Weeds and weeding

Future research. Ample research has been conducted to demonstrate the allelopathic potential of numerous weedy species, and of their associated crops. Future research should be directed to discerning how much of this potential is realized in the field under humid, warm conditions such as that found in the Southeast United States. Newman (33), in a reflective article, concludes that "—it cannot be said with confidence that allelopathy has any significance for agriculture." The evidence so far certainly substantiates his conclusion. To get a better feel for allelopathy in the field, field studies should minimally include the weed and weed residues. 

The experimental design should include a weed-free control, a weedy control, a weed free but with weed residue treatment, and at least one treatment with weeds and residue present. Various levels of weeds and weed residue could be incorporated into the study. 

As with all perennial plants, appropriate soil preparation, including removal of all perennial weeds, is essential before planting (see The Soil, pp.34-35, Weeds and Weeding, pp.76-79, and also Herbaceous plants, pp.190-191). 

The move into continuous cereal production and away from mixed farming with firm rotations meant that farmers could cultivate high value crops on all available land without the need for fallow. This could not have been achieved without the use of chemical herbicides. The movement of people from the land to the urban environment during the industrial revolution and thereafter reduced the available labour for hand weeding and weed control became a real problem for the farmer. The revolution was the introduction of 2,4-D and MCPA that allowed broad-leaved weeds to be controlled selectively in the previously dirty cereal crops. 

Klingman, G.C. and F.M. Ashton (1982). Biology of weeds and weed seeds, in Weed Science Principles and Practices. New York John Wiley and Sons, pp. 37-57. 

Atkinson, D. and G.C. White (1980). The effects of weeds and weed control on temperate fruit orchards and their environment. 

Peters, E.J. and R.A. Peters (1972). Weeds and weed control. In C.H. Hanson, ed., Alfalfa Science and Technology. Madison, WI American. Society of Agron, pp. 555-573. 

H. Trozelli, Fluroxypyr-a new herbicide in cereals, Weeds and Weed Control 27 (1) (1986) 65-75. 

Dedek, W. and Partish, M. (1976) Biochemie tmd Physiologie der Pftanzen, Leipzig, 169, 399. Fiveland, T. J. (1978) Weeds and Weed Control. 19th Swedish Weed Control Conf, Uppsala, K5, KIO. Folmar, L. C., Sanders, H. O. and Julin, A. M. (1979) Arch Environ. Contam. Toxicol., 8, 269. 

In essence, the overall objective of chemical regulation is to minimise the aggregate cost of (1) agricultural losses due to weeds and weed control,... 

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