The influence of mowing, fertilization, and plant removal on the botanical composition of an artificial sward

1990 ◽  
Vol 68 (5) ◽  
pp. 1080-1085 ◽  
Author(s):  
Roberta Parish ◽  
Roy Turkington ◽  
Elena Klein
Keyword(s):  
Species Diversity ◽  
Interaction Effect ◽  
Growth Rates ◽  
Competitive Exclusion ◽  
Dactylis Glomerata ◽  
Botanical Composition ◽  
Growing Seasons ◽  
Seed Mixture ◽  
Plant Removal ◽  
Fraser Valley

An artificial pasture was established using a forage seed mixture commonly used in the Fraser Valley of British Columbia. For five growing seasons, the plots were subjected to all combinations of two fertilizer levels, four frequencies of mowing, and the removal or not of small divots to create small gaps. All species were still present at the end of the study, but only Dactylis glomerata was found in all treatments; the abundance of ryegrasses (Lolium spp.) and clovers (Trifolium spp.) declined considerably, and there were significant [Formula: see text] between-year differences for all species. Mowing [Formula: see text] and fertilization [Formula: see text] had significant impacts on the abundance of all species, and there was a significant [Formula: see text] fertilization × mowing interaction effect on all species except Festuca sp. Divot removal had little impact. The number of species per plot and species diversity were highest, but the abundance of species was lowest, in unfertilized and frequently mown plots. The results are discussed in the context of tolerance to shading, nutrient application and growth rates, and competitive exclusion. Key words: mowing, fertilization, disturbance.

SOD-SEEDING BIRDSFOOT TREFOIL IN ESTABLISHED ORCHARDGRASS WITH OVERALL OR BANDED HERBICIDES

1983 ◽  
Vol 63 (1) ◽  
pp. 267-276 ◽  
Author(s):  
R. L. NICHOLS ◽  
R. A. PETERS
Keyword(s):  
Dry Matter ◽  
Dactylis Glomerata ◽  
Lotus Corniculatus ◽  
Birdsfoot Trefoil ◽  
No Tillage ◽  
Botanical Composition ◽  
Stand Establishment ◽  
Matter Production ◽  
Herbicide Treatments ◽  
Dactylis Glomerata L

Birdsfoot trefoil (Lotus corniculatus L. ’Viking’) was seeded directly into a predominantly orchardgrass (Dactylis glomerata L.) sward following overall or banded applications of paraquat (1,1′-dimethyl-4, 4′-bipyridinium ion, as dichloride salt) or glyphosate [N-(phosphonomethyl)glycine, as isopropylamine salt] to determine the degree of sward control necessary for stand establishment without tillage. Effects of the herbicide treatments and the seeding on botanical composition and dry matter production were determined by a vertical intercept technique and by hand separations of harvests into botanical components. Trefoil establishment was proportional to the degree of sward control during the seeding year. Little trefoil was established by direct seeding without herbicides. The banded herbicide treatments were less effective than overall herbicide applications for trefoil establishment. Trefoil yield obtained following overall application of paraquat was approximately 65% of that obtained following overall glyphosate treatment.Key words: Dactylis glomerata, glyphosate, Lotus corniculatus, herbicide, no-tillage, paraquat

scholarly journals Contribution of different grass species to plant-atmosphere ammonia exchange in intensively managed grassland

2009 ◽  
Vol 6 (1) ◽  
pp. 59-66 ◽  
Author(s):  
M. Mattsson ◽  
B. Herrmann ◽  
S. Jones ◽  
A. Neftel ◽  
M. A. Sutton ◽  
...  
Keyword(s):  
Species Diversity ◽  
Lolium Perenne ◽  
Dactylis Glomerata ◽  
Phleum Pratense ◽  
Compensation Point ◽  
Grass Species ◽  
Festuca Pratensis ◽  
Apoplastic Ph ◽  
Intensively Managed ◽  
Ammonia Exchange

