Advances in Soil Science was conceived in 1982 to provide a forum for leading international scientists to analyze and summarize the available scientific information on a subject, assessing its importance and ident ifying additional research needs. This goal seems even more appropriate today. Much is known about our soil resources. The principles learned and the technology developed need to be used to increase food pro duction, particularly in developing countries, and sustain the productivity of the resource base. Advances in Soil Science fills a gap between the scientific journals and the comprehensive reference books. Scientists can delve in depth on a particular subject relating to soil science. Contributors are asked in particular to develop and identify principles that have practical applications to both developing and developed agricultures. Advances in Soil Science was established to be international in scope and cover all subjects relating to soil science. This volume certainly fulfills that objective. The first chapter is concerned with denitrification. The significance of denitrification in nitrogen use efficiency in agricultural, grassland, and forest ecosystems, and in global nitrogen cycling is now well recognized. Therefore, an understanding of denitrification is essential for the efficient use of nitrogen fertilizers and for protecting the environ ment. The second chapter looks at the effects of subzero temperatures on the physical, biological, and chemical processes. This is an important area of soil science that has not been studied in great detail.

Inhalt
Soil Denitrification: Significance, Measurement, and Effects on Management.- I. Introduction.- II. Significance to N Cycle.- III. Factors Controlling Denitrification.- IV. Methodology for Field Measurements.- V. Impact of Management Systems.- VI. Conclusions and Future Research Needs.- Acknowledgments.- References.- Freezing and Its Effect on Chemical and Biological Properties of Soil.- I. Introduction.- II. Factors Influencing the Degree of Frost Penetration.- III. Influence of Rate and Degree of Freezing on the Structure of Ice.- IV. Effects of Freezing on Individual Physical Characteristics of Soil.- V. Chemical and Biological Effects of Soil Freezing.- VI. Consequences for Soil Fertility.- VII. Possible Effects on Natural Surface Water.- VIII. Conclusions.- Acknowledgment.- References.- Soil and Fertilizer Phosphorus and Crop Responses in the Dryland Mediterranean Zone.- I. Introduction.- II. Factors Governing the Behavior of Phosphorus in Mediterranean Soils.- III. Phosphate Reactions in Soils.- IV. Assessing Plant-Available Soil Phosphorus.- V. Field-Crop Responses to Phosphorus Fertilizer.- VI. Factors Associated with Crop Phosphorus Responses.- VII. Regional Research Infrastructure.- VIII. Future Research and Extension.- References.- Distribution and Management of Drylands in the People's Republic of China.- I. Introduction.- II. Main Characteristics of the Drylands.- III. Distribution of Different Drylands.- IV. Soils in the Dryland Areas.- V. Management of the Drylands.- VI. Future Strategies for Management of Drylands.- References.