Bothriochloa macra, investigated the effects of biomass manipulation, seed level modification, site preparation and pasture composition on the recruitment of native perennial grass seedlings. The experiments coincided with drier than average years and although successful emergence of seedlings occurred, survival was extremely low. In the Austrodanthonia experiment, control treatments resulted in the emergence of only 1 seedling/m2, whereas there were 130/m2 in the best treatment which had biomass cut with plant material removed, seed added, and the soil surface scarified. Insecticide treatments increased emergence as seed-harvesting ants are common in these systems, but the benefits were small. Similarly, B. macra had no emergence in the control treatment compared with 73 seedlings/m2 in the best treatment, which was pasture cropped, and had seed added and herbicide applied. Availability of microsites may be a major constraint to B. macra emergence, as soil disturbance through pasture cropping substantially increased seedling numbers (279/m2). The effects of herbicide on emergence were small with the largest being related to bare ground and litter biomass. Austrodanthonia seedling numbers at emergence were related to bare ground, litter and green biomass. Survival of young Austrodanthonia plants 24 weeks after emergence was negatively related to plant cover, but only in treatments where plant material was cut and removed. The success of survival was determined at 52 weeks after emergence and the number of young plants that survived in both experiments seemed to have been influenced by the presence of competitive biomass of existing plants.

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 Improving soil properties and productivity of crop-pasture rotation in arid steppe of the Southern Urals

2021 ◽  
Vol 36 ◽  
pp. 03003
Author(s):  
Yakhiya Kaipov ◽  
Rifkat Akchurin ◽  
Rustam Kirayev ◽  
Asiya Nizaeva
Keyword(s):  
Soil Properties ◽  
Crop Rotation ◽  
Field Experiments ◽  
Humus Content ◽  
Perennial Grass ◽  
Southern Urals ◽  
Perennial Grasses ◽  
Reduced Tillage ◽  
The Southern Urals ◽  
Arid Steppe

Field experiments were conducted in the arid steppe zone of the Southern Urals, in the Republic of Bashkortostan of the Russian Federation. The soil is common chernozem. The precipitation during the growing season (May-September) is 166 mm. The experimental crop rotation consisted of 7 fields: 4 with perennial herbs (a mixture of Bromus inermis and Medicago varia), 3 with annual crops. The study analysed soil properties and carrying capacity in perennial grass rotation, conventional and reduced tillage. During the crop-pasture rotation, the humus content in the soil changes insignificantly depending on the tillage, being within 7.6-8.0 %. Perennial grasses loosened the soil, positively affecting moisture accumulation under crop rotation by the beginning of the pre-sowing period. The arable layer of common chernozem in the reduced tillage had a density of 1.05 g/cm3, less than 0.06 g/cm3 in conventional cultivation. Fertilizer application increased yields at 0.49-0.51 t/ha of feed units. Reduced tillage resulted in higher feed units by 0.06-0.08 tons per 1 ha. Crop-pasture rotation implementation and development ensures bioclimatically-determined yields of fodder crops and maintains soil fertility at an optimal level.

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.

Effects of disturbance and rabbit grazing on seedling recruitment of six mesic grassland species

1999 ◽  
Vol 9 (2) ◽  
pp. 145-156 ◽  
Author(s):  
Grant R. Edwards ◽  
Michael J. Crawley
Keyword(s):  
Seedling Recruitment ◽  
Plantago Lanceolata ◽  
Plant Cover ◽  
Seedling Emergence ◽  
Soil Disturbance ◽  
Seedling Mortality ◽  
Grassland Species ◽  
Rabbit Grazing ◽  
Plant Densities ◽  
Seed Sowing

AbstractSeeds of two grass (Arrhenatherum elatius and Festuca rubra), two herb (Plantago lanceolata and Rumex acetosa) and two legume (Lotus corniculatus and Trifolium repens) species were sown in summer 1995 at four densities (no seed, 1000, 10 000 and 50 000 seeds m−2) into an established rabbit-grazed grassland given factorial combinations of rabbit fencing (with and without fences) and soil disturbance (with and without cultivation). On plots where no seeds were sown, only the species with persistent seed banks (P. lanceolata, L. corniculatus and T. repens) showed enhanced seedling emergence in response to disturbance. In disturbed soil, seedling densities of all species increased with increasing density of sown seeds, the effects of which were still evident for plant cover 2 years after seed sowing. In undisturbed vegetation, A. elatius, F. rubra, P. lanceolata and R. acetosa showed increased seedling densities following seed sowing; but in each case, there was an upper asymptote to seedling recruitment, presumably due to microsite limitation. Rabbit grazing reduced seedling densities, with this reduction being more pronounced with disturbance than without. However, the effect of rabbit grazing did not persist for some species; seedling mortality of R. acetosa, P. lanceolata, L. corniculatus and T. repens was higher on plots without rabbit grazing, so that plant densities of these species in summer 1996 and plant cover in summer 1997 were greater on grazed plots. The results indicate interactions between soil disturbance, propagule availability and herbivory, rather than disturbance alone, will play an important role in controlling seedling recruitment and species habitat distributions in grasslands.

