The presence - or absence - of soil organic matter (SOM) has important implications for agricultural productivity. It could also have significant implications for global climate due to its role as a source/sink of carbon. Therefore, it is important to understand the issues related to the accumulation or loss of SOM, to use what we have learned from experiments to make sound decisions about soil and crop management, and to test models and future concepts concerning SOM management. A database is included with the book, presenting tabular data for 34 sites in North America. Soil Organic Matter in Temperate Agroecosystems discusses all of these issues and more, answering such questions as:

After a summary of world sugar production from beets, the authors cover the plant's need of each macro and micronutrient and effects on growth, yield and crop quality. The soil's supply of nutrients is examined as the basis for use of mineral fertilizers, organic manures and foliar applications. The book provides an up-to-date review of relevant research and the authors draw out practical guidelines so that all concerned with growing the crop can make use of this latest information. The book is destined to become the standard reference on the subject for many years to come. It represents the only significant work in English since Dr. Draycott's earlier title on the same subject, published 30 years ago.

Molecular Mechanisms of Plant and Microbe Coexistence presents studies on the complex and manifold interactions of plants and microbes at the population, genomics and proteomics level. The role of soil microbial diversity in enhancing plant health and plant microbe beneficial symbioses is discussed. Microbial communities are shown in the light of evolution. Main topics include genome coexistence and the functional genomics and proteomics of plant-associated microbes, which could form the basis for new environmentally benign strategies to combat infectious plant diseases and regulate plant growth. Further chapters focus on the role of signaling during the different stages of plant microbe coexistence, in symbiotic or pathogenic relationships, in quorum sensing and plant viral infections. Methods for studying the interactions in the root zone complement the book, which will certainly be of relevance in the practical application to agriculture, food security and for maintaining the balance of our ecosystems.

Masters Theses in the Pure and Applied Sciences was first conceived, published, and dis· seminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS) *at Purdue University in 1957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dissemination phases of the ac· tivity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all concerned if the printing and distribution of the volume were handled by an international publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Corporation of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 20 (thesis year 1975) a total of 10,374 theses titles from 28 Canadian and 239 United States universities. We are sure that this broader base for theses titles reported will greatly enhance the value of this important annual reference work. The organization of Volume 20 is identical to that of past years. It consists of theses titles arranged by discipline and by university within each discipline.

This is the first work to focus on microbes in gut systems of soil animals. Beginning with an overview of the biology of soil invertebrates, the text turns to the gut microbiota of termites, which are important soil processors in tropical and subtropical regions. Coverage extends to intestinal microbiota of such other litter decomposers as earthworms, springtails, millipedes, and woodlice. Thoroughly illustrated, including color photographs.