Chapter 37 - Soil and Plant Nutrition

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Chapter 37 - Soil and Plant Nutrition

  1. 1. Plant Nutrition
  2. 2. Physiological adaptationDogs pee on trees…Why don’t trees pee on dogs? plant nutrient NH3animal waste
  3. 3. Nutritional needs Autotrophic does not mean autonomous  plants need…  sun as an energy source  inorganic compounds as raw materials  water (H2O)  CO2  minerals
  4. 4. Macronutrients  Plants require these nutrients in relatively large amounts  C, O, H, N, P, K, Ca, Mg, S
  5. 5. For what & from where?C macromolecule synthesis CO2O macromolecule synthesis CO2H macromolecule synthesis & proton pumps H2ON protein & nucleic acid synthesis soilP nucleic acids, ATP, phospholipids soilK stomate control, water balance soilCa cell wall & membrane structure, regulation soilMg chlorophyll soilS proteins, enzymes soil
  6. 6. Local Long Island soil issues Quartz silica based soils - low in P - can be acid Acid soils bind up mineral ions pH by adding lime Granite
  7. 7. Micronutrients  Plants require in very small amounts  Cl, Fe, Mn, Bo, Zi, Ni, Mb  primarily cofactors for enzyme function
  8. 8. Nutrient deficiencies  Lack of essential nutrients  exhibit specific symptoms  dependent on function of nutrient  dependent on solubility of nutrient
  9. 9. Take 2 fertilizer pellets & call me inMagnesium deficiency the morning  Symptoms  chlorosis = yellowing of leaves  Why? What is magnesium’s function?
  10. 10. ChlorophyllWhy does magnesiumdeficiency cause chlorosis?The chlorosis shows up in olderleaves first, because plant movesMg+ to newer leaves. Why?
  11. 11. Agronomists really dig dirt!The role of soils Plants are dependent on soil quality  texture / structure  relative amounts of various sizes of soil particles  composition  organic & inorganic chemical components  fertility
  12. 12. Importance of organic matter So don’t rake Topsoil your lawn or  most important to plant growth bag your leaves  rich in organic matter  humus  decomposing organic material  breakdown of dead organisms, feces, fallen leaves & other organic refuse by bacteria & fungi  improves soil texture  reservoir of minerals  organisms  1 tsp. of topsoil has ~5 billion bacteria living with fungi, algae, protists, insects, earthworms, nematodes
  13. 13. Soil health as a global issueNot taking care of soil health hasfar-reaching, damagingconsequences  1920’s Dust Bowl  lack of soil conservation  growing the same crop year after year (wheat)  grazing by cattle  bare ground exposed to wind erosion in winter  drought
  14. 14. Soil health as a global issue  Soil conservation & sustainable agriculture  maintaining healthy environment  sustainable production of food supply  economically viable farming industry “A sustainable agriculture does not deplete soils or people.” – Wendell Berrycontour plowing cover crops crop rotation
  15. 15. Global issues  soil fertility  erosion  irrigation  forestry destruction
  16. 16. Fertilizers  “Organic” fertilizers  manure, compost, fishmeal  “Chemical” fertilizers  commercially manufactured  N-P-K (ex. 15-10-5)  15% nitrogen  10% phosphorus  5% potassium What are the political, economic, environmental issues?
  17. 17. Nitrogen uptake  Nitrates  plants can only take up nitrate (NO3-)  Nitrogen cycle by bacteria  trace path of nitrogen fixation! root What will the plant use N for?
  18. 18. Soybean root nodules  N fixation by Rhizobium bacteria  symbiotic relationship with bean family (legumes)
  19. 19. Plow it under? Why would youIncreasing soil fertility do that?  Cover crops  growing a field of plants just to plow them under  usually a legume crop  taking care of soil’s health A farmer…  puts nitrogen back in soil outstanding in his field? erosion control, too
  20. 20. Some plant oddities… 2006-
  21. 21. Parasitic plants  tap into host plant vascular system Indian pipe Mistletoe
  22. 22. Plants of peat bogs  High acid environment  most minerals & nutrients bound up & are not available to plants  must find alternative sources of nutrients
  23. 23. Carnivorousplants Sundew Venus fly trap Pitcher plant
  24. 24. Pitcher plant
  25. 25. Any Questions??

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