Weeds in New Seedings of Alfalfa (Medicago sativa) for Seed Production: Competition and Control

Weed Science ◽  
1982 ◽  
Vol 30 (1) ◽  
pp. 20-25 ◽  
Author(s):  
J. H. Dawson ◽  
C. M. Rincker
Keyword(s):  
Medicago Sativa ◽  
Seed Yield ◽  
Weed Management ◽  
Management Systems ◽  
Mixed Species ◽  
Dense Population ◽  
Alfalfa Seed ◽  
Labor Inputs ◽  
Annual Weeds ◽  
And Control

Alfalfa (Medicago sativaL. ‘Vernal′) seeded in April in rows 55 cm apart and kept free of weeds produced 820 kg/ha of seed during the year of seeding. Competition from a dense popualtion (40 plants/m of row) of mixed species of annual weeds reduced the seed yield to 45 kg/ha. Competition from a dense population (55 plants/m of row) of broadleaf weeds, a light population (4 plants/m of row) of broadleaf weeds, or a heavy population (75 culms/m of row) of barnyardgrass [Echinochloa crusgalli(L.) Beauv.] reduced yields to 80, 310, and 160 kg/ha, respectively. A weed management system, consisting of EPTC (S-ethyl dipropylthiocarbamate) or profluralin [N-(cyclopropylmethyl)-α,α,α-trifluoro-2,6-dinitro-N-propyl-p-toluidine] applied at or before planting, 2,4-DB [4-(2,4-dichlorophenoxy) butyric acid] applied postemergence, trifluralin (α,α,α- trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) incorporated with the soil when the alfalfa was 20 cm tall, interrow tillage, and a modest input of hand labor brought the crop to harvest free of weeds, and the yields of alfalfa seed were similar to those from plots kept weed-free by hand labor only. When weeds within the rows were controlled by hand labor only, labor inputs as great as 930 h/ha were required to bring the crop to harvest free of weeds, whereas labor inputs of 7 to 17 h/ha removed all surviving weeds when effective weed management systems had been applied.

EFFECTS OF ESTABLISHMENT METHOD AND A RAPESEED COMPANION CROP ON ALFALFA SEED YIELD

1987 ◽  
Vol 67 (1) ◽  
pp. 263-266 ◽  
Author(s):  
J. WADDINGTON ◽  
N. MALIK
Keyword(s):  
Medicago Sativa ◽  
Seed Production ◽  
Seed Yield ◽  
Brassica Campestris ◽  
Establishment Method ◽  
Alfalfa Seed ◽  
Medicago Sativa L ◽  
Companion Crop

In two experiments at Melfort using alfalfa (Medicago sativa L. ’Beaver’) seeded at a rate of 2 kg ha−1 with and without a Polish rapeseed (Brassica campestris L. ’Candle’) companion crop seeded at 5.5 kg ha−1, rapeseed yields in the establishment year were maximum when alfalfa and rapeseed were mixed and planted in 15-cm rows. Alfalfa showed no consistent seed yield differences between broadcast seeding, seeding in 15- or 61-cm rows, or seeding with or without the companion crop.Key words: Alfalfa, rapeseed, Brassica campestris, seed production

Chemical Control of Dandelion (Taraxacum officinale) and Perennial Sowthistle (Sonchus arvensis) in Alfalfa (Medicago sativa) Grown for Seed

Weed Science ◽  
1980 ◽  
Vol 28 (2) ◽  
pp. 164-167 ◽  
Author(s):  
J. Waddington
Keyword(s):  
Medicago Sativa ◽  
Seed Yield ◽  
Chemical Control ◽  
Growing Season ◽  
Taraxacum Officinale ◽  
Alfalfa Seed ◽  
Visible Effect ◽  
Sonchus Arvensis ◽  
Dichlorophenoxy Acetic Acid ◽  
Seed Yields

