Grass Stage Research Articles

Natural regeneration dynamics of Pinus merkusii in northern Thailand

The effect of ground fire and subsequent exposure of mineral soil on germination and early development of Pinus merkusii Jungh. et de Vriese, and morphological development throughout the grass stage of naturally borne seedlings were studied in northern Thailand, within the natural distribution range of the species. The study was carried out with the major aim to find out whether and to what extent the natural regeneration of mainland P. merkusii is controlled by fire, and what the main adaptive advantage is of the prolonged grass stage characteristic to the species. Finally, silvicultural implications of the findings are discussed. We found that the total volume of stem and tap root in the grass stage controls the shoot growth rather distinctly: seedlings emerge from the grass stage soon after a certain minimum volume (approx. 15–20 mm diameter at ground level) is reached. The growth of the tap root is steady throughout the grass stage. Formation of the deep tap root promotes the volume growth of the stem. Two-thirds of the diameter of the short stem is formed by cortex, which functions as a carbohydrate store to be later utilized in the fast shoot growth. There were no significant differences in germination and early development of P. merkusii seedlings between a burnt and an unburnt area. Considerable numbers of seedlings (11 042–34 250 ha −1) were found in stands burnt 2, 4 and 6 years previously. P. merkusii seeds germinate well beneath a dense cover of grass, giving rise to an abundant ephemeral seedling stock. Mortality due to competition by grass is, however, high. Successful natural regeneration requires a 4–6 year period without a fire. Within this period, seedlings have developed into the grass stage and are better protected against seasonal drought and ground fires.

Influence of Nitrogen Application and Stage of Harvesting on the Dry Matter Production of Sorghum Sudanense-Lablab purpureus Mixtures in Central Sudan

SUMMARYThe effects of cropping system, nitrogen application and harvesting stage on the quantity and quality of the forage produced by Sudan grass-lablab mixtures were studied in central Sudan. Mixing increased the number of tillers plant-1 of Sudan grass and the plant dry weight of both crops. Application of nitrogen increased the number of tillers and dry weight plant-1 of Sudan grass but had no significant effect on the growth parameters of lablab. Growth parameters of both crops were appreciably increased by harvesting at the milk-ripe stage of Sudan grass. The largest total dry matter yield was obtained from a mixture of 20 kg Sudan grass and 40 kg lablab ha-l, but the largest protein yield was obtained from sole lablab.Nitrógeno en combinaciones de sorgo sudanés y Lablab purpureus

Effect of maturity stage of Italian rye grass and lucerne on ruminal nitrogen degradability

Effect of maturity stage of Italian rye grass and lucerne on ruminal nitrogen degradability

Effects of even-aged management on forest birds at northern hardwood stand interfaces

Breeding birds were counted along transects across edges of even-aged northern hardwood stands in the White Mountain National Forest, New Hampshire, U.S.A. Two replicate transects across each of 7 edge types representing 3 classes of contrast (abrupt, intermediate, and subtle) were sampled during June 1983–1985 to define species assemblages at stand edges and estimate the width and longevity of functional edges under even-aged management. Of 52 bird species, 28 occurred across all three classes of edges, but no unique species or assemblages were evident at the edges between stands. Across edges between young stands, bird species richness declined linearly from seedling stand interior to pole stand interior, but no differences in cumulative bird species richness by edge contrast type were found. The proportion of edge-detected species was higher in the younger stand in all edge contrast types except the most subtle edge type between mature stands. Only across seedling-sawlog and sapling-large sawlog edges were bird assemblages more different than similar. Edge “avoidance” was pronounced when stands were most different. The distributions of foraging and nesting guilds differed ( P < 0.05) only when seedling or sapling stands abutted stands that were pole-sized, or larger. Edges between even-aged northern hardwood stands, even of greatly contrasting age or height, are different from field-forest edges. Northern hardwood clearcuts regenerate rapidly and do not develop a grass stage nor a brushy border. Foliage profiles in stands of widely disparate ages are similar, and effects of boundaries between even-aged stands on breeding birds are ephemeral.

