Lawn weeds are other plants on the lawn except for cultivating lawn plants. The concept of lawn weeds is relative. For example, tall fescue is a kind of lawn grass, but if it appears in the delicate grass of plum blossom, it is also considered a weed. Weeds can be spread by wind, water, birds, animals and humans.
(2) Species of lawn weeds
(1) Control weeds according to the classification of herbicides. Can be divided into three categories:
A. undergraduate weeds (pointed leaf leather). Leaves are long, veins are parallel, stems are round, and roots are fibrous roots.
B. Broad-leaved weeds (round leaf grass). The leaves are wide, the veins are reticulate, the stem section is round or square, the roots are straight roots, and there are straight roots.
C. Cyperaceae weeds (Fenugreek). The leaves are long, the veins are parallel, the stem section is triangular and the roots are fibrous roots.
② Classification by living environment. It can be divided into aquatic type, wet type and dry type. Mainly xerophytic type.
③ Classification by growth period. It can be divided into annual, biennial and perennial types.
A. annual plants. Start from the seed and complete the life cycle within 1 year. It includes winter annuals (which germinate in late summer or early autumn and die in the following summer) and summer annuals (which germinate in summer and die after the first severe frost in autumn).
B. biennial plants. Plants that can survive for more than 1 year, but not more than 2 years.
C. Perennial plants. Plants that have survived for more than two years. It can reproduce not only through seeds, but also through vegetative organs that usually hibernate for winter. Perennial weeds are more resistant to drugs than the other two weeds, so it is difficult to control.
④ Classification according to taxonomic characteristics. Can be divided into monocotyledonous weeds and dicotyledonous weeds. Most weeds in monocotyledonous lawn belong to Gramineae and a few belong to Salviaceae. Its morphological characteristics are rootless, slender leaves, parallel veins and no petiole. Dicotyledonous weeds have wider leaves than monocotyledonous weeds.
(3) The harm of lawn weeds
The harm of lawn weeds is various, as follows:
① Affect the growth and development of turfgrass. Weeds usually compete with turfgrass for sunlight, moisture and nutrition, thus reducing the vitality of turfgrass.
② Some weeds are the host plants of some diseases and insect pests, which aggravate the diseases and insect pests of lawn grass.
③ Destroy the overall appearance of the lawn.
(4) those that affect the safety of people and animals, such as poisonous wheat seeds, bowl flowers and poppy milk.
(4) Control methods of lawn weeds
The control methods of lawn weeds mainly include agricultural control, biological control and chemical control, as shown in Table 8-3.
Table 8-3 Control Methods of Lawn Weeds
Table 8-3 Lawn Weed Control Methods (Continued)-1