scholarly journals Conventional and organic cropping systems at Suitia IV: weeds

1990 ◽  
Vol 62 (4) ◽  
pp. 331-337
Author(s):  
Raimo Kauppila
Keyword(s):  
Winter Wheat ◽  
Dry Matter ◽  
Cropping Systems ◽  
Chenopodium Album ◽  
First Year ◽  
Weed Species ◽  
Stellaria Media ◽  
Cultivated Barley ◽  
Almost All ◽  
Grass Ley

At Suitia, Southern Finland, weed populations in different crop rotations at conventional and organic cropping systems were investigated in 1982—1988. The number of weeds and the dry matter yields of weeds were greater in organic cropping (on average 324 weeds/m2 and 425 kg DM/ha) compared to conventional cropping (94 weeds/m2 and 61 kg DM/ha). There were least weeds in the conventionally cultivated ley. The first year, clover ley in organic cropping prevented the growth of weeds as well as the grass ley in conventional cropping. Overwintering damages in organically cultivated leys increased the amounts of weeds in the following ley years. Organically cultivated winter wheat reduced the amount and weight of weeds almost as well as conventionally cultivated winter wheat although its biomass was three-fourths of the conventionally cultivated winter wheat. The biomass of organically cultivated barley later on in the rotations was only one-fifth of the conventionally cultivated barley and had five times more weeds. In conventional cropping, the number of weeds in almost all weed species was decreased or stayed at the same level during the experiment. In organic cropping, the number of most weeds in weed species increased from the level for 1982. Most increased Stellaria media, Fallopio convolvulus, Lamium sp and Chenopodium album.

Efficacy of some herbicides in wheat crop

Pesticidi ◽  
2002 ◽  
Vol 17 (1-2) ◽  
pp. 23-29
Author(s):  
Ljiljana Radivojevic ◽  
Radmila Stankovic-Kalezic ◽  
M. Budimir
Keyword(s):  
Winter Wheat ◽  
Chenopodium Album ◽  
Field Trials ◽  
Wheat Crop ◽  
Weed Species ◽  
Convolvulus Arvensis ◽  
Stellaria Media ◽  
Galium Aparine ◽  
Winter Wheat Crop ◽  
Fumaria Officinalis

In 2001 and 2002 field trials were carried out to evaluate efficacy of eight herbicides, alone or in the combinations, in winter wheat crop, in the Juzni Banat region. The next herbicides were examined: 2,4-D, Fluroksypyr Tribenuronmethyl, 2,4-D+Florasulam, Bentazon+Dicamba, Triasulfuron+Dicamba lodosulphuron-methylodium+Amidosulphuron Herbicides were applied after tillering of wheat was over. More frequent weed species were: Anthemis arvensis, Chenopodium album, Cirsium arvense, Convolvulus arvensis Delphinium consolida, Fumaria officinalis, Galium aparine, Lamium purpureum Polygonum convolvulus, Ranunculus arvensis, Sinapis arvensis, Stellaria media, Veronica polita i Viola tricolor. The most sensitive weed species to all herbicides were S. arvensis and Ch. album. The most tolerant was G. aparine (exept to fluroxipyr). The other species were less sensitive and herbicides eficacy were good or satisfactory, exept to V. polita and D. consolida. These results sugest that all applied herbicides could be successful in broad leaves weed control in the winter wheat crop in the Juzni Banat region.

scholarly journals Weed infestations in soybean grown in succession to cropping systems with sorghum and cover plants

2020 ◽  
Vol 55 ◽  
Author(s):  
Joilson Sodré Filho ◽  
Ricardo Carmona ◽  
Robélio Leandro Marchão ◽  
Arminda Moreira de Carvalho
Keyword(s):  
Cover Crops ◽  
Dry Matter ◽  
Cropping Systems ◽  
Block Design ◽  
Weed Species ◽  
Importance Value ◽  
Randomized Complete Block Design ◽  
Weed Diversity ◽  
Weed Infestation ◽  
Urochloa Brizantha

Abstract: The objective of this work was to evaluate the influence of sorghum and cover plant cropping systems before soybean cultivation on the occurrence of weeds during soybean growing in the Brazilian Cerrado. The experiment was carried out in a randomized complete block design, with four replicates. The treatments comprised six cropping systems before soybean: sorghum (Sorghum bicolor), palisade grass (Urochloa brizantha), and Congo grass (Urochloa ruziziensis) as cover plants, alone or intercropped, in addition to fallowing. Weeds were evaluated as to: density, dry matter mass, diversity, importance value, and similarity. The greatest similarity of weeds ocurred in single crops of sorghum, palisade grass, and Congo grass, in comparison with their intercroppings. Congo grass before soybean promoted a greater reduction in weed diversity overtime, when compared with palisade grass. The absence of cover crops before soybean cultivation increased weed infestation during the soybean cycle. The cropping systems with sorghum intercropped with cover crops before the soybean cultivation affect the diversity and the importance value of weed species.