Lactobacillus graminis sp. nov., a New Species of Facultatively Heterofermentative Lactobacilli Surviving at Low pH in Grass Silage

A group of 11 facultatively heterofermentative rod-shaped bacteria were isolated at a late fermentation stage of pre-wilted grass. These bacteria were found to differ from currently described lactobacilli in the spectrum of fermented sugars, in particular in their ability to ferment xylose. The isolates were similar to Lactobacillus curvatus and Lactobacillus sake with respect to D(-)- and L(+)- lactate formation, R f -values of the D- and L-LDH, G+C content of the DNA and the L-Lys-D-Asp murein type. Teichoic acid was lacking. DNA-DNA homology among the isolates was high, while low homology values were obtained with the type strains of L. curvatus and L. sake , indicating only a distant relationship. It is proposed that the isolates represent a new species named Lactobacillus graminis sp. nov.

Planted Longleaf Pine Seedlings Respond to Herbaceous Weed Control Using Herbicides

Abstract Height initiation, and height and diameter growth of longleaf pine (Pinus palustris) seedlings were compared on plots receiving herbaceous weed control treatments and on unweeded check plots during the first 4 years after planting. Treatments initiated during the spring following planting included: broadcast weed control for 1 and 2 years, banded weed control in 5-foot bands for 1 and 2 years, and no weed control (check). Weed control had a positive effect on fourth-year height, groundline diameter, and the percentage of seedlings out of the grass stage, while survival was unaffected. The duration of weed control (2 years vs 1 year) had a similar effect on the same response variables, while the method of weed control (broadcast vs. band) had no effect. Trees on plots receiving 2 years of weed control were approximately 3 feet taller and 0.5 inch greater in groundline diameter than trees receiving no weed control. One year of weed control resulted in trees approximately 2 feet taller and 0.3 inch greater in groundline diameter than with no weed control. Weed control treatments shortened the time seedlings were in the grass stage by approximately 1 year, decreasing the time period during which a serious brown-spot needle blight infection could develop.¹

Pensacola Bahiagrass Can Be Used to Improve the Forage Resource when Regenerating Southern Pines

Abstract Many native forage plants in the South are low quality, poor producers, and unpalatable to cattle. Replacement of these plants with more desirable species would improve the forage resource. One approach is to seed grasses during site preparation when regenerating southern pines. Following site preparation by shearing and strip-disking, Pensacola bahiagrass (Paspalum notatum) was seeded at 15 pounds per acre in the spring and longleaf pine (Pinus palustris) was row-seeded on 12-foot centers in December of the next year. The bahiagrass became established among the residual native plants and was heavily utilized by cattle grazing yearlong. A light application of fertilizer after 3 years tripled bahiagrass yields the first year and doubled it the next year compared to unfertilized plots. Fertilizer improved some nutritional qualities of bahiagrass but digestibility was lowered. Longleaf pine seedlings came out of the grass stage more rapidly and were 50% taller at age 9 with grazing than without it; and in spite of heavier mortality with grazing (36% vs. 21%), stocking was 967 trees per acre at age 11.

Stimulation of early height growth in longleaf pine with growth regulators

Longleaf pine (Pinuspalustris Mill.), although it has many excellent qualities, is not extensively planted because of its extended seedling "grass stage" accompanied by poor field survival. Treatments with cytokininlike substances in spring and early summer stimulated seedling height growth, and this effect was enhanced by gibberellic acid (GA3) and DPX 3778, an experimental triazinone derivative that is synergistic with gibberellins. The synthetic cytokinin benzyladenine and other active purine derivatives, although potent, tended to cause bud proliferation and death. A seaweed extract with cytokinin activity, Cytex, proved effective without the deleterious side effects. A promising technique is thus to apply combination sprays of Cytex, GA3, and DPX 3778 in the nursery to stimulate height growth during the 1st year in the field.

Crested Wheatgrass Vigor as Affected by Black Grass Bug and Cattle Grazing

Crested Wheatgrass Vigor as Affected by Black Grass Bug and Cattle Grazing

Fall Fertilization Helps Longleaf Pine Nursery Stock

Abstract Fall fertilization resulted in substantial overwinter dry weight gains and increases in nutrient content and concentrations in one-year-old longleaf pine (Pinus palustris Mill.) nursery stock. Recovery of applied nutrients in the seedling crop was greatest for N. In the field, height growth and the rate of emergence from the grass stage were improved as a result of fall fertilization in the nursery. This practice thus offers a means of increasing seedling size and nutrient reserves prior to out-planting on the relatively infertile sites where seedlings are normally established.

