Stoloniferous Grass Research Articles

Long term water integration in interconnected ramets of stoloniferous grass, buffalograss

-1 ) water supply; the whole experiment lasted for 91 days. In heterogeneous treatment, water translocation was equally effective in acropetal and basipetal directions. Elder ramet was more efficient in water use, but rooted ramet of elder ramet in moist condition experienced significant cost when it was connected to younger ramet in dry condition; whereas, no cost was found in any fragment of younger donor ramet. Ramet in dry condition produced more biomass than its connected ramet in moist condition and developed larger leaves. This oversharing phenomenon indicated that no net cost was involved in water integration, and water might not be the only resources transported within stolon xylem. Overall, long term water integration is an important strategy for buffalograss to cope with adverse natural drought conditions.

Short-term ingestive behaviour of cattle grazing tropical stoloniferous grasses with contrasting growth forms

SUMMARYRelationships between sward height and short-term ingestive behaviour of cattle were examined for two tropical stoloniferous grasses with contrasting growth forms: centipede grass (Eremochloa ophiuroides(Munro) Hack.; (CG); strongly prostrate) and bahia grass (Paspalum notatumFlügge; (BG); more erect). Turves (500×500 mm) were extracted from field monoculture swards of each grass after the varying duration of re-growth, and presented to animals for a short period (10 bites) to measure bite dimensions (area, depth and volume), bite mass, time per bite and intake rate. In the same re-growth period, CG was always shorter and denser than BG. Bite dimensions, the bite mass and the intake rate of animals increased at a declining rate as the sward height increased for both grasses, showing a tendency for a steeper initial increase, an earlier plateau and a lower maximum in CG than in BG. Due to the difference in the shape of the intake rate response, animals on BG were estimated to require a longer grazing time than those on CG to attain the same daily herbage intake, when the sward is shorter than about 200 mm. The sward height below which the daily intake of animals may be restricted was lower for CG (61–70 mm) than for BG (71–92 mm). The results indicate an advantage of strongly prostrated, highly dense grasses (e.g. CG) over more erect, less dense grasses (e.g. BG) when grazed at a relatively low height (<200 mm). In relation to increasing bite mass, the time per bite pooled over CG and BG was constant until the bite mass reached a critical value (0·55 g dry matter (DM)) and thereafter increased linearly with the bite mass, confirming that cattle are able to perform compound jaw movements that gather herbage into the mouth (manipulative jaw movement) and chew herbage already in the mouth (chewing jaw movement) within one cycle of opening and closing of the jaws.

Patch dynamics in grazed subtropical native pastures in south‐east Queensland

Abstract Patch formation is common in grazed grasslands but the mechanisms involved in the formation and maintenance of patches are not clear. To increase our knowledge on this subject we examined possible reasons for patch formation and the influence of management on changes between patch states in three experiments in native pasture communities in the Crows Nest district, south‐east Queensland. In these communities, small‐scale patches (tall grassland (dominated by large and medium tussock grasses), short swards (dominated by short tussock grasses and sedges), and lawns (dominated by stoloniferous and/or rhizomatous grasses)) are readily apparent. We hypothesized that the formation of short sward and lawn patches in areas of tall grassland was due to combinations of grazing and soil fertility effects. This was tested in Experiment 1 by applying a factorial combination of defoliation, nutrient application and transplants of short tussock and stoloniferous species to a uniform area of tall grassland. Total species density declined during the experiment, was lower with high nutrient applications, but was not affected by defoliation. There were significant changes in abundance of species that provided support for our hypotheses. With light defoliation and low nutrients, the tall grassland remained dominated by large tussock grasses and contained considerable amounts of forbs. With heavy defoliation, the pastures were dominated by medium tussock grasses and there were significant decreases in forbs and increases in sedges (mainly with low nutrients) and stoloniferous grasses (mainly with high nutrients). Total germinable seed densities and those of most species groups were significantly lower in the heavy defoliation than the light defoliation plots. Total soil seed numbers were not affected by nutrient application but there were fewer seeds of the erect forbs and more sedge seeds in plots with high nutrients. The use of resting from grazing and fire to manage transitions between patches was tested. In Experiment 2, changes in species density and abundance were measured for 5 years in the three patch types with and without grazing. Experiment 3 examined the effects of fire, grazing and resting on short sward patches over 4 years. In Experiment 2, total species density was lower in lawn than short sward or tall grassland patches, and there were more species of erect forbs than other plant groups in all patch types. The lawn patches were originally dominated by Cynodon spp. This dominance continued with grazing but in ungrazed patches the abundance of Cynodon spp. declined and that of forbs increased. In the short sward patches, dominance of short tussock grasses continued with grazing but in ungrazed plots their abundance declined while that of large tussock grasses increased. The tall grassland patches remained dominated by large and medium tussock species. In Experiment 3, fire had no effect on species abundance. On the grazed plots the short tussock grasses remained dominant but where the plots were rested from grazing the small tussock grasses declined and the large tussock grasses increased in abundance. The slow and relatively small changes in these experiments over 4 or 5 years showed how stable the composition of these pastures is, and that rapid changes between patch types are unlikely.

