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Cropsci > 3 Facors Affecting Crop Production > Flashcards

3 Facors Affecting Crop Production Flashcards

1
Q

1 – at the CROP level
2 – at the SYSTEMS level

A

Crop production can be viewed from two perspectives:

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2
Q

Crop production at the crop level:
In the form of an equation:

	Y = f [G + E + (G x E)]

where, Y = yield
G = genotype
E = environment
G x E = interaction of genotype and environment

A

Crop production equation

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3
Q
  • genetic design of a plant which dictates the ceiling of how much a variety/cultivar can yield.
    - genes controlling a character (yield, plant height, taste, color, etc.)
    - varies among and even within species
    - sets the ultimate limit for plant variation
A

Genotype

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4
Q
  • any factor external to the plant that influences its growth and development.
    - may be biotic or abiotic
    examples are climate, soil, topography, pest and diseases
A

Environment

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5
Q

A high yielding variety grown under poor environment will have___________________.

A

low yield

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6
Q

An ___________________ therefore is one that has a wide range of environmental

A

ideal genotype

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6
Q

A low yielding variety grown in optimum (good) environment will still have __________.

A

low yield.

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7
Q

An ___________________ is one that poses a minimum of constraints to crop growth and development

A

optimum environment

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8
Q

Through ___________, some particular elements of the environment may draw varying responses from different genotypes.

A

G x E interaction

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9
Q

Need for continuous development of improved varieties/cultivars.
Develop management practices that can remove or avoid environmental constraints.
Continuously assess G x E interactions

A

Practical implications of GxE interaction

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10
Q

in a production system,
– controllable, manageable resources such as seeds, fertilizers, pesticides, etc.

A

inputs

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11
Q

in a production system,

 – yield
A

output

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12
Q

in a production system,

 – uncontrollable factors external to the system
A

environment

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13
Q

in a production system,

– component crops, processes and activities

A

system

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14
Q

Man (management has only partial control of the system.
Certain factors/conditions are given to which the system has to fit or adjust.
The design of the system emanates from man (his needs, objectives, knowledge and capabilities)

A

Practical implications for system level

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15
Q

includes CLIMATIC or above-ground factors and EDAPHIC or soil factors (abiotic factors)
also includes pests and beneficial organisms (biotic factors)

A

Environmental factors

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16
Q

Climate and weather

A

Abiotic factors

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17
Q
  • the seasonal pattern of a particular place occuring from year to year.
    - a composite of day-to-day weather conditions described in both averages and variability
A

Climate

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18
Q
  • a momentary state of the atmosphere brought about by the combination of elements, e.g., temperature, pressure, moisture content, air movements, radiation, etc.
    - day-to-day changes of the state or condition of the atmosphere
A

Weather

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19
Q
  • generally refers to the climatic environment one meter below the canopy in the case of tall plants or the climate within the leaf canopy for short (below one meter) plants.
A

Microclimate

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20
Q
  • the climatic environment one meter above the plant canopy
A

Macroclimate

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21
Q

– is any form of water particles falling on the ground in liquid or solid form (rainfall, hail, snow, etc.)
Average rainfall in the Philippines = 2553 mm (Luzon – 2724 mm; Visayas – 2391.7 mm; Mindanao – 2349.8 mm

A
  1. Precipitation
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22
Q

> as a reactant in many biological reactions
enters into the structure of biological molecules
serve as medium of transport of nutrients and other substances
helps regulate plant temperature

A

Role of water in plants

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23
Q

Categories of plants based on need for moisture
- desert plants

A

xerophytes

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24
Q

Categories of plants based on need for moisture

  • aquatic plants
A

hydrophytes

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25
Q

Categories of plants based on need for moisture

  • land plants; most economically important plants
A

mesophytes

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26
Q

> Topography greatly influences the amount and distribution of rainfall
Mountain ranges present barriers to clouds, causing them to rise to higher elevations and generally colder temperatures causing vapor to condense and water to fall on the windward sides as the clouds pass over, leaving the leeward side relatively dry. Example is Los Banos in Laguna and Sto. Tomas in Batangas. Sto. Tomas is drier than Los Banos due to the presence of Mt. Makiling.
Air circulation patterns affect the seasonal distribution of precipitation.