Long-Term Impact of Aerial Application of 2,4,5-T to Longleaf Pine (Pinus palustris)

Twenty years after aerial application of 2.24 kg ae/ha of the butoxy ethanol ester of 2,4,5-T [(2,4,5-trichlorophenoxy)acetic acid] to release grass stage longleaf pine (Pinus palustris Mill.) seedlings, stocking was the same for each of three treated and control 4-ha plots. Treated plots, however, had significantly greater tree diameter (10%), taller trees (17%), and more merchantable tree volume/ha (40%). Merchantable tree volume differences 20 yr after treatment represent an 8 yr growth advantage for treated plots.

Effect of Rhizosphere Bacteria of Aristida oligantha on Rhizobium and Azotobacter

Revegetation of abandoned fields in central Oklahoma is characterized by the prolonged duration of the annual grass stage dominated by triple-awn grass, Aristida oligantha. This is due largely to the increasing nitrogen requirements of the grasses of stages III and IV and the suppression of biological nitrogen fixation by a variety of plants from stages I and II, including Aristida. Rhizosphere bacteria from the roots of A. oligantha were isolated and tested for inhibitory or stimulatory effects on three strains of Rhizobium and three of Azotobacter. Of the 28 isolates, five (18%) showed antagonistic activity toward one or more of the test strains while two (7%) showed evidence of stimulation. Overall, 14 instances of inhibition and three of stimulation were recorded. The most striking results were the marked inhibition of all six Rhizobium and Azotobacter strains by Xanthomonas axonopodis. Other bacteria found to inhibit one or more of the test strains were Arthrobacter citreus, Arthrobacter simplex, Enterobacter aerogenes, and Micrococcus luteus. Stimulatory bacteria were Bacillus cereus and B. megaterium. This allelopathic activity of rhizosphere bacteria of A. oligantha against nitrogen-fixing bacteria adds an additional dimension to the direct effect of Aristida on biological nitrogen fixation, thus delaying nitrogen accumulation and helping to prolong the annual grass stage in Oklahoma old fields.

Changes in Community Structure in Oklahoma Old Field Succession

Species composition and community structure of four fields characteristic of pioneer weed, annual grass, bunch grass, and climax tall grass prairie communities (seral stages of old-field succession in central Oklahoma) were studied over a 5-yr period. Diversity indices and dominance-diversity curves were evaluated as a means of assessing certain ecological processes of the communities. The dominance-diversity curves for early pioneer weed and early annual grass stages revealed a geometric distribution indicative of a niche-preemptive situation. This pattern appears to be a reliable indicator of strong dominance influenced by allelopathic processes.

Acetylene reduction (N 2-fixation) in soil and old field succession in central Oklahoma

Abstract The N 2-fixing activities of two old field successional plots (P 1—pioneer weed stage, P 2—annual grass stage) and one prairie site ( P 2) were estimated using the C 2H 2 reduction assay. Fresh soil samples generally had very low activity. The average p moles C 2H 4.g soil −1.h −1 for each site was P 1, 23; P 2, 15; P 3, 83. Statistical comparisons were made between C 2H 2 reduction and soil moisture, soil temperature, numbers of Azotobacter. g −1, and numbers of blue green algae, g −1. The population size of the blue green algae was highly correlated ( r = 0.735) with C 2H 2-reduction in p 2 soils but not with P 2 or P 3 soils. N 2-fixing organisms isolated from the soils were Azotobacter chroococcum, Enterobacter aerotgenes, Clostridium sp., Nostoc sp., and Anabaena sp. Numbers of blue green algae decreased whereas numbers of Azotobacter increased through the successional stages. It was inferred that the anaerobic forms progressively increased in numbers through the successional stages. Selected phenolic acids, ferulic, sinapic, p-coumaric, vanillic, gallic, ellagic, and chlorogenic were found to be most inhibitory to E. aerogenes and least inhibitory to Clostridium sp. The data support a prior hypothesis that relates the longevity of the P 2 seral stage to a biological suppression of the accumulation of soil N.

