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Environmental Requirements

Environmental Requirements. Soil. composed of sand, silt, and clay, organic matter, living organisms, and pore spaces. Soil. classified according to percentage of sand, silt, and clay they contain. Soil Particles. vary greatly in size sand is the largest silt - medium clay - smallest.

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Environmental Requirements

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  1. Environmental Requirements

  2. Soil • composed of sand, silt, and clay, organic matter, living organisms, and pore spaces

  3. Soil • classified according to percentage of sand, silt, and clay they contain.

  4. Soil Particles • vary greatly in size • sand is the largest • silt - medium • clay - smallest

  5. Clay • particles hold moisture and plant food elements more effectively than larger particles.

  6. Soil Profile • consists of 3 basic layers • topsoil • subsoil • soil bedrock

  7. Topsoil • represents depth normally plowed

  8. Subsoil • deep rooting plants send roots down into subsoil

  9. Sandy Soil • silt and clay make up less than 20% by weight • drain well • little water holding capacity

  10. Clayey Soil • must contain at least 30% clay • holds more moisture than is good for plants • poor drainage

  11. Loamy Soil • most desirable soil • equal parts sand, silt and clay

  12. Soil Improvement • Drainage • change soil structure • add organic matter to encourage earth worms

  13. Worms • their tunnels and castings result in better soil structure - aggregation - clinging together

  14. Drainage • drainage tiles • raise planting beds • ditching between beds

  15. Moisture retention • adding organic matter (o.m.) • sources of o.m. • animal manure • green manure - crop grown and plowed under to improve the soil

  16. Sources of O.M. • peat moss • sawdust • mulches - compost or wood chips

  17. Mulches • placed on the surface to help retain moisture • reduce runoff and evaporation • reduce weeds

  18. Moisture retention • irrigation

  19. Fertilizing • fertilize according to soil test results

  20. Diseases • plant resistant varieties • chemicals • soil pasteurization • heat to 180 degrees F for 30 minutes.

  21. Nutritional deficiencies • show on leaves of plants • Nitrogen - pale green leaves • Phosphorus - purple color on underside of leaves

  22. Planting Media Mixes • Soil less mixes • advantages include : uniformity - doesn’t vary in pH, fertility or texture

  23. advantages • sterile • lightweight • good moisture retention and drainage • fee of weed seeds

  24. disadvantages • light weight - pots tip in strong wind • minor elements are missing • transplants may not adjust well to new media

  25. Content of mixes • perlite • improve aeration • volcanic origin

  26. Vermiculite • exploded Mica • improves aeration

  27. Plant food and fertilizers • divided into two groups • Major elements (macro) • Nitrogen - N • Phosphorus - P • Potassium - K

  28. minor elements (micro) • Calcium - Ca • Magnesium - mg • Sulfur - S • Iron - Fe

  29. minor elements (micro) • Manganese - Mn • Boron - B • Copper - Cu • Zinc - Zn

  30. Plant requirements • large amounts of major elements • relatively small amounts of minor elements

  31. Commercial fertilizers • shows % or pounds per cwt. (100#) of the three major elements in large numbers on the container or bag.

  32. Commercial fertilizers • 5-10-5 • 5% N, 10% P, 5% K • remaining 80% is filler • NP&K are always listed in that order.

  33. Soil tests • determine amount of elements needed for various plants.

  34. Nitrogen • generally purchased in one of four forms • Nitrate of soda • ammonium nitrate

  35. Nitrogen • ammonium sulfate • urea formaldehyde

  36. Nitrogen • has most noticeable effect on plants • encourages above ground vegetative growth • regulates use of other elements

  37. Too much N • lower disease resistance • weaken stem because of long soft growth • lower fruit quality

  38. Too much N • delay maturity • increase winter damage to plants

  39. Not enough N • yellow or light green color • stunted root and top growth

  40. N lost easily from soil • leaching - being filtered down through soil with water • not held by soil particles, dissolved in water • O.M. holds insoluble N for slow release

  41. Don’t use excess N • quickly lost through leaching • can damage plants

  42. Phosphorous • held tightly by soil particles • not easily leached

  43. Phosphorous • effects plants in several ways • encourage cell division

  44. Phosphorous • flowers and seeds don’t form without it • hastens maturity, offsetting quick growth caused by N.

  45. Phosphorous • encourage root growth • makes K more available • increase disease resistance • improves quality of grain, root and fruit crops

  46. Phosphorous • container plants can be damaged by excess P • increases soluble salt content of medium • causes dehydration of roots

  47. Phosphorous • Insufficient P • purple color on underside of leaf • reduced flower fruit and seed production

  48. Insufficient P • susceptibility to cold injury • susceptibility to plant diseases • poor quality fruit and seeds

  49. Potassium • modifies both fast soft growth of N and early maturity of P • is essential

  50. Potassium • increase disease resistance • encourages healthy root systems • essential for starch formation

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