Eragrostis Curvula Research Articles

Perennial pastures for marginal farming country in southern Queensland. 2. Potential new grass cultivar evaluation

Trials in the Condamine-Balonne basin, Australia, compared 11 promising perennial pasture grass accessions (4 Bothriochloa, 2 Cenchrus, 2 Urochloa and 1 each of Digitaria, Eragrostis and Panicum species) against the best similar commercial cultivars on the basis of ease of establishment from seed, persistence once established, forage yield and ease of seed production. Accessions sown at a site were determined by prior experience with them on a range of soils. High quality seed was relatively easy to produce for both Urochloa species and for Eragrostis curvula CPI 30374 but problematic for the Bothriochloa spp. Once established, all accessions persisted for 3–5 years and most were well grazed, but adequate establishment was sometimes a problem with Panicum stapfianum and Bothriochloa ewartiana. The dry matter yield ratings of the non-commercial lines were similar to those of the commercial equivalents of the same species. While agronomically valuable, none of the promising new grasses was considered worthy of commercialization at this point because their strengths did not warrant the setting up of a seed-production business in competition with current commercial enterprises. Long-standing cultivars such as Gayndah buffel and Nixon sabi grass continued to exhibit their superior pasture qualities.Keywords: Herbicide tolerance, persistence, forage yield, establishment ease, commercialization, seed production.DOI: 10.17138/TGFT(3)15-26

Evaluating Bermudagrass (Cynodon dactylon), Seashore Paspalum (Paspalum vaginatum), and Weeping Lovegrass (Eragrostis curvula), as a Vegetative Cap for Industrial Brine Landform Stabilization and Phytoremediation

Bermudagrass (Cynodon dactylon), seashore paspalum (Paspalum vaginatum), and weeping lovegrass (Eragrostis curvula) were evaluated for use as a vegetative cover over a brine solid waste surface impoundment. Grass seed and sod were established at soil cap depths of 0, 5.1, 10.2, and 15.3 cm over a brine field. Results indicated that each grass species had benefits for either soil stabilization, phytoremediation, and/or establishing a suitable vegetative cap. Results indicated that seashore paspalum leaf tissue assimilated significantly greater quantities of essential elements potassium (K), magnesium (Mg), sulfur (S), and molybdenum (Mo) compared to bermudagrass, and weeping lovegrass. Seashore paspalum also contained the highest concentration of chloride in the plant tissue, indicating that seashore paspalum could be a potential brine remediator. Seashore paspalum and bermudagrass were suitable vegetative grass species selections for the Gulf Coast states. Bermudagrass and seashore paspalum successfully germinated from seed and established from seed and sod. Weeping lovegrass leaf uptake of Ba and Hg was highest. Therefore, each grass species had benefits being used in a stabilization or remediation environment.

Exotic grassland species have stronger priority effects than natives regardless of whether they are cultivated or wild genotypes.

During community assembly, early arriving exotic species might suppress other species to a greater extent than do native species. Because most exotics were intentionally introduced, we hypothesize there was human selection on regeneration traits during introduction. This could have occurred at the across- or within-species level (e.g. during cultivar development). We tested these predictions by seeding a single species that was either native, exotic 'wild-type' (from their native range), or exotic 'cultivated' using 28 grassland species in a glasshouse experiment. Priority effects were assessed by measuring species' effect on establishment of species from a seed mix added 21 d later. Exotic species had higher germination and earlier emergence dates than native species, and differences were found in both 'wild' and 'cultivated' exotics. Exotic species reduced biomass and species diversity of later arriving species much more than native species, regardless of seed source. Results indicate that in situations in which priority effects are likely to be strong, effects will be greater when an exotic species arrives first than when a native species arrives first; and this difference is not merely a result of exotic species cultivation, but might be a general native-exotic difference that deserves further study.

