Intraspecific competition in experimental populations of weeds

1974 ◽  
Vol 52 (6) ◽  
pp. 1415-1421 ◽  
Author(s):  
J. Marc Deschênes
Keyword(s):  
Seed Production ◽  
Reproductive Behavior ◽  
Dry Matter ◽  
Vegetative Reproduction ◽  
Root Production ◽  
Festuca Rubra ◽  
Red Fescue ◽  
Matter Production ◽  
High Germination ◽  
Respective Species

Red fescue (Festuca rubra L.), yarrow (Achillea millefolium L.), and mouse-eared chickweed (Cerastium vulgatum L.) were seeded at six densities under greenhouse conditions. Total dry matter production per pot (shoots and roots) increased as density increased for every species until a point was reached where a further increase of the density did not result in a higher production per pot. All species produced about the same shoot yield per pot. Root production per pot, however, was different among the species. The shoot–root ratio was the highest for mouse-eared chickweed, the lowest for red fescue, and intermediate for yarrow. All species exhibited fairly high germination and very low mortality, except yarrow. The three species displayed considerable plasticity in yield and in seed production per pot from low to high densities. The reproductive behavior varied between the species. Red fescue remained vegetative. Sexual reproduction of yarrow decreased drastically with increasing density. Mouse-eared chickweek maintained a large seed production over the whole range of densities. The population of the respective species seemed regulated by (1) individual plasticity and vegetative reproduction (red fescue), (2) individual plasticity, mortality, and limited seed production (yarrow), and (3) individual plasticity and high seed production (mouse-eared chickweed).

Effect of method and time of application of nitrogen fertiliser on yield and quality of seed of creeping red fescue

2000 ◽  
Vol 80 (4) ◽  
pp. 809-811 ◽  
Author(s):  
N. A. Fairey ◽  
L. P. Lefkovitch
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Seed Quality ◽  
Early Spring ◽  
Festuca Rubra ◽  
Grass Seed ◽  
Red Fescue ◽  
Time Of Application ◽  
Vigorous Plant ◽  
Tiller Density

Six trials were conducted on commercial seed fields of creeping red fescue (Festuca rubra L. var. rubra) in the Peace region to evaluate the sensitivity of seed production to the method and time of application of N fertiliser. In each trial, 68 kg ha−1 N was applied using three methods (surface-broadcast, granular, ammonium nitrate 34-0-0; foliar/soil spray of 28-0-0 solution N; soil-injected 28-0-0 solution N) at each of three times (fall, early spring, late spring). No statistically significant (P = 0.05) interaction, or main effect, of method and time of N were revealed for seed yield, fertile tiller density or for several seed quality characteristics. Seed yield varied greatly among trials (142 to 1240 kg ha−1) and averaged 566 kg ha−1. The results indicate that there is considerable flexibility in the method and time of application of N fertiliser for seed production of creeping red fescue in the Peace region, provided it is applied before the commencement of vigorous plant growth in the spring. Key words: Creeping red fescue, Festuca rubra L., nitrogen fertility, grass seed production, grass seed quality

scholarly journals Seed Production, Dry Matter Production, and Light Intercepting Characteristics of Soybean Cultivar‘Misato-zairai’

2011 ◽  
Vol 80 (3) ◽  
pp. 326-332 ◽  
Author(s):  
Kiyoshi Nagasuga ◽  
Shunsuke Uchida ◽  
Hideyuki Kaji ◽  
Yuki Hayakawa ◽  
Sumiyo Nose ◽  
...  
Keyword(s):  
Seed Production ◽  
Dry Matter ◽  
Dry Matter Production ◽  
Matter Production

Control of Several Perennial Weeds in Creeping Red Fescue (Festuca rubra) Grown for Seed

1995 ◽  
Vol 9 (2) ◽  
pp. 294-300 ◽  
Author(s):  
A. Lloyd Darwent ◽  
Leonard P. Lefkovitch
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Seed Weight ◽  
Festuca Rubra ◽  
Red Fescue ◽  
Perennial Weeds ◽  
Crop Seed

In commercial fields of creeping red fescue, spring applications of sethoxydim at 500 g/ha and fluazifop-P at 250 g/ha consistently reduced the heading, and consequently the seed production, of foxtail barley and volunteer bromegrass by ≥90% without affecting crop seed yield, 100-seed wt or germination. The effectiveness of sethoxydim at 500 g/ha and fluazifop-P at 250 g/ha to reduce heading of grass weeds was not affected by tank mixing with metsulfuron at 4.5 g/ha but was reduced when tank mixed with either dicamba plus 2,4-D at 280 plus 560 g/ha or 2,4-D alone at 560 g/ha. Metsulfuron alone, or in tank mixtures with sethoxydim (500 g/ha) or fluazifop-P (250 g/ha), effectively controlled dandelion and volunteer alsike clover (probability of ≥80% control was 0.94 or more). Dicamba plus 2,4-D provided a similar level of volunteer alsike clover control but was less effective on dandelion, while 2,4-D was ineffective on both weeds. Treatments containing dicamba plus 2,4-D reduced crop seed yield and germination, and increased seed weight.

