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Ch. 4: Soil Water, Plant Nutrition, Soil Symbioses. Soil. Supplies H2O & nutrients 1) What influences soil water? 2) What nutrients plants need, & what influences nutrient supply?. Plant nutrition. 17 essential elements Deficiency : < needed Toxicity : > needed. Molybdenum (Mo) deficiency
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Soil • Supplies H2O & nutrients • 1) What influences soil water? • 2) What nutrients plants need, & what influences nutrient supply?
Plant nutrition • 17 essential elements • Deficiency: < needed • Toxicity: > needed Molybdenum (Mo) deficiency in citrus Aluminum (Al) toxicity
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” • “CHOPKiNSCar is an Mg” • >1% plant dry weight is C,H,O,N,K (Chonk!) Chuck Hopkins and his car
Plant nutrition • 17 essential elements • Micronutrients (8): < 0.02% plant • Fe, Mo, B, Cu, Mn, Zn, Cl, Ni • “A festive mob comes in clapping nicely” • “A Festive MoBCuMnZnClapping Nicely”
Plant nutrition Another Moe • Ex, Mo deficiency Australia • Mo used N-fixing bacteria • 140 g/ha (13 oz/acre!) Mo every 5-10 yr • Increased growth 6-7 times!
Soil Fertility: Recall….. • CEC (organic matter and clay): “potential fertility” • pH determines BS & influences “actual fertility” • Overall, hi CEC & hi BS means pH high & soil fertile
Recall…… • pH influences nutrient availability
Nutrient sources • 1) Soil • 2) Some nutrients mobile: recycled old to new leaves • Removal nutrients: resorption • Important N, P, K, Mg (mobile nutrients)
Soil Taxonomy • Soils classified Tony Danza?
Soil Taxonomy • Smallest unit: series. Basic unit classification. = species (biology) • Largest: order (ends in -sol). = domain (biology) What official AL state soil??
Soil Taxonomy • Bama series!
Soil Taxonomy Tour • 7 orders (AL) • Major profile characteristics, vegetation
1: Entisols • Named for RECENT • Little profile (young): A/C or A/R • Steep rocky places, new sediments, etc. A/C A/R
1: Entisols • Scattered AL
2: Inceptisols • Little profile (inceptus=beginning): > Entisols • A & weak B • Steep slopes, young soils Appalachian forest soil on sandstone
2: Inceptisols • Widespread AL
3: Histosols • Histos=tissue: High organic matter (20-30%) • Thick O • Drainage restricted: little decomposition—flooded, anaerobic
3: Histosols • Shrink when dry (subsidence) Everglades swamp histosol 1924: post top @ surface 1975: photo taken (4 ft drop)
3: Histosols • Burns when dry! Peat = fuel • When farmed: can burn/blow away N. Carolina histosol
3: Histosols • AL: pitcher plant bogs & swamps (lower coastal plain)
4: Vertisols • High clay (shrink-swell type) • Cracks when dry • Self-turning (verto=to turn)
4: Vertisols • Self-turning: little profile development • Peds have slickensides (smooth shiny surfaces) Engineering problems
4: Vertisols • AL: common Black Belt
5: Mollisols • From mollis=soft • Grassland (prairie) soils
5: Mollisols • From mollis=soft • Grassland (prairie) soils • Thick, dark A. Hi OM • Hi CEC & BS. (Fertility?)
5: Mollisols • Good ag soils. Little prairie left
5: Mollisols • Few N AL
6: Alfisols • Hi Al & Fe (AlFe) • Well developed (A, E, B) • B claypan (Bt layer) • BS high (>35%)
6: Alfisols • Fertile ag soils • Most midwest/north US
7: Ultisols • Well developed, acidic. Humid climate • B: claypan (Bt), red/yellow Fe oxides
7: Ultisols • Low BS (<35%) • Good ag soil if fertilized & limed.
7: Ultisols • #1 AL (SE US)