Care for these RESOURCES Starting with The Basics What is soil Naturally deposited MIXTURE of R ock particles Organic materials Air Water Soil Components Soil Components Air Mixture of atmospheric gases ID: 656188
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Slide1
Nutrients and
Soil Organic Matter for Crops:
Care for these RESOURCESSlide2
Starting with The Basics!Slide3
What is soil
Naturally deposited MIXTURE of:
R
ock particles
“Organic” materials
Air
WaterSlide4
Soil ComponentsSlide5
Soil Components
Air
= Mixture of atmospheric gasesSlide6
Soil Components
MINERAL
= Solid compound of known composition:
NaCl
,
SiO
2
,
Al
2
Si
2
O
5
(OH)
4
ROCK
= Mixture of minerals
(more on
these
in a little while…)Slide7
Soil Components
WATER
=
H
2
O
Every living thing needs water
Water shapes the planetSlide8
Soil Components
Organic Matter
= Solid material originating from living organismsSlide9
A deeper look at
Soil Organic Matter
WHERE does it come from?Slide10
Plants ARE Organic Matter!
Well, WHERE do plants come from?
AIR ~ WATER ~ LIGHTSlide11
AIRSlide12
WATERSlide13
LIGHTSlide14
PHOTOSYNTHESIS- conversion of
Light Energy into Chemical Energy
Creates carbon-based plant life-
“FIXED CARBON” or
“REDUCED CARBON”
-from
CO
2
Water
Light Energy
GLUCOSESlide15
SO: Plants produce
their own food (ENERGY)!!
Glucose=Basic Sugar
Immediate energy for plant
Building Block of:
Starch- energy storage
Cellulose- structural carbohydrate
Fats, oils, waxesSlide16
Cellulose: basic structural unit of plant cell walls
Most abundant organic polymer on Earth
Makes up:
90
% of Cotton fiber
40-50% of Wood
Microorganisms
can digest it!!!Slide17
Plants=Food
Food=Energy
Energy=Fuel
Fuel “BURNS”
All life requires FuelSlide18
About ENERGY… The CARBON Cycle
CO
2
“Reduced Carbon”
RESPIRATION
PHOTOSYNTHESIS
(GLUCOSE)Slide19
Plant material is the ULTIMATE Source of SOIL ORGANIC MATTER and ENERGY
Agricultural Production Systems
sIMulator
(
APSIM
)
Chemical Energy
of organic matter is converted into new organisms
Accumulation of organic matter
Organisms mineralize nutrients
Plants and animals grow and die
Residues enter the soil ecosystem
…and are broken down and transformed by soil microbes and faunaSlide20
Energy feeds the Soil Food WebSlide21
Plants SYNTHESIZE Biomolecules
Not all biomolecules are carbohydrates!
Fats, Proteins, Vitamins, Cofactors, and Nucleic Acids all have CARBON backbones
MORE INGREDIENTS REQUIRED FOR THESE… Slide22
Plant Nutrients-
Elements obtained from the SOIL
Phosphorus (P)
Potassium (K)
Calcium (Ca)
Magnesium (Mg)
Sulfur (S)
MACRONUTRIENTS
MICRONUTRIENTS
Iron (Fe)
Manganese (
Mn
)
Zinc (Zn)
Copper (Cu)
Nickel (Ni)
Molybdenum (Mo)
Boron (B)Slide23
One more… SUPER IMPORTANT
NITROGEN (N)
acquired by plant roots BUT
All N is ultimately derived from the air
In nature: Bacteria are able to use atmospheric N, which then becomes available to plants
In agriculture: Atmospheric N is converted to ammonium (
NH
4
) by an industrial process called Haber-BoschSlide24
Q: Where do these elements come from?Slide25
A: From the crust of the EarthSlide26
So Rocks dissolve- SLOWLY!!Slide27
Ionic forms of Plant Nutrients
NO
3
-
PO
4
-3
NH
4
+
K
+
Ca
+2
Mg
+2
SO
4
-2
Fe
+2
Mn
+2
Cu
+2
Zn
+2
BO
3
-3
Cl
-
MoO
4
-2
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
H
+
Al
+3
Al
+3
Al
+3
Al
+3
Al
+3
Al
+3
Al
+3
Al
+3
Al
+3
Slide28
Sources of Plant Nutrients
Weathering of soil minerals- very little
Added fertilizers- VERY IMPORTANT
Organic matter, including crop residues, manures, compost (more on this in a bit…)Slide29
Q: Why are fertilizers necessary for CROP production?
Hint: What does the word “CROP” mean?Slide30
Most added fertilizers are derived from rock deposits
Phosphate Rock, Potash Rock, Limestone, Gypsum, Talc, othersSlide31
Some fertilizer nutrients are applied as MANURES
Manure is an
ORGANIC
nutrient source- remember what we mean by ORGANIC…
BUT- there aren’t enough manure nutrients to meet more than 10% of US cropland needsSlide32
Why do manures have plant nutrients?
Livestock do not digest everything they eat
Manure can have 10 to 40
lbs
/ton of N and P
Organic nutrient sources release slowlySlide33
Agricultural Production Systems
sIMulator
(
APSIM
)
Nutrient Cycling through
Organic matterSlide34
All elements have cycles
Legumes!!
Nitrogen
Alflafa
Clovers
TrefoilsSlide35
All elements have cycles
PhosphorusSlide36
Caring for these Resources
Nutrients
:
They are necessary for growing agricultural crop plants
They are expensive
They are in limited supply
They can pollute ecosystems and groundwater if excessiveSlide37
Making the most of Nutrients
Some are removed with the crops
Some can be cycled through crop residues and manures
Losses should be minimized: a) for Cost
S
aving, b) for Water
R
esource
P
rotection, c) for Ecosystem ProtectionSlide38
Minimizing Nutrient Loss
Prevent soil erosion (loss of Phosphorus)
Allow space for vegetated buffer zones between crop fields and water bodies
Grow cover crops in fallow seasons to absorb excess soil nutrients
Apply manure responsibly
GROW LEGUME COVER CROPS FOR NSlide39
Caring for these Resources
Soil Organic Matter
:
Provides a slow release supply of plant nutrients, especially N and P
Has extremely important soil benefits, especially as FUEL for microorganismsSlide40
Caring for these Resources
Conservation of Soil Organic Matter
:
Minimize soil disturbance- aeration helps the microorganisms to “burn” SOM
Leave crop residues in the field
Apply additional organic materials if they are available
PLANT COVER CROPSSlide41
Questions?