Early Stages of Vascular Plant Succession in a Central New York Old Field

Changes in pioneer community structure in an 0.8-ha central New York field were monitored during a year of cultivation and the 1st 2 years of abandonment. Species composition was unlike that of old fields in more southerly location, but similar to southeastern Michigan old fields. High diversity (Shannon-Wiener Index) and high proportion of perennials in the 1st year of abandonment and the establishment of a perennial grass stage during the 2nd year were attributed to persistence of propagules in the soil after 1 year of cultivation or possibly to rapid restocking due to the small size of the field. Maximum productivity occurred during June of the 2nd year of abandonment when dominance was established by Phleum pratense; however, total production over the growing season was lower than in the 1st year when dominance was shared by several species early in the growing season. Eighty-four percent of the species identified during the 1st year of abandonment were exotics, primarily European in origin. This percentage was much higher than reported for 1st-year fields in southeastern and mid-Atlantic regions. INTRODUCTION Secondary succession has been intensively studied in the eastern deciduous forest region of the United States. Much of the work has been done in the southeastern and mid-Atlantic Coastal Plain (McCormick and Buell, 1957; Odum, 1960; Woodwell and Oosting, 1965; Golley, 1965; Golley and Gentry, 1966; Levin, 1966), Piedmont (Oosting, 1942; Keever, 1950; Bard, 1952; Daniel and Platt, 1968; Hanks, 1971; Buell et at., 1971), and in the Midwest (Evans and Cain, 1957; Beckwith, 1954; Wiegert and Evans, 1964; Bazzaz, 1968). Very little has been published about secondary succession in the northeastern Appalachian Plateau. Swan (1970) studied the response of various seral stages to burning in S-central New York. Hurd et al. (1971) studied two abandoned hayfields in central New York in an attempt to ascertain the effect of nutrient enrichment on stability and diversity on the old-field ecosystem. This paper reports on the first phase of a study designed to compare succession on a central New York old field with old-field succession in southeastern, mid-Atlantic, and Midwestern regions. MATERIALS AND METHODS The study is being carried out at the Suny College at Oneonta Biological Field Station near Cooperstown. The elevation is 512 m (1680 ft) above sea level. The soil type is Volusia channery silt loam, an imperfectly drained, acid soil of glacial origin. Soils of this type typically have a fragipan at a depth of 30 cm (1 ft). These soils are used principally as pasture land, or for the production of oats or

Effects of Species Removal on an Old‐field Plant Community

The effect of removing the dominant grasses on the net productivity of subordinate forb species was investigated in the perennial—grass stage of old—field succession. Removing the dominants increased the net productivity of subordinate species from 0.49 g/m2°day to 1.44 g/m2°day. The increased net productivity of subordinates was due to increased productivity by almost all subordinate species. This increase was not sufficient to equal the total net productivity of the unaltered community (2.26 g/m2°day). Net productivity by subordinates in the absence of dominants was less than that reported for earlier successional stages where the forbs are the dominant producers. However, this difference might have been caused by relatively low rainfall at the time of this experiment.

EFFECTS OF GROWTH STAGE ON TRANSLOCATION OF GLYPHOSATE IN QUACK GRASS

Visual symptoms of toxicity (inhibition of leaf growth and bud germination) were used to study the influence of growth stage of quack grass (Agropyron repens (L.) Beauv.) on glyphosate (N-phosphonomethyl glycine) transport and efficiency. Glyphosate (or a toxic metabolite) moved in sufficient quantity from the point of application on the leaf within 1 day to significantly affect the regrowth and within 2 days to affect the regenerative potential of rhizomes. As quack grass plants developed to the four-leaf stage the effect of glyphosate treatment increased. When only one shoot was sprayed on a rhizome supporting two shoots at the same leaf stage, glyphosate inhibited leaf growth on the untreated shoot at the two-leaf stage but not at the four-leaf stage. Similarly, glyphosate inhibited leaf growth on tillers when only the main shoot was sprayed. However, when only the tiller was sprayed, leaf production was not affected on the main shoot suggesting that glyphosate is phloem mobile.

