Effects of weed competition on flag leaf photosynthesis and grain yield of spring wheat

1999 ◽  
Vol 132 (1) ◽  
pp. 23-30 ◽  
Author(s):  
J. IQBAL ◽  
D. WRIGHT
Keyword(s):  
Grain Yield ◽  
Leaf Area ◽  
Nitrogen Uptake ◽  
Competitive Ability ◽  
Stomatal Density ◽  
Flag Leaf ◽  
Dry Weight ◽  
Weed Competition ◽  
Weed Species ◽  
Weed Density

Three pot experiments were performed at the University of Wales, Bangor, Gwynedd, UK during 1993 to determine if differences in the competitive ability of three annual weeds (Chenopodium album L., Sinapis arvensis L. and Phalaris minor Retz.) were related to their relative effects on leaf growth, gas exchange and nitrogen uptake of spring wheat (cv. Alexandria). In all experiments, wheat density (316 plants m−2) was similar to that in a commercial crop and five weed density treatments (between 0 and 600 plants m−2) were tested. Measurements of gas exchange were made on fully expanded, attached wheat flag leaves on four occasions between emergence and complete senescence in the control and highest weed density treatments. High weed density resulted in a lowering of net photosynthetic rate due to stomatal and non-stomatal factors. Lamina area and stomatal density of wheat flag leaves were decreased, and specific leaf area was increased by weed competition, but the effects on these variables were smaller than on net photosynthesis. Weed density did not affect wheat plant height, but dry weight, grain yield and total N-uptake were decreased with an increase in density of all weed species. The rank order of competitive ability of the species (C. album>P. minor>S. arvensis) was unaffected by weed density and was the same irrespective of whether it was based on the % decreases in wheat grain yield or in total plant dry weight. Averaged over the four measurements made during the grain-filling period there were only small differences between the weed species in their effects on net photosynthetic rate. However, when these were combined with effects on flag leaf area, there were larger differences in calculated net photosynthetic productivity, which were related to differences in the effects of weeds on grain yield. Differences in the competitive ability of weeds were not related to differences in their effects on wheat flag leaf lamina area, specific leaf area, stomatal density or total nitrogen uptake. Differences in competitive ability between weed species were not related to differences in weed plant height, dry weight or nitrogen uptake. It was concluded that the observed effects of weeds on wheat were due either to shading, or to competition for a nutrient other than nitrogen.

THE RELATIONSHIP BETWEEN PHOTOSYNTHETIC AREA AND GRAIN YIELD PER PLANT IN WHEAT

1967 ◽  
Vol 47 (4) ◽  
pp. 359-365 ◽  
Author(s):  
H. D. Voldeng ◽  
G. M. Simpson
Keyword(s):  
Grain Yield ◽  
Leaf Area ◽  
Flag Leaf ◽  
Correlation Coefficients ◽  
Dry Weight ◽  
Major Portion ◽  
The Relationship

Shading treatments with a high- and a low-yielding line of wheat indicated that the ear and flag leaf contributed the major portion of grain dry weight. Correlation coefficients calculated between flag-leaf area and grain yield, and ear area and grain yield, from tillers within seven lines of wheat ranged from + 0.54 to + 0.90. The combination of a large flag leaf plus a large ear area showed promise as an index for selecting higher yielding individuals from a mixture of genotypes.

scholarly journals Effect of rice residue on weed suppression and yield performance of boro rice

2020 ◽  
Vol 5 (3) ◽  
pp. 320-327
Author(s):  
Md. Abdus Salam ◽  
Jannatul Ferdus ◽  
Afroza Sultana ◽  
Abu Salek
Keyword(s):  
Grain Yield ◽  
Weed Management ◽  
Block Design ◽  
Dry Weight ◽  
Weed Suppression ◽  
Weed Species ◽  
Weed Density ◽  
Herbicide Treatment ◽  
Effect On Yield ◽  
Boro Rice

The experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh during the period from December 2017 through May 2018 to study the effect of rice residue on weed suppression and yield of boro rice. The experiment consisted of four different rice residue treatments such as no rice residue, 2.5, 5 and 7.5t ha-1rice residue, and five different herbicidal treatments such as no herbicide (H0), 25% of the recommended dose (RD), 50% RD, 75% RD and 100% of RD. The experiment was laid out in a randomized complete block design with three replications. Seven weed species belonging to five families infested the experimental plots. Weed density and weed dry weight were significantly affected by incorporation of rice residue and herbicidal treatment. The maximum weed growth was noticed with no rice residue incorporation and application of no herbicide. The minimum weed density and dry weight were found in incorporation of 5 t rice residue ha-1 and application of 100% of RD of herbicide treatment. Rice residue exerted significant effect on yield and yield contributing characters like plant height, number of total tillers hill-1, number of effective tillers hill-1 and grain yield. The highest grain yield (4.89 t ha-1) was recorded with the incorporation of 2.5 t ha-1 rice residue which was statistically identical with5 and 7.5 t ha-1 rice residues. The grain yield (5.70 t ha-1) produced by 75% of RD of herbicide was the highest among the other herbicidal treatments. The highest number of effective tillers hill-1 (12.80), 1000-grain weight (21.07), grain yield (5.87 t ha-1) and straw yield (7.21 t ha-1) were observed with the incorporation of 5 t rice residue ha-1 and 75% of the RD of herbicide treatment. Results of this study indicate that rice residue showed potentiality to inhibit the growth of weed and exerted significant effect on the yield of boro rice. Rice residue @ 5 t ha-1 with application of herbicide of 75% RD might be suggested to use for effective weed management and better grain yield of boro rice.

scholarly journals Effect of weed control on the performance of transplant BRRI Dhan 32

2018 ◽  
Vol 28 (4) ◽  
pp. 271-278
Author(s):  
MS Islam ◽  
H Akter ◽  
S Aktar ◽  
J Miah ◽  
SSF Hossain
Keyword(s):  
Field Experiment ◽  
Grain Yield ◽  
Weed Control ◽  
Dry Weight ◽  
Net Income ◽  
Weed Species ◽  
Weed Density ◽  
Panicum Repens ◽  
Hand Weeding ◽  
Higher Doses

A field experiment was carried out at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh during July to December 2003 to find out the effect of weed control on the performance of transplant Aman rice cv. BRRI Dhan 32. Weed control treatments  Included in the study were no weeding, one hand weeding, two hand weeding, one hand weeding+one weeding with Japanese rice weeder, Rift@ 0.5, 0.75, 1.0,  and 1.25 L ha-1 and Rostar@ 1.0, 1.5, 2.0, and 2.5 L ha-1. Important weed species found to infest the crop were Angta (Panicum repens), Acidgras (Ammania bacifera L.) Nackphulee (Cyperous difformis), Khudeshama (Echinochloa crusgalli) was the least important weed species. Higher doses of Rift 1.25L ha-1 and Ronstar 2.5 L ha-1 showed the best performance in reducing weed density and weed dry weight. The highest grain yield (5.0 4ton ha-1) was obtained from Ronstar 2.0 L ha-1 which was identical with the second highest grain yield (4.93 t ha-1) obtained from Rift 1.0 L ha-1. The highest net income of tk. 38915 ha-1 was obtained from Ronstar 2.0 L ha-1 and the next highest from Rift 1.0L ha-1.Progressive Agriculture 28 (4): 271-278, 2017

Characteristics of the canopy, root system and grain yield of a crop of Lupinus angustifolius cv. Unicrop

1975 ◽  
Vol 26 (3) ◽  
pp. 497 ◽  
Author(s):  
EAN Greenwood ◽  
P Farrington ◽  
JD Beresford
Keyword(s):  
Carbon Dioxide ◽  
Grain Yield ◽  
Leaf Area ◽  
Time Course ◽  
Dry Weight ◽  
Grain Filling ◽  
Main Axis ◽  
Carbon Dioxide Exchange ◽  
Area Index ◽  
Plant Parts

The time course of development of a lupin crop was studied at Bakers Hill, Western Australia. The aim was to gain insight into the crop factors influencing yield. Weekly measurements were made of numbers and weights of plant parts, and profiles of roots, leaf area and light interception. A profile of carbon dioxide in the crop atmosphere was taken at the time of maximum leaf area, and the net carbon dioxide exchange (NCE) of pods was estimated for three successive weeks. The crop took 10 weeks to attain a leaf area index (LAI) of 1 and a further 9 weeks to reach a maximum LAI of 3.75, at which time only 33% of daylight reached the pods on the main axis. Once the maximum LAI was attained at week 19, leaf fall accelerated and rapid grain filling commenced almost simultaneously on all of the three orders of axes which had formed pods. Measurements of NCE between pods on the main axis and the air suggest that the assimilation of external carbon dioxide by the pods contributed little to grain filling. Grain dry weight was 2100 kg ha-1 of which 30%, 60% and 10% came from the main axis, first and second order apical axes respectively. Only 23% of the flowers set pods and this constitutes an important physiological limitation to grain yield.