Applications of 2,4-D [(2,4-dichlorophenoxy)acetic acid] at 1.1 kg/ha at the start of each growing season severely damaged established alfalfa (Medicago sativaL. ‘Beaver’) and reduced seed yield 32% over a 4-yr period. Dandelion (Taraxacum officinaleWeber) populations were reduced but perennial sowthistle (Sonchus arvensisL.) increased in frequency. Dichlobenil (2,6-dichlorobenzonitrile) applied at 2.1 kg/ha controlled both dandelion and perennial sowthistle. Alfalfa was damaged initially but rapid recovery resulted in an increase in seed yield in 2 yr out of 4. Terbacil (3-tert-butyl-5-chloro-6-methyluracil) applied at 1.1 kg/ha also controlled dandelion and perennial sowthistle. No alfalfa damage was evident and seed yields were increased 34% over a 3-yr period. Seed yield increased 30% where asulam (methyl sulfanilylcarbamate) was applied at 4.5 kg/ha, but there was no visible effect on the growth of either alfalfa or weeds. Simazine [2-chloro-4,6-bis (ethylamino)-s-triazine], propham (isopropyl carbanilate) + PCMC (p-chlorophenyl-N-methyl carbamate), pronamide [3,5-dichloro(N-1,1-dimethyl-2-propynyl)benzamide], and diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea], did not affect alfalfa seed production significantly, although simazine and diuron did reduce dandelion populations.

Alfalfa (Medicago sativa) Seed Yield Loss Due to Canada Thistle (Cirsium arvense)

1991 ◽  
Vol 5 (4) ◽  
pp. 723-728 ◽  
Author(s):  
James R. Moyer ◽  
G. Bruce Schaalje ◽  
Peter Bergen
Keyword(s):  
Medicago Sativa ◽  
Linear Equation ◽  
Seed Yield ◽  
Yield Loss ◽  
Linear Equations ◽  
Cirsium Arvense ◽  
Average Yield ◽  
Canada Thistle ◽  
Southern Alberta ◽  
Alfalfa Seed

Alfalfa seed yield and Canada thistle densities were measured in 10 fields in southern Alberta to assess the effect of thistles on seed yield. Thistle density and seed yield from each field were fitted to the Weibull, hyperbolic, and linear equations and a random coefficient and linear equation were used to obtain an “average yield loss curve”. Estimated average losses in alfalfa seed yield were >34% and >48% at thistle densities of 10 and 20 shoots m–2, respectively.

Systems Approach to Weed Management in Irrigated Crops

Weed Science ◽  
1988 ◽  
Vol 36 (6) ◽  
pp. 840-845 ◽  
Author(s):  
Edward E. Schweizer ◽  
Donald W. Lybecker ◽  
Robert L. Zimdahl
Keyword(s):  
Weed Management ◽  
Systems Approach ◽  
Conventional Tillage ◽  
Management Systems ◽  
Weed Seed ◽  
Irrigated Crops ◽  
System 2 ◽  
Annual Weeds ◽  
System 1 ◽  
The Impact

The impact of four weed management systems on weed seed reserves in soil, yearly weed problem, and production of barley, corn, pinto bean, and sugarbeet was assessed where these crops were grown in rotation for 4 consecutive years in four cropping sequences. Weeds were controlled in each crop with only conventional tillage or conventional tillage plus minimum, moderate (system 1), and intensive (system 2) levels of herbicides. Seed of annual weeds from 11 genera were identified, with barnyardgrass and redroot pigweed comprising 66 and 19%, respectively, of the initial 90 million weed seed/ha present in the upper 25 cm of the soil profile. After the fourth cropping year, overall decline in total number of weed seed in soil was 53% when averaged over four cropping sequences and four weed management systems. Over the 4-yr period, about 10 times more weeds escaped control in system 1 than in system 2; and within a crop, the fewest number of weeds escaped control annually in barley. System 2 had the highest herbicide use in each cropping sequence, the fewest weeds at harvest, and the smallest adjusted gross return over the 4-yr period in three of four cropping sequences.

Effects of row spacing and plant growth regulation on alfalfa seed yield (Medicago sativa L.)

2020 ◽  
Vol 52 (5) ◽  
Author(s):  
Duro Pajcin ◽  
Savo Vuckovic ◽  
Vera Popovic ◽  
Aleksandar Simic ◽  
Sandra Popovic ◽  
...  
Keyword(s):  
Plant Growth ◽  
Medicago Sativa ◽  
Seed Yield ◽  
Growth Regulation ◽  
Row Spacing ◽  
Plant Growth Regulation ◽  
Alfalfa Seed ◽  
Medicago Sativa L

Quackgrass (Elytrigia repens) Interference and Control in Seed Alfalfa (Medicago sativa)

1993 ◽  
Vol 7 (1) ◽  
pp. 58-64 ◽  
Author(s):  
James R. Moyer ◽  
G. Bruce Schaalje
Keyword(s):  
Seed Yield ◽  
Hyperbolic Model ◽  
Threshold Density ◽  
Economic Threshold ◽  
Elytrigia Repens ◽  
Southern Alberta ◽  
Herbicide Treatments ◽  
Alfalfa Seed ◽  
Seed Yields ◽  
And Control

