SOILS Flashcards
a hexagonal column of soil measuring from 1 to 10
m2 in top surface area
Pedon
an essential soil individual, comprising an
identifiable series of soils in an area
an essential soil individual, comprising an
identifiable series of soils in an area
the study of soils
with principal interest on characterization and
differentiation of their properties and with only
minor emphasis on their practical use
Pedological approach
the study of soils
with emphasis on their practical use, particularly
the relationship of soil properties to plant growth
Edaphological approach
characteristics, processes, or reactions of
a soil caused by physical forces
Soil Physics.
interactions of solid, liquid, and gaseous…,·
phases or components of soil
Soil Chemistry
protection of
soil against physical loss by erosion or cher:n1ca
deterioration
Soil Conservation and Management.
deals witfi tche
structural characteristics, mode of origin, and systematic
arrangement of soils
Soil Survey and Classification
structural chemistry of the solid
components of soil
Soil mineralogy
deals with the allocation of lands for general
or broad purposes such as agriculture, forestry,
settlement and military reservations
Land use:
Mineral matter, 45%
Organic matter, 5%
most soils contain less than 20%
organic matter, thus classified as mineral soils
Soil pores N O2 and C02
78, 20 , 0.5
a solvent that can release
nutrients from minerals.
carbonic acid
aggregates of minerals
Rocks
study of rocks
Petrology
The most common soil-forming igneous rocks are
granite, diorite, gabbro, ryolite, andesite, basalt,
and obsidian
Granite and diorite are lighter in color due to the
high proportion of light-colored minerals such as
feldspar and muscovite.
Gabbro is dark in color due to the predominance of
dark-colored minerals such as
biotite, hornblende,
and augite.
Granite is acidic while basalt is basic.
are among the dominant soilforming
rocks in the Philippines
Basalt and andesite
The most important soil-forming sedimentary
rocks are
limestone, dolomite, sandstone, and
shale.
process of sedimentation
fragmentation, transport, and recementation
Limestone is made up chiefly of the
mineral, calcite or CaC03.
also a carbonated material composed
of calcium magnesium carbonate CaMg(C03h.
Dolomite
is made up of fine particles of clay which
become consolidated after deposi’t’on · bedie of
water.
Shale
Soils derived from limestone are soil series-.,, of
Faraon, Bolinao, Binangonan, and Alimodian which
are the soils in Cebu and Bohol
Soils derived from shale/ sandston are soil series
of
Alaminos, Bantay, Bauang, Lugo and Ubay.
The most typical soil-forming metamorphic rocks
are
gneiss, schist, quartzite, slate, and marble
metamorphic form of limestone.
marble
happens when the magma is ejected out of the
earth’s crust through volcanic eruption and
solidifies on the surface
There is abrupt cooling
Extrosive {volcanic} formation
happens when magma solidifies within the earth’s
crust
Introsive {plutonic} formation
Oxygen
46.6
Silicon
27.7
Aluminum
8.13
Iron
5
magnesium
2.09
calcium
3.63
sodium
2.83
potassium
8.13
a naturally occurring inorganic substance with
more or less definite chemical composition and
specific physical properties
Mineral
study of minerals and their properties
Mineraloqv
persist in the soil in their original state due to high
resistance to decomposition
Primary minerals
contributes K
upon weathering
Orthoclase, (anorthite)
contributes Na upon weathering
Sodium-plagioclase, (albite)
cotributes calcium upon weathering
calcium palgioclase
white mica
muscovite
black mica
biotite
quartz
microline
most important primary minerals
Quartz
Orthoclase
Sodium-plagioclase
Calcium-plagioclase
Muscovite
Biotite
Hornblende
Augite
Apatite
arise from the chemical breakdown of the least
resistant primary minerals
Secondary minerals
The more commonly occurring secondary minerals
are:
Calcite
dolomite
gypsum
limonite
hematite
gibbsite
kaolinite
montmorillonite
illite
refers to the
imperceptible movement of rock formation
towards the earth’s surface resulting in cracking or
rocks.
unloading
the reaction of water with the
mineral resulting in the destruction of the
original chemical structure and the formation
of an acid and base
hydrolysis
nvolves the reaction of water
with the mineral but not leading to the
destruction of the chemical structure; The
result is a rigid attachment or association with
a water molecule.
hydration
reaction of carbonic acid with a mineral to produce a
soluble product
carbonation
the dissolution of minals thrgh
the solvent action of H2C03 o H ions which
results into the separation or dissociation of
component cations
solution
affects the amount of leaching that takes
place in the soil and the speed with which soil horizons
develop
Climate
factors of soil fomation
climate
living organism
relief or topography
parent material
time
For every 10 °C rise in temperature, the rate of
biochemical reactions doubles.
the mixing of the soil by o ganisms
bioturbation
Soils of forested areas
dipterocarps
the partly weathered mineral or organic debris
from which true soil (solum) is formed
Parent material
those that develop in
place and formed from the rock below where it
is found
sedentary or residual.
those which are transported by
various agents and deposited in other sites
where they form the soil. The different types
based on the agent and manner of transport
are the following:
transported.
accumulated from running
water
Alluvium
materials that are
accumulated in former lakewaters
Lacustrine
materials that are
accumulated in former oceans
Marine
those that are
carried and deposited by moving
glaciers
galcial till or moraine
those that are carried and
deposited by the wind
aeolian
a stratified rock
hardened (lithified) from deposited
fine dust or ash emitted on a volcanic
eruption
volcanic tuff
transported and deposited by gravity
collovium
is generally a young soil because ot
the constant deposition which re\ev s the parent
material.