Effect of nitrogen fertilizer on growth and yield of semi-dwarf and tall varieties of winter wheat

1978 ◽  
Vol 91 (1) ◽  
pp. 31-45 ◽  
Author(s):  
I. Pearman ◽  
S. M. Thomas ◽  
G. N. Thorne
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Leaf Area ◽  
Dry Weight ◽  
The Other ◽  
Growth And Yield ◽  
Shoot Dry Weight ◽  
Phosphorus And Potassium ◽  
Main Effects ◽  
Dwarf Variety

SummaryEight amounts of nitrogen ranging from 0 to 210 kg N/ha were applied to two tall and one semi-dwarf variety of winter wheat in the spring of 1975 and 1976. The tall varieties were Cappelle-Desprez and Maris Huntsman; the semi-dwarf variety was Maris Fundin in 1975 and Hobbit in 1976. Interactions between varieties and nitrogen were few and small compared with the main effects. All varieties produced their maximum grain yields with 180 kg N/ha. The yield of the semi-dwarf varieties, but not the others, decreased slightly with more nitrogen.Cappelle-Desprez yielded less grain than the other varieties in both years. In 1975 the yields of Maris Fundin and Maris Huntsman were similar and in 1976 Hobbit yielded more than Maris Huntsman. The varieties had similar numbers of ears at maturity and similar patterns of tillering. The semi-dwarf varieties had most grains per spikelet, and hence grains per ear, and Cappelle-Desprez had least. The semi-dwarf varieties had the smallest grains. The semi-dwarf varieties had less straw than the other varieties and hence the largest ratios of grain to total above-ground dry weight. The decrease in dry weight of stem and leaves between anthesis and maturity was similar for all varieties. In 1975 the efficiency of the top two leaves plus top internode in producing grain was the same for all varieties, but in 1976 Hobbit was more efficient than the other two. There were some small differences between varieties in nutrient uptake that were not related to differences in growth. Maris Fundin tended to have a greater phosphorus and potassium content than the tall varieties. Hobbit contained slightly less nitrogen than the tall varieties at maturity, and had a smaller concentration of nitrogen in the grain.Applying 210 kg N/ha doubled grain yield in 1975. Applying nitrogen resulted in a largeincrease in number of ears and a small increase in number of grains per ear due to the development of more fertile spikelets per ear. Nitrogen decreased dry weight per grain, especially of the semi-dwarf varieties. With extra nitrogen, straw dry weight at maturity, shoot dry weight atanthesis and leaf area were all increased relatively more than grain yield, and stems lost moredry weight between anthesis and maturity than without nitrogen. The year 1976 was exceptionallydry and nitrogen had only small effects in that it affected neither straw dry weight nor numberof ears but slightly increased grain yield by increasing the number of spikelets and number of grains per spikelet. It also increased leaf area proportionately to grain yield. In 1975 nitrogen increased evaporation of water from the crop before anthesis but decreased it after anthesis, even though it continued to increase the extraction of water from below 90 cm.

Effects of Soil pH on Competitive Ability and Leaf Nutrient Content of Corn (Zea maysL.) and Three Weed Species

Weed Science ◽  
1985 ◽  
Vol 33 (4) ◽  
pp. 447-451 ◽  
Author(s):  
Susan E. Weaver ◽  
Allan S. Hamill
Keyword(s):  
Soil Ph ◽  
Competitive Ability ◽  
Leaf Tissue ◽  
Dry Weight ◽  
Nutrient Content ◽  
Setaria Viridis ◽  
Weed Species ◽  
Field Corn ◽  
Green Foxtail ◽  
Companion Plant