Abstract. Species diversity in grasslands usually declines with increasing input of nitrogen from fertilizers or atmospheric deposition. Conversely, species diversity may also impact the build-up of soil and plant nitrogen pools. One important pool is NH3/NH4+ which also can be exchanged between plant leaves and the atmosphere. Limited information is available on how plant-atmosphere ammonia exchange is related to species diversity in grasslands. We have here investigated grass species abundance and different foliar nitrogen pools in 4-year-old intensively managed grassland. Apoplastic pH and NH4+ concentrations of the 8 most abundant species (Lolium perenne, Phleum pratense, Festuca pratensis, Lolium multiflorum, Poa pratensis, Dactylis glomerata, Holcus lanatus, Bromus mollis) were used to calculate stomatal NH3 compensation points. Apoplastic NH4+ concentrations differed considerably among the species, ranging from 13 to 117 μM, with highest values in Festuca pratensis. Also apoplastic pH values varied, from pH 6.0 in Phleum pratense to 6.9 in Dactylis glomerata. The observed differences in apoplastic NH4+ and pH resulted in a large span of predicted values for the stomatal NH3 compensation point which ranged between 0.20 and 6.57 nmol mol−1. Three species (Lolium perenne, Festuca pratensis and Dactylis glomerata) had sufficiently high NH3 compensation point and abundance to contribute to the bi-directional NH3 fluxes recorded over the whole field. The other 5 grass species had NH3 compensation points considerably below the atmospheric NH3 concentration and were thus not likely to contribute to NH3 emission but only to NH3 uptake from the atmosphere. Evaluated across species, leaf bulk-tissue NH4+ concentrations correlated well (r2=0.902) with stomatal NH3 compensation points calculated on the basis of the apoplastic bioassay. This suggests that leaf tissue NH4+ concentrations combined with data for the frequency distribution of the corresponding species can be used for predicting the NH3 exchange potential of a mixed grass sward.

scholarly journals Jack Pine Regeneration Following Postcut Burning under Seed Trees in Central Saskatchewan

1988 ◽  
Vol 64 (4) ◽  
pp. 315-319 ◽  
Author(s):  
Z. Chrosciewicz
Keyword(s):  
Populus Tremuloides ◽  
Growth Rates ◽  
Pinus Banksiana ◽  
Forest Regeneration ◽  
Black Spruce ◽  
Timber Harvest ◽  
Jack Pine ◽  
Growing Seasons ◽  
Pine Regeneration ◽  
Slash Burning

An experimental burn in conjunction with a seed-tree system was successful in regenerating jack pine (Pinus banksiana Lamb.) on a fresh to somewhat moist upland, loamy till, cutover site in central Saskatchewan. About 20 well-formed, uniformly spaced seed trees per hectare were left standing during timber harvest. The ignition of logging slash was carried out under preselected weather and fuel conditions so that favorable seedbeds and adequate seed dispersal from the seed trees were produced. Four growing seasons after burning, jack pine stocking by 4-m2 quadrats was 90% with 12 195 seedlings/ha. Aspen (Populus tremuloides Michx.), to a lesser degree black spruce (Picea mariana [Mill.] B.S.P.), and other companion tree species also regenerated with the pine. Various seedbed and regeneration characteristics as well as height growth rates are discussed. Key words: Pinus banksiana, slash burning, seed-tree system, forest regeneration, growth rates, central Saskatchewan.

scholarly journals Applying modern coexistence theory to priority effects

2019 ◽  
Vol 116 (13) ◽  
pp. 6205-6210 ◽  
Author(s):  
Tess Nahanni Grainger ◽  
Andrew D. Letten ◽  
Benjamin Gilbert ◽  
Tadashi Fukami
Keyword(s):  
Growth Rates ◽  
Competitive Exclusion ◽  
Abiotic Factors ◽  
Priority Effects ◽  
Competitive Interactions ◽  
Competing Species ◽  
Coexistence Theory ◽  
Dependent Growth ◽  
Established Population ◽  
Positive Frequency

