The use of nitrogen, phosphorus and lime to limit the competitive ability of Aristida armata in the establishment phase

1993 ◽  
Vol 44 (1) ◽  
pp. 165 ◽  
Author(s):  
RD Armstrong ◽  
RF Brown ◽  
KR Helyar
Keyword(s):  
Competitive Advantage ◽  
Competitive Ability ◽  
Cenchrus Ciliaris ◽  
Replacement Series ◽  
Red Earth ◽  
Competitive Species ◽  
Per Se ◽  
Grazing Lands ◽  
Establishment Phase ◽  
Nitrogen Phosphorus

The de Wit replacement series methodology was used to see if applying phosphorus, nitrogen and lime to the sandy red earth soils of mulga grazing lands can give a competitive advantage to the desirable species Cenchrus ciliaris C.V. U.S.A., Digitaria ammophila, and Thyridolepis mitchelliana over the less desirable Aristida armata. In monoculture, all species responded strongly to added nutrients, especially phosphorus. In mixtures, the preferred grasses responded even more strongly to nutrients, whereas A. armata responsed proportionally less. C. ciliaris, D. ammophila, and T. mitchelliana suppressed the growth of A. amnata in all but three situations: without added nutrients, A. armata was equally competitive with C. ciliaris; when P was added without lime, A. armata suppressed C. ciliaris; if P was added without N, A. armata suppressed T. mitchelliana. Adding either or both nitrogen or phosphorus usually increased the relative crowding coefficients, indicating that the degree of suppression of Aristida was increased by adding nutrients. Thus, C. ciliaris, D. ammophila, and T. mitchelliana appear to be equally competitive with or more competitive than A. armata if the soil is not fertilized and adding nutrients generally enhances this competitiveness. In all cases, except for A. armata/C ciliaris mixtures in soils low in phosphorus, the plants appeared to be competing for the same resource. The study demonstrated that A. armata is not a highly competitive species per se under controlled conditions and was generally suppressed by the preferred grasses, especially when nutrients were added.

scholarly journals Impact of growing conditions on the competitive ability of Camelina sativa (L.) Crantz (Camelina)

2013 ◽  
Vol 93 (2) ◽  
pp. 243-247 ◽  
Author(s):  
Phillip B. Davis ◽  
Bruce Maxwell ◽  
Fabian D. Menalled
Keyword(s):  
Great Plains ◽  
Competitive Ability ◽  
Bromus Tectorum ◽  
Sandy Soils ◽  
Camelina Sativa ◽  
Northern Great Plains ◽  
Replacement Series ◽  
Competitive Species ◽  
Growing Conditions

Davis, P. B., Maxwell, B. and Menalled, F. D. 2013. Impact of growing conditions on the competitive ability of Camelina sativa (L.) Crantz (Camelina). Can. J. Plant Sci. 93: 243–247. It has been claimed that Camelina sativa, a recently introduced crop in the northern Great Plains, is a highly competitive species. However, this issue has not been formally tested. Utilizing replacement series diagrams, we assessed the importance of growing conditions in the competitive ability of C. sativa. Results indicated that canola and Bromus tectorum were superior competitors in both loam and sandy soils, thus providing evidence that C. sativa may not be as competitive as previously indicated.

scholarly journals Competitiveness of alexandergrass or Bengal dayflower with soybean

2010 ◽  
Vol 28 (3) ◽  
pp. 515-522 ◽  
Author(s):  
A.C.R. Dias ◽  
S.J.P. Carvalho ◽  
L.W. Marcolini ◽  
M.S.C. Melo ◽  
P.J. Christoffoleti
Keyword(s):  
Competitive Ability ◽  
Dry Mass ◽  
Total Density ◽  
Weed Species ◽  
Replacement Series ◽  
Commelina Benghalensis ◽  
Randomized Design ◽  
Full Flowering ◽  
Completely Randomized Design ◽  
Soybean Plants