Genetic divergence analysis in turf grasses based on morphological traits

Despite of enhancing interest on turfs in India, all the available varieties of turf grasses in the country are being imported and are often poorly adapted to the prevailing climatic conditions. This prompted to begin a collection activity of turfgrass species, with the ultimate goal of identifying promising materials for further development of lawns suitable for various conditions. The present investigation conducted on eight species and four varieties of turf grasses depicted significant differences in all the growth related traits studied. All turf grasses under study exhibited fine leaf texture except Eragrostis curvula (Schrad.) Nees having medium coarse texture, Paspalum notatum Flugge and Argentine bahia having coarse texture and Poa pratensis L. which exhibited medium fine leaf texture. The Agrostis palustris L. exhibited maximum mean performance for shoot density/25 cm2 (277.33), whereas minimum was exhibited by Cynodon dactylon L. var Panama (57.67). The coefficient of variation was minimum for relative water content (GCV = 13.77, PCV = 14.60) and maximum for root length (GCV = 64.70, PCV = 66.46). Heritability estimates for all the traits were generally moderate to high. High heritability was observed for shoot density per 25 cm2 (98.00), whereas moderate heritability was observed for dry root/shoot ratio (64.12). High heritability along with high genetic advance was observed for shoot density per 25cm2 (h2 = 98.00, GA = 142.02) and germination percentage (h2 = 96.50, GA = 48.16).

Increased apomixis expression concurrent with genetic and epigenetic variation in a newly synthesized Eragrostis curvula polyploid

Eragrostis curvula includes biotypes reproducing through obligate and facultative apomixis or, rarely, full sexuality. We previously generated a “tetraploid-dihaploid-tetraploid” series of plants consisting of a tetraploid apomictic plant (T), a sexual dihaploid plant (D) and a tetraploid artificial colchiploid (C). Initially, plant C was nearly 100% sexual. However, its capacity to form non-reduced embryo sacs dramatically increased over a four year period (2003–2007) to reach levels of 85–90%. Here, we confirmed high rates of apomixis in plant C, and used AFLPs and MSAPs to characterize the genetic and epigenetic variation observed in this plant in 2007 as compared to 2003. Of the polymorphic sequences, some had no coding potential whereas others were homologous to retrotransposons and/or protein-coding-like sequences. Our results suggest that in this particular plant system increased apomixis expression is concurrent with genetic and epigenetic modifications, possibly involving transposable elements.

Establishment of three new genera in the family Geminiviridae: Becurtovirus, Eragrovirus and Turncurtovirus

The family Geminiviridae includes plant-infecting circular single-stranded DNA viruses that have geminate particle morphology. Members of this family infect both monocotyledonous and dicotyledonous plants and have a nearly global distribution. With the advent of new molecular tools and low-cost sequencing, there has been a significant increase in the discovery of new geminiviruses in various cultivated and non-cultivated plants. In this communication, we highlight the establishment of three new genera (Becurtovirus, Eragrovirus and Turncurtovirus) to accommodate various recently discovered geminiviruses that are highly divergent and, in some cases, have unique genome architectures. The genus Becurtovirus has two viral species, Beet curly top Iran virus (28 isolates; leafhopper vector Circulifer haematoceps) and Spinach curly top Arizona virus (1 isolate; unknown vector), whereas the genera Eragrovirus and Turncurtovirus each have a single assigned species: Eragrostis curvula streak virus (6 isolates; unknown vector) and Turnip curly top virus (20 isolates; leafhopper vector Circulifer haematoceps), respectively. Based on analysis of all of the genome sequences available in public databases for each of the three new genera, we provide guidelines and protocols for species and strain classification within these three new genera.

