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Weed seeds

Cell Division Inhibitors. The most common mode of action of soil-appHed herbicides is growth inhibition, primarily through dkect or indkect interference with cell division (163). Such growth inhibitory activity is the basis for most pre- or post-emergent herbicides intended to control germinating weed seeds. In germinating seeds, cell division occurs in the meristems of the root and the shoot. Meristematic cells go through a cycle... [Pg.45]

Nonchemical or traditional practices, such as weed seed removal, optimal crop seeding rates, crop selection, enhanced crop competitiveness, crop rotation, and mechanical weed control are all important components of an effective weed management program (458,459). In the context of modern intensive chemical herbicide appHcation, nonchemical practices may even represent an innovative approach to weed management and should receive careful consideration. [Pg.55]

The primary use for methyl bromide is in the extermination of insect and rodent pests. Methyl bromide is used in space and stmctural fumigation except in California. The material is suitable for the fumigation of food commodities such as dried fmits, grain, flour, and nuts, and the faciHties in which these foods are processed or stored, as weU as for tobacco and many kinds of nursery stock. The usual dosage is 2—4 kg/28 m for 12—24 h. In soil fumigation methyl bromide controls weed seeds, nematodes, wireworms, and soil fungi. The usual dosage is 0.5—1 kg/9 m for 24 h at 16°C and above (82). [Pg.294]

In organic systems the number of hours of hand weeding needs to be reduced, as labour, particularly in the developed countries, is expensive. This can be achieved by competition, the timing of cultivations, adaptation of the rotation nutrient management system and by crop density (Kropff, et al., 2000). Barberi, et al. (2002) experimented with a system of soil disinfection using hot steam to sterilise weed seeds. [Pg.80]

The classic seed burial studies of W. J. Beal and his successors have shown seeds of at least one weed species, Moth Mullein (Verbascum blattaria L.) can remain viable in soil for a peiod of 100 years, whereas three species continued to germinate after 80 years of burial (30). Weed seeds not only resist decay by soil microbes, but they vary in dormancy characteristics. There is considerable evidence that chemical inhibitors are responsible for both phenomena. Unsaturated lactones and phenolic compounds in particular, are potent antimicrobial compounds present in many seeds (4J. Fruits and seeds are also known to contain diverse germination inhibitors including phenolic compounds, flavonoids and/or their glycosides and tannins. Unique methods to destroy inhibitors could provide an excellent weed management strategy. [Pg.7]

The germination regulation effects of ten sesquiterpene lactones, the flavonoid artemetin and the diterpene lactone, 17-acetoxyacanthoaustralide, on 12 crop and weed seeds are presented. [Pg.133]

Under no-till conditions, many parameters are affected in such a manner as to alter germination of weed seeds. Putnam et al. (16) stated that "eliminating tillage reduces densities of many annual species presumably because numerous seeds are isolated from... [Pg.244]

Much remains to be accomplished in the separation, isolation, and identification of both naturally occurring and synthetic bioactive materials effective in the germination of parasitic weed seeds. Structure-activity studies suffer from the lack of separation of isomers in most synthetic samples. Strigol is an important tool in basic studies on the effect of chemicals on seed germination, but it is highly unlikely that the compound will meet practical field... [Pg.454]

Arora A, Yaduraju NT (1998) High-temperature effects on germination and viability of weed seeds in soil. J Agron Crop Sci 181 35—43... [Pg.253]

Economou G, Mavrogiannopoulos G, Paspatis EA (1997) Weed seed responsiveness to thermal degree hours under laboratory conditions and soil solarization in greenhouse. In Proceedings of the second conference on soil solarization. FAO Plant Production and Protection Paper 147, Rome, Italy, pp 246-263... [Pg.257]

Egley GH (1983) Weed seed and seedling reduction by soil solarization with transparent polyethylene sheets. Weed Sci 31 404-409... [Pg.257]

A chemical stimulant, a root exudate, is required to break seed dormancy of a parasitic weed and initiate seed germination. Upon receiving a signal for germination, a radicle emerges from the seed coat. However, an additional chemical signal is needed for the radicle to penetrate host roots and form a haustorium. Therefore several plants can serve as catch crops or trap crops for the reduction of the parasitic weed seed bank in infested soil. [Pg.398]

Species of Datura, Hyoscyamus and other tropane-containing genera are of more risk to humans than animals. These plants and their seeds have been used for religious or social functions with ritualistic emphasis. Numerous cases of bizarre and often aggressive behavior have been reported in people using seeds or teas from these plants (Burrows and Tyrl, 2002). As recently as October of 2003, a report appeared at CNN.com of four teenagers who ate Jimson weed seeds. All hallucinated and had to be hospitalized. Two were sedated and placed on life-support to prevent danger to themselves and others. The same press release reported that Centers for Disease Control and Prevention... [Pg.48]

If you fill the compost bin all at once with a good mixture of materials, the pile should get hot, speeding the process and killing weed seeds. [Pg.41]

Mulching is a key technique in organic soil management but it is also an incredibly useful way of suppressing weeds. A thick covering of a loose mulch will prevent weed seeds in the soil from germinating. A mulch membrane—such as cardboard or permeable plastic—laid over the soil will prevent weed growth. [Pg.72]

On a no-dig plot, weeds are drastically reduced as dormant seeds are not brought to the surface by the soil s being turned over. A mulch further reduces weed numbers, but is not essential. Light hoeing is effective on bare soil and gradually depletes the reserve of weed seeds. Loosen any perennial weeds with a fork and lift them out, disturbing the soil as little as possible. [Pg.217]

Small seeds and root crops are unsuitable for sheet mulches in the first year, but in the following season the surface of the ground should be crumbly and very suitable for sowing. It is useful to continue to keep the soil mulched to prevent the germination of weed seeds, protect the soil from crusting after heavy rain, and conserve moisture. [Pg.217]

Mulching bare soil reduces water loss through evaporation and prevents germination of weed seeds. If a high- to medium-fertility soil improver is used, this also adds plant nutrients. Apply mulches to warm, moist soil in spring and summer. [Pg.265]

Uses Manufacture of acrolein, allyl compounds, glycerol, plasticizers, resins, military poison gas contact pesticide for weed seeds and certain fungi intermediate for pharmaceuticals and other organic compounds herbicide. [Pg.88]


See other pages where Weed seeds is mentioned: [Pg.10]    [Pg.38]    [Pg.46]    [Pg.56]    [Pg.56]    [Pg.56]    [Pg.56]    [Pg.370]    [Pg.570]    [Pg.80]    [Pg.47]    [Pg.143]    [Pg.260]    [Pg.261]    [Pg.286]    [Pg.446]    [Pg.191]    [Pg.375]    [Pg.470]    [Pg.480]    [Pg.217]    [Pg.221]    [Pg.222]    [Pg.225]    [Pg.256]    [Pg.324]    [Pg.343]    [Pg.1018]    [Pg.166]    [Pg.33]    [Pg.77]   


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