A

Factors affecting amount and distribution of rainfall

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27
Q

-high relative humidity (RH)
-sufficiently low temperature (below condensation point)
-condensation nuclei
-sufficiently low pressure

A

Rain formation requires

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28
Q

– insuficiency of rainfall/moisture which seriously affect plant growth.

A

Drought

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29
Q

– 29 consecutive days without rainfall of at least 0.25 mm.

A

Absolute drought

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30
Q

– 15 consecutive days without rainfall of at least 0.25 mm.

A

Partial drought

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31
Q

– the degree of hotness or coldness of a body
- every chemical, physiological and biological process in plants is influenced by temperature.

A
  1. Temperature
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32
Q

minimum temperature – that temperature below which the velocity of the reaction becomes zero, due to the deactivation of enzymes.
optimum temperature – temperature where the velocity of the reaction is at maximum.
maximum temperature – that temperature above which the velocity of the reaction becomes zero, due to the denaturation of enzymes.

A

Three (3) cardinal temperatures

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33
Q

– that temperature above which the velocity of the reaction becomes zero, due to the denaturation of enzymes.

A

maximum temperature

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34
Q

– temperature where the velocity of the reaction is at maximum.

A

optimum temperature

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35
Q

– that temperature below which the velocity of the reaction becomes zero, due to the deactivation of enzymes.

A

minimum temperature

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36
Q

solar radiation – vertical rays are more energy efficient/unit area than oblique rays (in polar regions).
surrounding land masses or bodies of water.
altitude – for every 100 meter rise in elevation, there is a 0.6 C decrease in temperature.
In the Philippines: high elevation – 13. 2 – 24.6 C
low elevation – 23.3 – 31.5 C

A

Temperature of the environment depends upon

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37
Q

– vertical rays are more energy efficient/unit area than oblique rays (in polar regions).

A

solar radiation

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38
Q

high elevation – 13. 2 – 24.6 C
low elevation – 23.3 – 31.5 C

A

Altitude temperature

In the Philippines:

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38
Q

In the Philippines:

low elevation – ___________________

A

23.3 – 31.5 C

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39
Q

In the Philippines:
high elevation – ___________________

A
  1. 2 – 24.6 C
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40
Q

cool season crops – e.g., cole crops like cabbage, broccoli, cauliflower
warm season crops – e.g., rice, banana
tropical – e.g., coconut
sub-tropical – e.g., citrus

A

Classification of crops according to temperature requirement

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41
Q

Classification of crops according to temperature requirement
___________________ – e.g., cole crops like cabbage, broccoli, cauliflower

A

cool season crops

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42
Q

Classification of crops according to temperature requirement

___________________ – e.g., rice, banana

A

warm season crops

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43
Q

Classification of crops according to temperature requirement

___________________ – e.g., coconut

A

tropical

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44
Q

Classification of crops according to temperature requirement
___________________ – e.g., citrus

A

sub-tropical

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45
Q

Effect of temperature on crops

___________________ requirement of certain crops for flowering (e.g., celery seed exposed to 4.4-10 C for 10 days under imbibed condition)

A

vernalization

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46
Q

Effect of temperature on crops

(crops mature faster in hotter environments than n colder ones)

A

effect on crop maturation

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47
Q

normal wind speed in the Philippines = 7.2 km/hr
at 30 km/hr = leaf tearing may already occur especially in banana and abaca

A

Wind or air in horizontal motion

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48
Q

increase transpiration
destructive effects of strong winds, typhoon (e.g., crop lodging, grain shattering)
sterility due to loss of pollens
disease spore dispersal
reduced CO2 levels especially in enclosed spaces
affects plant form

A

Effects of wind on plants

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49
Q

Air circulation in the atmosphere results from the sun’s radiation falling more directly on the tropical regions than on the polar regions, the warmer air rises and flow forward the poles, cools and sinks as cold polar air and then returns toward the equator as ground flow

The interactions cause the establishment of regions, large and small, each with a different climate.

