园林苗圃化学除草技术（Chemical weeding techniques in garden nursery）.docVIP

园林苗圃化学除草技术（Chemical weeding techniques in garden nursery） Chemical weeding techniques in garden nursery Weeds grow rapidly, not only with flowers and seedlings competing for nutrients and moisture, but also a variety of pests and diseases of the intermediate host, if not timely control will spread, affecting the growth of flowers and trees. The physical methods of weed control are mainly artificial extraction, cultivation and use of mulch. Biological control is rarely used in garden nurseries, and the simplest and most effective method is chemical weed control. First, the species of weeds Weeds are non conscious plants cultivated in farmland and are divided into annual, biennial, and perennial weeds on the basis of their life cycles. Annual weed; annual summer and winter annual weeds. The summer annual weeds germinate in spring, summer or autumn, mature, winter death; winter annual weeds in seedling germination in autumn, winter, spring summer fruit growth, death, such as grass and sheep is the type of senecio. Biennial weeds for a period of two years, the first year of sprout leaves, the energy accumulated in the roots, second years by using the stored energy to weed growth, usually in the summer or autumn of second knot after death, such as Verbascum, burdock and thistle is a common biennial plant. Perennial weeds, including common perennial perennial and bulbous creeping perennial weeds, their growth period for more than two years, in most circumstances do not produce seeds for one year, second years. Common perennial weeds propagate only by seeds, and weeds themselves can reproduce, such as dandelions and plantain grasses. In nursery production involves little bulbous weeds, they can be propagated by seed or underground bulb. Creeping perennial weed that grows on seeds and creeping roots, as in Canada thistle. Perennial weeds usually need repeated control, such as herbicides, cultivation, or artificial extraction. Effective weed control should not only understan