Frost heaving in a boreal soil in relation to soil scarification and snow cover

2001 ◽  
Vol 31 (6) ◽  
pp. 1084-1092 ◽  
Author(s):  
Urban Bergsten ◽  
France Goulet ◽  
Tomas Lundmark ◽  
Mikaell Ottosson Löfvenius
Keyword(s):  
Snow Cover ◽  
Field Experiments ◽  
Soil Surface ◽  
Control Treatment ◽  
Tree Seedlings ◽  
Frost Heaving ◽  
Humus Layer ◽  
Soil Scarification ◽  
Natural Snow ◽  
Surface Ice

Vertical uplift of seedlings and rods on the soil surface and at a depth of 5 cm, and of reference trees, was monitored using a theodolite from autumn to spring in two adjacent field experiments on a silt soil in northern Sweden. Treatments involving scarification (control and square patches of 0.1, 0.2, 0.4, and 0.8 m at natural snow cover) and snow cover (simulated maximum cover, snow free, and natural cover for control and 0.4-m patches) were compared. For snow free and natural snow cover, diurnal variation of soil surface temperature, duration and magnitude of freezing temperatures, and uplift increased with patch size. At the end of the winter under natural snow cover, uplift of the soil surface and shallow soil was between 4.4 and 5.3 cm for the control treatment without scarification and the 0.1-m patch while the uplift for the 0.4- and 0.8-m patches reached 7.6–11.5 cm. The highest uplift value, 14.6 cm, was observed for the snow-free treatment with 0.4-m patches. Maximum uplift of trees averaged 4.4 cm, which was similar to values observed for seedlings and rods with an intact humus layer and a natural snow cover, indicating that the highest observed uplift was mainly due to needle and soil surface ice. In conclusion, size of the scarified area and duration and thickness of snow cover largely influence frost heaving of tree seedlings in a susceptible soil.

Population biology of Microlaena stipoides in a south-eastern Australian pasture

2014 ◽  
Vol 65 (8) ◽  
pp. 767 ◽  
Author(s):  
M. L. Mitchell ◽  
J. M. Virgona ◽  
J. L. Jacobs ◽  
D. R. Kemp
Keyword(s):  
Seed Predation ◽  
Population Biology ◽  
Seedling Recruitment ◽  
Perennial Grass ◽  
Early Summer ◽  
Seed Rain ◽  
Perennial Grasses ◽  
South Eastern ◽  
Eastern Australia ◽  
Microlaena Stipoides

Microlaena (Microlaena stipoides var. stipoides (Labill.) R.Br.) is a C3 perennial grass that is native to areas of south-eastern Australia. In this region, perennial grasses are important for the grazing industries because of their extended growing season and persistence over several years. This series of experiments focused on the population biology of Microlaena by studying the phenology (when seed was set), seed rain (how much seed was produced and where it fell), seed germination, germinable seedbank, seed predation and seedling recruitment in a pasture. Experiments were conducted at Chiltern, in north-eastern Victoria, on an existing native grass pasture dominated by Microlaena. Seed yields were substantial (mean 800 seeds m–2), with seed rain occurring over December–May. Microlaena has two distinct periods of high seed rain, in early summer and in early autumn. Seed predation is high. Within a 24-h period during peak seed production, up to 30% of Microlaena seed was removed from a pasture, primarily by ants. Microlaena seedlings recruited throughout an open paddock; however, seedling density was low (5 seedlings m–2). Microlaena represented only low numbers in the seedbank (0.01–0.05% of total); hence, any seedlings of Microlaena that germinate from the seedbank would face immense competition from other species. Management strategies for Microlaena-dominant pastures need to focus on the maintenance of existing plants.

