Agriculture - a community process control plants to produce useful products from a small set of spe

Crops and weeds. "Other" series of species of plants | GRAIN
Agriculture - a community process control plants to produce useful products from a small set of species, which is called culture. The weeds are the "other" set of plant species present in agroecosystems. Although weed species have been on purpose and they did not work out the targeted selection, they are well adapted to the environment, which is dominated by men. Weeds related with the beginning of the agricultural ted monte crop production. (Published in 7.2011g numbers).
The most common weeds seen as intruders in agroecosystems

in competition for limited resources, lower yields and require huge amounts of human labor and a variety of technologies ted monte to prevent crop loss. In developing countries, it is possible to manually remove weeds from one hectare to farmers go 25-120 days, and they could lose a quarter of the potential ted monte crop due to weeds (Parker & Fryer, 1975) yet. In the United States, where farmers spend all year $ 6000000000 herbicides, mechanical cultivation to control weeds (Chandler, 1991), crop losses due to weeds more than now $ 4 billion per year (Bridges & Anderson, 1992) . However, weeds can be seen as a valuable part of agroecosystems. It can be used as a by-product obtained during ted monte the growth of crops. In India and Mexico, for example, to eat farmers types Amaranth (amaranthus), the cruciferous (Brassica) and Chenopodiaceae (Chenopo-dium) household consumption before the crop species are ready for harvest. In western Rajasthan, sesame and millet yields can increase, if left to grow weed indigo (Indigofera cordifolia) of the legume family (Bhandari & Sen, 1979). Some weeds can limit the damage to crops by insects, preventing them from moving or providing habitat for natural enemies of the pests. In addition, weeds can reduce soil erosion, provide an important source of food and medicines, provide habitat for beneficial species of wild animals and birds. Thus, weed plants are able to damage to agricultural crops, as well as benefits. Weed management objectives
Experimental studies have offers for some species, that the relationship between crop yield loss and weed density described ted monte equilateral hyperbola (Cousens, ted monte 1985; Weaver, Smits & Tan, 1987; Norris, 1992; Blackshaw,

1993; Knezevic Weise & Swanton 1994; Chikoye, Weise & Swanton,

1995). ted monte The specific parameters of the relationship ted monte depends on moisture, soil physical and chemical characteristics, a combination of other factors, but the overall reduction in weed density decrease culture yield loss (Figure 1). Although ted monte the relationship is shown in Figure 1 and shows the advantages of end whole weed up culture, the struggle that they cost too much to have a negative impact on the environment and deprive farmers of environmental interests that the individual weeds. Therefore, except as malicious or invasive species, it is desirable to control weeds, but not completely eliminate them.
Weeds can negatively affect the culture may be limited not only to reduce the density of weed growth, ted monte and minimize resource consumption, reduced growth and competitiveness each weed survivor. This can be achieved by: weed growth delay compared with the growth of the culture, increasing the share of available resources, captured bar damage ted monte (destroy not required) weeds by chemical, mechanical or biological methods .
Weed species differ in degree: the cultural harm they cause to crops, management complexity; complexity harvest crops. As part of the weed community is desirable for the balance of dominance species harmful to transfer the surplus of more suitable to the crops and livestock farmers (Fig. 1). This can be achieved through the addition of optional ted monte and just unwanted ted monte weeds amended by conditions to prevent malicious weeds recovery. Selective vegetation control is suitable for agro-dominated perennial plants, such as orchards ted monte and pastures. Important to control weeds and other broader goals. Because agriculture is characterized by constant change ted monte in prices, the weather, pests and diseases, farmers looking to control ted monte weeds that prevent predictable and stable, and reduced risk of loss of crop production. Account for convenience and profitability of farmers forced to look for weed control, which uses a combination of the required labor, priobretaemy