Front Cover; Advances in Agronomy, Volume III; Copyright Page; Contents; Contributors to Volume III; Preface; Chapter 1. The Subsoil; I. Introduction; II. Concept of Subsoil; III. Nature and Properties of Subsoil Layers; IV. Relationship of Subsoil to Plant Growth; V. Management of Unexposed Subsoil; References; Chapter 2. The Management of Alfalfa Meadows; I. Introduction; II. The Effect of Cutting Systems on Amount and Quality of Hay; III. The Effect of Different Systems of Cutting on Root Reserves; IV. The Relation of Various Factors to the Time of Cutting

V. Summary of Practical Recommendations for CuttingVI. Cultivation of Established Alfalfa; VII. Other Weed Control Methods in Alfalfa; References; Chapter 3. The Chemistry of Soil Potassium; I. Introduction; II. Forms of Soil Potassium and their Availability to Plants; III. Influences of other Cations on Forms of Soil Potassium; IV. Relationships of Soil Microorganisms to Soil Potassium; V. Effect of Aeration and Compaction on Availability of Potassium; VI. Movement and Distribution of Potassium in the Soil Profile; VII. Epilogue; References

Chapter 4. The Changing Pattern of Agriculture in England and WalesI. The Period 1921-1938; II. The Period 1939-1945; III. The Period 1946-1950; IV. Future Trends; Chapter 5. The Adaptability and Breeding of Suitable Grasses for the Southeastern States; I. Introduction; II. The Problem of Evaluating Grasses; III. The Grasses; References; Chapter 6. Chemical Treatment of the Soil for Nematode Control; I. Introduction; II. The Practice of Soil Fumigation; III. The Effects of Soil Fumigation; IV. Summary; References; Chapter 7. Problems and Progress of Soil Conservation in the United States

I. IntroductionII. Educational and Financial Incentives for Soil Conservation; III. Research for Soil and Water Conservation; IV. Summary; References; Chapter 8. Irrigation Agriculture and Soil Research in the United States; I. Introduction; II. Historical Developments; III. The Modern Period; IV. The Future; References; Author Index; Subject Index