Alluvial soil
Old soils have thick solum but are generally acidic
and low in fertility
a vertical cross section of the soil exposing
all of its horizons
Soil profile
a layer of soil or soil material
approximately parallel to the land surface and differing
from adjacent horizons in physical, chemical and biological
properties
Soil horizon
process wherein each horizon
acquires distinctly different properties from the others due
to various mechanisms of addition, losses, translocation
and transformation
Horizon differentiation
mechanism of addition and transformation
enrichment
melanization
comulization
mechanism of translocation
illuviation
calcification
decalcification
salinization
akalinization
podzolization
laterization
leucinization
lessivage
general term for the addition of any
material to the soil body
Enrichment
admixing of organic matter to the
mineral matter which darkens the soil
Melanization
addition of mineral matter trough wind
and water to the soil body
€umulization:
general term for the movement of soil
material from one part of the soil to another resulting in
the formation of argillic (clayey) layers
illuviation
the transfer and accumulation of calcium
carbonate in particular soil horizon
Calcification
removal of calcium carbonate from the
soil horizon
decalcification
accumulation of soluble salts of sulfates
and chlorides of calcium, magnesium, sodium and
potassium in certain horizons
salinization
accumulation of sodium
ions
Alkalinization (solonization)
the translocation of
aluminium and iron and/or organic matter thus,
concentrating the silica in the leached layer
Podzolization (Silication)
the transfer of silica from
the solum, thus concentrating the aluminium and iron
oxides and sesquioxides in the leached layer
Laterization (Desilication
paling or loss of dark colorof the soil
due to the removal of organic matter from the solum
Leucinization
movement fo the fine mineral particles from the top soil resulting in the enrichment of clay of lower horizons
lessivage
A and B, zone of pedogenic activity; considered
as the true soil because these are the layers reacheqand
used by the roots as source of water and nutrient
Solum
all loose materials above the bedrock (A,B,
and C horizons)
Regolith
Horizon dominated by organic matter
o
Organic-rich, mineral horizon at or adjacent to the
surface
A
Mineral horizon of maximum eluviation
E
Mineral horizon of maximum illuviation and formed
beneath an O,A, or E
B
Weathered parent material
C
underlying consolidated bedrock
R
Mainly influenced by the addition of
organic matter
Surface Horizons:
developed due to the translocation,
transformation and losses
Subsurface horizons
the relative proportion of the various size
fractions: sand, silt and clay in the soil
Soil Texture
No amount of organic matter added can alter soil
texture
provide for the
framework for the soil
sand and silt fractions
usda
United States Department of Agriculture
issa
International Soil Science Society
Sand
2 - .05 (USDA)
2 -.02
silt
.05 - .002
.02 - .002
clay
<.002
shows the percentage of sand, silt
and clay at various textural classes.
Textural Triangle:
The moist sample is kneaded into a od an
texture is approximated by the abilit to form
or of the rods to remain intact bent i
loop
Roll method
states that the settling
velocity of soil particles in an aqueous medium is
directly proportional to the square of their
diameter multiplied by a constant
Stoke’s Law of
sedimentation
-Destroying the organic matter to remove the
cementing material of the soil separates
-Dispersing the soil vigorously with sodium
hexametaphosphate
Hydrometer method
refers to the clustering of the soil particles into
characteristic aggregates of various sizes, shapes
and stability
Soil structure
The major cementing agents in soil structure
formation are
colloidal clay, oxides of iron and
aluminium (sesquioxides) and organic matt r
Calcium-rich ( calcareous) soils are generally
well granulated while sodium -rich (sodic) soils
are highly dispersed
The best soil structure for good plant growth is the
granular specifically, crumb structure because it
has good distribution of large and small pores.
The best soil structure for good plant growth is the
Granular / crumb structure
pillar-like with level tops
Prismatic structure
pillar-like with rounded tops; like
prismatic structure, commonly occur in subsoils and in
soils of arid and semi-arid regions
Columnar structure
cube-like and has more or less sharp
edges and the rectangular faces are distinct
Blocky structure
has edges which are
more or less rounded; like the blocky structure, typical in
clayey subsoils particularly in humid regions
Sub-angular blocky structure
has disc-like aggregates; commonly
found in virgin soils and subsoils
Platy structure
rounded aggregates which are
more porous; characteristic of surface soils especially
those high in organic matter content
Spheroidal structure
fraction of the soil volume occupied by air and
water
Soil pore spaces
are formed in
between aggregates; they drain excess water
macropores
are formed
within the aggregate; they store water.
micropores
-the mass (dry weight) per unit volume of soil
-a measure of degree of compaction of the soil
and an indicator of porosity
Bulk density
The range of bulk density values for sand and
sandy loam soils is
1.2 - 1.8
The range of bulk density values for clay, clay
loam and silt loam is
1 - 1.6
normal bulk density
1 - 1.3
- mass (dry weight) per unit volume of soil
excluding the pore spaces within that soil volume - may indicate the mineral ancestry of the soil
Particle density
may indicate soils have
high organic matter
PD of < 2.5
P. D. of organic matter is
1.2 - 1.5
As the bulk density approaches the value of the
particle density, the percentage porosity
approaches zero.
the volume of soil pore spaces left occupied by air after the other pore spaces are filled with moisture
aeration porosity
the force by which water is held in the soil
Soil moisture tension {SMT)
1 atm
1.01325 bar
1 bar
0.9869 atm
A graph showing the relationship between
moisture content and moisture tension of the soil,
and the characteristic of the soil itself
Soil moisture -release curve
MC by weight (MCw)
- the weight ( or mass) of water per unit weight of
soil in which it is contained
Gravimetric.