A

Wind

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50
Q

___________________ – energy given out by the sun through radiation

A
  1. Solar radiation or light
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51
Q

Three aspects important to plants

___________________ – expressed in foot-candle or lux.
- plants are generally spaced so that maximum leaf area is exposed to sunlight
- some plants do not require high light intensity (shade-loving) because they have low light saturation point.
- some plants require subdued light to survive. e.g., some ornamentals

A

light intensity

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52
Q

___________________ – expressed in hours per day

A

b. duration or daylength

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53
Q

___________________– expressed in Angstrom or nanometers or identified by color
- not all wavelengths of light are equally effective
in Photosynthesis - red and blue wavelength
in Photoperiodism - far red and red wavelength

A

c. wavelength

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54
Q

in ___________________ - red and blue wavelength

A

Photosynthesis

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55
Q

in ___________________ - far red and red wavelength

A

Photoperiodism

56
Q

Effect of light on plants
___________________ – direct effect on photosynthesis (intercepted radiation is important)
photocybernetic effect – effect on plant development (light quality is rather important than quantity of light)
photoperiodic effect (or response) – plant response as conditioned by daylength

A

photoenergetic effect

57
Q

a. Heliophytes - sun loving
- light saturated at about 5000 foot candles
- examples: banana, chrysanthemum, corn, cotton, cowpea,cucurbits, eggplant, papaya, peanut, sugarcane
b. Sciophytes - shade loving
- light saturated at about 500 foot candles
- examples: ginger, african violet, ferns, philidendron, coffee, begonia, black pepper
Plants belonging to the intermediate group may be converted through acclimatization into either heliophytes or sciophytes.

A

Classification of plants according to light intensity requirements

58
Q
  • sun loving
    - light saturated at about 5000 foot candles
    - examples: banana, chrysanthemum, corn, cotton, cowpea,cucurbits, eggplant, papaya, peanut, sugarcane
A

a. Heliophytes

59
Q
  • shade loving
    - light saturated at about 500 foot candles
    - examples: ginger, african violet, ferns, philidendron, coffee, begonia, black pepper
    Plants belonging to the intermediate group may be converted through acclimatization into either heliophytes or sciophytes.
A

b. Sciophytes

60
Q

a. day neutral – will flower over a wide range of daylength
- examples: banana, citrus, coconut, corn, tomato
b. short-day plant – requires a dark period exceeding some critical length to induce flowering
- examples: coffee, kenaf, lima bean, rice, sesame, soybean, winged bean
for cassava, sweet potato, taro and yambean, short-day condition is required for tuber formation
c. long-day plant – inhibited from flowering when the dark period exceeds some critical length
- examples: aster, castor oil, onion, radish

A

Classification of plants according to photoperiodic response

61
Q

– will flower over a wide range of daylength
- examples: banana, citrus, coconut, corn, tomato

A

a. day neutral

62
Q

– requires a dark period exceeding some critical length to induce flowering
- examples: coffee, kenaf, lima bean, rice, sesame, soybean, winged bean
for cassava, sweet potato, taro and yambean, short-day condition is required for tuber formation

A

b. short-day plant

63
Q

– inhibited from flowering when the dark period exceeds some critical length
- examples: aster, castor oil, onion, radish

A

c. long-day plant

64
Q

________________ – proportion/amount of moisture in the air
Average RH in the Philippines = 82%
Importance in Crop Production
a. pest and disease incidences e.g., powdery wildew
b. postharvest behavior of commodities
very dry atmosphere wilting
high humidity not conducive to grain drying
enhance mold, aflatoxin buildup
c. supplying water requirement during crop production
low RH, high temperature high evapotranpiration
high RH, high temperature low evapotranspiration

A
  1. Relative humidity
65
Q

Carbon dioxide
hardly limiting in crop production except at no or little air circulation in dense plant populations
critical in enclosed environments like greenhouses
Air pollution
becomes crucial as the world becomes more industrialized
toxic substances: lead, sulfur dioxide, smog, carbon monoxide, hydrofluoric acid (HF)

