Weeds management

Chemical, cultural, and mechanical weed control practices have been relatively successful ia reducing yield losses from weeds (448). However, herbicide-resistant weed populations, soil erosion, pesticide persistence ia the environment, and other problems associated with technologies used (ca 1993) to control weeds have raised concerns for the long-term efficacy and sustainability of herbicide-dependent crop production practices (449). These concerns, coupled with ever-increasing demands for food and fiber, contribute to the need for innovative weed management strategies (450). 

Nonchemical or traditional practices, such as weed seed removal, optimal crop seeding rates, crop selection, enhanced crop competitiveness, crop rotation, and mechanical weed control are all important components of an effective weed management program (458,459). In the context of modern intensive chemical herbicide appHcation, nonchemical practices may even represent an innovative approach to weed management and should receive careful consideration. 

Biological systems produce an extremely wide variety of natural products. This ecological and genetic diversity offers researchers a vast index of compounds to search for innovative weed management agents. 

M. A. Altieri and M. Liebman, eds.. Weed Management in Mgroecogystems Ecological Approaches, CRC Press, Boca Raton, Pla., 1988. 

Frankenberger, Jr., and Muhammad Arshad Handbook of Weed Management Systems, edited by Albert E. Smith Soil Sampling, Preparation, and Analysis, Kim H. Tan Soil Erosion, Conservation, and Rehabilitation, edited by Menachem Agassi Plant Roots The Hidden Half, Second Edition, Revised and Expanded, edited by Yoav Waisel, Amram Eshel, and Uzi Kafkafi Photoassimilate Distribution in Plants and Crops Source-Sink Relationships, edited by Eli Zamski and Arthur A. Schaffer Mass Spectrometry of Soils, edited by Thomas W. Boutton and Shinichi Yamasaki... 

Faust, R.H. (2000) The use of Hair Sheep in Organic/Poly-Culture Tree Crop Weed Management. Proceedings of the 13th International IFOAM Scientific Conference, Basel, Switzerland, p. 425. 

The classic seed burial studies of W. J. Beal and his successors have shown seeds of at least one weed species, Moth Mullein (Verbascum blattaria L.) can remain viable in soil for a peiod of 100 years, whereas three species continued to germinate after 80 years of burial (30). Weed seeds not only resist decay by soil microbes, but they vary in dormancy characteristics. There is considerable evidence that chemical inhibitors are responsible for both phenomena. Unsaturated lactones and phenolic compounds in particular, are potent antimicrobial compounds present in many seeds (4J. Fruits and seeds are also known to contain diverse germination inhibitors including phenolic compounds, flavonoids and/or their glycosides and tannins. Unique methods to destroy inhibitors could provide an excellent weed management strategy. 

Baranenko, V.V. (2001). Pea chloroplasts under clino-rotation lipid peroxidation and superoxide dismutase activity. Advances in Space Research 27 973-976. Bhowmik, P.C. and Inderjit (2003). Challenges and opportunities in implementing allelopathy for natural weed management. Crop Protection 22 661-671. 

Weed management by soil solarization was widely investigated with variable responses either in field or greenhouse studies (Elmore 1991b Yaduraju and Mishra 2004), though the best results were always reported in hot climate countries (Al-Masoom et al. 1993 Saghir 1997) (Fig. 9.5). 

Al-Masoom AA, Saghir AR, Itani S (1993) Soil solarization for weed management in the UAE. Weed Technol 2 507-510... 

Hatcher PE, Melander B (2003) Combining physical, cultural and biological methods prospects for integrated non-chemical weed management strategies. Weed Res 43 303-322. doi 10.1046/ j. 1365-3180.2003.00352.x... 

Saghir AR (1997) Soil solarization an alternative technique for weed management in hot climates. In Stapleton JJ, DeVay JE, Elmore CL (eds) Proceedings of the second international conference on soil solarization and integrated management of soil-borne pests, Aleppo, Syrian Arab Republic, 16-21 March 1997. FAO Plant Protection and Production Paper 147, FAO, Rome, Italy, pp 206-211... 

Yaduraju NT, Mishra JS (2004) Soil solarization an ecofriendly approach for weed management. 

Weed management in organic agriculture use preventive methods such as an appropriate crop rotation, precise soiled preparation before sowing crops, narrow seed spacing, etc. (Labrada 2003). Many of them include ways in which allelopathy (often together with competition) could play an important role (Fig. 14.1). 

Fig. 14.1 Utilization of allelopathy in organic weed management. Weed management in organic agriculture includes four groups of different methods for weed reduction. Allelopathy plays an important role in some cultural and biological methods...

Other Possible Application of Allelopathy in Weed Management... 

Liebman M, Dyck E (1993) Crop rotation and intercropping strategies for weed management. Eco Appl 3 92-122... 

Sullivan P (2003b) Principles of sustainable weed management for croplands. Agronomy Systems Guide. Fayetteville, AR ATTRA - National Sustainable Agriculture Information Service, www.attra.org/attra-pub/weed.html... 

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