WEEDS

WEEDS C화학적 특성, 용도, 생산

농업용

Weeds are unwanted plants, growing in competition with the cultivated crop for space, light, nutrients, etc. They can be classified on the basis of their leaf forms (narrow leaf weeds or broad leaf weeds), life span (perennials) and growth or habitat. Fig.W.7 shows Parthenium grass, a common weed, covering a large area.
Fertilizers do not discriminate - they supply useful nutrients to both the weed and the crop. The problem becomes one of keeping the infestation of weeds below a tolerable limit. Some fertilizers give the crop a competitive advantage over some weeds, but also increase the growth of tall and fast growing weeds, especially perennials.
Frequent planting of winter cereals increases the weed problem. plowing and soil cultivation, or using chemical weed-killers (herbicides) are among the main control measures used for destroying weeds and are parts of weed management. Demand for herbicides is constantly on the rise for combating perennial weeds. There are also other aspects of weed management which involve removing the weed seeds in the soil, and resorting to, what may be broadly classified as, cultural, biological, chemical and integrated weed control methods.
Weeds can be a major problem in all rice growing areas where a yield reduction of up to 30% is observed. Weeds can be a major constraint in labor-intensive, small-scale farm operations. For instance, on Nigerian savannahs losses of 65 to 92% have been reported due to weeds. A parasitic flowering plant, known as witch weed (Striga sp), is a major pest in a large part of Sub-Saharan Africa.
Weeds may act as hosts for plant pests, providing an adjacent source of inoculums and allowing pests to survive or proliferate even in the absence of crop plants. Weeds may also serve as alternative hosts to allow for the sexual recombination of specific diseases or as a means of surviving a stress period.
Unwanted plants significantly increase the farmer's work. Weeds can interfere with the yield and the quality of crops, clog waterways and canals, poison livestock, cause dermatitis, induce hay fever and other respiratory problems in humans, create fire hazards, damage pavements in parking lots and roadways, interfere with utility lines and occasionally produce an attractive but poisonous fruit which if eaten can lead to human health problems or even death. Annual losses to society worldwide arising from weeds are estimated to exceed 10 billion dollars. Most weeds on land are grasses, sedges or broad leaved. Parasitic weed plants like dodders, broomrape, witch weed and certain mosses are among the important weeds found along with agricultural, ornamental and forest plants. Some examples of aquatic plant weeds are cattails, arrowheads, water hyacinth, pondweeds and algae.

WEEDS 준비 용품 및 원자재

원자재

준비 용품

WEEDS 공급 업체

공급자	전화	이메일	국가	제품 수	이점