Effects of soil pH on growth, competitive ability, and leaf nutrient content of corn (Zea maysL.), Powell amaranth (Amaranthus powelliiS. Wats. ♯ AMAPO), velvetleaf (Abutilon theophrastiMedic. ♯ ABUTH), and green foxtail [Setaria viridis(L.) Beauv. ♯ SETVI] were measured in the field. Corn yields were significantly reduced by weed competition at all pH levels, but leaf nutrient content, as a percentage of dry weight, was not affected. Aboveground dry weights of Powell amaranth and velvetleaf were significantly lower at pH 4.8 than at pH 6.0 or 7.3, whereas growth of green foxtail was greater at pH 4.8 than at pH 7.3. Weed competitive ability, as evidenced by reductions in dry weight, varied with soil pH and companion plant. Powell amaranth and velvetleaf had higher levels of S, Zn, and especially Mn, at pH 4.8 than at pH 7.3. N and K in the leaf tissue were greater in the weed species than in corn at all soil pH levels. The dicot species had higher percentages of Ca and Mg in leaf tissue at all soil pH levels and accumulated higher percentages of Mn at low pH than the monocot species.

Early Interference between Cotton (Gossypium hirsutum) and Four Weed Species

Weed Science ◽  
1983 ◽  
Vol 31 (2) ◽  
pp. 200-207 ◽  
Author(s):  
C. Dennis Elmore ◽  
Michael A. Brown ◽  
Elizabeth P. Flint
Keyword(s):  
Gossypium Hirsutum ◽  
Leaf Area ◽  
Competitive Ability ◽  
Dry Weight ◽  
Cyperus Rotundus ◽  
The Other ◽  
Competing Species ◽  
Purple Nutsedge ◽  
Prickly Sida ◽  
Large Crabgrass

Early weed and crop interference was examined in a greenhouse pot experiment combining aspects of additive, substitutive, and diallel designs. Cotton (Gossypium hirsutumL. 'Stoneville 213′) and four weeds {purple nutsedge (Cyperus rotundusL.), large crabgrass [Digitaria sanguinalis(L.) Scop.], velvetleaf (Abutilon theophrastiMedic.) and prickly sida (Sida spinosaL.)} were grown singly and in all possible combinations of pairs including reciprocals for 5 weeks in 10-cm plastic pots. After 5 weeks large crabgrass was the tallest species in all combinations except when grown with purple nutsedge. Purple nutsedge, however, had more leaf area and greater dry weight than all other species. Height, leaf area, and dry weight were lowest in prickly sida. Mean relative yields in mixtures (a measure of competitive ability) were 1.90, 1.15, 1.13, 0.86, and 0.41 for purple nutsedge, large crabgrass, cotton, velvetleaf, and prickly sida, respectively, when grown with the other four species as associates. Conversely, purple nutsedge and cotton as associates depressed mean relative yields of competing species to 0.59 and 0.94. Large crabgrass, velvetleaf, and prickly sida as associates increased mean relative yields of competing species to 1.17, 1.18, and 1.55, respectively. Analysis of these data and replacement-series diagrams indicated that purple nutsedge was the most competitive, prickly sida the least, and the other species were intermediate and approximately equivalent in competitive ability.

scholarly journals Green manure and phosphorus fertilization affect weed community composition and crop/weed competition in organic maize

2019 ◽  
Vol 35 (5) ◽  
pp. 493-502 ◽  
Author(s):  
Stefano Carlesi ◽  
Federica Bigongiali ◽  
Daniele Antichi ◽  
Corrado Ciaccia ◽  
Fabio Tittarelli ◽  
...  
Keyword(s):  
Community Composition ◽  
Green Manure ◽  
Competitive Ability ◽  
Early Growth ◽  
Phosphorus Fertilization ◽  
Weed Competition ◽  
Weed Species ◽  
Green Manuring ◽  
Density And Biomass ◽  
Crop Weed Competition

