Plant Nutrients

Jason Gehrke

2164A, B, E, F, G

Macro/Micro Nutrients

• Macro– Nitrogen

– Phosphorus

– Potassium

– Magnesium

– Calcium

– Sulfur

• Micro– Boron

– Copper

– Chlorine

– Manganese

– Molybdenum

– Nickel

– Zinc

– Iron

Macro-Nutrients

• Nitrogen– Amino acid synthesis

– Proteins

– Chlorophyll

– Enzymes

• Phosphorus– Storage and transfer of

energy as ATP

– Proteins

– Co-enzymes

– Make phospholipids and nucleic acids

Macro-Nutrients

• Potassium– Maintain plant cell

structure (turgidity)

– Plant cell processes• Enzyme activation

• Sugar translocation

• Magnesium– Central atom of the

chlorophyll molecule

– Aids in phosphorus uptake

Macro-Nutrients

• Calcium– Maintains Plant cell

walls and cell division

• Sulfur– Required for several

amino acids

– Cell respiration

– Crucial for protein synthesis

Deficienies

• Color– Yellowing of leaves (chlorosis)

• Nitrogen

• Potassium

• Plant Stunting

• Decrease in flower budding

• Decrease in Plant Size

MicroNutrients

• Boron– Flowering, fruiting,

cell division

– Translocation of sugars in plants

• Copper– Chlorophyll synthesis

– Catalyst for respiration

– Catalyst for carbohydrate and protein metabolism

MicroNutrients

• Manganese– Crucial in chlorophyll

synthesis

– Phosphorylation

– Activation of enzymes

– Carbohydrate metabolism

• Molybdenum– Protein Synthesis

– Required by some enzymes

MicroNutrients

• Zinc– An enzyme activator

– Chlorophyll production

• Iron– Enzyme reactions

– Chlorophyll production

Nutrient Uptake

• Process– Minerals dissolve in water and become small

electrically charged particles (ions)– Soil surface is negatively charged– Positive minerals bind to negative soil surface– Water displaces the minerals in the soil – Free minerals are absorbed by plant root cells

pH

• Indicates the level of acidity or alkalinity– Acidity pH < 7 (less than)– Alkalinity pH > 7 (greater then)

• Plants prefer soil pH around 6.0-7.0• Many nutrients are abundant in this range• pH preference is different for each plant• Low pH can kill microorganism

Example: nitrogen fixing bacteria

pH and Nutrient Availability

www.avocadosource.com/ tools/FertCalc_files/pH.htm

Nutrient Sources

• Natural Organisms

• Crop Residues

• Animal Wastes

• Commercial Fertilizers

Nutrient Sources

• Natural Organisms– Nodulation– Mycorrhiza

http://www.arspb.org/publications/soy97/rootc.jpg

Nodulation

• Symbiotic relationship is Mutualism between legume plants roots and bacteria

• Rhizobacteria- living soil bacteria convert nitrogen gas N2 to ammonia NH3

• Attach to root hairs of plants and plant roots curl around them

• Bacteria stimulate the root cortex cells to divide – Form a nodule www.anbg.gov.au/cpbr/ program/ub2002/rhiz_host.htm

Nodulation

• Nodule is a modified lateral root with own meristem and vascular tissue.

• 1/3 of nitrogen for plant comes from fixation

• 3 different rhizobacteria, each specific to a legume species

http://www.legumetechnology.co.uk/Pics/bi1.jpg

Mycorrhiza

• Symbiotic relationship is Mutualism

• Fungal hyphae closely associate with active root

• Fungus uses photosynthates flowing from shoot to root as a source of food

• Plant receives phosphate taken up by mycorrhiza from the soil • http://www.apsnet.org/education/

IllustratedGlossary/PhotosI-M/mycorrhiza.jpg

Crop Residues

• Left over crops are chopped up and plowed under soil

• Corn stalks• Alfalfa• Sunflowers

http://abe.www.ecn.purdue.edu/~epados/erosbmp/images/cropresi.jpg

Animal Wastes

• Animal wastes differ with different – Animal types

– Feeds fed to animals

– Human handling (dry or wet storage)

www.ontariocorn.org/.../ soilccr_mcropres.htm

Commercial Fertilizers

• Types– Dry granules

– Liquids

– Gas

• Grades– (N-P-K)

www.ars.org/About_Roses/ fertilizing_food.htm

Examples

• Nitrogen – Ammonium Nitrate (33-0-0) dry granules– Urea (45-0-0) dry granules– Ammonium Sulfate (21-0-0) dry granules

• Phosphorus– Super phosphate (0-20-0) contains 24% sulfur

• Potassium– Potassium chloride (0-0-62) dry granules

10-10-10

http://www.agr.state.nc.us/cyber/kidswrld/plant/Fertbag.GIF

Conversions

• Nitrogen– No conversion needed 100% nitrogen

• Phosphorus is in the form P2O5– Atomic weight P=31, O=16– 2(31) + 5(16) = 142– P = %P/total weight, so 62/142 = 0.44– P= 44% of P2O5

• Potassium is in the form K2O– Atomic weight K=39.1, O=16– 2(39.1) + (16) = 94.2– K = %/K/total weight, so 78.2/94.2 = 0.83– K= 83% of P2O5

Example Conversion 10-25-30

In 1500 lbs of Fertilizer

N= 1500 x .10 = 150 lbs

P2O5= 1500 x .25 = 375 lbs

K2O= 1500 x .30 = 450 lbs

Example Conversion 10-25-30

In 1500 lbs of Fertilizer

N= 1500 x .10 = 150 lbs

P2O5= 1500 x .25 = 375 lbs

K2O= 1500 x .30 = 450 lbs

Total amount of N-P-K

N= 150 Lbs

P = 375 x .44 = 165 lbs

K= 450 x .83 = 373.5 lbs

Nutrient Testing

To determine how much fertilizer to apply have soil tested– Take soil sample to

lab

– Lab will test for available P & K in soil

http://www.agry.purdue.edu/turf/images/fertsprd.jpg

Environmental Factors

• Soil Composition– Sandy soils will drain faster, hold less nutrients– Clay soils will retain more nutrients, but will drain

slower

• Water/Rain– Need some rain so fertilizer will dissolve if it is in dry

granule form– Heavy rain will cause fertilizer to leach through soil

pass plant roots– Too Little Water (drought conditions) and fertilizer

application is worthless