 | Soils, Crops and Fertilizer Use |
 |  | About this manual |
| | Acknowledgements |
|  | Chapter 1: Down to earth - Some Important Soil Basics |
| | What is soil, anyway? |
| | Why do soils vary so much? |
| | Topsoil vs. subsoil |
| | The mineral side of soil: sand, silt, and clay |
| | Distinguishing "tropical" soils from "temperate" soils |
| | Organic matter - a soil's best friend |
| | The role of soil microorganisms |
| | Chapter 2: Trouble-shooting soil physical problems |
| | Getting to know the soils in your area |
| | Soil color |
| | Soil texture |
| | Soil tilth |
| | Soil water-holding capacity |
| | Soil drainage |
| | Soil depth |
| | Soil slope |
| | Chapter 3: Basic soil conservation practices |
| | Rainfall erosion |
| | Wind erosion |
| | Chapter 4: Seedbed preparation |
| | The what and why of tillage |
| | Common tillage equipment |
| | The abuses of tillage and how to avoid them |
| | Making the right seedbed for the crop, soil, and climate |
| | How deep should land be tilled? |
| | How fine a seedbed? |
| | Some handy seedbed skills for intensive vegetable production |
| | Chapter 5: Watering vegetables: When? How Often? How Much? |
| | It pays to use water wisely |
| | Some common watering mistakes and their effects |
| | Factors influencing plant water needs |
| | Ok, so get to the point! how much water do plants need and how often? |
| | Some methods for improving water use efficiency |
| | Chapter 6: Soil fertility and plant nutrition simplified |
| | Let's Make a Deal |
| | How plants grow |
| | Available vs. unavailable forms of mineral nutrients |
| | Soil negative charge and nutrient holding ability |
| | Soil pH and how it affects crops growth |
| | Important facts on the plant nutrients |
| | Chapter 7: Evaluating a soil's fertility |
| | Soil testing |
| | Plant tissue testing |
| | Fertilizer trials |
| | Using visual "hunger signs" |
| | Chapter 8: Using organic fertilizers and soil conditioners |
| | What are organic fertilizers? |
| | Organic vs. chemical fertilizers: which are best? |
| | Some examples of successful farming using organic fertilizers |
| | How to use organic fertilizers and soil conditioners |
| | Chapter 9: Using chemical fertilizers |
| | What are chemical fertilizers? |
| | Are chemical fertilizers appropriate for limited-resource farmers? |
| | An introduction to chemical fertilizers |
| | Common chemical fertilizers and their characteristics |
| | The effect of fertilizers on soil pH |
| | Fertilizer salt index and "burn" potential |
| | Basic application principles for N, P, and K |
| | Fertilizer application methods explained and compared |
| | Troubleshooting faulty fertilizer practices |
| | Getting the most out of fertilizer use: crop management as an integrated system |
| | Understanding fertilizer math |
| | Chapter 10: Fertilizer guidelines for specific crops |
| | Cereals |
| | Pulses (grain legumes) |
| | Root crops |
| | Vegetables |
| | Tropical fruit crops |
| | Tropical pastures |
| | Chapter 11: Liming soils |
| | The purpose of liming |
| | When is liming needed? |
| | How to measure soil pH |
| | How to calculate the actual amount of lime needed |
| | How and when to lime |
| | Don't overlime! |
| | Chapter 12: Salinity and alkalinity problems |
| | How salinity and alkalinity harm crop growth |
| | Lab diagnosis of salinity and alkalinity |
| | Appendixes |
| | Appendix A: Useful measurements and conversions |
| | Appendix B: How to determine soil moisture content |
| | Appendix C: Spacing guide for contour ditches and other erosion barriers* |
| | Appendix D: Composition of common chemical fertilizers |
| | Appendix E: Hunger signs in common crops |
| | Appendix F: Legumes for green manuring and cover-cropping in tropical and subtropical regions |
| | Appendix G: Some sources of technical support |
| | Appendix H: A bibliography of useful references |
What is soil, anyway?
Most soils evolve slowly over centuries through the weathering of underlying rock and the decomposition of plants. Others are formed from deposits laid down by rivers and seas (alluvial soils) or by wind (loess soils).
Soils have 4 basic components:
• Mineral particles: sand, silt, and clay
• Organic matter
• Water
• Air
A sample of typical topsoil contains about 50 percent pore space filled with varying proportions of air and water, depending on the soil's current moisture content. The other 50 percent of the volume is made up of mineral particles (sand, silt, clay) and organic matter; most mineral soils range from 2-6 percent organic matter by weight in the topsoil. Organic soils like peats are formed in marshes, bogs, and swamps, and contain 30-100 percent organic matter.
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