Plant Nutrition and Soils

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Plant Nutrition and Soils
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Soil profiles
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Whats in topsoil?

• Mineral particles
• sand, silt, clay
• Pore space (50)
• Air
• Water
• Living organisms
• Humus

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pH matters
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Essential Elements from the Soil(Mineral
nutrients)

• Macronutrients
• P,K,N,S,Ca,Mg
• Micronutrients
• Fe,Cl,Cu,Mn,Z,Bo,Mo, Ni

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Functions of Mineral Nutrients

• Structural units
• Part of metabolic compounds
• Enzyme activation (or inactivation)
• Alter osmotic potential
• NPK most often limiting, found in fertilizers

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Nutrient Cycles

• Phosphorus
• reservoir is earths crust
• likely to limit growth
• Nitrogen
• reservoir is N2
• shortage often limits growth

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Carnivorous plants get nitrogen another way
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The End
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Nitrogenase is inhibited by O2
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Legume
Pg 642
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Rhizobia bacteria are aerobic
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Leghemoglobin in root nodule carries oxygen
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Phosphorus cycle
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Mycorrhizal Roots
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Ectomycorrhizae
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Endomycorrhizae