Modern coexistence theory is increasingly used to explain how differences between competing species lead to coexistence versus competitive exclusion. Although research testing this theory has focused on deterministic cases of competitive exclusion, in which the same species always wins, mounting evidence suggests that competitive exclusion is often historically contingent, such that whichever species happens to arrive first excludes the other. Coexistence theory predicts that historically contingent exclusion, known as priority effects, will occur when large destabilizing differences (positive frequency-dependent growth rates of competitors), combined with small fitness differences (differences in competitors’ intrinsic growth rates and sensitivity to competition), create conditions under which neither species can invade an established population of its competitor. Here we extend the empirical application of modern coexistence theory to determine the conditions that promote priority effects. We conducted pairwise invasion tests with four strains of nectar-colonizing yeasts to determine how the destabilizing and fitness differences that drive priority effects are altered by two abiotic factors characterizing the nectar environment: sugar concentration and pH. We found that higher sugar concentrations increased the likelihood of priority effects by reducing fitness differences between competing species. In contrast, higher pH did not change the likelihood of priority effects, but instead made competition more neutral by bringing both fitness differences and destabilizing differences closer to zero. This study demonstrates how the empirical partitioning of priority effects into fitness and destabilizing components can elucidate the pathways through which environmental conditions shape competitive interactions.

Orius insidiosus (Hemiptera: Anthocoridae) in the lower Fraser Valley, British Columbia, Canada,

2006 ◽  
Vol 138 (4) ◽  
pp. 590-593 ◽  
Author(s):  
David R. Gillespie ◽  
D.M.J. Quiring
Keyword(s):  
Biological Control ◽  
British Columbia ◽  
Competitive Exclusion ◽  
North American Species ◽  
Indigenous Species ◽  
Orius Insidiosus ◽  
Lower Fraser Valley ◽  
Low Incidence ◽  
Non Indigenous Species ◽  
Fraser Valley

AbstractPopulations of Orius spp. were surveyed in the lower Fraser Valley, British Columbia, to determine whether O. insidiosus Say, a non-indigenous species, had established in the region as a result of being released inside greenhouses for biological control of pests. Field collections over 8 years revealed a low incidence of O. insidiosus (10 specimens, <1% of total Orius spp. collected). Numbers in collections did not increase, and collection localities did not become more widespread over the 8 years of survey. Competitive exclusion and temperature and diapause thresholds are discussed as possible mechanisms limiting the establishment of this otherwise widespread North American species.

scholarly journals Species Diversity and Botanical Composition of Permanent Grassland as a Response to Different Grazing Management Practices

2015 ◽  
Vol 63 (4) ◽  
pp. 1201-1209 ◽  
Author(s):  
Marie Štýbnarová ◽  
Josef Hakl ◽  
Pavlína Mičová ◽  
Hana Karabcová ◽  
Oldřich Látal ◽  
...  
Keyword(s):  
Species Diversity ◽  
Management Practices ◽  
Diversity Index ◽  
Nutrient Status ◽  
Careful Consideration ◽  
Botanical Composition ◽  
Mineral Fertilization ◽  
Elytrigia Repens ◽  
Pasture Fertilization ◽  
Similar Site

The effects of different levels of grazing utilization (two, three and four grazing cycles per year) and mineral fertilization (nil-fertilization; N100P30K60) on the botanical composition of permanent grasslands were studied in the locality of Rapotín (Czech Republic, 332 m a.s.l.) from 2003–2010. The vegetation of the experimental pasture was classified as Cynosurion. It was found that moderate treatment (three grazing cycles per year) without mineral fertilization showed the highest value of diversity index (DI = 6.08), and maximum dominance of legumes (Dmax = 9.1%), particularly Trifolium repens. The highest dominance of grasses (Dmax = 77.7%), mainly Dactylis glomerata and Elytrigia repens, was achieved with the fertilized treatment utilized in two grazing cycles per year. Based on RDA results, tested management treatments explained 26% of species composition variability, where effect of number of grazing cycles per year was five-times higher than effect of fertilization. We recommend grassland utilization in three grazing cycles per year as the most suitable way from the objective of both species diversity and botanical composition of pastures in similar site conditions. Pasture fertilization should be more controlled by careful consideration of individual pasture goals, actual nutrient status of the soil and possible environmental risks.