Comparative digestibility by cattle versus sheep: Effect of forage quality1,2

The objective was to determine the effect of forage quality on apparent total tract digestibility and ruminal fermentation in cattle versus sheep. Five yearling English crossbred (Hereford × Angus) steers (440.4 ± 35.6 kg of initial BW) and 5 yearling whiteface (Rambouillet × Columbia × Debouillet) wethers (44.4 ± 4.6 kg of initial BW), each fitted with a ruminal cannula, were randomly assigned to 1 of 3 forage sources within ruminant specie, and the study was conducted over 3 periods. For forage source, both animal and period served as the blocking factor with all forage sources represented once within each animal and all forage sources represented at least once within each period. The treatment structure was arranged in a 2 × 3 factorial with ruminant species (2) and forage source (3) as the factors. Forage sources were 1) alfalfa hay (Medicago sativa; 17.5% CP and 34.1% NDF, DM basis), 2) warm-season grass hay mix (Bothriochloa ischaemum and Cynodon dactylon; 7.3% CP and 74.7% NDF, DM basis), and 3) lovegrass hay (Eragrostis curvula; 2.5% CP and 81.9% NDF, DM basis). As a percent of BW, steers and wethers consumed similar (P ≤ 0.06) amounts of forage, and intake was more influenced by forage quality (P < 0.001) than ruminant species (P = 0.35). When expressed per unit of metabolic BW, cattle consumed more (P < 0.001) DM, NDF, and N than sheep. Apparent total tract digestibility was similar among steers and wethers when alfalfa or grass hay was fed, but decreased to a greater extent in wethers when low-quality lovegrass hay was fed (ruminant species × diet interaction, P ≤ 0.01). Rate (%/h) of ruminal NDF disappearance was greater (P = 0.02) for alfalfa and grass hay than lovegrass, but was not influenced (P = 0.12) by ruminant species. In addition, ruminal DM fill was influenced more (P < 0.01) by forage than by ruminant species (P = 0.07). Steers and wethers had greater (P < 0.01) DM fill from grass hay and lovegrass hay than alfalfa before and 5 h after feeding. Ruminal VFA were generally not influenced (P ≥ 0.06) by ruminant specie. Results suggest that apparent total tract digestibilities are more similar among ruminant species when moderate- to high-quality forages are evaluated. However, sheep are not an adequate model for cattle when low-quality forages are compared because cattle digest low-quality forages to a greater extent than sheep. Expressing digestibility as digestible intake per unit of BW allows for a wider range of forage qualities to be compared when substituting sheep for cattle.

Evaluating pasture species for less fertile soils in a subtropical aseasonal low rainfall zone

Grasses, legumes, saltbushes and herbs were evaluated at 6 sites in southern inland Queensland to identify potential pasture and forage plants for use on marginal cropping soils. The region experiences summer heat waves and severe winter frosts. Emphasis was on perennial plants, and native species were included. Seedlings were transplanted into the unfertilized fields in either summer or autumn to suit the growing season of plants, and watered to ensure estab-lishment. Summer-growing grasses were the most successful group, while cool season-growing perennials mostly failed. Summer legumes were disappointing, with Stylosanthes scabra and Indigofera schimperi performing best. Some lines such as I. schimperi and the Eragrostis hybrid cv. Cochise were assessed as potential weeds owing to low animal acceptance. Native Rhynchosia minima grew well at some sites and deserves more study. Cenchrus ciliaris was always easy to establish and produced the highest yields. Persistence of some Digitaria and Bothriochloa species, Eragrostis curvula and Fingerhuthia africana at specific sites was encouraging, but potential weediness needs careful assessment. Standard species were identified to represent the main forage types, such as Austrostipa scabra for cool season-growing grasses, for incorporation into future trials with new genetic materials. The early field testing protocol used should be considered for use elsewhere, if unreliable rainfall poses a high risk of establishment failure from scarce seed.

Vegetation Formation in Estuarine Tidal Flats: Influences of Basin Scale and River-Crossing Structures of the Eight Rivers of Ise Bay in Mie and Aichi Prefectures, Japan

In this study, we examined the influences of the differences in basin scale and river-crossing structures of 8 rivers of Ise Bay in Mie and Aichi Prefectures, Japan on the vegetation in the estuarine tidal flats of these rivers. The dominant plant communities of the estuarine tidal flats formed from rivers of large-scale river basins (exceeding 300 km2) were determined. In the Miya River, the dominant plant community was the Suaeda maritima and Artemisia fukudo community. In the Kushida River, the dominant plant community was composed of Phacelurus latifolius, Artemisia fukudo, Phragmites australis, and bamboo. In the Kumozu River, the dominant community was composed of the coastal plants Calystegia soldanella, Lathyrus japonicus, and Carex pumila and the exotic plant of Lolium multiflorum. The plant community of Suzuka River was dominated by the exotic plant of Eragrostis curvula. Among the estuarine tidal flats influenced by a small-scale river basin (50 km2 or less), the plant community of Shinbori River (Fukue tidal flat) was dominated by Suaeda maritima, and the plant communities of the Shio and Harai Rivers were dominated by Phragmites australis. The plant community of Tanaka River was dominated by Phragmites australis and coastal plants. Regarding the relationship between the vegetation and the river environment for each study site, we hypothesised that in a large basin area with few structures crossing the river, the river water catchment in the estuary after heavy rains caused large areas of disturbance and formed bare land, providing suitable habitat for an annual salt marsh plant community. In contrast, in cases with many structures crossing the river, a stable channel, an excavated riverbed and the suppression of runoff and the resulting disturbance of the estuary, flooding did not occur during high tide. Moreover, we hypothesised that in a small basin with many structures crossing the river, disturbance to the estuary was not likely, and the perennial salt marsh plant community of Phragmites australis would be widely distributed, except for a river type such as the Shinbori River, in which tide and river flow were managed by a final closure.