Micro-patch and community scale spatial distribution of herbaceous cover in a grazed eucalypt woodland

This study described changes in spatial distribution of herbaceous cover in experimental paddocks in a eucalypt woodland of northern Australia after 5 years of different grazing pressures and drought. Herbaceous cover was irregularly distributed, with high cover zones in distinct bands across slopes on paddocks in stable and degrading condition, and irregular patches in a degraded paddock. Size and density of these zones declined with paddock condition, as native perennial tussock grasses were lost and replaced by an exotic stoloniferous grass. Describing disturbance responses of herbaceous cover in this community requires sampling at multiple spatial scales.

Germinable soil seedbanks in native pastures near Crows Nest, south-east Queensland

The soil seedbanks in three patch types (tall grassland, short sward and lawn) were measured in native pastures near Crows Nest, south-east Queensland in two experiments. In the first experiment, seedbanks were measured at four sites, and in the second, the variation in seedbanks during the year was measured at one site. In each experiment the size and composition of the seedbanks were determined by germinating the seeds in soil samples. In the first experiment, total seed numbers ranged from ~6000 to 12,000 per m2. There were no significant differences between sites for total seeds or for seeds of any species group except legumes which comprised only a small portion of the seedbanks. There were significant differences between patch types for total seeds and for the following species groups, medium tussock grasses, short tussock grasses, stoloniferous grasses, legumes and forbs but not large tussock grasses and sedges. Total seed numbers, and those of medium tussock grasses, stoloniferous grasses and forbs were highest in the lawn patches and lowest in the short sward patches. Legumes had higher numbers in the tall grassland patches than in other patch types. In the second experiment, there were large differences between total seed numbers at the different sample dates (January, May, September and November). Numbers were highest in January and then declined throughout the year. This pattern was largely a reflection of the changes in numbers of forb seeds, the species group with the most seeds. There were no significant differences between patch types for total seeds but there were for medium tussock grasses, stoloniferous grasses, sedges and forbs. There was no relationship between the composition of the pasture sward and the composition of the seedbank for any of the three patch types. Twenty-eight species were allocated to persistent and transient seedbank types; all seedbank types occurred in all three patch types. The major species in the seedbanks were sedges (Cyperus gracilis, C. sesquiflorus), forbs (Gamochaeta spp., Paronychia brasiliana, Daucus glochidiatus) and Eragrostis spp.