Response of Dwarf Wheat (Triticum aestivum) and Four Weed Species to Herbicides

Weed Science ◽  
1981 ◽  
Vol 29 (5) ◽  
pp. 521-524 ◽  
Author(s):  
O. P. Kataria ◽  
Vijay Kumar
Keyword(s):  
Triticum Aestivum ◽  
Dry Matter ◽  
Chenopodium Album ◽  
Wheat Crop ◽  
Weed Species ◽  
Convolvulus Arvensis ◽  
Matter Production ◽  
Dwarf Wheat ◽  
Hand Weeding ◽  
High Degree

Control of littleseed canarygrass (Phalaris minor Retz.), wild oat (Avena fatua L.), common lambsquarters (Chenopodium album L.), and field bindweed (Convolvulus arvensis L.) in dwarf wheat (Triticum aestivum L.) fields was studied with five herbicides and hand weeding. Terbutryn [2-(tert-butylamino)-4-(ethylamino)-6-(methylthio)-s-triazine] and 1-benzthiazol-2-yl-1,3-dimethylurea controlled the weeds more effectively than did two hand weedings. Diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea], nitrofen (2,4-dichlorophenyl p-nitrophenyl ether), and dichlormate (3,4-dichlorobenzyl methylcarbamate), proved only partially effective against weeds, and were therefore significantly inferior to two hand weedings. Spikes per meter of row length and test weight of wheat were increased significantly by 1-benzthiazol-2-yl-1,3-dimethylurea (1.5 to 2 kg/ha), terbutryn (0.5 kg/ha), and two hand weedings over the yields of the weedy check. The 1-benzthiazol-2-yl-1,3-dimethylurea showed a high degree of selectivity in the wheat crop at 2 kg/ha and increased yields to those of weed-free plots. Terbutryn was almost as effective as 1-benzthiazol-2-yl-1,3-dimethylurea, which increased the wheat yields over those of the weedy check by 19.8 and 42.4% during the 1974/75 and 1975/76 seasons, respectively. Tolerance of dwarf wheat to terbutryn at 0.75 kg/ha was variable, resulting in significant decreases in yield components and grain yield. Dry-matter yield of wheat was negatively correlated with the dry matter production of weeds.

Weed seed contamination in white clover seedlots

1990 ◽  
pp. 99-102
Author(s):  
J.S. Rowarth ◽  
A.A. Johnson ◽  
P.T.P. Clifford ◽  
M.P. Rolston
Keyword(s):  
White Clover ◽  
Chenopodium Album ◽  
Cirsium Arvense ◽  
Weed Seed ◽  
Weed Species ◽  
Stellaria Media ◽  
Seed Testing ◽  
Rumex Acetosella ◽  
Weed Seeds ◽  
Californian Thistle

Weed seeds are the major reason for white clover (Trifolium repens) seedlots being downgraded or rejected from certification. The occurrence of weed species in 537 white clover seedlots tested at the Official Seed Testing Station, Palmerston North, was analysed. The most commonly occurring species were field madder (Sherardia arvensis), chickweed (Stellaria media), fathen (Chenopodium album), sheep's sorrel (Rumex acetosella) and scarlet pimpernel (Anagaflis arvensis). The percentage occurrence of four specified undesirable weeds including Californian thistle (Cirsium arvense) and dodder (Cuscuta epithymum) are reported, and the implications of seed contamination are discussed. Keywords: white clover, contamination, weed seeds

Allelochemicals from Plants as Herbicides

1988 ◽  
Vol 2 (4) ◽  
pp. 510-518 ◽  
Author(s):  
Alan R. Putnam
Keyword(s):  
Weed Control ◽  
Higher Plants ◽  
Cropping Systems ◽  
Plant Residues ◽  
Perennial Species ◽  
Weed Species ◽  
Plant Densities ◽  
Almost All ◽  
Chemical Groups ◽  
Toxic Plant