Terrestrial Plant Invasion onto a Drained Lake Bed

Terrestrial plants were collected frown the drained lake bed of Lyon Countsr Stane Lakes Kansas9 during the 1963 and 1965 growing seasons. Plants of the first year growth consisted of annual species of grasses and herbs. The species making up the plant community on the lake bed during the second year consisted of 40 per cent perennial plants. A six-fold increase in number of species was observed after two years. Trans. Kans. Acad. Sci., 76 (4), 1973. Introduction This study serves as a documentation of the plant species comprising the first subseral stage of a tall grass prairie association in east-central Kansas. Description of the Study Area Lyon County State Lake is located approximately 12 miles northeast of Emporia, Kansas (R12E, T17, SEC 26, 27). The Kansas Forestry, Eiish and Game Commission purchased 600 acres of prairie for its site in 1931; its final construction was completed by the Civilian Conservation Corps in 1934. A park surrounding the lake and a shelter house of native limestone were added in 1950 (Grove, 1951). Fo 26 years the lake served as a fishing and recreational resource receivine, runoff from a grassland drainage (1,400 acres) predominated by plants belonging to the Andsopogosz xcoparizls, Andropogov (gerardi, Sosghaxtsgm slgtans, Panirzlon risgcgtzassz and Bogtelogcz cgrtipewzdzzla association. During the summer of 1962 the lake was drained by the State Fisherie3 Division to restore its spcrts isheries. By October of that year the drasvdown had -educed the lake surface to approximately 2 acres. Refilling commenced in the spring of 1963 and by midsummer water covered a surface of approximately 25 acres. The amount of exposed lake Transactions of the Kansas Academy of S,cience, Vol. 76, No, 4, 1973. Published September 20, 1974

Seed Production of Species in the Highveld Secondary Succession

After cessation of cropping in the Trachypogon-other species grassland of the South African Highveld, the usual secondary succession was described as follows by Rose-Innes (1939). (1) The ruderal or weed stage, dominated by species such as Erigeron canadensis.t Grasses such as Eleusine indica can dominate with high soil fertility (Davidson 1962). (2) The primary grass stage, usually dominant 2-3 years after abandonment. Characteristic species are the tussock grass Eragrostis curvula and the stoloniferous Cynodon dactylon. (3) The secondary grass stage, usually dominant some 10 years after abandonment. The characteristic species is the tussock grass Hyparrhenia hirta. (4) The sub-climax grassland. Rose-Innes suggested that after 30 or so years the seral areas would have a botanical composition similar to undisturbed Trachypogon-other species grassland. The undisturbed grassland will be referred to as sub-climax grassland, a term used by previous workers (e.g. Davidson 1962). Characteristic species are T. spicatus and Tristachya hispida. In almost all seral communities there are some species from each of the first three stages, although one particular stage may be dominant. Seral grasses are also found scattered throughout sub-climax grassland. Studies by Rose-Innes (1939) showed that seed viability of species in the Highveld succession declined as succession advanced, but no studies have been made of the seed output of different seral stages of the Highveld succession. Salisbury (1942) showed that in general seed output of dicotyledons decreased as species came from later seral stages, but no reports have been encountered which have followed seed output through succession in one particular locality. Investigations of seed production were made during the 1961-62 growing season on the Frankenwald Research Station of the University of the Witwatersrand. The station is on latitude 26?S and longitude 28?E. The soils are acid and light textured. The annual rainfall is approximately 30 in. (760 mm) per year and is virtually confined to the summer months.

The Influence of Edaphic Factors on the Species Composition of Early Stages of the Subsere

The secondary succession (subsere) on the sandy soils of the Transvaal Highveld has been described by Innes (1939), based on examination of disturbed sites of known history, and the terms ruderal stage, primary grass stage, secondary grass stage, grassland subclimax and scrub climax were proposed. It seems preferable to divide the early stages into communities which are distinctive when grazing and other biotic factors operate, and the following stages are proposed: