Front Cover; Advances in Agronomy, Volume 31; Copyright Page; Contents; Contributors to Volume 31; Preface; CHAPTER 1. EFFECTS OF PESTICIDES ON THE SOIL MICROFLORA; I. Introduction; II. Methodology Applied in the Study of the Effects of Pesticides on the Soil Microflora; III. Effects of Pesticides on the Microorganisms and on the Total Activity of the Soil; IV. Effects of Pesticides on the Biological Cycles of the Soil; V. Action on Pathogenic Microorganisms; VI. Degradation Effect of Pesticides on the Microflora Responible for pesticide Degradation; VII. Conclusion; References.

CHAPTER 2. FACTORS AFFECTING ROOT EXUDATION II: 1970-1978I. Introduction; II. Plant Factors; III. Effects of Environmental Factors; IV. Foliar Application of Chemicals; V. Biotic Factors Affecting Root Exudation; VI. Summary; References; CHAPTER 3. RED CLOVER BREEDING AND GENETICS; I. Introduction; II. Taxonomy; III. Reproduction; IV. Heritability and Gene Action; V. Sources of Genetic Variation; VI. Alteration of Populations through Selection and Hybridization; VII. Use of Selected Materials; VIII. Maintenance of Genetic Stability during Seed Multiplication; References.

CHAPTER 4. THE AVAILABILITY OF NUTRIENTS IN THE SOIL AS DETERMINED BY ELECTRO-ULTRAFILTRATION (EUF)I. Introduction; II. Problems of Conventional Soil Testing Practice; III. Electro-ultrafiltration; IV. The EUF Values Required for Optimal Plant Nutrition and Their Calculation; V. Conclusions for Practical Soil Analysis; References; CHAPTER 5. VOLATILIZATION LOSSES OF NITROGEN AS AMMONIA FROM SURFACE-APPLIED FERTILIZERS ORGANIC AMENDMENTS AND CROP RESIDUES; I. Introduction; II. Measurement of NH3 Volatilization Losses.

III. NH3 Losses from NH3-N and Urea Fertilizers, Including Moisture and Temperature EffectsIV. NH, Losses from Urea; V. NH3 Losses from Anhydrous NH3 and NH4OH; VI. NH3 Losses from Organic Amendments and Crop Residues; VII. NH3 Losses from Flooded Soils; VIII. NH3 Losses in Forest Fertilization; IX. NH, Sorption by Soils and Vegetation; X. Conclusions; References; CHAPTER 6. DIFFUSION OF IONS AND UNCHARGED SOLUTES IN SOILS AND SOIL CLAYS; I. The Diffusion Process and Its Range; II. The Mechanism of Ion Movement; III. Diffusion of Adsorbed Ions in Soil Clays and Clay-Type Minerals.

IV. Diffusion of Ions and Molecules in SoilV. Prediction of Diffusion Coefficients in Soil; VI. Volatile Solutes; VII. Methods of Measurement of lon Diffusion Coefficients in Soil; VIII. Diffusion in Practice; References; CHAPTER 7. BORON NUTRITION OF CROPS; I. Introduction; II. Boron-Containing Fertilizers; III. Methods of Determining Boron in Plants and Soils; IV. Role of Boron in Plants.; V. Factors Affecting Boron Requirement and Uptake in Plants; VI. Deficient Sufficient and Toxic Levels of Boron in Plants; VII. Deficiency and Toxicity Symptoms of Boron in Plants.