MC by volume (MCv)
- the volume of water per unit of bulk volume
including soil solids plus pore spaces of the soil
Volumetric.
All pore spaces are completely filled with water
(maximum water holding capacity)
Water at saturation; SMT = 0
An estimate of the upper limit of the available
moisture range
Field Capacity {FC}; SMT = 1/3 bar;
an estimate of the lower limit of the available
moisture range
Permanent Wilting Point {PWP}; SMT = 15
the water film at the immediate surface of the soil
particle
Hygroscopic {water} coefficient; SMT 31
Computed by getting the difference between FC
and PWP
Available Water{AW}
- also called drainage water; the water which soon
drains out of the macropores - the difference between the water at saturation and
the water at field capacity
Gravitational water
small cubes of gypsum connected to wires and
buried at specified depths of the soil where water
status is to be monitored
Gypsum blocks
consists of a long tube filled with water and with a
porous cup buried in the soil and a mercury gauge
above the ground
Tensiometer
Upward movement of water
capillary movement
Downward movement of water
Infiltration and percolation
the downward entry of water via the
soil surface
Infiltration
the downward movement of water
through the soil; the water moves at a greater
depth in the soil profile
Percolation
the physical condition of the soil manifesting
cohesion and adhesion forces acting within the soil
at various moisture contents
Soil Consistency
soil is easily puddled
which is attained at paddy rice culture.
Liquid consistency
the soil is plastic and
sticky
Plastic consistency
Soil best for cultivation
since it is soft, friable, mellow and soil
structure is rejuvenated.
Friable consistency.
the soil is hard and
requires high energy to pull the plow, resulting
to cloddy seed bed.
Harsh/ hard consistency
are very old soils which
are acidic and low in basic cations.
reddish soils
in subsoils indicates good
drainage.
Red yellowish color
indicates poor drainage.
Dark bluish or grayish color
are generally more fertile
dark colored soils
the standard color comparison chart
munsell color chart
the dominant spectral color
hue
darkness or lightness of color
value
gradation of purity of color
intensity or brightness of a color
chroma
very small particles of matter (0.2 micron to 1
micron)
Soil colloids
-constituted by organic complexes occurring in
colloidal form
- represented by humus
constituted by organic complexes occurring in
colloidal form
The main source of negative charges in humus
dissociation of H+ from carboxylic and phenolic
functional groups at high pH.
types of inorganic colloids
Crystalline Silicate clays
Amorphous {non-crystalline} silicate clays
Amorphous Non-silicate clays
composed of sheet-structured alluminosilicates of
various types
Crystalline Silicate clays
types of crystallines sylicate clays
1: 1 non expanding type
2: 1 expanding type
2: 1 limited expansion type
2:1 non expanding type
2:2 type
1: 1 non expanding type
kaolinite and
halloysite
2: 1 expanding type
smectites
(montmorillonite)
2: 1 limited expansion type
(vermiculite)
2:1 non expanding type
(Illite)
2:2 type
( chlorite)
most chemically reactive type of crystalline sylicate clays
montmorillonite
represented by allophone and imogolite
Amorphous {non-crystalline} silicate clays
occur as amorphous hydrous oxides of Iron and
Aluminum
Amorphous Non-silicate clays
examples of amorphous non silicate clays
hematite
geothite
limonite
boehmite
gibbsite
arise mainly from exposed hydroxyl groups at the broke nedges of crystals
negative charges
Agriculture important soils are net-negatively
charged.
arise from the protonation or addition of H+ to OHgroups
on the edge of minerals such as
sesquioxides, allophone and kaolinite
positive charges
does not lsoe its color when it reacts to positve ly charged soil
eosin red
loses its color when it reacts to negatively charged soil
gentian violet
a reversible process by which ions are exchanged
between solid and liquid phases and between solid
phases if in close contact with each other
ion exchange
list of important cations
(NH4+, Ca2+,Mg2+, Na+, H+, K+)
list of important anions
(NO3-, PO4-, SO4- )
the ability of the soil to adsorb and exchange
cations with those in the surrounding
soil solution
as well as with the plant roots
Cation Exchange Capacity (CEC}
adsorption stregth order of cations
(Al3+ , H+)> Ca2+ > Mg2+ > K+ > Na+
the degree by which the exchange sites in the
colloids are occupied by basic cations
Percent Base Saturation (0/o BS}
list of basic cations
Ca2+, Mg2+, K+, Na+, NH4+,
the degree by which the exchange sites of colloids
are occupied by sodium ions
Exchangeable Sodium Percentage (ESP}
also referred to as soil reaction
soil pH
The lower the pH value, the higher is the W
concentration and the lower is the OHconcentration.