Weeds compete with field crops mainly for water, light and nutrients, and the degree of competition is affected by the weed density and the intrinsic competitive ability of each plant species in coexistence. The objective of this research was to compare the competitiveness of alexandergrass (Brachiaria plantaginea) or Bengal dayflower (Commelina benghalensis) in coexistence with soybean, cv. M-Soy 8045. A factorial experiment (2 x 5) with two weed species and five competition proportions was carried out in a completely randomized design with four replicates. Proportions were based on a replacement series competition design, always maintaining the total density of four plants per 10 L plastic pots, which corresponded to 60 plants m ². The weed-crop proportions were: 0:4; 1:3; 2:2; 3:1; 4:0; that corresponded to the proportion of 100, 75, 50, 25 and 0% of soybean plants and the opposite for weeds, B. plantaginea or C. benghalensis plants. Leaf area, shoot dry mass of the weeds and soybean and number of soybean trifoliate leaves were evaluated when the soybean reached the phenologic stage of full flowering. B. plantaginea was a better competitor than soybean plants. Otherwise, C. benghalensis revealed a similar competitive ability that of the soybean. In both cases, there were evidences that intraspecific competition was more important.

scholarly journals Initial growth and competitive ability of yellow nutsedge and irrigated rice

2013 ◽  
Vol 31 (4) ◽  
pp. 813-821 ◽  
Author(s):  
N.R. Westendorff ◽  
D. Agostinetto ◽  
A.R. Ulguim ◽  
A.C. Langaro ◽  
L. Thürmer
Keyword(s):  
Leaf Area ◽  
Competitive Ability ◽  
Growth Cycle ◽  
Rice Crop ◽  
Initial Growth ◽  
Rice Cultivars ◽  
Replacement Series ◽  
Irrigated Rice ◽  
Yellow Nutsedge ◽  
Dry Biomass

Weeds cause significant reduction in the irrigated rice crop yield. Cyperus esculentus (yellow nutsedge) is adapted to irrigate environment. Information on the competitive ability of the weed to the culture, and their environmental adaptation, are scarce. In this study, we sought to determine the initial growth and competitive ability of yellow nutsedge and irrigated rice, as a function of cultivar growth cycle. Initial growth and competition studies were conducted in a randomized complete design in a greenhouse in the agricultural year 2010/11. For the initial growth study, the treatments consisted of a factorial combination of a biotype of yellow nutsedge and two rice cultivars in the function of the vegetative cycle (BRS Querência: early cycle - IRGA 424: intermediate cycle) and six evaluation times (10, 20, 30, 40, 50, and 60 days after emergence). Were evaluated: plant height, leaf area, aboveground dry biomass and root dry biomass. In the competitive ability study in the replacement series, the cultivar BRS Querência (early cycle) and yellow nutsedge were utilized and tested in different proportions of competition (100:0, 75:25, 50:50, 25:75, and 0:100). Were evaluated leaf area and aboveground dry biomass. In general, rice cultivars have an adaptive value equivalent to yellow nutsedge. IRGA 424 cultivar has less height than weed, becoming the weed control more important in this cultivar. For rice crop, intraspecific competition is more important, whereas for the weed, interspecific competition is the most pronounced.

The influence of buffel grass (Cenchrus ciliaris) on biodiversity in an arid Australian landscape

2009 ◽  
Vol 31 (3) ◽  
pp. 307 ◽  
Author(s):  
A. Smyth ◽  
M. Friedel ◽  
C. O'Malley
Keyword(s):  
Community Dynamics ◽  
Functional Group ◽  
Ground Vegetation ◽  
Cenchrus Ciliaris ◽  
Native Flora ◽  
Buffel Grass ◽  
Hot Climate ◽  
Environmental Weed ◽  
Grazing Lands ◽  
Land Types