Morphology and growth of stolons and rhizomes in three clonal grasses, as affected by different light supply

In this paper, the hypothesis is tested that, in clonal grasses producing stolons and/or rhizomes, stolons always show a higher morphological plasticity than rhizomes in response to variation in light availability.Agrostis stolonifera (a stoloniferous grass),Holcus mollis (a rhizomatous grass) andCynodon dactylon (a grass forming both stolons and rhizomes), were grown in pots and subjected to three levels of light intensities. Both stolons and rhizomes branched more intensively under higher light levels. Irrespective of species, stolons consisted of longer internodes under lower light levels, while rhizome morphology did not respond significantly. Biomass partitioning to rhizomes was lower under lower light intensities while partitioning to stolons was not affected. Rhizomes usually had more dormant buds than did stolons. Our results suggest that stolons serve primarily as foraging organs for light, whereas the main function of rhizomes is storage of meristem and carbohydrates, irrespective of whether the grass species involved produces both rhizomes and stolons or only one type of spacer.

The Dynamics of Five Grasses and White Clover in a Simulated Mosaic Sward

(1) Two types of simulated swards were constructed to investigate spatiotemporal changes and the importance of species interactions in creating and maintaining pattern among six grassland species: Lolium perenne, Agrostis capillaris, Holcus lanatus, Poa trivialis, Cynosurus cristatus and Trifolium repensv. (2) Neighbour effects were studied in mosaic swards consisting of twenty hexagonal patches. Each hexagonal patch was sown with a single species. A species never had itself as a neighbour. To study the colonization of empty space, each of six trapezia, surrounding an empty central hexagon, was sown with one of the same six species. After twenty-seven months, the swards were destructively harvested and the contents of each hexagon separated into species. (3) Each species had its own rate and scale of change. Trifoliurn was by far the most mobile species. Only 20%/o of its biomass was in native hexagons, i.e. in which it had been sown. The stoloniferous grasses Agrostis and Poa divided their biomass about equally between native hexagons and those in which they were not sown. The stoloniferous species were most effective in colonizing empty space. Cynosurus was the least mobile species with almost 90%/o of its biomass in native hexagons. (4) The hypothesis that the spread of species into adjacent hexagons is independent of the specific identity of neighbours was falsified. Evidence for cyclic regeneration on the scale of the patch as postulated by Watt was not found. In contrast, each species was invaded to the same relative extent by all the others. The decreasing order of preference of neighbours was established as: Trifolium > Poa > Lolium > Cyno,surus > Holcus > Agrostis. It is suggested that pattern in plant communities cannot be viewed on a single spatial or temporal scale.

Growth, morphology and nutritive quality of shaded Stenotaphrum secundatum, Axonopus compressus and Pennisetum clandestinum

SUMMARYThe response to shade in growth and nutritive quality of buffalo grass (Stenotaphrum secundatum) was compared with that of two other stoloniferous grasses, mat grass (Axonopus compressus) and kikuyu grass (Pennisetum clandestinum). The grasses were grown outdoors in Brisbane, Australia, in soil in pots over two growing seasons in 1985/86. Treatments in the first season (Expt 1) were shading at 0 (full sun), 42, 59 and 68% with moderate N (two spaced applications of 50 kg/ha) and, in the second season (Expt 2), 0 and 59% shade with high (50 kg/ha every 2 weeks) and low (5 kg/ha every 2 weeks) N.Unusually for tropical grasses, the top yield of all species was higher under shade than in full sun, except for S. secundatum at high N in Expt 2. S. secundatum and A. compressusshowed an increase in top yield up to 68% shading whereas P. clandestinum reached a maximum at 42% shading. Shade increased shoot:root ratio and specific leaf area in all species but had little effect on leaf:stem ratio and the proportion of dead material in the tops. Stubble yield (stem bases and stolons) was reduced under shade but to a much smaller extent than root yield. S. secundatum and A. compressus had similar morphological characteristics. Their yield was lower than that of P. clandestinum in Expt 1 (autumn growth) but was similar to that of P. clandestinum in Expt 2 (summer growth). These grasses had a higher leaf:stem ratio and lower proportion of dead material in tops than P. clandestinum.Shade generally increased herbage nutritive value through an increase in N concentration and drymatter digestibility. The latter response was somewhat variable and mostly small (1–3% units). Under shade, the general trend was towards a decrease in total nonstructural carbohydrates, cell-wall content and insoluble ash, and an increase in lignin content. A. compressus was higher in digestibility and soluble carbohydrates than the other grasses.S. secundatum was not clearly superior in response to shade and its nutritive quality was lower than that of A. compressus.