The most favourable pH for growing most
agricultural plants is between
6-7
The range of pH in the Philippines is
5.5 -6.5
When the pH is too low ( < 5.0, strongly acidic) these nutrients become less available
Ca, Mg, K, P, Mo, N
When the pH is too low ( < 5.0, strongly acidic) these nutrients become more soluble and toxic
Fe, Al, and Mn
When pH is too high (>8.0, strongly alkaline) most micronutrients becoem unavailable except
Mo
sources of acidity
H and Al3+ ions
Carbonic acid (H2CO3) dissociation
Organic Acids from OM decomposition
MIneral weathering
acid rain
heavy cropping
long term use of acidifying fertilizers
in high pH P becomes complexed with calcium
in high pH K also competes with the now abundant Ca for plant absorption
in high pH iron deficiency develops
in low pH P becomes complexed into insoluble forms with Fe and Al
in low pH P becomes complexed into insoluble forms with Fe and Al
In low pH P can also be precipitated as insoluble
manganese phosphate compounds
acidity due to W ions in soil solution
Active acidity
acidity due to H + and Al3+ ions adsorbed in
colloid surfaces
Reserve acidity
sources of alkalinity
Base forming cations
carbonates and bicarbonates
the strength of the lime in correcting soil
acidity with reference to calcium carbonate;
relative neutralizing value
RNV fo CaCO3
100%
RNV of Dolomite
109%
RNV of CaO
179%
RNv of Ca(OH)2
136%
list of liming materials
limestone
burned or quick lime
slaked lime
made up of CaCO3 and dolomite
limestone
made by
igniting calcium or magnesium carbonates;
quick lime
hydroxide of lime made by reacting
Cao or MgO with water
slaked lime
lowering the pH
acidification
facilitate the oxidation of sulfur compounds to sulfate
Thiobacillus
The acidity is due to the oxidation of sulfur
compounds in soils that are rich in sulfur
acid sulfate soils
- soils with toxic amount of soluble salt content
- with electrical conductivity (EC) greater than
4 mmhos/cm
saline soils
soils with excessive amount of soluble sodium (Na
content more than 15% of the CEC)
sodic soils
also referred to as dryland soils
upland soils
also referred to as paddy soils
lowland soils
in upland soil most nutrients exist in their oxidized state
in lowland soils most nutrients exist in their reduced state
probably the most significant microorganisms in
humid temperate region soils
7000 species worldwide
earthworm
most common species of earthworms
lumbricus terrestris and allolobophora calignosa
worms living the litter layer
epigeic (eisenia foetida)
worms living in the top 10-30 cm of soil
endogeic (allolobophora caliginosa)
worms living in the vertical burrow up to 1 meter
anecic (lumbricus terrestris)
Single-celled animals (20-50 microns in diameter)
-helps released the immobilized nutrients in the
bacteria
Protozoa
probably the most important in terms of their
effect on soil properties
bacteria
morphological grouping of bacteria
Cocci (speherical)
Rods (short, long, curved)
Spiral (vibrio)
- most adaptable and versatile soil organism
- able to decompose the resistant organic
compounds such as lignin, cellulose, and gums - acid loving
fungi
an association between fungi and
plant roots which help plants in solubilization of P
and its absorption
Mycorrhizae
attack and simplify complex organic compounds
such as cellulose, chitin, and phospholipids
actinomycetes
actinomycetes antibiotic producers
Streptomycin,
Erythromycin
chlorophyll bearing organisms which thrive mostly
in soil surfaces
Algae
refers to the totality of all carbon-containing
compounds in the soil derived from either plants
or animals
Soii ‘organic Matter {SOM}
Cellulose
(15 - 60%)
Hemicellulose
(10 - 30%)
Lignin
(5 - 30%)
Water-soluble fractions: amino sugars, amino
acids
(5 - 30%)
cultivated soil contain an average % of organic matter
2-3
is the enzymatic oxidation by soil
organisms under aerobic condition with CO2, heat
or energy and water as the major products.
Decomposition
Bacteria and Actinomycetes: inhibited at pH
5.5
is a
convenient tool for predicting the rate of
decomposition and regulating the quantity of
mineral nitrogen available to plant.
carbon nitrogen ratio
The higher the C/N ratio (usually 30), the slower is
the rate of organic matter decomposition because
the nitrogen is immobilized by microorganisms.
Soil microbes use whatever N is available
is the optimum C/N ratio of organic materials
for faster decomposition
20:1
conversion of organic N to inorganic N;
renders N available for plant use
Mineralization
conversion of inorganic N to organic N; renders N
unavailable for plant use
Immobilization
- the biological formation of NO3- or NO2 from
compounds containing reduced nitrogen - The most common initial substrate is NH4- and the
final product is NO3-
Nitrification
chemoautotrophic, gramnegative,
non spore forming, ellipsoidal or
short rods, responsible for the oxidation of
NH4+ to NO2-
Nitrosomonas.
hemoautotrophic, gram-negative,
non- spore forming, short rods, further
oxidizes nitrite to nitrate.