Evaluation of the allelopathic potential of five South African mesic grassland species

The recent success of Aristida junciformis Trin. and Rupr. and Eragrostis curvula Schrad. Nees in dominating South African grasslands has posed agricultural and ecological threats. With the objective of examining if the current success of the species is related to allelopathy, the present study assessed the allelopathic potential of five common perennial grassland species (Poaceae). Aqueous extracts prepared by soaking separately 2, 10, 25 and 40 g of leaf and root material in 100 mL of distilled-water for 36 h were bioassayed using a biotest species i.e. Grand Rapids lettuce seeds (Lactuca sativa L. cv.). Species, dilution level and plant-part had a highly significant (P < 0.001) effect on germination percentage, as well as shoot and root elongation of the biotest species. At higher concentrations, the leaf extracts of all species showed significant inhibitory activities which declined with increases in dilution level. A. junciformis, E. curvula and Megathyrsus maximus (Jacq.) BK Simon and SWL Jacobs. demonstrated the highest degree of inhibition in germination percentage and subsequent seedling length; with complete inhibition recorded at dilution levels ≥25 % w/v. At high concentration levels, root extracts of all species, except Themeda triandra Forssk. exhibited significant inhibitory effects on germination; with Hyparrhenia hirta (L.) Staph being most inhibitory. Relatively speaking, E. curvula, A. junciformis and M. maximus showed the highest degree of inhibition. These findings suggest that these three species possess strong allelopathic potential. Such an allelopathic supremacy may contribute to their dominance in natural grasslands. Further studies, however, are still required to isolate responsible phytochemicals and to better understand if allelopathic advantage is the key factor contributing to population dynamics in the field.

REVEGETATION OF DECOMPOSED GRANITE ROADCUTS IN KOREA: DEVELOPING DIGGER, EVALUATING COST EFFECTIVENESS, AND DETERMINING DIMENSIONS OF DRILLING HOLES, REVEGETATION SPECIES, AND MULCHING TREATMENT

ABSTRACTDecomposed granite roadcuts are difficult to revegetate after losing the topsoil and vegetation cover. We developed a new drilling machine, Digger, to efficiently drill six holes simultaneously on decomposed granite roadcuts to facilitate revegetation. The Digger consists of a base machine (0.7 m3‐level excavator) and a mounting body with six hydraulic motors instead of a bucket. We tested its performance on two roadcuts in southwest Korea using time‐motion studies, which showed that the Digger can drill 240 m2 of decomposed granite roadcuts daily. The unit cost of the Digger was less than a half of other roadcut stabilization and revegetation techniques in Korea, making the Digger a cost‐effective revegetation technology. Field germination and growth tests were also conducted to identify appropriate diameter and depth of drilling holes, suitable revegetation species, and mulching treatment. We drilled holes with three different diameters and depths, filled the holes with a mixture of plant seeds and cultivated soil, applied mulching treatments (coir geotextile, shade net, and no mulching), and measured the germination and growth results at two field plots after 1 month and 1 year. The results showed that drilling diameter 10 cm and depth 10 cm were large enough to result in better plant germination and growth. Erosion control species, Poa pratensis L. and Eragrostis curvula (Schrad.) Nees, survived and grew better than native woody species. Coir geotextile improved the plant germination and growth. The time‐motion and revegetation results show that the Digger can be a promising technology to restore decomposed granite roadcuts. Copyright © 2013 John Wiley &amp; Sons, Ltd.