Allelochemicals representing numerous chemical groups have been isolated from over 30 families of terrestrial and aquatic plants. Some of the compounds also have been isolated from soil in quantities sufficient to reduce plant growth. Although selected allelochemicals are believed to influence plant densities and distributions, none isolated from higher plants have been considered active enough for development as commercial herbicidal products. Almost all herbicidal allelochemicals exist in plants in nontoxic, conjugated forms. The toxic moiety may be released upon exposure to stress or upon death of the tissue. The most successful use of allelochemicals in weed control has been management of selectively toxic plant residues. For example, rye residues have controlled weeds effectively in a variety of cropping systems. Several weed species may interfere with crop growth through chemicals released from their residues. A number of noxious perennial species appear to exploit allelochemicals in their interference processes. This review focuses on the more recent chemical discoveries and how they might be exploited for weed control.

scholarly journals Infestation maps and spatial stability of main weed species in maize culture

2014 ◽  
Vol 32 (2) ◽  
pp. 275-282 ◽  
Author(s):  
I.M. Calha ◽  
E. Sousa ◽  
J.L. González-Andújar
Keyword(s):  
Spatial Distribution ◽  
Chenopodium Album ◽  
Species Number ◽  
First Year ◽  
Distribution Analysis ◽  
Herbicide Application ◽  
Weed Species ◽  
Spatial Stability ◽  
Representative Species ◽  
The Difference

A study on the spatial distribution of the major weeds in maize was carried out in 2007 and 2008 in a field located in Golegã (Ribatejo region, Portugal). The geo-referenced sampling focused on 150 points of a 10 x 10 m mesh covering an area of 1.5 ha, before herbicide application and before harvest. In the first year, 40 species (21 botanical families) were identified at seedling stage and only 22 during the last observation. The difference in species richness can be attributed to maize monoculture favouring reduction in species number. Three of the most representative species were selected for the spatial distribution analysis: Solanum nigrum, Chenopodium album and Echinochloa crus-galli. The three species showed an aggregated spatial pattern and spatial stability over both years, although the herbicide effect is evident in the distribution of some of them in the space. These results could be taken into account when planning site-specific treatments in maize.

Buckwheat Residue Effects on Emergence and Growth of Weeds in Winter-Wheat (Triticum aestivum) Cropping Systems

Weed Science ◽  
2011 ◽  
Vol 59 (4) ◽  
pp. 567-573 ◽  
Author(s):  
Virender Kumar ◽  
Daniel C. Brainard ◽  
Robin R. Bellinder ◽  
Russell R. Hahn
Keyword(s):  
New York ◽  
Winter Wheat ◽  
Weed Management ◽  
Cropping Systems ◽  
Soil Surface ◽  
Bare Soil ◽  
Weed Species ◽  
Winter Annual ◽  
Winter Annual Weeds ◽  
Annual Weeds

Field and pot studies were conducted in Central New York to determine the potential weed-management benefits of a buckwheat cover crop grown before winter wheat. Specific objectives were to determine buckwheat residue effects on (1) emergence and growth of winter annual weeds; (2) wheat establishment and yield; and (3) emergence of summer annual weeds in the spring following overwinter seed burial. In a field study, buckwheat was sown at two timings (July or August), mowed, and either incorporated or left on the soil surface. Winter wheat was drilled into buckwheat residue in September and weed and crop growth were monitored. In a complementary pot study, four winter annual weeds were sown in soil removed from buckwheat and bare-soil plots at 0 or 15 d after incorporation and monitored for emergence and early growth. To assess buckwheat residue effects on spring emergence from overwintering seeds, seeds of three weed species were buried in buckwheat residue and bare-soil plots in the fall, exhumed in April, and evaluated for emergence. To investigate the mechanism for possible effects of buckwheat residue on overwintering seeds, two levels each of seed treatment (none or fungicide) and fertilization (none or 170 kg ha−1) were applied before burial. Buckwheat residue had no negative effect on wheat yields but suppressed emergence (22 to 72%) and growth (0 to 95%) of winter annual weeds, although effects were often small and inconsistent. Buckwheat residue had no effect on the emergence of buried weed seeds in spring. However, fungicide treatment enhanced the emergence of Powell amaranth seeds by 12.5 to 25.5% and of barnyardgrass seeds by 0 to 12%. Our results suggest that buckwheat residue can contribute to weed management in wheat cropping systems, but that further studies investigating the mechanistic basis for the inconsistent selective effects of buckwheat residue on weeds are needed before buckwheat use can be optimized.