Nitrobacter
the excess growth of plant and
algae,
eutrophication
health problem in infants and
animals led by excess nitrogen
methemog!obinemia
biochemical reduction of nitrate-N to gaseous N by
facultative anaerobic soil organisms
Denitrification
Denitrification is all aerobic but nitrate is used as
the electron acceptor in the absence of 02*
microorgansims involved in denitrification
Pseudomonas,
Achromobacter, Bacillus and Micrococcus
breakdown of organic matter such as dead anii:nals
and plants or waste materials like excrement
ammonification
enter and irritates the roothair causing
the formation of root nodules
rhizobia
microorganism involved in non symbiotic N fixation
Azotobacter
Beijinckia and CLostridium pasteurianum
common Blue Green algae in the PH
Anabaena
uariabilis, Gloetrichianatans, Nostoc commune,
Nostoccarneum, Hapalosophon sp., Anabaenopsis
spp. and Tolypothrix sp
Genera of bacteria capable of solubilizing Calcium
phosphates
o Pseudomonas
o Mycobacterium
o Bacillus
o Micrococcus
Genera of fungi capable of solubilizing Calcium
phosphates
o Penicillium
o Fusarium
o Aspergillus
fungus forms a mantle
around root exteriors hyphae enters into
spaces between plant cells
Edotrophic
fungus penetrates the
cells of the plants examples
Endomycorrhiza
The major sulfur in soil is in the organic fraction
In anaerobic conditions, sulfate availability may be
limited in the soil.
bacteria that reduces sulfate to sulfide
Desulfovibrio and Desulfotomaculum
bacterias capable of oxidizing sulfur to sulfate
Tiobacillus
bacteria that precipitates iron
iron bacteria
After composting, the C/N ratio of organic
materials is reduced to about
14-20:1
different stages of composting
mesophilic and thermophilic stage
one of the most abundant organic
matter in nature
Cellulose
genera of cellulose decomposting bacterias
bacillus,
Cellulomonas, Clostridium, Clorynebacterium,
Cytophaga, Polyangium, Sporioccytophaga and
Vibrio
genera of cellulose decomposting fungi
Aspergillus,
Chaetomium, Cuvularia, Fusarium,
Memnoniella, Phoma, Thielavia and
Trichoderma
aerobic, spore-f-orming, grampositive
rods
bacillus
short gram-negative rods
that produces yellow, water-insoluble
pigments
Cellulomonas
anaerobic, non-motile, gram
negative rod, which does not ferment
carbohydrates other than cellulose;
produces a yellow pigment
Clostridium
aerobic, long, flexuous rod
with pointed ends; abundant in soils
receiving straw or manure
Cytophaga
the capability of the soil to supply the nutrients in
the right amounts and proportions to meet the
nutrient requirement of the crop,
Soil fertility
the ability of the soil to support or produce a
desired quantity of plant yield
Soil productivity
A fertile soil is not necessarily a productive soil.
A productive soil is necessarily fertile.
the supply and absorption of chemical elements or
compounds required by the plant
Plant Nutrition
chemical elements or compounds required by
plants for normal growth
Nutrients
are mechanisms by which
elements are converted to cellular materials or as sources
of energy, or to drive reactions
Metabolic processes
major component of plant’s organic compounds
CHO
-Energy storage and transfer through ATP - ADP
conversion
-Important in seed formation and development of
reproductive parts of plants
-Associated with increased root growth, early
maturity particularly grain development
P
-Enzyme activator
-Regulates osmotic pressure in roots
-Maintains turgor pressure of guard cells and
regulates opening of stomata, thus controlling
photosynthesis and transpiration.
-Needed in ATP synthesis
-Increases pest and disease resistance
K
-Enhances NOrN uptake and regulates cation
uptake
-Essential for cell elongation and division
Ca
-Constituent of chlorophyll molecule
-Structural component in ribosome
-Associated with energy transfer reactions from AP
in metabolic processes like photosynthesis,
glycolysis, TCA cycle, and respiration
Mg
Sulfur containing amino acids
cystine, cysteine and methionine
-Needed in synthesis of sulfur-containing amino
acids
-Needed in synthesis of coenzyme A, biotin, thiamin and gluta
-Enhances oil formation in flax and soybeans
-responsible for the
characteristic taste and smell of mustard and
onion.
S
Chlorophyll synthesis and in enzymes for electron
transfer
Fe
Catalyst for respiration, enzyme constituent
Cu
In enzyme systems that regulate various metabolic
activities
Zn
Controls several oxidation-reduction
formation of 02 in photosynthesis
Mn
believed to be important in sugar translocation and
carbohydrate metabolism
B
Needed for nitrogen fixation
Mo
Activates system for the production of O2 in photosynthesis
Cl
involved in the mobilization of nitrogenous
compounds
Ni
Essential for symbiotic nitrogen fixation
Co
Macronutrients
CHONPKCaMgS
Micronutrients
FeMnCuZnMoBClNiCo
the deficiency can be seen on older leaves
mobile nutrients
the deficiency can be seen on younger leaves
immobile nutrients
list of mobile nutrients
NPKMgZn
List of immobile nutrients
CuMnBoSCaFe
nutrients are carried by mass movement of water
as water is absorbed the roots
massflow
nutrients absorbed in massflow
Ca, Mg,
Zn, Cu, B, and Fe
the movement of ions from a zone of high
concentration to a zone of low concentration
Diffusion (ficks law)
nutrients supplied by diffusion
P and K
the direct exchange of ions between the toots and
soil colloids as roots come in contact with the
colloid
Contact exchange {interception)
proposes that ions enter an outer space in the
roots by diffusion
and a carrier energized by plant metabolism picks up
the ion and carries it to the inner space of the
roots
Carrier theory of nutrient uptake
occurs outside the casparian strip and
plasmalemma as a barrier to diffusion and ion
exchange
passive uptake
transport of ions into the inner cells requiring
energy due to the higher concentration of ions
beyond the plasmalemma and into the cytoplasm
which is against an electrochemical gradient (selective)
active uptake
nitrogen is taken up as
NO3 and NH4+
NH/ uptake is optimum at neutral pH and
decreases as pH decreases.