Plant growth and survival of five introduced and two native/naturalized perennial grass genotypes exposed to two defoliation managements in arid Argentina

AbstractThe field performance of the native Pappophorum vaginatum, the naturalized Eragrostis curvula and various cultivars of the introduced Achnatherum hymenoides and Leymus cinereus was evaluated as potential forage resources in rangelands of arid Argentina during the warm seasons of 2007/2008 and 2008/2009. Plants of these grass species, obtained from seeds, were transplanted to the field in 2006, when they were 1 year old. During the study years, there were two defoliation managements: plants of all study genotypes either remained undefoliated (controls) or were defoliated twice a year during spring at 5 cm stubble height. Despite tiller number being lower (P &lt; 0·05) on defoliated than on undefoliated plants, and total leaf length per unit basal area being similar (P &gt; 0·05) between defoliation managements by mid‐spring, there were no differences (P &gt; 0·05) in dry weight production between defoliated and undefoliated plants in all genotypes at the end of the second growing season. Plants of one or more of the introduced genotypes showed a similar (P &gt; 0·05) or greater (P &lt; 0·05), but not lower, tiller number per plant and per square centimetre, daughter tiller production, total leaf length and dry weight production per unit basal area than the native species at the end of the first and/or second growing seasons. These morphological variables were similar (P &gt; 0·05) or greater (P &lt; 0·05) in the native than in the naturalized genotype. Plant survival, however, was lower (P &lt; 0·05, overall mean = 20%) in the introduced than in the native (&gt;70%) or naturalized (&gt;39%) genotypes at the end of the first or second growing seasons.

Municipal sludge as source of nitrogen and phosphorus in perennial pasture &lt;i&gt;Eragrostis curvula&lt;/i&gt; production: Agronomic benefits and environmental impacts

Land application of sludge has been shown to improve soil properties and aid crop growth, but the possibility of constituent nutrients such as nitrogen and phosphorus reaching environmentally toxic levels has caused governing authorities to set limits to how much sludge can be applied to agronomic land. The high nitrogen utilisation potential of pasture grasses suggests that more sludge can be used in this cropping system without the risk of excess nitrates. This study investigates the effect of exceeding the South African sludge application limit on hay yield, soil nitrates and phosphorus. Field plots were arranged in a complete block design comprising 4 replications of 4 treatments planted to Eragrostis curvula. The treatments consisted of 0, 4, 8 and 16 Mg∙ha-1 anaerobically digested sludge. Soil samples were collected before treatment application and at the end of each growing season for N, P, NO 3 , NH 4 + , and Bray-1P analyses. Plant samples were collected at flower ing stage for hay yield and N and P uptake determination. Statistical analyses were conducted using analysis of variance (ANOVA) and general linear model (GLM) procedures of Windows SAS 9.0 to evaluate the effect of sludge application rates on hay yield. Results over 4 growing seasons indicate that exceeding the recommended limit increased hay yield by 4% in a dry season (11.7 vs. 12.36 Mg∙ha-1) and by 16% in a wet season (14.19 vs. 17.31 Mg∙ha-1) and also increased nitrogen uptake by 15%. Sludge applied at double the recommended limit did not cause the accumulation of nitrate and ammonium in the soil, however, both total and Bray-1P were doubled. The study shows that the potential long-term environmental risk of doubling the sludge application rate norm would be from labile P accumulation in the soil profile despite a sludge P:Fe molar ratio of less than unity.

The behavior of multiple independent managers and ecological traits interact to determine prevalence of weeds

Management of damaging invasive plants is often undertaken by multiple decision makers, each managing only a small part of the invader's population. As weeds can move between properties and re-infest eradicated sites from unmanaged sources, the dynamics of multiple decision makers plays a significant role in weed prevalence and invasion risk at the landscape scale. We used a spatially explicit agent-based simulation to determine how individual agent behavior, in concert with weed population ecology, determined weed prevalence. We compared two invasive grass species that differ in ecology, control methods, and costs: Nassella trichotoma (serrated tussock) and Eragrostis curvula (African love grass). The way decision makers reacted to the benefit of management had a large effect on the extent of a weed. If benefits of weed control outweighed the costs, and either net benefit was very large or all agents were very sensitive to net benefits, then agents tended to act synchronously, reducing the pool of infested agents available to spread the weed. As N. trichotoma was more damaging than E. curvula and had more effective control methods, agents chose to manage it more often, which resulted in lower prevalence of N. trichotoma. A relatively low number of agents who were intrinsically less motivated to control weeds led to increased prevalence of both species. This was particularly apparent when long-distance dispersal meant each infested agent increased the invasion risk for a large portion of the landscape. In this case, a small proportion of land mangers reluctant to control, regardless of costs and benefits, could lead to the whole landscape being infested, even when local control stopped new infestations. Social pressure was important, but only if it was independent of weed prevalence, suggesting that early access to information, and incentives to act on that information, may be crucial in stopping a weed from infesting large areas. The response of our model to both behavioral and ecological parameters was highly nonlinear. This implies that the outcomes of weed management programs that deal with multiple land mangers could be highly variable in both space and through time.