Metabolism and distribution of grasses in tropical flooded savannas in Venezuela

ABSTRACTFlooded savannas in south-west Venezuela consist of seasonal, marshy and flooded grassland communities, the distribution of which depends on soil level. Seasonal grasslands are dominated by tuft-forming, rhizomatous C4-grasses (exemplified byPaspalum chaffanjoniiin this study), while flooded grasslands are dominated by stoloniferous grasses which develop rooted, floating culms during the rainy season(Leersia hexandraandHymenachne amplexi-caulis).The interface between these two communities is a marshy grassland dominated by stoloniferous grass species which tolerate flooding to a depth of 10 to 25 cm(Panicum laxumandLeersia hexandra).All perennial grass species in flooded grasslands behave as typical C3 plants, while marshy grasslands are dominated byPanicum laxum,a species with reduced photo-respiration, low RuBP/PEP-carboxylase ratios, and low absolute RuBP-carboxylase activity compared to C3 grasses. It also has lower photosynthetic rates than the other grass species.Hymenachne amplexicaulisappears to be the least drought tolerant from the species selected, in accordance with its distribution in the wettest side of the flooding gradient studied. The other species showed marked reduction in relative water content and pronounced increase in leaf proline content in drought experiments lasting 6 to 30 days. Alcohol dehydrogenase increased markedly in response to anaerobiosis in the root environment in the tuft forming grasses, while the stoloniferous species with ascending culms were least affected by this treatment, probably as a result of better aeration inside the culms and also to the production of adventitious roots in upper nodes. Nitrate reductase activity increased as a result of anaerobiosis in the roots but not in the leaves, of all species exceptLeersia hexandra.No difference among the species was found in malate accumulation, or the activity of malic enzyme.

Sex-Ratios and Related Characteristics in Spinifex sericeus (Poaceae)

Spinifex sericeus R.Br. is a dioecious, stoloniferous grass which occurs on sand dunes around much of the south-eastern coastline of Australia, New Zealand and New Caledonia. Sex ratios of ramets of S. sericeus and some associated characteristics were studied on the mid-north coast of New South Wales. Generally there was a male bias in the observed ramet sex ratio, although the extent of this bias varied with the beach investigated, the position in the dunes and the time of sampling. Male inflorescences matured and died more rapidly than females, and hence the observed male bias was greatest at the beginning of the flowering period. Male ramets were found to have more sexual tillers per clump than female ramets. The genet sex ratio was estimated from plants grown from seed and separated from each other throughout the experimental period. Males and females were found to be equal in number, although this equality may not be a true reflection of the genet sex ratio in the field.

Leaf and Shoot Demography of an Arctic Stoloniferous Grass, Puccinellia Phryganodes, in Response to Grazing

(1) Swards ( < 2 5 cm in height) of Puccinellia phryganodes are heavily grazed by lesser snow geese (Chen caerulescens caerulescens) on intertidal flats on the shores of Hudson Bay. This paper describes the morphological changes that account for the increased net primary production due to grazing. (2) Demographic techniques were used in 1983 to monitor the births and deaths of leaves and shoots in grazed and ungrazed swards (exclosures) between mid-June ('spring melt') and early September (before 'freeze-up'). (3) Overall, the mean number of axillary shoots produced per main shoot of Puccinellia was significantly higher in grazed plots (2 03) than that in ungrazed plots (1 47). Shoots remained alive beyond one growing season. (4) There was no significant difference in the mean number of leaves produced per main shoot by plants from grazed and ungrazed swards. Leaf births per axillary shoot were significantly greater in grazed plots compared with ungrazed plots. Overall 64% of all leaves produced between June and September were grazed or partially grazed. (5) Within-season cumulative deaths were 6 9 and 6 0 leaves per main shoot and 2 2 and 1 1 leaves per axillary shoot, respectively, in grazed and ungrazed plots. Life expectancies for leaves exserted between June and early August were as follows: partially grazed leaves 24 9-30 2 days, ungrazed leaves in grazed plots 27 5-34 4 days, leaves in ungrazed plots 32 7-42 5 days. This indicates a rapid turnover of leaves in this arctic salt marsh. Leaves produced late in the season survived the winter but died in early summer of the following year. (6) These results are compared with those of Carex subspathacea, the other important forage species. In C. subspathacea the greater net primary production in response to grazing is achieved by the growth of existing shoots and not by the production of new shoots.