A
  1. Gaseous environment
66
Q

hardly limiting in crop production except at no or little air circulation in dense plant populations
critical in enclosed environments like greenhouses

A

Carbon dioxide

67
Q

_______
becomes crucial as the world becomes more industrialized
toxic substances: lead, sulfur dioxide, smog, carbon monoxide, hydrofluoric acid (HF)

A

Air pollution

68
Q

cloud, including smog and fog, affect the amount of radiation received by plants. Most of the solar radiation is reflected by clouds.
clouds are also believed to be responsive for the GREENHOUSE EFFECT:
- clouds, acting similarly as the glass covering of a greenhouse, stop the transfer of thermal radiant energy from the earth to the cold sky thereby slowing down the cooling process of the earth.
- on the global scale air and water molecules present on clouds trap long-wave radiation and reduce their outward flow to the space because the shorter wave lengths reaching the earth’s surface when re-radiated as longer waves cannot pass through the clouds as readily as the shorter wavelengths.

A
  1. Cloudiness
69
Q

Type 1. Pronounced wet and dry season
Example: Ilocos, Occ. Mindoro, Antique, Negros Occ.
November – May = dry
June – October = wet
Type 2. No dry season with pronounced maximum rain period
Example: Most of Bicol, Samar, Leyte, Surigao, Agusan, Davao
November – January = maximum rain period
Type 3. No very pronouced maximum rain period with short dry season lasting from one to three months
Example: Cagayan, N. Viscaya, Capiz, Cebu, Negros Oriental, Masbate, Mt. Province
February – April = dry season
Type 4. No pronounced maximum rain period and no dry season
Example: Isabela, Bohol, Cotabato, Lanao, Zamboanga, Bukidnon
Rainfall is distributed throughout the year

A

CLASSIFICATION OF PHILIPPINE CLIMATE (Corona Classification)

70
Q

Pronounced wet and dry season
Example: Ilocos, Occ. Mindoro, Antique, Negros Occ.
November – May = dry
June – October = wet

A

Type 1.

71
Q

_________ No dry season with pronounced maximum rain period
Example: Most of Bicol, Samar, Leyte, Surigao, Agusan, Davao
November – January = maximum rain period

A

Type 2.

72
Q

_________ No very pronouced maximum rain period with short dry season lasting from one to three months
Example: Cagayan, N. Viscaya, Capiz, Cebu, Negros Oriental, Masbate, Mt. Province
February – April = dry season

A

Type 3.

73
Q

___________________ No pronounced maximum rain period and no dry season
Example: Isabela, Bohol, Cotabato, Lanao, Zamboanga, Bukidnon
Rainfall is distributed throughout the year

A

Type 4.

74
Q
  1. Typhoon
  2. Ozone Destruction
  3. Global warming
  4. El Niño/La Niña
  5. Acid rain
  6. Lahar
A

CLIMATIC STRESSES

75
Q
  1. Typhoon and weather variations
    Typhoon - strong winds with speed greater than
    121 kph.
    tropical storm typhoon
    depression
    - usually originate from the Pacific
    Ocean; circulation (800 km diameter) with a
    low
    central pressure (-72 cm Hg)
    with air spirals towards the calm eye (30 km
    diameter)
A

Typhoon

76
Q
  • strong winds with speed greater than
    121 kph.
    tropical storm typhoon
A

Typhoon

77
Q
  • usually originate from the Pacific
    Ocean; circulation (800 km diameter) with a
    low
    central pressure (-72 cm Hg)
    with air spirals towards the calm eye (30 km
    diameter)
A

depression

78
Q
  1. Destruction of the ozone layer
    ■ reported to be 50% (Antartica)
    ■ Ozone – protective shield against the
    harmful UV rays
    ■
    - it is 6-30 miles above the earth
    Harmful effects:
    a． Depressed photosynthesis
    b． Reduced levels of seed protein, lipids and
    carbohydrates
    c． Deleterious effects on human (skin cancer, etc.)
A