Yield and species composition of a mesic grassland savanna in South Africa are influenced by long‐term nutrient addition

AbstractSpecies composition and productivity of natural grasslands are influenced by soil nutrient status. With high resource availability, productivity is expected to increase, and competition is assumed to gain prominence with predicted exclusion of species of lower competitive ability. During 2010 and 2011 we used the dry weight rank method to measure above‐ground phytomass production of herbage in 96 plots (9 m × 2.7 m) fertilized for 60 years with two forms of nitrogen (N as limestone ammonium nitrate or ammonium sulphate at four levels: 0, 7.1, 14.1, 21.2 g m−2), phosphorus (P as superphosphate at two levels: 0, 33.6 g m−2), and lime (two levels: 0, 225 g m−2). Light attenuation was measured as the proportion of photosynthetically active radiation reaching the lower leaf layers of the grasses and the ground surface. Light conditions beneath the grass layer were reduced by nutrient addition to 30% of full sunlight but remained above 60% in non‐fertilized plots. Grass total above‐ground phytomass production increased with nutrient addition. The strongest yield responses were attained with N plus P addition. Species responses showed that Themeda triandra and Hyparrhenia hirta decreased in above‐ground phytomass production with nutrient addition while Panicum maximum, Eragrostis curvula and E. plana increased. These findings are discussed in terms of competitive interactions among species, their position in the grass canopy and their physiological tolerances to high nitrogen environments.

Spectral discrimination of increaser species as an indicator of rangeland degradation using field spectrometry

Discriminating increaser species is important for mapping rangeland degradation. The main objectives of this paper were to (1) determine whether four increaser species could be discriminated from each other and (2) determine the key wavelengths that have high discriminatory power. Spectral data were taken at canopy level from Hyparrhenia hirta, Eragrostis curvula, Sporobolus africanus and Aristida diffuse from Okhombe rangeland, KwaZulu-Natal province, South Africa. A field portable analytical spectral device with spectral range from 350 nm to 2500 nm was used in the analysis. Three-tier hierarchical techniques of One-way ANOVA, stepwise discriminant function analysis and canonical function analysis were used. The results revealed that there were statistically significant differences in spectral reflectance among four species on 439 wavelengths. The most important eight wavelengths (665 nm, 729 nm, 848 nm, 895 nm, 1039 nm, 998 nm, 681 nm and 972 nm) that have been selected for spectral discrimination were largely located in the visible, red-edge and near-infrared regions of the spectrum. The three tiers of analysis yielded species discrimination with an overall accuracy of 83 percent and a KHAT value of 0.77. The use of the spectroscopic approach applied in this study indicated that the increaser species were spectrally different. Therefore, these results encouraged further investigation into the possibility of mapping increaser species as indicators of different levels of rangeland degradation.

Vegetation communities in estuarine tidal flats in the different river and basin environments of the four major rivers of Ise Bay (Suzuka, Tanaka, Kushida), Mie Prefecture, Japan

In this study, we compared and analysed vegetation communities in the estuarine tidal flats of the four major rivers of Ise Bay (Suzuka River, Tanaka River, Kushida River and Miya River) in Mie Prefecture, Japan. Along the Suzuka River, Eragrostis curvula of the exotic plant accounted for 60.0% or more of the entire surface area, and the plant volume was high. Along the Tanaka River, Suaeda maritima community occupied the sand-mud zone in the vicinity of the shoreline on gravel bars, while Phragmites australis community was distributed along a shallow lake upstream. In the Kushida River, a salt marsh plant community (a community type found in areas flooded at high tide) of Suaeda maritima, Phragmites australis and Artemisia fukudo was distributed on the sand-mud surface along the main river. A salt marsh plant community (a community type found in areas that do not flood at high tide) of Phacelurus latifolius accounted for least 50.0% of the entire surface area. Along the Miya River, the area covered by the annual salt marsh plant community type was larger than the area occupied by this community type along the other rivers. The flow volume of the Miya River was high in April, June and August-October of 2006, July and September of 2007 and April-June of 2008. The flow volume was especially high in July 2007, when it reached levels above 1500.0 m3/s; change in flow volume was also large. We suggest that a large-scale disturbance occurred in the estuary, resulting in the formation of a gravelly sandy surface where an annual salt marsh plant community of Suaeda maritime and Artemisia fukudo has been established and grown as the annual precipitation and catchment volume of the basin have increased.

