Volume 70 contains six excellent treatises dealing with two of the leitmotifs in the plant and soil sciences - environmental quality and crop improvement. Chapter 1 is a comprehensive treatment of the role of carbon sequestration in affecting climate change. Issues of science, monitoring, and degraded lands are fully discussed. Chapter 2 deals with ways to improve the nutritional quality of foods to alleviate a major human nutrition problem, micronutrient malnutrition. Nitrogen cycling under different soil management is the topic of Chapter 3, including aspects of carbon/nitrogen interactions. Chapter 4 provides thorough coverage on methane emissions from rice fields, including aspects of quantification, mechanisms, role of management, and mitigation options. Agronomic and environmental implications of organic farming systems, including an historical and current perspective, development of governmental policies, characteristics of organic farming systems, and effects on the environment, are discussed in Chapter 5. Chapter 6 addresses the state-of-the-art of biodegradation of BTEX under anaerobic conditions. Advances in Agronomy is rated the highest impact publication in Agriculture by the Science Citation Index 1996 report with an impact factor over 2.1 and a cited half-life of over 10 years