NO3- uptake increases with decreasing pH and
decreases with increasing pH
higher P
uptake at low pH (____) than at high pH (____).
4.0
8.7
is the only one essential nutrient cation which
can be transported against an electrochemical gradienst into plant cell
K
K uptake is high when plant is sufficiently supplied
with
N
K uptake and retention in plants are competitively
affected by
H+, ca++, Mg++ and Na+.
Plants with enough amount of K have lower
transpiration rate and require relatively lower
amounts of water
Ca content of legumes is higher in dicotyledons than in
monocotyledons and also higher in legumes than in other
species
Competitive relationship of Magnesium
NH4, K, Ca, Mn
upward translocation
acropetal
Plant growth is limited by that nutrient present
below the minimum requirement
Liebig’s Law of Minimum
If plants were supplied with adequate amounts of
all nutrients except one, the growth is proportional
to the amount of this limiting element which was
added to the soil.
Mitscherlich’s equation
temperature range for agricultural crops
15 - 45
soil physical properties
(texture, structure, bulk density;.,(10rosity,
water holding capacity, hydraulic conductivity)
soil chemical properties
(pH, CEC, base saturation, salinity, toxic
elements)
quantitative methods of soil fertility evaluation
soil analysis
plant tissue analysis
fertilizer field trials
pot experiments
qualitative method of soil fertility evaluation
nutrient deficiency symptoms
Principle: the amount of nutrient extracted by
chemical reagents at any one time is the amount
available throughout the growth period of the crop
Soil analysis
Main objective is to collect a small amount of soil
sample weighing
soil sampling
weight of soil collected in soil samplign
.5 kg
The nutrient content in the plant tissue is related
to the available nutrient supply of the soil.
Plant analysis
assesses the effect of fertilizer and their
interactions with all existing factors of in crop growth
and development in any given location
fertilizer field trials
comparison of several fertilizer treatments
including a control using small amount of soil in
pots to have a better control of environmental
factors
pot experiment
any substance that is applied to the soil or to the
plantin solid, liquid, or gaseous form to supply one
or more of the essential nutrient elements required
for the nutrition and growth of plants
fertilizer
no chemical has been
added to the finished product to increase
nutrient content.
pure organic fertilizer
has been enriched with
microbial inoculants, hormones or chemical
additives to increase nutrient content.
fortified or enriched organic fertilizer
kakawate N content
4% (glyricidia sepium)
single nutrient fertilizers are also called
straight fertilizer
multinutrient fertizers are also called
complex, compound or mixed fertilizers
contains the 3 primary
nutrients which are historically known to be
deficient in most soils
complete fertilizers
The nutrient content in fertilizers is written in
%N,
%P205 and %K20 in that order
highest N content among the solid
N-fertilizers (NH2)2CO; Hygroscopic and 100%
soluble
Urea
82% N has the highest
amount of N among all fertilizers; contained in
pressure tanks and is usually custom-applied by
injecting into the soil
Anhydrous ammonia
hygroscopic and
nearly 100% soluble; contains sulfur ( ~24%),
recommended for 5-deficient soils
Ammonium sulfate (20-0-0):
contains 20%
P2Os; Pelleted as grayish granules and has a faint
acid odor
Ordinary superphosphate {OSP}
monocalcium
phosphate monohydrate
triple superphosphate
common k fertilizer
muriate of potash or potassium chloride
weight percentage of the nutrients contained in a
fertilize
fertilizer grade
relative proportion of each of the primar nutrients
fertilizer ratio
when the fertilizer is spread evenly on
the soil surface; suitable for rice crop since they
are closely planted
broadcast
applied on the row
below the seed level or slightly on the side of the
seeds along the row; usually done for crops like
corn, sorghum, tobacco, and fruit trees
band placement
fertilizer is applied along the bottom
of furrow
In the row
fertilizer is applied around the base of the
plant or tree
ring
fertilizer is dropped in holes around the tree
hole
fertilizer is dropped in small amount on the
side of each hill or plant
spot
application sometime after plants have
emerged
topdress
In sandy soils, N is necessarily split as well as K
For heavy clays, all of N is sometimes placed at
planting
process by which raindrops
splash soil sediments from the soil surface into the runoff;
Detachment/dispersion
ransport of suspended soil particlesfrom
upslope to downhill direction whether in rills, between
rills and in sheet flow
Entraintment
process by which sediment settles out under
the action of gravity; a selective process depending on
particle size, being rapid for sand and slow for clay
Deposition
types of erosion