Microhabitat availability and seedling recruitment ofLobelia urens: a rare plant species at its geographical limit

2000 ◽  
Vol 10 (4) ◽  
pp. 471-487 ◽  
Author(s):  
J.M. Dinsdale ◽  
M.P. Dale ◽  
M. Kent
Keyword(s):  
Large Scale ◽  
Seedling Recruitment ◽  
Higher Plants ◽  
Plant Cover ◽  
Soil Surface ◽  
Potential Effect ◽  
Plant Litter ◽  
Higher Plant ◽  
Precise Role

AbstractIn Britain,Lobelia urens(L.) (the heath lobelia) occurs in rough grassland, is rare and only found in southern England, where it is at the northern limit of its range. Emergence and survival ofL. urenswas investigated at six locations in two geographically distinct sites experiencing spring, autumn or no grazing in two consecutive years. Four factors were evaluated qualitatively, as a means of characterizing microhabitats for germination and survival: all permutations of higher plant cover, bryophytes, plant litter and surface depressions. The potential effect of adjacent plants on recruitment was also assessed using the nearest neighbour distance (NND). Grazing created depressions, removed plant litter and increased the proportion of sites with higher plant cover. It also resulted in a more open sward with higher NNDs. None of these changes stimulated recruitment. Instead, small increases in the frequency of some rare or very rare microhabitat types were vital in making grazed rough grassland more suitable for emergence. Reduced litter loads and a greater quantity of moss were two key responses. Overall, survival ofL. urenswas less than 1% and was particularly favoured by moss and an increase in NNDs. Shading from higher plants, with or without plant litter, decreased emergence, but the precise role of litter was complex and most probably related to its quantity. In an experimental seed bed, only empty depressions favoured emergence. The microhabitat relationships ofL. urenswere unusually consistent among locations and consecutive years.L. urensrequires high soil surface temperatures but also adequate water for large scale recruitment, and such conditions are encouraged by grazing. The particular problems of experimental design and statistical analysis of data from recruitment experiments are also discussed.

scholarly journals Changes in yellow bristle grass (Setaria pumila) abundance after drought implications for pasture management

2009 ◽  
Vol 62 ◽  
pp. 211-216 ◽  
Author(s):  
K.N. Tozer ◽  
T.K. James ◽  
C.A. Cameron
Keyword(s):  
Key Management ◽  
Perennial Grass ◽  
Perennial Grasses ◽  
Botanical Composition ◽  
Annual Grass ◽  
Bare Ground ◽  
Pasture Management ◽  
Soil Calcium ◽  
Annual Grasses ◽  
Previous Summer

Yellow bristle grass (YBG) which is a summeractive annual grass reduces pasture quality and becomes unpalatable to stock as panicles mature Farmers are concerned that an extreme drought from November 2007 to March 2008 may have facilitated the spread of YBG and other summeractive annual grass weeds Botanical composition was assessed on 12 Waikato dairy farms in February 2009 and YBG abundance was related to key management factors These findings were compared with data collected from the same farms (February 2008) during the drought Between years ryegrass cover and the proportion of bare ground decreased These components were replaced by two summeractive annual grasses YBG and summer grass and to a lesser extent summeractive perennial grasses clovers and dicots In 2009 YBG cover was negatively associated with summeractive perennial grass cover and pH and positively associated with YBG cover in the previous summer and soil calcium levels

The nature of the perennial response in Mediterranean grasses. I. Water relations and summer survival in Phalaris

1968 ◽  
Vol 19 (3) ◽  
pp. 381 ◽  
Author(s):  
JR McWilliam ◽  
PJ Kramer
Keyword(s):  
Surface Soil ◽  
Perennial Grass ◽  
Soil Surface ◽  
Water Source ◽  
Perennial Grasses ◽  
Natural Conditions ◽  
Deep Roots ◽  
Surface Moisture ◽  
Summer Stress ◽  
Controlled Environments

An important factor in the survival of Phalaris tuberosa, a typical Mediterranean perennial grass, is the ability of its deep root system to supply water during the summer to the dormant culms at the soil surface. This behaviour contrasts with that of the related annual P. minor, which is unable to exploit subsoil moisture, and dies as soon as the surface moisture is exhausted. The volume of water supplied by the perennial roots is sufficient to offset transpiration losses and maintain a favourable water balance in the dormant culms during the summer stress. The importance of this water source for survival is indicated by the death of plants whenever this supply is interrupted by severing deep roots. In field soils under drought conditions roots of the perennial have been followed to a depth of 7 ft in subsoil containing available moisture. The large metaxylem vessels and heavily suberized endodermis which are a feature of these roots suggest that they are well adapted to transport water up through the dry surface soil to the base of the dormant culms. The culms also show typical xerophytic characteristics which help to minimize water loss during the summer, and maintain favourable conditions for the survival of the dormant buds which develop at the basal nodes. These conclusions concerning the survival of the perennial have been drawn from plants growing under natural conditions, and also from more detailed studies under controlled environments. They appear to be of general significance for the perennial grasses adapted to the drier Mediterranean environments and form the basis of the perennial response found in this group.

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.

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