The influence of density and nitrogen on the outcome of competition between two annual pasture grasses (Hordeum leporinum Link and Lolium rigidum Gaud.)

1974 ◽  
Vol 25 (2) ◽  
pp. 247 ◽  
Author(s):  
PS Cocks
Keyword(s):  
Soil Nitrogen ◽  
Competitive Ability ◽  
Total Density ◽  
Lolium Rigidum ◽  
High Nitrogen ◽  
Original Hypothesis ◽  
Pasture Grasses ◽  
Hordeum Leporinum ◽  
Low Nitrogen

The hypothesis that the outcome of competition between Hordeum leporinum Link and Lolium rigidum Gaud. depended predominantly on the density of Hordeum was tested in two experiments. In the first experiment it was postulated that increasing the density of Hordeum increased its competitive ability; in the second experiment the interaction between soil nitrogen and density was studied. Under the conditions of the first experiment the hypothesis was shown to be true. The competitive ability of Hordeum was closely related to its density, and neither the density of Lolium nor the total density had a significant effect. Hordeum was most competitive when its density was highest. The second experiment showed that soil nitrogen was an important modifying factor. At low nitrogen Hordeum was the successful competitor, but its competitive ability decreased with increase in its density. At high nitrogen Lolium became the successful competitor, although the effect of Hordeum density was similar to that in experiment 1. At the lower levels of nitrogen the density of Lolium also affected the outcome of competition, but its effect was never as great as that of the density of Hordeum. The results are explained in terms of the original hypothesis and of the different abilities of the two species to absorb soil nitrogen.

Yield, oil and protein content of oilseed rape as affected by soil and fertilizer nitrogen and phosphorus

1978 ◽  
Vol 18 (90) ◽  
pp. 107 ◽  
Author(s):  
GJ Osborne ◽  
GD Batten
Keyword(s):  
Oilseed Rape ◽  
Soil Nitrogen ◽  
Available Phosphorus ◽  
Wagga Wagga ◽  
High Nitrogen ◽  
Nitrogen And Phosphorus ◽  
Matter Production ◽  
Wide Range ◽  
High Level ◽  
Low Nitrogen

The Zephyr cultivar of oilseed rape (Brassica napus) was grown on two sites at Wagga Wagga. Both sites had a wide range in levels of available phosphorus; one had a low and the other a high level of soil nitrogen. On both sites superphosphate applied prior to, and during, the current cropping phase caused significant increases in dry matter production, seed yield, oil and protein yields. Pod numbers increased significantly only on the high nitrogen site. On the high nitrogen site, seed, protein and oil yields (kg ha-1) were higher than on the low nitrogen site, even when the latter site was cropped using nitrogen fertilizer. Oil yields ranged from 237 to 1273 kg ha-1 on the high nitrogen site and from 229 to 91 6 kg ha-1 on the low nitrogen site. The rape crop responded to drilled superphosphate on sites with low to medium levels of 'available' phosphorus. Soil tests developed for wheat indicated sites with adequate soil nitrogen and phosphorus.

The germination and establishment of two annual pasture grasses (Hordeum leporinum Link and Lolium rigidum Gaud.)

1973 ◽  
Vol 24 (1) ◽  
pp. 1 ◽  
Author(s):  
PS Cocks ◽  
CM Donald
Keyword(s):  
High Temperatures ◽  
Mediterranean Region ◽  
Soil Surface ◽  
Lolium Rigidum ◽  
High Moisture ◽  
Pasture Grasses ◽  
Annual Grasses ◽  
Similar Range ◽  
Hordeum Leporinum ◽  
Pasture Plants

The germination and establishment of Hordeum lepovinum Link and Lolium rigidum Gaud., two Mediterranean annual grasses, were studied under controlled conditions. Results were related to the ecology of these species as pasture plants in southern Australia. Seeds of the two species germinated over a similar range of constant temperatures (8-30�C); Hordeum germinated much more rapidly than Lolium at all temperatures. Lolium has a marked requirement for alternating temperatures for maximum germination, while Hovdeum has a weak or nil requirement. Both species withstood prolonged wetting at high temperatures without germinating or losing all viability. Prior soaking and redrying before germination increased the rate of germination of both species. Light rains which fall before the first germinating autumn rains usually wet the seed only for short periods and this further increases the advantage of Hordeum over Lolium in rate of germination. Hordeum germinated and established much more readily on the soil surface than did Lolium, even though Lolium absorbed water more rapidly. The success of Houdeum was due both to its rapidity of germination, which allowed it to establish before the soil surface dried out, and to its ability to germinate at high moisture tensions. Because of these features Hordeum leporinum has the potential to germinate earlier, more rapidly, and more freely than Lolium rigidum in the autumn of the Mediterranean region of southern Australia.