절개사면 녹화지역과 인접 자연지역의 식생 비교

This study was compared to the differences in the habitat, species composition and community structure of revegetation and nature area in Korea. Plant number in plot of revegetation and nature area was 10.3 and 15.0 taxa, respectively, and coverage was 90.6 and 88.1%, respectively. Revegetation and nature area was very heterogeneous, due to low similarity index (0.38) and less common plants. Festuca arundinacea frequency (56.7%) was highest in revegetation area, and Oplismenus undulatifolius frequency (66.7%) was highest in nature area. Plant appearing of revegetation and nature area was 111 and 136 taxa, respectively. Herb appearing of revegetation and nature areas was 93 (83.3%) and 72 (52.9%) taxa, respectively, tree was 18 (16.2%) and 64 (47.1%) taxa, respectively. Plant communities of revegetation area was classified into Lespedeza bicolor, Indigofera amblyantha, Alnus sibirica, Festuca arundinacea, Eragrostis curvula, Miscanthus sinensis, Humulus japonicus, Setaria faberii, Rudbeckia bicolor, Pueraria lobata community. Plant communities of nature area was classified into Pinus densiflora, Quercus aliena, Quercus acutissima, Quercus variabilis, Quercus serrata, Castanea crenata, Pinus rigida, Robinia pseudoacacia, Populus tomentiglandulosa, Phyllostachys bambusoides community. Habitat, species composition and community structure of revegetation and nature area showed a large difference.

Classifying increaser species as an indicator of different levels of rangeland degradation using WorldView-2 imagery

The development of new multispectral sensors with unique band settings is critical for mapping the spatial distribution of increaser vegetation species in disturbed rangelands. The objective of this study was to evaluate the potential of WorldView-2 imagery for spectral classification of four increaser species, namely Hyparrhenia hirta, Eragrostis curvula, Sporobolus africanus, and Aristida diffusa, in the Okhombe communal rangelands of South Africa. The 8-bands were extracted from the WorldView-2 image, and 24 of the most widely used vegetation indices in estimating grassland biophysical parameters were calculated. The random forest algorithm and forward variable method were applied to identify the optimal variables (WorldView-2 spectral bands, vegetation indices, and a combination of bands and indices) for classifying the species. The random forest algorithm could classify species with an overall accuracy of 82.6% (KHAT[an estimate of κ]=0.76 ) using six of the WorldView-2 spectral bands and an overall accuracy of 90% (KHAT=0.87 ) using a subset of vegetation indices (n=9 ). Three bands selected were located at the new WorldView-2 spectral regions of coastal blue, yellow, and the red-edge. There was no significant improvement in increaser species classification by using a combination of bands and indices. Overall, the study demonstrated the potential of the WorldView-2 data for improving increaser separability at species level.

Weeping Lovegrass Yield and Nutritive Value Provides an Alternative to Beef Cattle Feeding in Semiarid Environments of Argentina

ABSTRACTWeeping lovegrass [Eragrostis curvula (Schrad.) Nees] supports extensive beef cattle operations in arid and semiarid environments worldwide. This perennial grass is preferred in low production areas of Argentina because it has a high biomass production with minimal management requirements. Therefore, we evaluated yield and nutritional value of seven different cultivars and accessions of weeping lovegrass in a field experiment during two consecutive years (2008/2009 and 2009/2010). Two tetraploid cultivars (Tanganyika and Morpa), three hexaploid cultivars (Don Pablo, Don Juan, and Don Eduardo), and two accessions (UNST9355 and UNST9446) were included in a complete randomized block design. To evaluate yield and nutritional value, dry weight, leaf length, crown diameter, crude protein, in vitro dry matter digestibility (IVDMD), neutral detergent fiber, acid detergent fiber, and lignin were determined. Biomass and IVDMD data indicated that hexaploid cultivars performed better than tetraploid ones under limiting environmental conditions observed throughout the study. Therefore, we concluded that breeding programs could select suitable parents from hexaploid cultivars such as Don Pablo and UNST9446 to be used in arid environments while tetraploid cultivars such as Tanganyika and Morpa could be used in environments with less water restrictions.