Buffel grass [Cenchrus ciliaris L. syn. Pennisetum ciliare (L.) Link] is an exotic species that has been widely planted in Australian arid and semi-arid grazing lands, and has become an important resource for livestock. It establishes readily and has expanded into such a diversity of land types beyond grazing lands that it is also regarded as a serious environmental weed. Although there is an abundance of literature on the production benefits of buffel grass, there is relatively little about its influence on native flora and fauna in arid Australia, particularly when its cover levels are low. This study attempted to clarify the influence of buffel grass and environmental patterns on the occurrence of ground vegetation, birds, reptiles and ants in a gneissic hill habitat in central Australia where buffel grass has encroached. Despite poor conditions for growth, we were able to distinguish the influence of buffel grass from that of other variables like overstorey cover, soil pH, fire and transect orientation. Cover of buffel grass did not exceed ~20% but it still accounted for a small amount of the variation in the composition of ground vegetation and birds, and of the ‘ground-dwelling’ bird guild and the ‘hot climate specialist’ functional group of ants. There were insufficient reptiles for analysis. We conclude that, even when cover is low, buffel grass can have a detectable influence on some aspects of community dynamics. Given the evidence from published literature and from this study, we expect the influence of buffel grass on the diversity of native flora and fauna to increase, particularly if buffel grass expands into land types previously thought unsuited to its environmental needs.

scholarly journals Competitiveness of ALS inhibitors resistant and susceptible biotypes of Greater Beggarticks (Bidens subalternans)

2011 ◽  
Vol 29 (2) ◽  
pp. 457-464 ◽  
Author(s):  
F.P. Lamego ◽  
R.A. Vidal ◽  
N.R. Burgos
Keyword(s):  
Competitive Ability ◽  
Germination Rate ◽  
Rio Grande ◽  
Rio Grande Do Sul ◽  
Replacement Series ◽  
Relative Growth Rates ◽  
Temperature Conditions ◽  
Als Inhibitors ◽  
The University ◽  
Continuous Use

The continuous use of ALS-inhibiting herbicides has led to the evolution of herbicide-resistant weeds worldwide. Greater beggarticks is one of the most troublesome weeds found in the soybean production system in Brazil. Recently, a greater beggarticks biotype that is resistant (R) to ALS inhibitors due to Trp574Leu mutation in the ALS gene was identified. Also, the adaptive traits between susceptible (S) and R to ALS inhibitors biotypes of greater beggarticks were compared. Specifically, we aimed to: (1) evaluate and compare the relative growth rates (RGR) between the biotypes; (2) analyze the seed germination characteristics of R and S biotypes under different temperature conditions; and (3) evaluate their competitive ability in a replacement series study. The experiments were conducted at the University of Arkansas, USA, in 2007 and at Universidade Federal do Rio Grande do Sul (Federal University of Rio Grande do Sul), Brazil, in 2008. Plant proportions for replacement series studies were respectively 100:0, 75:25, 50:50, 25:75 and 0:100, with a total population of 150 plants m-2. There was no difference in RGR between R and S biotypes. The R-biotype germination rate was lower than that of the S biotype. However, at low temperature conditions (15 ºC), the reverse was observed. In general, there is no difference in the competitive ability between R and S greater beggarticks biotypes.

Phosphorus effects on competitive interactions of smooth pigweed (Amaranthus hybridus) and common purslane (Portulaca oleracea) with lettuce (Lactuca sativa)

Weed Science ◽  
1998 ◽  
Vol 46 (3) ◽  
pp. 307-312 ◽  
Author(s):  
Bielinski M. Santos ◽  
Joan A. Dusky ◽  
William M. Stall ◽  
Donn G. Shilling ◽  
Thomas A. Bewick
Keyword(s):  
Competitive Ability ◽  
Organic Soils ◽  
Weed Species ◽  
Population Densities ◽  
Replacement Series ◽  
Amaranthus Hybridus ◽  
Extractable P ◽  
Common Purslane ◽  
Smooth Pigweed ◽  
Water Extractable