The effect of copper supply on vegetative and seed yield of pasture legumes and the field calibration of a tissue test for detecting copper deficiency. II. Strawberry clover (Trifolium fragiferum L.)

1989 ◽  
Vol 40 (4) ◽  
pp. 833
Author(s):  
JD McFarlane
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Dry Matter ◽  
Copper Concentration ◽  
Copper Deficiency ◽  
Critical Concentration ◽  
Dry Matter Production ◽  
Pasture Legumes ◽  
Critical Range ◽  
Matter Production

Seven rates of copper were applied to the soil prior to the sowing of strawberry clover (Trifolium fragiferumL. cv. Palestine) on an alkaline peat deficient in copper. Symptoms of copper deficiency were evident only on the untreated plots where the clover did not set seed nor persist into the second year.Over five years� production, 1.0 kg Cu/ha continued to provide adequate copper, with regular dressings of superphosphate, for maximum dry matter production and seed yield. It was found that seed yield was more sensitive than vegetative dry matter yield to sub-optimal copper supply. At the lowest rate of applied copper (0.125 kg/ha), the vegetative yield ranged from 53% to 80% of the maximum harvest yield, whereas the seed yield ranged from 15% to 50% of maximum yield.For tissue sampled in the spring, the proposed critical range for copper concentration in the youngest open leaf (YOL) for vegetative dry matter production is 3-35 mg Cu/kg whereas that for seed production is 4.5-5.5 mg Cu/kg. At other times of the year the critical concentrations were higher. It was not clear if this was due to environmental conditions or changing internal requirements for copper.The critical copper concentration range in whole top (WT) tissue of 3.0-4.0 mg/kg for vegetative dry matter production could be applied to all samplings. For seed yield the critical range for copper concentration in WT was 4.0-5.0 mg/kg for the spring harvests. The critical copper concentration in seed for seed production was 5.0-6.0 mg/kg. In the pasture situation a critical concentration of 5.0-6.0 mg Cu/kg in the WT should be adopted when the animal requirement is considered.

Effects of water and nitrogen on seed production of creeping red fescue

2008 ◽  
Vol 88 (3) ◽  
pp. 439-446 ◽  
Author(s):  
N. A. Fairey
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
N Fertilization ◽  
Festuca Rubra ◽  
Seed Crop ◽  
Red Fescue ◽  
Peace River ◽  
River Region ◽  
Seed Crops

In order to address a paucity of information, a study was conducted in the Peace River region of northwestern Canada to determine the effects on seed production of creeping red fescue (Festuca rubra L. var. rubra) of six water treatments [natural precipitation and 100, 125, 150, 175 and 200% of the average, cumulative, long-term precipitation (LTP) of 459 mm yr-1] in combination with four N-fertilization regimes (zero + 102, 34 + 68, 68 + 34, and 102 + zero kg ha-1 N for the first + second crops, respectively). The 2-yr seed yield exceeded 2900 kg ha-1 when N was supplied to just one of the two seed crops, viz. with 150 to 200% LTP when N was applied only to the first seed crop, and with 125 to 150% LTP when N was applied only to the second seed crop. Under the prevailing, long-term, moisture environment at the study site (100% LTP), total seed yield over two production years was greatest (2136 kg ha-1) with 68 + 34 kg ha-1 N. The effects of the water and N treatments on seed yield were not associated with the mass of root organic matter recovered after the harvest of the second seed crop. These results confirm, and begin to quantify, numerous visual observations in the Peace River region that seed yields of creeping red fescue are restricted by insufficient precipitation. Key words: Creeping red fescue, Festuca rubra, grass seed production, nitrogen fertility, water, soil moisture

Crop density and seed production of creeping red fescue (Festuca rubra L. var. rubra). 1. Yield and plant development

