ABSTRACT
World soybean production has increased dramatically during the past 50 years. The increase has been facilitated by several factors, including market demand for soybean byproducts, adaptation and development of high-yielding varieties, and improvement in production practices and equipment. Soybean is highly adaptable, and the crop is grown in all areas from the tropics to very short-season areas in northern China and Canada. The expansion in production is the result of new areas of production, e.g., Argentina and Brazil, and expanded production and more frequent cropping of traditional areas, e.g., the United States and China. During the past 25 years there has been less crop rotation and monoculture has increased in many areas. Decreased rotation has resulted in increased disease problems, and even in new soybean production areas in South America, there have been enough crop cycles to promote an increase in soybean diseases.