Ozone layer

79
Q

■ increased concentration of carbon dioxide in the
atmosphere
■ Carbon dioxide concentration might double to
around 600ppm in 30-75 years
■ Methane gas contributes to global warming
■ Results to high atmospheric temperature which
affect the ocean level by a few mm per year
■ Ingress of saline water to a 15km distance inland
■ Ocean levels will rise by as much as 30 cm in year
2010 and up to 150 cm by 2050

A

Global warming
3. Global Warming

80
Q

■ a periodic ocean – warming and atmospheric
disturbance characterized by deficient rainfall or
prolonged drought in some areas, while heavy rains,
storms or hurricanes occur in other areas of the
globe
■ for the past 30 years, the Philippines has been hit by
some seven (7) El Niño episodes.
■ The 1982-83 episode is rated as the most intense in
the past century
■ The 1997-98 episode, has comparable intensity –
bringing immense damage to Philippine crops,
water/electric supply aside from contributing to
poisoning of sea foods (red tide)

A
  1. “EL NIÑO”
    What is El Niño?
81
Q

El Niño
Origin of El Niño
■ From the Spanish word meaning “___________________”
■ Used to be considered as a local event along
the coasts of Peru and Ecuador - describing
the appearance of warm ocean currents
flowing the South and Central American
coasts around Christmas time - believing that
the temporary heavy harvest of fish was a gift
of the Christ child.

A

Boy child
or Little child

82
Q

■
El Niño occurs in the Pacific Basin
every 2 to 9 years. It usually starts
during the Northern winter (December
to February). Once established, it lasts
until the first half of the following year,
although at times, it stays longer. It
exhibits phase-locking in annual cycles.

A

El Niño
El Niño Watch

83
Q

El Niño
___________________ in the Philippines
include
■ delayed onset of the rainy season
■ early termination of the rainy season
■ weak monsoon activity
■ weak tropical cyclones activity
■ El-Niño is said to be triggered when the
strong westward-blowing trade winds
weaken and reverse direction.

A

Climatic indicators of El Niño

84
Q

a. fish kill especially cold water fish
- tuna and milkfish catch declines
b. decrease in yield for most crops
c. human death

A

Effects of El Niño

85
Q

■ Sulfur dioxide produces S which is
released from natural sources and
human activities
■ Oxides of S and water will produce
acid rain

A
  1. Acid rain
86
Q

■ Mt. Pinatubo eruption in the early 1990’
s
■ lead to decreased in agricultural lands
resulting to low production

A

Lahar
6. Lahar

87
Q
  • refers to the soil as a factor in crop
    production
A

EDAPHIC FACTORS

88
Q

Water mineral
Organic matter+ organisms
Air
Water (25%)

A

What is soil

89
Q

PSolid – mineral + organic matter
PLiquid – soil solution
PGas – various gases

A

Soil as a three-phase system

90
Q
  • from where crops obtain
    most of the nutrients. Also, where
    organic matter is concentrated.
A

Top soil

91
Q
  • storage of nutrients and
    water, but often less fertile than top soil
A

Sub soil

92
Q
  • the relative proportion of primary soil particles, i.e., sand,
    silt and clay in a particular soil
A

Soil texture

93
Q

:
- the arrangement of soil particles into
aggregates

A

Soil Structure

94
Q

✓
ped natural structure
✓
dod structure formed with the application of
external force, e.g., plowing
✓
organic matter - binding agent

A

How soil structure is formed?

95
Q

■ blocky
■ granular
■ columnar

A

Types of soil structure

96
Q

■ to some extent, soil tillability is related to
structure. There are soils that are relatively
easier to break up because of their structure.
■ soil structure influences the infiltration of
water through the soil.
■ soil structure influences soil aeration which is
critical during seed germination and seedling
emergence.1.3
Soil Depth
■ particularly, the top soil relative to the subsoil.