1996 ◽  
Vol 76 (2) ◽  
pp. 291-298 ◽  
Author(s):  
N. A. Fairey ◽  
L. P. Lefkovitch
Keyword(s):  
Population Density ◽  
Seed Production ◽  
Seed Yield ◽  
Row Spacing ◽  
Initial Population ◽  
Festuca Rubra ◽  
Initial Population Density ◽  
Red Fescue ◽  
Clean Seed ◽  
Seed Crops

The natural growth habit of creeping red fescue (Festuca rubra L. var. rubra) involves a steady proliferation of tillers, which eventually become too dense to form seedheads. A field study was conducted to evaluate whether seed yield of fescue can be optimized for one, two or three consecutive crops by manipulating the initial population density and arrangement of plants. Individual seedling plants were transplanted at seven densities (1.6, 3.1, 6.3, 12.5, 25, 50 and 100 plants m−2) and three row spacings (20, 40 and 80 cm), and characteristics of seed production were determined for 3 yr (1991–1993). Heading commenced at dates differing by 16 d in the 3 yr and was delayed by up to 7 d as density increased. Seed maturity occurred in a 7-d period in each year (15–22 July). For a single harvest, an initial density of 12–100 plants m−2 on a row spacing of 20 cm or 12–50 plants m−2 on a row spacing of 40 cm is required to optimize yield and produce about 600 kg ha−1 of clean seed. For two consecutive harvests, an initial population density of 6–25 plants m−2 on a row spacing of 20 cm or 6–50 plants m−2 on a row spacing of 40 cm is required to optimize yield and produce a total of about 800 kg ha−1 of clean seed. For producing for either 1 or 2 yr, a density of 12–25 plants m−2 on rows no wider than 40 cm is required to optimize seed yield in each year. The probability of producing a third seed crop decreases markedly as the initial plant density increases and as the row spacing decreases. It is probably uneconomic to harvest more than two consecutive seed crops with current management practices. Key words: Red fescue; Festuca rubra var. rubra, population density, plant spacing, seed production

scholarly journals The place of amenity grass seed production.

1980 ◽  
Vol 1 ◽  
pp. 24-25
Author(s):  
G.S. Robinson
Keyword(s):  
New Zealand ◽  
Seed Production ◽  
Lolium Perenne ◽  
Festuca Rubra ◽  
Agrostis Palustris ◽  
High Quality ◽  
Grass Seed ◽  
Red Fescue ◽  
Agrostis Tenuis

In recent years the supply of seed of local types of fine turf grasses has decreased. This has resulted in the need for the importation of overseas cultivars of browntop, creeping bent grass and red fescue. These have generally proved to be very effective in producing high-quality turf. The coarser types of turf used in sportsfields for football and cricket are ideally ryegrass-dominant. Fine-leaved perennial ryegrasses have been developed overseas. and experimental plantings of these in New Zealand look very promising. Keywords: Amenity grass, New Zealand, Agrostis tenuis Lolium perenne, Agrostis palustris, Festuca rubra.

Mutual Influences of Seedling Johnsongrass (Sorghum halepense), Sicklepod (Cassia obtusifolia), and Soybean (Glycine max)

Weed Science ◽  
1990 ◽  
Vol 38 (2) ◽  
pp. 139-147 ◽  
Author(s):  
Barry D. Sims ◽  
Lawrence R. Oliver
Keyword(s):  
Glycine Max ◽  
Seed Production ◽  
Seed Yield ◽  
Dry Matter ◽  
Field Experiments ◽  
Growing Season ◽  
Growth And Yield ◽  
Sorghum Halepense ◽  
Competitive Effects ◽  
Matter Production

Field experiments were conducted to evaluate competitive effects of johnsongrass and sicklepod on growth and yield of irrigated and nonirrigated soybeans. Johnsongrass reduced soybean growth early in the growing season. Sicklepod was competitive all season, but competitiveness was greatest during the soybean reproductive stage. Soybean yields were reduced 31% by sicklepod, 14% by johnsongrass, and 36% by both weeds growing together. Nonirrigated soybeans yielded less than irrigated, but percent yield reductions were similar. Johnsongrass dry matter production and seed yield were reduced more than sicklepod by soybean interference. Soybean and sicklepod interference reduced johnsongrass seed production 73 to 95%. Johnsongrass produced 245 to 1238 seeds per plant when interfering with soybeans and sicklepod. Sicklepod seeds per plant were reduced 6 to 31% by johnsongrass interference and 47 to 75% by soybeans and soybeans plus johnsongrass.

Sign in / Sign up

Export Citation Format

Share Document