Effect of Grazing by Canada Geese on the Winter Growth of Rye

Canada geese (Branta canadensis) often graze during the fall and winter in fields of rye that are planted as cover crops to reduce soil erosion and improve soil qualities. I used exclosures to document whether grazing by Canada geese had an adverse impact on rye. In 11 Connecticut fields frequented by geese, the leaf biomass of rye by mid-winter was 535% higher inside exclosures than in grazed portions of the same fields. By spring, rye leaf biomass was 177% higher inside than outside of the exclosures. In another experiment, rye was clipped to simulate grazing by Canada geese to determine whether leaf loss slowed the rye plants' growth during winter and spring. Plants that suffered leaf loss had lower total biomass, leaf and stem biomass, and root biomass than uninjured plants regardless of time during fall and winter when the leaves were clipped. Plants receiving multiple clippings grew slower than those receiving only a single clipping. J. WILDL. MANAGE. 52(1):76-80 Canada geese often graze during the fall and winter in grain fields. The damage they cause by grazing and trampling plants can be substantial (Hunt 1984). The damage, however, may be less than initial appearances suggest because of the growing plants' ability to compensate for damage. Pirnie (1954) was unable to document any loss in wheat yields caused by grazing by Canada geese on dormant wheat plants in Michigan, and Allen et al. (1985) reported losses ?13% in Maryland. Clark and Jarvis (1978) observed no difference in seed production between ryegrass plots which had been grazed by Canada geese and those which had not. In contrast, Kahl and Samson (1984) allowed captive Canada geese to graze on wheat, and in some cases heavy grazing resulted in shorter plants and lower grain yields. Tests with other goose species have not demonstrated that grazing by geese has an adverse impact on the plants. Kear (1963b) noted that grazing on winter oats and winter wheat by a captive flock of graylag (Anser anser) and pinkfooted geese (A. brachyrhynchus) had no effect on grain or straw yields at harvest time. Clipping to simulate goose damage on winter wheat and silage grass also had no effect on harvest yields (Kear 1963b). Cargill and Jefferies (1984) showed that grazing by lesser snow geese (A. caerulescens caerulescens) in a sub-arctic salt marsh incre sed primary production of a stoloniferous grass (Puccinellia phryganodes) and a sedge (Carex subspathacea), possibly by accelerating nitrogen cycling in the marsh. In many parts of North America rye is grown in fields during winter as a cover crop for soil This content downloaded from 207.46.13.101 on Sat, 08 Oct 2016 04:13:19 UTC All use subject to http://about.jstor.org/terms J. Wildl. Manage. 52(1):1988 CANADA GOOSE GRAZING ON RYE * Conover 77 management. The leaves and stems of the cover crop can reduce wind-borne soil erosion by reducing wind velocity at the ground surface (Kohnke and Bertrand 1959), and water-borne soil erosion by intercepting rain drops before they hit the soil (Bennett 1939, Kohnke and Bertrand 1959). The roots reduce erosion by holding the soil (Kohnke and Bertrand 1959). Because rye is usually plowed under, it can maintain or increase the amount of organic matter in the soil (Tisdale and Nelson 1956, Thompson and Kelly 1957, Cook 1962). Rye can also help conserve soluble plant nutrients, especially nitrates. Unless there are growing plants present to absorb them, some of these nutrients will be lost during fall and winter by leaching (Tisdale and Nelson 1956, Cook 1962). Because Canada geese often graze in rye fields during the fall and winter, they may be damaging the rye, thus reducing its beneficial qualities. Unfortunately, little information is available about whether this is a problem or if rye can compensate for any damage inflicted by geese. In this experiment I used exclosures to document whether grazing by Canada geese had an adverse impact on rye in Connecticut fields. I also evaluated the ability of rye plants to compensate for damage by recording the growth of rye biomass following simulated grazing at different intensities and at different times of the