AbstractGreen manure and compost-enriched in phosphorus can promote the sustainability of cropping systems by increasing soil fertility over the long term. They can also be used to manage crop/weed interactions, a key element in guaranteeing an appropriate level of satisfactory crop yields. We studied how green manuring with hairy vetch (Vicia villosaRoth.) and the application of different types of phosphorous-enriched compost affect weed/maize (Zea maysL.) interactions in an organic stockless Mediterranean agroecosystem for two consecutive dry years. Green manure stimulated the expression of maize traits related to a higher competitive ability against weeds, such as early growth, height and leaf area index, while the effect of compost was less clear. Regarding crop/weed competition, both green manuring and a phosphorus-enriched compost application gave a significant advantage to maize. Neither green manure nor compost increased total weed density and biomass compared to the control. Green manuring significantly affected the weed community composition. The relative density of ruderal and competitive-ruderal species (according to Grime's classification) was higher in plots where the green manure was applied. The use of green manure, together with novel composting techniques, significantly affected crop/weed competitive interactions, favoring maize, but also creating favorable conditions for unwanted weed species such as competitive-ruderals. Increasing nitrogen availability in the early growth stages of maize through green manuring can increase crop competitive ability. However, this may not suffice to preserve the system from future weed problems, should potentially detrimental species be selected. Dedicated strategies for the control of emerging weed species may thus be needed.

scholarly journals Weeds of Paddy Field at Kirtipur, Kathmandu

1970 ◽  
Vol 5 (5) ◽  
pp. 100-106 ◽  
Author(s):  
Sailaza Manandhar ◽  
Bharat B Shrestha ◽  
Hari D Lekhak
Keyword(s):  
Grain Yield ◽  
Seedling Growth ◽  
Shoot Elongation ◽  
Weed Competition ◽  
Root Extract ◽  
Aqueous Extracts ◽  
Weed Species ◽  
Ageratum Conyzoides ◽  
Straw Yield ◽  
Crop Weed Competition

Paddy (Oryza sativa L. var. Taiching-127) fields of Kirtipur, central Nepal, were studied to evaluate the effects of weeds on crop yield during June to October 2003. Weed community was recorded in permanently marked plots (2 x 2 m2 each), and grain and straw yields were measured. The effect of aqueous extracts (2 to 10%) of leaf, stem and root of dominant weeds (Echinochloa colona, E. crusgalli, Cyperus iria and Ageratum conyzoides) on germination and seedling growth of the paddy (Taiching-127) was examined in the laboratory. Altogether 52 weed species (27 dicot and 25 monocot) belonging to 32 genera and 15 families infested the paddy. The maximum weed density was observed in September (105 pl/m2). There was significant reduction in straw and grain yield of paddy in weedy plots and negative correlation between weed species richness and straw yield. Crop weed competition reduced straw yield by 13% to 38% and grain yield by 25% to 47%. Weed growth changed pH and reduced soil nitrogen and phosphorus content. Aqueous extracts of root, stem and leaf of dominant weeds (Echinochloa colona, E. crus-galli, Cyperus iria and Ageratum conyzoides) showed a weak effect on seeds germination however most of them had inhibitory effect on root and shoot elongation of paddy seedlings. Root elongation was more sensitive to allelopathic inhibition than shoot elongation. Stem extract of these weeds showed higher inhibition on seedling growth of paddy than leaf and root extract except in Ageratum conyzoides in which root extract showed highest inhibition. Keywords: Allelopathy; Crop-weed competition; Soil nutrients; Germination; Grain yield. DOI: 10.3126/sw.v5i5.2665 Scientific World, Vol. 5, No. 5, July 2007 100-106

scholarly journals Relationship between Flag Leaf Characteristics and Main Yield Components in Oat (Avena sativa L.)

2019 ◽  
Vol 76 (1) ◽  
pp. 71
Author(s):  
Ionuṭ RACZ ◽  
Rozalia KADAR ◽  
Sorin VȂTCĂ ◽  
Ioana Virginia BERINDEAN ◽  
Adrian CECLAN ◽  
...  
Keyword(s):  
Grain Yield ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Avena Sativa ◽  
Yield Components ◽  
Flag Leaf ◽  
Chlorophyll Concentration ◽  
Area Index ◽  
Leaf Chlorophyll ◽  
Leaf Chlorophyll Concentration

The objective of this study was to investigate relationships between leaf area index, leaf chlorophyll concentration, yield components and grain yield in oat (Avena sativa L.). Ten oat varieties were analyzed in field conditions regarding those traits. Flag leaf chlorophyll concentration range between 451.51 and 747.79 units of μmol of chlorophyll per m2. Also, leaf area index range between 13.68 to 32.84 cm2. Significant correlation indices were highlighted between yield components and leaf area index, yield/yield components and chlorophyll concentration of flag leaf.

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