1. Ch. 4: Soil Water, Plant Nutrition, Soil Symbioses

2. Soil Supplies water & nutrients to plants
1) What influences soil water supply?
2) What nutrients do plants need, and what influences soil nutrient supply?

3. Plant nutrition 17 essential elements Deficiency: < needed
Toxicity: > needed
Molybdenum (Mo) deficiency
in citrus
Aluminum (Al) toxicity

4. Plant nutrition 17 essential elements
Macronutrients (9): > 0.1% of plant
C, H, O, P, K, N, S, Ca, Mg
“C Hopkin’s car is an MG”
“C HOPKiNS Car is an Mg”
>1% plant dry weight is C,H,O,N,K (Chonk!)
Chuck Hopkins and his car

5. Plant nutrition 17 essential elements
Micronutrients (8): < 0.02% plant dry wt. Tiny amounts!
Fe, Mo, B, Cu, Mn, Zn, Cl, Ni
“A festive mob comes in clapping nicely”
“A Festive MoB CuMnZn Clapping Nicely”

6. Plant nutrition Ex, Mo deficiency Australia
Mo used by N-fixing bacteria.
140 g/ha (13 oz per acre!) Mo every 5-10 yr increased pasture growth 6-7 times!
Another
Moe

7. Soil Fertility: Recall…..
CEC (organic matter and clay) is “potential fertility
pH determines BS and influences “actual fertility”
Overall, high CEC and high BS means pH high and soil more fertile

8. Recall……
pH influences nutrient availability

9. Nutrient sources 1) Soil
2) Some nutrients mobile: recycled from old to new leaves
Removal nutrients from leaves: resorption
Important N, P, K, Mg (mobile nutrients)
Others less mobile