The yield potential and crude protein content of five rhizomatous and stoloniferous grass pastures in the escarpment areas of the eastern Transvaal

Whilst Cynodon aethiopicus and the Cynodon hybrid, ‘Coast Cross II’, proved to be unsuited to the cool high rainfall conditions, Acroceras macrum, Pennisetum clandestinum and Digitarla scalarum were well adapted. There was little difference in yield potential between local and improved cultivars of A. macrum. The cultivar Cedara Select should thus be recommended as it has improved disease resistance, whilst maintaining a high protein content. With respect to P. clandestinum there is some doubt whether the results obtained with the cv. Whittet should be ascribed to differences in establishment technique or to ecotypical differences. D. scalarum proved to have a good potential and despite doubts about its acceptability to livestock it definitely warrants further attention.

Sixty Years of Successional History Behind a Moving Sand Dune Near Olduvai Gorge, Tanzania

Sixty Years of Successional History Behind a Moving Sand Dune Near Olduvai Gorge, Tanzania

Herbage yields of thirty grasses fertilized heavily with nitrogen

Abstract Prior to 1962 it was thought that 90 to 135 kg N per ha annually gave satisfactory yields of grass herbage. Grasses were consequently selected for their productivity with this amount of applied nitrogen. It was subsequently shown that the yield response of grasses was linear with up to 450 kg N per ha. Thus it became necessary to test again many commonly‐grown grasses with this high rate of nitrogen. Thirty grasses were fertilized annually with 450 kg N, 90 kg P2O5 and 65 kg K2O per ha. Herbage yields were determined each time the grasses reached early anthesis . Mean herbage yields over four years varied from 1 700 to 17 900 kg dry matter per ha. Results showed clearly that stoloniferous grasses were more productive than tufted grasses. The significance of high yielding stoloniferous grasses in relation to beef production in Rhodesia is briefly discussed.

AN IMPROVED METHOD OF CONTROL OF PASPALUM CONJUGATUM WITH AMITROLE‐T AND PARAQUAT

Summary. Paraquat, amitrole‐T and disodiumn methylarsonate (DMA) were evaluated for the control of the stoloniferous grass Paspalum conjugatum in young rubber plantations in Malaya. The herbicides were tested alone, in mixtures and in split applications. Paraquat at 0–5 lb/ac gave good initial desiccation but regeneration was extremely rapid and repeated sprays of 0–25 lb/ac were required for a long period of suppression. Amitrole‐T at 15 lb/ac was very slow to act but gave complete kill after 10 weeks. DMA at 8–12 lb/ac gave marked suppression, but regeneration rapidly developed after 8 weeks. Mixtures of either amitrole‐T or DMA with paraquat gave less than the expected additive effects of the components, indicating an antagonistic action. Sub‐lethal rates of amitrole‐T or DMA applied to regenerating shoots after paraquat treatment gave results inferior to those from higher rates of the herbicides alone.When paraquat was applied 2 weeks after an initial sub‐lethal dose (0.375 lb/ac) of amitrole‐T, desiccation was rapid and complete eradication was achieved; this did not occur when a low rate of DMA was used as the first spray. In terms of both speed of kill and final effect, a split application of a low rate of amitrole‐T followed by paraquat was the most effective treatment. A possible explanation of the apparent synergism between amitrole‐T and paraquat applied in this way is advanced and suggestions for further work outlined. Une méthode améliorée pour la lutte centre Paspalum conjugatum avoc l'amitrole‐T et le paraquat