Mineral Nutrition chapter 4

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Mineral Nutrition (chapter 4)
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• Mineral Nutrition
• How plants acquire and use mineral nutrients
• 1. Why is mineral nutrition important?
• 2. What are the essential mineral nutrients?
• classification systems
• 3. Mineral nutrients in the soil
• nutrient availability
• adsorption to soil particles
• effects of pH
• 4. Roots and mineral nutrient acquisition
• root structure
• depletion zones
• 4. Mycorrhizae
• 5. Nitrogen - the most limiting soil nutrient

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Why is mineral nutrition important? 1.
Fertilization increases crop production
Crop Yield, tons/hectare
Fertilizer used, kg/hectare
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Add more fertilizer nitrogen, get more crop
production.
Crop Yield, tons/hectare
Nitrogen added, kg/hectare
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Trends in global use of fertilizer N, P, K
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• Why is mineral nutrition important?
• 2. In most natural soils, the availability of
  mineral nutrients limits plant growth and primary
  productivity.
• Nutrient limitation is an important selective
  pressure and plants exhibit many special traits
  related to the need to acquire and use mineral
  nutrients efficiently.

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2. What are the essential mineral
nutrients? Macronutrients - present in
relatively high concentrations in plant
tissues. N, K, P, Ca, Mg,S, Si Nitrogen is
most commonly limiting to productivity of natural
and managed soils. Phosphorus is next most
limiting, and is most limiting in some tropical
soils. Micronutrients - present in very low
concentrations in plant tissues.
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All mineral nutrients together make up less than
4 of plant mass, yet plant growth is very
sensitive to nutrient deficiency.
Not considered mineral nutrients
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Micronutrients are present in very low
concentrations
ppm
Very low concentrations, but still
essential because of specialized roles in
metabolism
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How to classify all of these macro and micro
nutrients?
By biochemical function
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3. Mineral nutrients in the soil
Larson
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Soils particles are generally negatively charged
and so bind positively charged nutrient ions
(cations). Cation Exchange Capacity refers to a
soils ability to bind cations.
NH4, NO3-, Cl-, PO4-2, SO4-2
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Soil pH influences availability of soil nutrients.
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4. Roots and mineral nutrient acquisition
Fine roots and root hairs mine the soil for
nutrients. Mycorrhizal hyphae do this even
better.
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Fig. 5.7
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Fig. 5.8
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• More on Nitrogen
• Why is N so important for plant growth?
• What percentage of the mass of plant tissues is
  N?
• What kinds of compounds is N found in?
• Why is there a strong relationship between the N
• concentration of leaves and photosynthesis?