scholarly journals Impact of National Food Security Mission (NFSM) on Growth Rates and Decomposition Analysis of Pulses Production in India

2020 ◽  
pp. 44-50
Author(s):  
R. Nagarethinam ◽  
M. Anjugam
Keyword(s):  
Growth Rate ◽  
Food Security ◽  
Interaction Effect ◽  
Growth Rates ◽  
Decomposition Analysis ◽  
Instability Index ◽  
Area Effect ◽  
Area Growth ◽  
National Food Security

This paper investigates the trends in area, production and yield of major pulses in India by using component growth rate, Instability index and decomposition analysis during last twenty years. Further the study period has been divided into three periods based on the implantation of NFSM: Pre NFSM period I (1995 to 2006), Post NFSM period II (2007 to 2016) and Overall period (1995 to 2017). The result of CGR in total pulses revealed that the area (1.87%), production (3.58%) and yield (1.89%) registered highly positive significance with increased growth in period II. The yield growth rate was higher than area growth rate implying that the area allocation under pulses is increasing poorly even after NFSM scheme, while improvement in yield is there. The instability of total pulses production and productivity has first decreased and then increased in the overall period its shows increased growth. Among the major crops, the area effect was high in lentil production and by yield effect was high in gram production and the interaction effect was high in moong production during the overall study period. In case of total pulses, area and yield effects were positively higher and they were responsible for total pulses production.

scholarly journals Plant dominance in a subalpine montane meadow: biotic vs. abiotic controls of subordinate diversity within and across sites

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5619 ◽  
Author(s):  
Erika LaPlante ◽  
Lara Souza
Keyword(s):  
Species Diversity ◽  
Observational Study ◽  
Plant Species ◽  
Functional Traits ◽  
Relative Abundance ◽  
Abiotic Factors ◽  
Biotic Interactions ◽  
Removal Experiment ◽  
Plant Removal ◽  
Montane Meadow

Background Understanding the underlying factors that determine the relative abundance of plant species is critical to predict both biodiversity and ecosystem function. Biotic and abiotic factors can shape the distribution and the relative abundance of species across natural communities, greatly influencing local biodiversity. Methods Using a combination of an observational study and a five-year plant removal experiment we: (1) documented how plant diversity and composition of montane meadow assemblages vary along a plant dominance gradient using an observational study; (2) tracked above- and belowground functional traits of co-dominant plant species Potentilla and Festuca along a plant dominance gradient in an observational study; (3) determined whether plant species diversity and composition was directly influenced by commonly occurring species Potentilla and Festuca with the use of a randomized plot design, 5-year plant removal experiment (no removal control, Potentilla removed, Festuca removed, n = 10). Results We found that subordinate species diversity and compositional dissimilarity were greatest in Potentilla and Festuca co-dominated sites, where neither Potentilla nor Festuca dominated, rather than at sites where either species became dominant. Further, while above- and belowground plant functional traits varied along a dominance gradient, they did so in a way that inconsistently predicted plant species relative abundance. Also, neither variation in plant functional traits of Festuca and Potentilla nor variation in resources and conditions (such as soil nitrogen and temperature) explained our subordinate diversity patterns. Finally, neither Potentilla nor Festuca influenced subordinate diversity or composition when we directly tested for their impacts in a plant removal experiment. Discussion Taken together, patterns of subordinate diversity and composition were likely driven by abiotic factors rather than biotic interactions. As a result, the role of abiotic factors influencing local-level species interactions can be just as important as biotic interactions themselves in structuring plant communities.

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