Replacement series studies were conducted under controlled conditions to determine the effect of phosphorus (P) rates and population densities on the competitiveness of smooth pigweed and common purslane with lettuce. Densities were 2, 4, and 8 plants per 113 cm2, whereas P rates were 0, 0.4, and 0.8 g PL−1soil. A P-deficient Histosol (0.3 mg water-extractable P L−1soil) was used. High P fertility enhanced the competitive ability of lettuce in smooth pigweed-lettuce mixtures. Smooth pigweed was not responsive to P rates. However, luxurious P consumption by smooth pigweed occurred, reducing the amount of the nutrient available for lettuce absorption. In common purslane-lettuce mixtures, the weed was responsive to P rates, increasing its competitive ability, whereas no increase in lettuce competitive ability was observed. Both weed species were more competitive than lettuce. Competition for P appears to be the main mechanism of common purslane interference on lettuce grown in low-P organic soils. Alternative fertilization strategies (i.e., banded applications) may reduce the effect of smooth pigweed on lettuce.

Residual effects of phosphorus fertiliser in a stylo-native grass pasture on a duplex red earth soil in the semi-arid tropics of North Queensland

1994 ◽  
Vol 34 (2) ◽  
pp. 173
Author(s):  
KA Shaw ◽  
MA Gilbert ◽  
JD Armour ◽  
MJ Dwyer
Keyword(s):  
Soil Analysis ◽  
Residual Effects ◽  
Native Grass ◽  
Soil P ◽  
Initial Application ◽  
Red Earth ◽  
P Application ◽  
Stylosanthes Scabra ◽  
Phosphorus Application ◽  
Establishment Phase

A field experiment was established to define the phosphorus (P) requirement for establishment and maintenance of a mixed legume pasture (Stylosanthes scabra cv. Seca, S. hamata cv. Verano, S. guianensis cv. Graham, Macroptilium atropurpureum cv. Siratro) introduced into a native grass pasture on an infertile duplex red earth. Rates of 0, 5, 10, 20, and 40 kg P/ha were applied to separate plots in year 1 (1982), 2, and 3. In year 5 (1986 growing season), half of each plot that had received 20 and 40 kg P/ha in year 3 was refertilised at the original rate to ensure that maximum yields were defined. Bicarbonate- or acid-extractable soil P concentrations of 8 mg/kg were sufficient for 80% maximum legume yield. The residual value of applied P in the surface soil, as measured by soil analysis, decreased exponentially, but an initial application of 40 kg P/ha was still sufficient to produce near-maximum legume yield after 5 years. Phosphorus application increased the dry matter yield of legume. During the establishment phase (years 1 and 2 after planting) yields reached maximum at 10 and 20 kg P/ha, respectively, but increased linearly in subsequent years. When the original rates were reapplied in year 5, peak yield occurred at 20 + 20 kg P/ha, and there was no difference between this yield and that from plots receiving 40 kg P/ha in year 1. Native grass yields increased with P application only in years 4 and 5 of the experiment. Stylos demonstrated good tolerance to low P supply. In year 1, 80% of the total legume yield consisted of Graham stylo and Siratro, whereas in subsequent years, Seca and Verano made up 70 and 20%, respectively, of the total, irrespective of treatment. Yield of legume at nil P, relative to maximum, increased from 5% in year 1 to 42% in year 5.

Plant nutrition studies on some yellow and red earth soils in northern Cape York Peninsula. 1. Soils and their nutrient status

1976 ◽  
Vol 16 (81) ◽  
pp. 532 ◽  
Author(s):  
RF Isbell ◽  
RK Jones ◽  
GP Gillman
Keyword(s):  
Chemical Properties ◽  
Acid Soils ◽  
Nutrient Status ◽  
Stylosanthes Humilis ◽  
Northern Cape ◽  
Copper Zinc ◽  
Red Earth ◽  
Cape York ◽  
Nitrogen Phosphorus ◽  
Basic Cations

