Transcript 幻灯片 1 - Michigan State University

A BRIEF INTRODUCTION ON PLANT
NUTRITION AND HYDROPONICS
Di Liang
Michigan State University
Kellogg Biological Station

Plants need the right combination of nutrients
to live, grow and reproduce.
The major source of plant
nutrition is the fixation of
atmospheric CO2 into sugar.
CO2 enters through the stomata.
Not sufficient?


Plants also need inorganic nutrients.
Macronutrients and Micronutrients
Macronutrients

Carbon, Hydrogen, Oxygen, Nitrogen,
Potassium, Calcium, Phosphorus,
Magnesium and Sulfur

Each may exceed 1% dry weight of plant.
Micronutrients

Iron, Chlorine, Copper, Manganese, Zinc,
Molybdenum, and Boron

Constitute from less than one, to several
hundred PPM in most plants.
Functions
Functions
The Story of Boron
Leybig’s Law of the Minimum

Plants will stop growing when a single nutrient
is lacking although all other nutrients are
sufficient.
N deficiency

General yellowing of older leaves (bottom of
plant). The rest of the plant is often light
green.
N deficiency
Corn: “V” shape on old leaves
P deficiency

Leaf tips look burnt, followed by older leaves
turning a dark green or reddish-purple.
P deficiency
Rice: decreased tiller
number, smaller ear, less
fruits
P deficiency
Citrus: thicker skin and lower quality
K deficiency

Older leaves may wilt, look scorched. Inter veinal
chlorosis begins at the base, scorching inward from
leaf margins.
K deficiency
Cotton: spots occurred between veins.
K deficiency
Tomato: “green back”
K deficiency
Ca deficiency

New leaves (top of plant) are distorted or
irregularly shaped. Causes blossom-end rot.
Mg deficiency

Yellowing occurs between veins. “web” pattern
is on old leaves.
Mg deficiency
Why hydroponics



Too much fertilizer
Easy to control
Straightforward
True Hoagland Solution
6 ml of 1 M potassium nitrate
4 ml of 1 M calcium nitrate
1 ml of 1 M monoammonium phosphate
2 ml of 1 M magnesium sulfate
1 ml of micronutrient stock solution
1 to 5 ml of iron chelate stock solution
Micronutrient stock solution per liter:
2.86 g boric acid
1.81 g manganese chloride - 4 hydrate
0.22 g zinc sulfate - 7 hydrate
0.08 g copper sulfate - 5 hydrate
0.02 g 85% molybdic acid
Hydroponics
ml
-N
-P
-Fe
1M KNO3
_
5
5
1M Ca(NO3)2
_
5
5
1M MgCl2
2
2
2
1M KH2PO4
1
_
1
0.05M FeEDTA
1
1
_
Micronutrient
1
1
1
1M CaCl2
5
_
_
0.5M Na2SO4
5
2
2
Total
15
16
16
Roots
+N
-N
Thank you!