Geologic and accelerated
accelerated erosion rate
10mm/yr
soil particles are detached due to
the impact of raindrops and splashed at a Ion e
in the downslope than in the upslope direction
Raindrop erosion
-the uniform removal of thin layer or “sheet” of soil
from the land surface by rainfall and surface runoff
-the most widespread and probably the most
damaging form of soil erosion
sheet erosion
occurs where surface water has concentrated, so
that a large mass of water supplies the energy
both for detaching and transporting the soil
channel erosion
an erosion process in which
numerous small channels of only several
centimeters in depth are formed;
rill erosion
also known as advance rill
erosion due to the increasing size of rills
gully erosion
the carrying off of the soil
material on the sides and on the bed of a
permanent or intermittent stream
stream erosion
the potential ability of the rain
to cause erosion
Rainfall erosivity
the soil’s vulnerability or
proneness to erosion which is influenced by
infiltration capacity and structural stability of the
soil
soil erodibility
Developed to estimate the rate of soil erosion
under various conditions
Universal soil loss equation
USLE-R
rainfall erosivity
USLE-K
erodibility
USLE-L
slopelength factor
USLE-S
slpe gradient
USLE-C
cropping system and management
USLE-P
erosion control practice
USLE-T
the maximum level of soil erosion that will
permit a high level of crop productivity to be
maintained economically and indefinitely
involves construction of broad channels
or benches across the slope to break the flow of
runoff water
terracing
refers to canals or channels
planted with grasses to provide outlets for disposal
of unavoidable runoff water
grassed waterways
a depression of considerable size located
below the check dam to collect runoff
pond
a structure above the pond which
retards run off velocity
check dam
the practice of covering the soil surface with
crop residues
mulching
involves planting of close-growing grasses and
legumes to cover and protect the surface of
the soil
cover cropping
recommended cover crops
tropical kudzu,
centrosema, calopogonium, guinea grass, para
grass, napier grass, Alabang
refers to the
growing of erosion-permitting crop and soilconserving
crop in alternate strips aligned on the
contour
Strip Cropping (Pilas-tanim)
the systematic planting of different crops in
succession on the same piece of land
Crop Rotation (Ikot-tanim)
involves the planting of two or more annual
crops with the second crop planted alter the
first crop has flowered or nearing its harvest
Relay Cropping (usod-tanim)
refers to a practice which increase crop
productivity while providing better protection
of the soil from erosion
Multiple Cropping
growing of two or
more crops a year in sequence
sequential cropping
growing
of two or more crops on the same piece of
land at the same time
inter or mixed cropping
system where arable crops are grown in the
alleys between rows of shrub/tree legumes
which are pruned periodically to prevent
shading and to provide green manure to the
companion crops
Alley Cropping (interhedgerow cropping)
commonly used contour hedges
ipil-ipil,
gliricidia, camachile
practice of increasing the
population of the crop per unit of land area with
due regard to the effect of crop competition
high density planting
refers to the system of land
management where woody perennials and
agricultural crops are raised at the same time or
sequentially
A groforestry
refers to a tillage system which leaves
30% residue cover after planting
Conservation tillage
plowing, harrowing and furrowing acros the
slope of the land
contour cultivation
preparation of the seedbed with minimal soil
disturbance
minimum tillage
tillage practice that leaves a large
percentage of residues
mulch tillage
preparation of seedbed by
conditioning the soil along narrow strips in and
adjacent to the seed rows
strip or zone tillage
practice of breaking up the hard pan
below the plow layer to increase infiltration and to
reduce runoff
subsoiling
the technique of connecting the ridges with
cross-ties to form depressions for storing
rainwater which is allowed to infiltrate later
ridge tying
an inventory of the soil resource describing the
characteristics of the soils in a given area
soil survey
refers to how many inches on the map
represents inches on the ground
map scale
- soil survey order
- very intensive ( detailed); experimental
plots, building sites; minimum size delineation is .< 1
hectare
first order
-SOIL SURVEY ORDER
intensive (detailed); general agriculture
urban planning; minimum size delineation is 0.6 to 4 has
SECOND ORDER
- SOIL SURVEY ORDER
extensive; rangeland, community area
planning; min. size delineation is 1.6 to 16 has
THIRD ORDER
- SOIL SURVEY ORDER
extensive (reconnaissaNce); ..for- br:Oad
land use potential and general land management; min.
size delineation is 16 to 252 has.