Eleven complete profiles and an additional 112 surface soils of deep sandy yellow and red earths in the far northern part of Cape York Peninsula have been sampled for laboratory studies. Chemical analyses showed that these acid soils are very low in organic carbon, nitrogen, phosphorus, potassium, sulphur, copper, zinc, manganese, cobalt, exchangeable basic cations, and base saturation. They have relatively high contents of exchangeable aluminium. The variability of surface soil chemical properties is relatively low. Glasshouse experiments with Stylosanthes humilis cv. Gordon conducted on soils from the 11 profile sites showed responses to sulphur, potassium, zinc and lime on all soils and to copper on about half the sites. Considering the results of both the laboratory and glasshouse studies, it is suggested that responses to nitrogen, phosphorus, zinc and probably calcium and copper are likely in the field. Responses to sulphur may be transitory because of the presence of appreciable levels of phosphate-extractable sulphur at depth.

Studies on mixtures of maize and beans (Phaseolus vulgaris) with particular reference to plant population

1972 ◽  
Vol 79 (3) ◽  
pp. 517-529 ◽  
Author(s):  
R. W. Willey ◽  
D. S. O. Osiru
Keyword(s):  
Competitive Ability ◽  
Maximum Yield ◽  
Plant Population ◽  
Population Pressure ◽  
Nitrogen Transfer ◽  
Replacement Series ◽  
Plant Populations ◽  
Intensive Farming ◽  
Optimum Proportion ◽  
High Level

SUMMARYTwo experiments are described in which the possible yield benefits of mixing maize and beans were examined under intensive farming conditions. A ‘replacement series’ of pure maize, two-thirds maize/one-third beans, one-third maize/two-thirds beans and pure beans was used at four plant populations. A high level of nitrogen was applied on the maize to eliminate the effects of nitrogen transfer from the beans.Yields of the mixtures were up to 38% higher than could be achieved by growing the crops separately. It is concluded that this occurred because the mixtures achieved a greater utilization of environmental resources; it is suggested that, because of the marked height differences of the two crops, an increased utilization of light was probably a major contributing factor. The need for high populations in mixtures is indicated, partly because the largest yield increases were achieved at high populations and partly because the mixtures required a higher population pressure to produce their maximum yield.The maize was found to have the higher relative competitive ability, and this increased with increase in plant population pressure. It is suggested that this was probably due to the shading effect which the maize had on the beans. The effects of a change in relative competitive abilities, or in relative selling prices, on the optimum proportion of two species in a mixture are also considered.

The relative competitiveness of atrazine susceptible and resistant populations of Chenopodium album and C. strictum

1981 ◽  
Vol 59 (5) ◽  
pp. 689-693 ◽  
Author(s):  
S. I. Warwick ◽  
L. Black
Keyword(s):  
Biomass Production ◽  
Aboveground Biomass ◽  
Competitive Ability ◽  
Chenopodium Album ◽  
Dry Weight ◽  
Replacement Series ◽  
Susceptible Population ◽  
Resistant Population ◽  
Reproductive Biomass ◽  
Susceptible Populations

The total aboveground biomass and reproductive dry weight of one atrazine resistant and one susceptible population from southern Ontario of each of two species of Chenopodium, C. album and C. strictum, were compared. The comparison was made between plants grown under both noncompetitive and competitive conditions. Results from a spaced noncompetitive trial provided evidence for: (1) greater total and reproductive biomass production and earlier flowering of resistant and susceptible populations of C. album as compared with both populations of C. strictum, (2) greater aboveground total and reproductive biomass production of the susceptible population of C. album as compared with the resistant population, and (3) greater total aboveground biomass production (but similar reproductive biomass) of the susceptible population of C. strictum as compared with the resistant population. Results from the competition trials (i.e., plants grown in a de Wit replacement series), provided evidence for inter- and intra-specific differences in competitive ability: (1) the susceptible population of C. album was found to be more competitive than the susceptible population of C. strictum, (2) the susceptible population of C. album was a superior competitor to the resistant population, and (3) the resistant and susceptible populations of C. strictum appeared to be equally competitive.

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