Organic agriculture is growing in importance worldwide. In the United States, the rate of increase of organic growers was estimated at 12% in 2000. However, many producers are reluctant to undertake the organic transition because of uncertainty of how organic production will affect weed population dynamics and management. The organic transition has a profound impact on the agroecosystem. Changes in soil physical and chemical properties during the transition often impact indirectly insect, disease, and weed dynamics. Greater weed species richness is usually found in organic farms but total weed density and biomass are often smaller under the organic system compared with the conventional system. The improved weed suppression of organic agriculture is probably the result of combined effects of several factors including weed seed predation by soil microorganisms, seedling predation by phytophagus insects, and the physical and allelopathic effects of cover crops.
Mathieu Ngouajio and Milton E. McGiffen Jr.
Satoru Motoki, Tianli Tang, Takumi Taguchi, Ayaka Kato, Hiromi Ikeura, and Tomoo Maeda
white asparagus spears ( Asparagus officinalis L.) Eur. Food Res. Technol. 222 32 35 Selloum, L. Bouriche, H. Tigrine, C. Boudoukha, C. 2003 Anti-inflammatory effect of rutin on rat paw oedema, and on neutrophils chemotaxis and degranulation Exp
Daniel P. Gillespie, Chieri Kubota, and Sally A. Miller
likely due to reduced infection at low pH (4.0). This may have been the result of negative effects on zoospore chemotaxis ( Allen and Harvey, 1974 ) and/or duration of zoospore motility ( Ho and Hickman, 1967 ). Low pH may reduce zoospore motility due to