FOURTH ORDER
- SOIL SURVEY ORDER
exploratory; regional planning, nationa
planning; min. size delineation is 252 to 4000 has
FIFTH ORDER
refers to the system of ification
developed by the USDA Soil Survey
Soil taxonomy
Soil-forming processes as indicated by presence or
absence of major diagnostic horizons
order
subdivision of soil order based on moisture and
temperature regime
suborder
subdivision of suborder based on differences,
arrangement, and degree of expression between
soil horizons
great group
typic (central concept of the great group);
intergrades or transitional forms to other orders,
suborders, or great groups
subgroup
Properties important for plant root growth; broad
soil textural classes averaged over control section
or “solum”; mineralogical classes for dominant
mineralogy of solum; soil temperature classes
family
a class of soils and the basic units used to classify
soils
parent material; kind, number and arrangement of
horizons in the profile; kind and arrangement of
horizons; color, texture, structure, consistence and
reaction of horizons; chemical and mineralogical
properties of the horizons
series
distinct types of horizons that
reflect nature of soil formation
diagnostic horizons
dominant type of clay materials
mineralogy
mean annual soil temperature
(MAT) measured at 50 cm from surface
temperature regimes
number of days when soil contains
available water during the period when soil temperature
at 50 cm below the surface is above S°C
mositure regimes
used for differentiating soil order level
diagnostic horizons
a horizon that forms at or
near the surface and in which most of the rock structure
has been destroyed
diagnostic surface horizon (epipedon)
dark, soft, surface
layer; thick, greater than 10 inches; high base saturation of > 50%; mineral soil; soils formed
under prairie vegetation
mollic
like mollic but contains more than
250 ppm of citric acid soluble P205
anthropic
like mollic, but low
base saturation
umbric
Organic soil (20-
30% organic matter); saturated with water
histic
thin, light colored
surface layers that do not fit any of the diagnostic surface horizon
Ochric
man-made,
surface horizon that is greater than 50 cm
thick created by many years of addition of
manure
Plaggen
list of diagnostic surface horizons
mollic
anthropic
umbric
histic
ochric
plaggen
illuvial horizon
of clay accumulation
argilic
has an accumulation of
clay and humus to the extent of 15% of the
soil volume
agric
same as argillic
but with > 15% exchangeable sodium (Na)
natric
lluvial
accumulation of oxides of Al and Fe
(sesquioxides) and OM; red or dark red color;
only found in acid sandy soils; with high
rainfall; generally found below E horizon;
contains a Bhs or Bs horizon
spodic
very weathered layer of only Fe and Al
oxides and 1:1 clay minerals; low pH and not
very fertile (found in tropical soils)
oxic
light-colored, low % base saturation
and well-drained
sombric
a thin black to dark reddish pan cemented by iron manganese or iron organic matter complex
placic
subsoil cemented by silica
duripan
subsoil that is hard when dry but brittle when moist
fragipan
light colored subsoil
from where clay and free iron oxides have
been leached out
albic
accumulation of CaCO3 or Ca Mg(CO3h
calcic
accumulation of gypsum
gypsic
cemented by CaCO3
petrocalcic
slightly altered layer; not weathered
enough to be argillic; Bw horizon designation
or development of color and or structure
cambic
mat is <0
pergelic
mat is 0-8
cryic
mat is <8
frigid
MAT is 8°C - 15°C
mesic
MAT is 15°C - 22°C
thermic
MAT is > 22°c
hyperthermic
in soil temperature regimes Prefix “Iso” is used if mean summer (June, July,
August) and winter (December, January, February)
temperature differ by <5°C
measured in terms of the absence or presence of
water held at a tension of < 15 bars in the
moisture control section by a period of one year
soil moisture regimes
soil moisture control section in clayey soil
10-30cm
soil moisture control section in loamy soils
20-60cm
soil moisture control section in sandy soils
30 -90 cm
soil is saturated and
no dissolved oxygen (reducing regime)
aquic moisture regime
soil moisture control section
is dry more than half the time when soil temp.
at 50 cm is >5°C; moist for < 3 months only
aridic and torric
dry for >3 months and
continuously moist for at least 3 months
ustic moisture regime
soil is dry for < 3
months only
udic moisture regime
soil is continuously dry
45 days after summer and continuously moist
45 days after winter
xeric moisture regime
very young soil showing very
limited profile development;
entisols
entisols make up what percent of the world
12.5
young soil with..·
moderate profile development;
inceptisol
soil order that has limited change in parent material due to dryness
aridisol
young soils with little
profile development; presence of permafrost layer;
gelisols
gelisol make up what percent of the world
8.6
soils with thick,
dark, soft surface; soils of the grassland
mollisols
soils from volcanic
ash and cinders; very light, low bulk density, earlystage
secondary minerals
andisol
andisol make up what percent of the world
.7
acid sandy
soils with thick E and red; Bhs, ochric and spodic;
subsoil has accumulation of Fe and Al oxides,
humus and amorphous clays
spodosols
soil horizon with argillic B horizon with
high base saturation; fertile forested soils with
ochric and argillic
alfisols
soil horizon that has the B horizon has
high amount soft clay but low base saturation; soils
more weathered than Alfisols
ultisols
highly weathered soil with
B horizon containing mainly 1: 1 Kaolinite clays
oxisols
shows large
cracks upon drying due to dominance of
montmorillonite
vertilsols
organic soils;
peat soils, organic material
histosols
undecomposed to slightly decomposed
organic matter in waterlogged areas;
peat
highly decomposed organic matter
muck
good land that can be cultivated safe and
extensively to most crops with ordinary good
farming practices
class a
good land which can be cultivated safely
using easily applied conservation practices
class b
moderately good land that can be used
regularly for cultivated crops in good rotation but
needs intensive soil conservation treatments
class c
fairly good land that is best suited for
pasture but which can be used for agricult□ral
crops in good rotation provided intensive ‘ 5oil
conservation practices are applied
class d
land that is flat but is too wet or stony
and therefore more suited to pasture or forest!)’.
class l
land that is too steep, eroded or shallow
for cultivation of regular agricultural crops and is
better left to pasture forestry
class m
land that is very steep, er-oded, ro□gh,
shallow or dry and is better suited to pasture
forestry if handled carefully
class n
level land that is wet most of the time
and cannot be drained economically; best suited tor,
ponds or recreational areas
class x
land that is too steep, eroded, barren and
rugged and should be left for wildlife or parks
class y
