Weeds are a fascinating study for specialists, not only because of their economic importance, but also since in this case biology must be combined with history and agriculture (and its economic aspects). Thus, weed scientists may be concerned with pure basic research, concentrating on general aspects, or with applied science, i.e. having a practical orientation. One of the aims of this book is to create a synthesis between these two branches of study and to review the literature of both fields. The agrestals, the weeds of arable land ~ the most important group from an economic point of view ~ was chasen as the main topic. Other weed groups could only be mentioned briefly (e.g. grassland weeds), or superficially (e.g. aquatic weeds), or had to be omitted completely (e.g. ruderals, because they are so heterogeneous), to keep this volume to an acceptable size and price. Nevertheless, nearly all subsections of botanical science have been treated.

Span lang=EN-GB style='mso-ansi-language:EN-GB'It was concluded that cultural weed management techniques that enhance radiation capture by the crop were effective in suppressing weed growth and seed production and increasing crop yields and should be incorporated into smallholder farmer's production practices in a systematic manner as part of Integrated Weed Management and cropping system design.

The series Tasks for Vegetation Science is devoted to a variety of research aspects in vegetation science, pure as wellas applied. Of the applied problems one of the most pressing is to achieve better knowledge and improvement of the pasture vegetation in tropical and subtropical regions. As series editor I was impressed by the sheer volume of useful scientific information concerning pasture plants from East Africa collected during many years by Dr. Boonman and compiled in one manuscript. Dr. Boonman first came to East Africa in 1963 on an overland journey along the river Nile which took him from Alexandria in Egypt to Lake Victoria in Uganda and Kenya and back again. After a brief spell as a cotton agronomist in the Sudan Gezira he joined the grassland research team at Kitale, Kenya in 1966. Improvement ofseed yield oftropical grasses was his principal interest which finally led him into the fieldof breeding grasses. Well-known varieties from his work include Boma & Elmba Rhodesgrass as wellas Clone 13Elephantgrass. In 1979he was recalled to The Netherlands to head a cooperative seedcompany involved in the breeding of grasses and cereals. The author has focused this study on one region, Eastern Africa.Global application of theories runs into conflicts too easily with local types of farming, if not with bare economics. Very few books can be found that describe existing practices and seek local answers by digging deep in the stacks of old, local reports.

Weeds severely affect crop quality and yield. Therefore, successful farming relies on their control by coordinated management approaches. Among these, chemical herbicides are of key importance. Their development and commercialization began in the 1940's and they allowed for a qualitative increase in crop yield and quality when it was most needed. This book blends review chapters with scientific studies, creating an overview of some the current trends in the field of herbicides. Included are environmental studies on their toxicity and impact on natural populations, methods to reduce herbicide inputs and therefore overall non-target toxicity, and the use of bioherbicides as natural alternatives.