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- 4. Calcium, magnesium, and sulfur are the secondary nutrient elements, so calledbecause they are essential to plant growth in a lesser quantity than the primary nutrients nitrogen, phosphorus,and potassium, and in greater quantity than the micronutrients.
- 6. N; a gas that occurs naturally in the air and soil, where it is converted into usable forms for plantuse by bacteria and other natural processes. This nutrient is a constituent of proteins and is vital to the plantgrowing processes. Nitrogen can be added to the soil in any of three fertilizer forms as urea, ammonia, ornitrates.
- 9. Mn; a metallic element found in soils from a mere trace to as much as 15 percent, but whenpresent, it is often in forms unavailable to plants. It is regarded as essential to normal plant growth and is oftenapplied, usually as manganous sulfate, to soils deficient in this element.
- 10. Zn; a metallic chemical element, one of the micronutrient elements in soils, essential for both plant andanimal growth.
- 13. P; a chemical element found in soils in various mineral forms, but only small amounts are readily available to plants at any one time. It stimulates early growth and root development, and hastens grain maturity.
- 14. For plants: boron, chlorine, cobalt, copper, iron, manganese, molybdenum, and zinc.
- 17. To check or hinder the growth or development of an animal or plant.
- 19. K; the chemical element, an alkali metal, which occurs widely in minerals. Regarded as an essential plant nutrient, potassium is present naturally in some form in all soils but in extremely variable amounts,and is likely to be in largest amounts in clay soils and in the least amounts in highly silicious soils and in peats.
- 21. Crops such as legumes or grasses that are grown to be plowed or spaded into the soil toincrease humus content and improve soil structure.
- 23. B; an element essential for plant growth. The original source of boron is tourmaline, but availableforms are from soil organic matter.
- 24. Cl; a heavy gas used in very small amounts for the growth of plants.
- 26. Yellowing or whitening of normally green leaves caused by lack of nutrients, air pollution, ordiseases.
- 27. Mg; a white metal, essential for people and animals, and for plant growth because it is aconstituent of chlorophyll.
- 28. Nitrogen, phosphorus, and potassium.
- 29. S; an elementary, yellow mineral, insoluble in water, easily fusible and inflammable. One of thesecondary but important elements in soil fertility and used in relatively large amounts by most plants, it is animportant constituent of both protein and protoplasm.
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- 1. An insufficiency in reference to amount, volume, proportion, etc.; a lack; a state ofincompleteness.
- 2. Mo; a gray metallic element, essential in very small amounts to the growth of plants, butusually present in sufficient amounts. Deficiencies have been discovered in a few highly acid soils.
- 3. A change in color of the lower leaves of green plants usually attributed to a lack of plant nutrients ormoisture deficiency.
- 5. Unit of weight equivalent to 2000 pounds.
- 7. Produced by plants and animals; of plant or animal origin.
- 8. Ca; a chemical element present in variable amounts in all soils. It is essential for plant and animalgrowth and is the principal mineral element in bones.
- 11. Fe; a metallic element essential to people, animals, and plants; very common in some minerals, mostrocks, and all soils. In plants, iron deficiency results in iron chlorosis.
- 12. Organic residues or their mixture, such as peat, manure, or discarded plant material and soil,placed in a pit or enclosure, moistened, and allowed to become decomposed. Sometimes lime and chemicalfertilizers are also added. Used as a fertilizer.
- 15. Cu; a metallic element found in soils at 1 to 50 parts per million, and in plants up to 100 parts permillion. It is necessary for all animal and plant life. High soil phosphorus, zinc, and molybdenum can induce acopper deficiency in plants. Also, high copper can reduce plant uptake of phosphorus, iron, zinc, andmolybdenum.
- 16. Any of certain chemical elements necessary in minute quantities for optimum growth anddevelopment of plants and animals.
- 18. When molecular nitrogen biologically or chemically converts to organic combinations or forms available for biological processes. Biological fixation occurs with legumes, whereas chemical fixationinvolves the manufacture of ammonia. Legume roots convert nitrogen gas to nitrates by bacteria.
- 20. Includes primary plant nutrients N, P, and K; and secondary plant nutrients Ca, Mg, and S.
- 22. Death of plant or animal cells in tissue, usually in localized areas.
- 25. Excreta of animals, dung and urine (usually with some bedding), used to fertilize the land.