The early vegetative growth of two annual pasture grasses (Hordeum leporinum Link and Lolium rigidum Gaud.)

1973 ◽  
Vol 24 (1) ◽  
pp. 11 ◽  
Author(s):  
PS Cocks ◽  
CM Donald
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Vegetative Growth ◽  
Root Weight ◽  
Lolium Rigidum ◽  
Pasture Production ◽  
Relative Growth ◽  
Pasture Grasses ◽  
Seedling Growth Rate ◽  
Hordeum Leporinum

The early vegetative growth of Houdeum Iepouinum and Lolium rigidum was studied at three temperatures in a controlled environment cabinet. The seedling growth rate in each species was much more rapid during the period of endosperm availability than after cndospcrm exhaustion. At the temperatures tested (10, 17, and 24�C) the relative growth rate of Lolium was greater than that of Houdeum, with a relatively slight difference at 10 and 24�, but with a considerable difference at 17�. In spite of the superior relative growth rate of Lolium, seedlings of Houdeum were, for a considerable period following emergence, larger in terms of total weight, leaf area, root weight, root depth, and plant height because of the greater seed size. The length of this period of greater size depended on the temperature, being least (c. 26 days) at 17�C, when the advantage of Lolium was greatest. The implications of these findings in pasture production in southern Australia, and especially in the competitive relationships of Hordeum and Lolium, are described.

Effects of endophyte infection on the competitive ability of Achnatherum sibiricum depend on endophyte species and nitrogen availability

2019 ◽  
Vol 12 (5) ◽  
pp. 815-824
Author(s):  
Yong Zhou ◽  
Xia Li ◽  
Hui Liu ◽  
Yubao Gao ◽  
Wade J Mace ◽  
...  
Keyword(s):  
Dominant Species ◽  
Competitive Ability ◽  
Nitrogen Availability ◽  
Inhibitory Effect ◽  
Nitrogen Supply ◽  
Tiller Number ◽  
High Nitrogen ◽  
Nitrogen Levels ◽  
Endophyte Infection ◽  
Low Nitrogen

Abstract Aims The leaves of almost all terrestrial plant species are colonized by endophytic fungi. Compared to agronomic grasses, which usually harbor few endophytes, native grasses generally possess greater endophyte species diversity. Existing studies examining endophyte effects on natural grasses under competition normally considered the infection status (infected or uninfected), and rarely considered endophyte species. Methods We examined the effects of endophyte infection and of endophyte species on the interspecific competitive ability of a subdominant species, Achnatherum sibiricum, at two nitrogen levels (high nitrogen and low nitrogen). Achnatherum sibiricum plants infected by two different species of endophyte (Epichloë sibirica and E. gansuensis) and uninfected plants were grown in monoculture and binary mixtures with a dominant species, Stipa grandis (six individuals per species for monocultures and three + three individuals of each species in mixtures). Shoot and root biomass, tiller number and total phenolic concentration were measured after 3 months. Moreover, the aggressivity index was calculated to compare the competitive ability of A. sibiricum relative to S. grandis. Important Findings Both E. gansuensis (Eg)- and E. sibirica (Es)-infected A. sibiricum plants showed a greater competitive ability than the uninfected plants under high nitrogen supply, while the opposite result occurred under low nitrogen supply. At high nitrogen levels, Eg plants had a higher tiller number and a greater shoot biomass inhibitory effect on S. grandis than Es plants had when growing in mixture, while Es plants showed better root growth performance than Eg and uninfected plants under mixture conditions at all nitrogen levels. A higher concentration of phenolic compounds in Eg plants than in Es plants might contribute to the higher inhibitory effect of Eg plants on competing plants. Our study indicates that the interaction between endophyte infection and nitrogen availability can alter the competitive ability of the host plant A. sibiricum but that these two endophyte species work in different ways, which may influence the coexistence of A. sibiricum with the dominant species.

