Soil Amendments and Fertilizers

1. Soil Amendments and Fertilizers • What is a soil amendment and what is a fertilizer? • Soil amendment – is a material that primarily adds _________________ matter to the soil • Organic matter important for soil organisms • Does contain nutrients needed by plants • Fertilizer – is a material that primarily adds _________________ to the soil • Some fertilizers may contain organic matter • May not have all the nutrients that plants need

2. Soil Amendments • The impact of soil amendments on the soil and vegetable plants is dependent on the amount of ____________ and nitrogen in the amendment • Carbon to nitrogen ratio • Normal carbon-to-nitrogen (C:N) ratio in soils is about _____:_____ • Adding organic matter alters this ratio • Problem • Materials with too ___________ a C:N ratio will tie up nitrogen making it unavailable for vegetable plants • Soil organism use the carbon as an energy source and the nitrogen for ________________

3. Soil amendments • Examples • _______________ • Is a living culture of organic matter similar to yogurt • Rule: anything that is entirely organic in origin can be composted • Peat ____________ • Sawdust • C:N ratio of 450:1 • Green manures

4. Soil amendments – Green manures Introduction • _____________ manures – are rapidly growing plants that are incorporated into the soil before planting the vegetables • Advantages • Can supply ____________ to the vegetable plant • Some green manures are legumes • _____________ loss of nutrients • Makes plant nutrients available to the vegetable crop • Improves the ___________

5. Soil amendments • What is a legume?

6. Soil amendments • What is a legume? • It is a plant that has nodules on their roots which contain ___________________ bacteria • The bacteria are able to convert nitrogen in the air into a form that plants can use • Were used as a ____________ source before synthetic fertilizers were widely available

7. Soil amendments - Cover crops • Cover crops – are plants that are rapidly growing and after they die they are left on the soil surface • Purpose • Protect the soil from _______________ • Tie-up nutrients • Prevent ____________ growth • Cover crops are most commonly fall-seeded • Examples of plants used • Cereal ______________ • _______________ vetch

8. Soil amendments/ Fertilizers Animal manures • Are intermediate between a soil amendment and a fertilizer • Vary greatly in their ___________ composition • Caused by: • Animal • Feed used • Type of litter or bedding • Degree of composting or decomposition • Must be _________________ before use

9. Animal Manures • Problems with manures • May contain harmful or undesirable contaminants • _________ and other harmful bacteria may be in fresh manure • Manures are _________ in nutrients compared to synthetic fertilizers • The most common commercially available types of manures • ____________ manure • Chicken (Poultry) manure

10. Animal manures

11. Table: Typical Composition of Manures Composition (% Dry Matter)

12. Fertilizers Introduction • Plants take up the same nutrients whichever category of fertilizer is used • Several categories of fertilizers • ____________ versus synthetic • Rapid versus slow _____________ • Solid versus liquid

13. Organic Fertilizers • Advantages • Nutrients are released ________________ • May improve the taste of the vegetable • Nutrients are less likely to leach • May benefit the soil microorganisms • Problems • Are low in potassium • “Semi-organic” or “________________ based” • Cost per unit of nutrient

14. Organic Fertilizers • Rapid release forms of plant nutrients • Most of the plant nutrients are available soon after application of the fertilizer • Most organic examples are general compound fertilizers contain a number of ________ nutrients

15. Organic Fertilizers – Rapid release • Animal byproducts • Source are processing plants or slaughterhouses • Include • Dried ________ • Fish meal • _________ meal

16. Organic Fertilizers – Rapid release • Bone meal • Excellent source of phosphorus and _____________ • Problem • Might transmit diseases • Mad cow • ____________ • No evidence that has occurred

17. Organic Fertilizers • Slow release • Are either plant byproducts or ground rock materials • Release nutrients over a growing season or more • Examples • _______________ meal • Rock __________ • Greensand

18. Organic Fertilizers • Slow release • Plant byproducts • _________ meal • Rich in minor nutrients • Contains 60 to 70 different chemical compounds

19. Organic Fertilizers • Rock phosphate • A finely ground natural rock powder • There are two kinds: • Hard rock phosphate • __________ phosphate • Potassium • Rock potash (greensand) • Wood ashes • Are very ____________

20. Organic Fertilizers • Liquid fertilizers • Fertilizer nutrients are dissolved in __________ • Advantages • Easy to apply • The nutrients are available immediately • Problems • Can injure plants • Easy to over apply • May ______________ or contaminate surface waters • Organic Examples • ________________ teas • Manure teas • Seaweed extract

21. Typical Composition of Some Organic Fertilizers Composition (% Dry Weight)

22. Synthetic Fertilizers Introduction • Many “_________________” fertilizers are derived from natural deposits • The nutrients are concentrated • Converted into a form that is readily available in the soil

23. Synthetic Fertilizers • Advantages • Easy to apply • ________________ • Are readily available • Disadvantages • May easily be over-applied • Can lead to ___________ build-up • May have adverse effects on soil organisms • Can be leached from __________ zone

24. Synthetic Fertilizers • Nitrogen fertilizer • Most important component of synthetic fertilizers • Synthesized from nitrogen in the air • Offshoot of World War II ammunition production • Production is very _________________ intensive • Forms of nitrogen fertilizer • Ammonia • _____________ • Urea