Alfalfa seed yield and quackgrass density were measured in seven irrigated fields in southern Alberta to assess the effect of quackgrass on seed yield. Six herbicides were tested to determine their effect on quackgrass growth and accompanying alfalfa seed yield. The effect of quackgrass on seed yield was adequately described by a hyperbolic model. Quackgrass densities of 50 and 100 heads per m2reduced seed yields by 56 and 74%, respectively. The economic threshold density was 3 quackgrass heads per m2. The most effective herbicide treatments, quizalofop and propaquizafop, resulted in good initial quackgrass suppression and yield increases similar to those predicted by the hyperbolic model.

scholarly journals The Effect of Foliar Boron Application on Seed Production of Alfalfa (Medicago sativa L.)

2020 ◽  
Vol 1 (2) ◽  
pp. 60-64
Author(s):  
Wurentuya ◽  
Lingling Chen
Keyword(s):  
Medicago Sativa ◽  
Seed Production ◽  
Seed Yield ◽  
Foliar Application ◽  
Pollen Viability ◽  
Positive Effects ◽  
Yield And Quality ◽  
Alfalfa Seed ◽  
Medicago Sativa L

Boron (B) is an essential micronutrient for plant reproductive growth and seed setting. A better understanding of the reasonable application rate of B could provide guidelines for improving seed yield and quality. In this study, we used five B concentrations (0, 400, 800, 1200, and 1600 mg B L-1) to study the effect of foliar application of B on seed yield and quality of alfalfa (Medicago sativa L.) in northern China. Our results indicated that foliar B application increased the pollen number, pollen viability, and dry weight and B concentration of alfalfa reproductive organs. The effect of B on alfalfa seed yield can be attributed to affecting the number of inflorescence and the seeds per pod. Foliar application with 800 mg B L-1 made quantitative and qualitative improvements in seed yield and quality of alfalfa. These results help to explain the positive effects of B on alfalfa seed production.

Residual Herbicides for Weed Control in Established Alfalfa (Medicago sativa) Grown for Seed

1993 ◽  
Vol 7 (2) ◽  
pp. 483-490 ◽  
Author(s):  
Najib Malik ◽  
Garry G. Bowes ◽  
John Waddington
Keyword(s):  
Medicago Sativa ◽  
Weed Control ◽  
Seed Yield ◽  
Weed Management ◽  
Early Spring ◽  
Term Effect ◽  
Canada Thistle ◽  
Long Term Effect ◽  
Average Control

The long-term effect of repeated late-fall versus early-spring imazethapyr, hexazinone, terbacil, metribuzin, dichlobenil, or chlorsulfuron treatments, when applied on dormant stands of alfalfa was investigated at three sites for weed management of alfalfa grown for seed. Dichlobenil applied at 1.2 to 2.4 kg ha−1and chlorsulfuron applied at 11 to 22 g ha−1in fall or spring were the only herbicides to injure alfalfa at one location. Hexazinone provided the most consistent weed control of the herbicides evaluated. Average control of Canada thistle, catchweed bedstraw, dandelion, perennial sowthistle, quackgrass, Russian pigweed, and scentless chamomile was 80%. When averaged over three sites, weed control by hexazinone resulted in a 33% increase in seed yield.

Weed Control in Corn (Zea mays) as Affected by Till-Plant Systems and Herbicides

1989 ◽  
Vol 3 (1) ◽  
pp. 162-165 ◽  
Author(s):  
Edward E. Schweizer ◽  
Robert L. Zimdahl ◽  
Rome H. Mickelson
Keyword(s):  
Weed Management ◽  
Management Systems ◽  
Weed Seed ◽  
Weed Species ◽  
Corn Production ◽  
Common Lambsquarters ◽  
Seed Reserves ◽  
Total Seed ◽  
Annual Weeds ◽  
The Impact

The impact of three till-plant and two weed management systems on weed seed reserves of soil, yearly weed problems, and corn production was assessed under center-pivot irrigation for 3 consecutive years. Annual weeds were controlled in disced, bedded, and strip rotary till-plant systems with a moderate or intensive level of herbicides. Weed seed of seven annual weed species were identified, with common lambsquarters and stinkgrass, comprising 45 and 41%, respectively, of the initial 305 million seed/ha in the upper 25 cm of the soil profile. After the third cropping year, overall decline in total seed number in soil was 45% when averaged over till-plant and weed management systems. Grain yields did not differ between weed management systems, but the disced till-plant system produced 16% less grain than the bedded and strip rotary till-plant systems over 2 yr.

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