The growth of barley grass (Hordeum leporinum) in annual pasture. 2. Growth comparisons with Wimmera ryegrass (Lolium rigidum)

1968 ◽  
Vol 8 (33) ◽  
pp. 484 ◽  
Author(s):  
DF Smith
Keyword(s):  
Soil Fertility ◽  
Soil Nitrogen ◽  
Frost Damage ◽  
Lolium Rigidum ◽  
Forage Plant ◽  
Nitrogen Levels ◽  
Rye Grass ◽  
Hordeum Leporinum ◽  
Wimmera Ryegrass

Experiments to compare the growth of barley grass (Hordeum leporinum) and Wimmera ryegrass (Lolium rigidum) were carried out in small plots and boxes at Dookie College in northern Victoria, and near Melbourne. These covered a range of density, defoliation, and temperature and soil fertility conditions. At equal densities barley grass generally out-yielded rye grass over the first 50 days of growth. Frost was the only factor reducing this superiority, but high levels of nitrogen in the foliage greatly reduced frost damage. Barley grass also recovered more rapidly from defoliation. The results suggest that in frosty areas soil nitrogen levels will greatly influence the herbage production and dominance of barley grass ; in areas with milder winters, growth will be more consistent and the grass will be a more reliable forage plant.

scholarly journals Genome-wide association of rice response to blast fungus identifies loci for robust resistance under high nitrogen

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Mathias Frontini ◽  
Arnaud Boisnard ◽  
Julien Frouin ◽  
Malika Ouikene ◽  
Jean Benoit Morel ◽  
...  
Keyword(s):  
Nitrogen Fertilization ◽  
Rice Blast ◽  
Genome Wide Association ◽  
Japonica Rice ◽  
High Nitrogen ◽  
Initial Finding ◽  
Blast Fungus ◽  
Genome Wide ◽  
A Genome ◽  
Low Nitrogen

Abstract Background Nitrogen fertilization is known to increase disease susceptibility, a phenomenon called Nitrogen-Induced Susceptibility (NIS). In rice, this phenomenon has been observed in infections with the blast fungus Magnaporthe oryzae. A previous classical genetic study revealed a locus (NIS1) that enhances susceptibility to rice blast under high nitrogen fertilization. In order to further address the underlying genetics of plasticity in susceptibility to rice blast after fertilization, we analyzed NIS under greenhouse-controlled conditions in a panel of 139 temperate japonica rice strains. A genome-wide association analysis was conducted to identify loci potentially involved in NIS by comparing susceptibility loci identified under high and low nitrogen conditions, an approach allowing for the identification of loci validated across different nitrogen environments. We also used a novel NIS Index to identify loci potentially contributing to plasticity in susceptibility under different nitrogen fertilization regimes. Results A global NIS effect was observed in the population, with the density of lesions increasing by 8%, on average, under high nitrogen fertilization. Three new QTL, other than NIS1, were identified. A rare allele of the RRobN1 locus on chromosome 6 provides robust resistance in high and low nitrogen environments. A frequent allele of the NIS2 locus, on chromosome 5, exacerbates blast susceptibility under the high nitrogen condition. Finally, an allele of NIS3, on chromosome 10, buffers the increase of susceptibility arising from nitrogen fertilization but increases global levels of susceptibility. This allele is almost fixed in temperate japonicas, as a probable consequence of genetic hitchhiking with a locus involved in cold stress adaptation. Conclusions Our results extend to an entire rice subspecies the initial finding that nitrogen increases rice blast susceptibility. We demonstrate the usefulness of estimating plasticity for the identification of novel loci involved in the response of rice to the blast fungus under different nitrogen regimes.

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.