CASSAVA LEAF LITTER ESTIMATION IN ON-FARM TRIALS

2004 ◽  
Vol 40 (3) ◽  
pp. 315-326 ◽  
Author(s):  
R. J. CARSKY ◽  
M. A. TOUKOUROU
Keyword(s):  
Leaf Litter ◽  
Rainy Season ◽  
Dry Matter ◽  
Cropping Systems ◽  
First Year ◽  
Litter Production ◽  
Nutrient Contents ◽  
K Fertilizer ◽  
3.0 T ◽  
The Relationship

Cassava (Manihot esculenta) returns organic matter and nutrients to the soil through leaf litter and these amounts need to be quantified to help understand and design sustainable cropping systems. Our objectives were to estimate dry matter and nutrient contents in cassava leaf litter and to derive relationships between litter fall and easily measurable cassava yield components. Litter traps (1 m2) were placed in farmers' fields for monthly monitoring during a three year period. Maximum monthly leaf litter production ranged from 0.5 to 1.0 t ha−1, and occurred at the end of the first rainy season and at the onset of the next rainy season. In the first year, the mean dry matter of leaves collected during 12 months of growth was 3.4 t ha−1 for the unamended treatment, and 4.1 t ha−1 when N-P-K fertilizer was applied. The totals were 2.4 and 3.0 t ha−1 in 2000–2001 and 1.6 and 2.5 t ha−1 in 2001–2002, respectively. Annual differences were apparently related to rainfall. The relationship with fresh root yield was best described using one slope and yearly intercepts giving an r2 of 0.63. This relationship can be exploited for estimating litter dry matter in agronomic experiments when rough estimates are sufficient, keeping in mind that the relationship may not be the same for cultivars of differing architecture. Otherwise, the use of litter traps gives the best estimate of annual litter production.

scholarly journals Effect of Crop Residues on Weed Emergence

Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 163
Author(s):  
Nebojša Nikolić ◽  
Donato Loddo ◽  
Roberta Masin
Keyword(s):  
Weed Management ◽  
Crop Residues ◽  
Cropping Systems ◽  
Chenopodium Album ◽  
Seedling Emergence ◽  
Amaranthus Retroflexus ◽  
Weed Species ◽  
Field Quantity ◽  
Crop Fields ◽  
No Till

Weed behaviour in crop fields has been extensively studied; nevertheless, limited knowledge is available for particular cropping systems, such as no-till systems. Improving weed management under no-till conditions requires an understanding of the interaction between crop residues and the seedling emergence process. This study aimed to evaluate the influence of maize and wheat residues, applied in three different quantities (1, the field quantity, 0.5, and 1.5-fold amounts of the field quantity), on the emergence of eight weed species: Abutilon theophrasti, Amaranthus retroflexus, Chenopodium album, Digitaria sanguinalis, Echinochloa crus-galli, Setaria pumila, Sonchus oleraceus, and Sorghum halepense. The experiment was conducted over two consecutive years. The results showed that the quantities 1 and 1.5 could suppress seedling emergence by 20 and 44%, respectively, while the quantity 0.5 seems to promote emergence by 22% compared with the control without residues. Weed species showed different responses to crop residues, from C. album showing 56% less emergence to S. halepense showing a 44% higher emergence than the control without residues. Different meteorological conditions in the two-year experiment also exhibited a significant influence on weed species emergence.

scholarly journals Weed flora and weed management of field peas in Finland

2008 ◽  
Vol 14 (2) ◽  
pp. 189 ◽  
Author(s):  
J. SALONEN ◽  
T. HYVÖNEN ◽  
H. JALLI
Keyword(s):  
Weed Management ◽  
Chenopodium Album ◽  
Good Control ◽  
Organic Production ◽  
Grass Species ◽  
Weed Species ◽  
Stellaria Media ◽  
Cropping Practices ◽  
Weed Flora ◽  
Crop Stand

The composition of the weed flora of dry pea (Pisum sativum L.) fields and cropping practices were investigated in southwestern Finland. Surveys were done in 2002–2003 in 119 conventionally cropped fields and 64 fields under organic cropping. Herbicides were applied to 92% of conventionally cropped fields where they provided relatively good control but were costly. Weeds were controlled mechanically only in five fields under organic production. A total of 76 weed species were recorded, of which 29 exceeded the 10% frequency level of occurrence. The average number of weed species per field was 10 under conventional cropping and 18 under organic cropping. The most frequent weed species in both cropping practices were Chenopodium album, Stellaria media and Viola arvensis. Elymus repens was the most frequent grass species. The difference in species composition under conventional and organic cropping was detected with Redundancy Analysis. Under conventional cropping, features of crop stand and weed control explained 38.7% and 37.6% of the variation respectively. Under organic cropping the age of crop stand and field location (y co-ordinate) respectively explained best the variation. Weeds could be efficiently managed with herbicides under conventional cropping, but they represented a significant problem for organic production. Mixed cultivation of pea with cereals is recommended, particularly for organic cropping, as it favours crop competition against weeds.;

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