The influence of diet on the nitrogenous components passing to the duodenum and through the lower ileum of sheep

1966 ◽  
Vol 166 (1002) ◽  
pp. 63-79 ◽  
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Nitrogen Content ◽  
Aspartic Acid ◽  
Total Nitrogen ◽  
Amino Nitrogen ◽  
Terminal Part ◽  
High Nitrogen ◽  
Low Nitrogen ◽  
Lower Ileum

Analyses of the alimentary contents flowing to the duodenum of sheep during 24 h show that when the sheep are consuming a low-nitrogen diet more total nitrogen and amino nitrogen pass to the duodenum than are eaten daily in the food whereas when the sheep are eating high nitrogen diets, less total nitrogen and less amino nitrogen pass to the duodenum. The disparity between the total nitrogen and amino nitrogen content of the diets largely disappeared by the time the alimentary contents reached the terminal part of the ileum. From 64 to 68% of the nitrogen entering the duodenum and 54 to 64% of the nitrogen in the ileal contents was in the form of amino nitrogen. Proportionately more of the amino nitrogen was in solution in the ileal contents than in the duodenal contents. Losses of amino acids in the stomach when a high-nitrogen diet was consumed were especially large for glutamic acid, aspartic acid, proline, arginine and leucine. They were least for cystine and threonine. Gains of amino acids in the stomach when low nitrogen diets were consumed were all substantial except for proline, where a loss was found when hay and flaked maize were given. When these changes are considered as proportions of the quantities eaten then trends are similar for all acids. Changes in the molar proportions of the amino acids present in hydrolysates of the duodenal and ileal contents are discussed together with the significance of these changes in relation to the nutrition of the sheep.

CLIPPING FREQUENCY AND FERTILIZER EFFECTS ON PRODUCTIVITY AND LONGEVITY OF FIVE GRASSES

1961 ◽  
Vol 41 (1) ◽  
pp. 97-108 ◽  
Author(s):  
D. H. Heinrichs ◽  
K. W. Clark
Keyword(s):  
Crude Protein ◽  
Competitive Ability ◽  
Forage Yield ◽  
The Other ◽  
Protein Yield ◽  
Agropyron Cristatum ◽  
Cold Climates ◽  
Agropyron Intermedium ◽  
Pasture Grasses

Agropyron cristatum, Agropyron intermedium, Agropyron riparium, Elymus junceus and Stipa viridula were studied in relation to clipping effects on productivity and longevity. All species, except Elymus junceus, produced progressively less as number of clippings increased. Agropyron intermedium yielded the most forage, especially when harvested only once per season, followed closely by Agropyron cristatum. Crude protein yield was less variable under various frequencies of clipping than forage yield, and differences between species were also smaller. Elymus junceus and Agropyron cristatum displayed the strongest competitive ability, especially under frequent clipping and Stipa viridula the lowest. The amount of root produced varied significantly between species. Agropyron cristatum and Elymus junceus produced the most root and Stipa viridula the least. Fertilizer applied in the fourth and fifth crop years increased the yield by 30 to 200 per cent. It was concluded that Agropyron cristatum and Elymus junceus were about equally persistent under frequent clipping and should be more useful long-term pasture grasses than the other three in dry cold climates.

Growth and ignitability of annual pastures in a Mediterranean environment. 2. Ignitability of swards of various annual species

1970 ◽  
Vol 10 (42) ◽  
pp. 76 ◽  
Author(s):  
RT Parrott ◽  
CM Donald
Keyword(s):  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Individual Species ◽  
Atmospheric Conditions ◽  
Annual Species ◽  
Lolium Rigidum ◽  
Mediterranean Environment ◽  
Desiccation Process ◽  
Hordeum Leporinum ◽  
Pasture Plants

A study was conducted at Adelaide of the ignitability of monospecific swards of four Mediterranean annual pasture plants under windless conditions throughout the normal field desiccation of the swards in the spring. For any individual species the ignitability depended almost wholly on the percentage of water or the very closely correlated percentage of dead herbage. Atmospheric conditions had no measurable influence on ignitability during desiccation. Trifolium subterraneum was much less ignitable at any particular level of moisture content than were the grasses. Lolium rigidum was more inflammable early in the desiccation process than was Hordeum leporinum of equal water content, presumably due to the greater continuity of dry leaf; but H. leporinum was ignitable much earlier in the spring because it matured and dried sooner than did L. rigidum. In the case of the grasses, only those firebrands that fell to or near the soil surface started a fire, whereas the more compact sward of T. subterraneum, when sufficiently dry, lit readily at the upper surface.

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