A

Importance of soil structure to crops:

97
Q

– composed of dead
plant residues and wastes

A

Soil organic matter content

98
Q

:
■ prevents loss of nutrients by forming complexes with
nutrient elements
■ facilties absorption and percolation of water into and
through the soil
■ increases water holding capacity
■ source of nutrients
■ improves penetration of roots
■ influences soil structure formation
■ influences soil chemical properties may contain N, P,
S, B, Zn
■ determines the biotic composition

A

Importance of soil

99
Q

– amorphous, collidad substance
which is resistant to further
decomposition

A

Humus

100
Q

– amorphous, collidad substance
which is resistant to further
decomposition
■ improves soil structure
■ increases CEC and water holding
capacity of soil
■ gives dark color to soil

A

Humus

101
Q
  1. Chemical Properties

■ degree of acidity or alkalinity
■ influences nutrient availability
■ negative logarithm of H+ activity
■ 7.0 – neutral pH (H+ = OH-)
■ decrease in soil pH
➡️acidity
■ increase in soil pH
➡️alkalinity

A

2.1 Soil pH or soil-reaction

102
Q

■ decrease in soil pH
➡️

A

acidity

103
Q

■ increase in soil pH
➡️

A

alkalinity

104
Q

■ pH below 5.0 – Al, Fe & Mn become toxic
Ca & Mo deficiency
■ pH below 5.5 – Mo, Za, K & S deficiency
■ pH 6-7 (neutral) – most nutrients are in
available form
■ pH above 7.5 – Al toxicity, salinity, Zn & Fe
toxicity
■ pH above 8.0 – formation of Ca phosphates
■ pH above 8.5 – salinity, Zn & Fe deficiency

A

pH Effects

105
Q

– Al, Fe & Mn become toxic
Ca & Mo deficiency

A

■ pH below 5.0

106
Q

– Mo, Za, K & S deficiency

A

■ pH below 5.5

107
Q

– most nutrients are in
available form

A

■ pH 6-7 (neutral)

108
Q

– Al toxicity, salinity, Zn & Fe
toxicity

A

■ pH above 7.5

109
Q

– formation of Ca phosphates

A

■ pH above 8.0

110
Q

– salinity, Zn & Fe deficiency

A

■ pH above 8.5

111
Q
  • ability of soil to absorb and release
    cations through the soil solution
    ■ how? - soil particles can be colloidal (e.g.,
    clay) and can contain excess (net) negative
    charges
    ■ how measured? - sum of exchangeable
    cations in a given wt. of soil expresses in
    me/100 g. soil
A

2.2. Cation Exchange Capacity

112
Q

2.2. Cation Exchange Capacity
- ability of soil to absorb and release
cations through the soil solution
■ __________ - soil particles can be colloidal (e.g.,
clay) and can contain excess (net) negative
charges
■ how measured? - sum of exchangeable
cations in a given wt. of soil expresses in
me/100 g. soil

A

how?

113
Q

2.2. Cation Exchange Capacity
- ability of soil to absorb and release
cations through the soil solution
■ how? - soil particles can be colloidal (e.g.,
clay) and can contain excess (net) negative
charges
■____________ - sum of exchangeable
cations in a given wt. of soil expresses in
me/100 g. soil

A

how measured?

114
Q

3.1 Macroscopic organisms
3.2 Microscopic organisms
a. Fungi
b. Actinomycetes and protozoa = decomposers
(aerobic)
c. Bacteria (billion/g topsoil)
- Thiobacillus
oxidizes
S
sulfate form
- Auxotrophic bacteria – oxidizes Mn & Fe to less
available form
- Nitrifying bacteria
- N fixing bacteria
d. Blue-green algae – Nitrogen fixation
3.3 Root – microoganism association found in the nuts of
legumes – Nitrogen fixation
a, bacteria – rhizobia in nodules
b. fungi
mycorrhizal fungi
- converts phosphorous to biological forms
3.4 Organic matter and humus
OM
5% N,
Only 2% available to plant
Philippine soils
2.4% OM
high fertility
>3.5%
medium
2-3.5%
low
<2%

A

Biological Properties

115
Q
  • small mammals, insects
    (springtails, ants, beetles, grubs), millipedes,
    centipedes, sowbugs, mites, slugs, snails,
    earthworms, spiders
A

Macro

116
Q

-
nematodes, protozoa

A

Micro

117
Q

Roots of higher plants
Algae – blue, blue green, diatoms
F
u
n
g
i –
mush
room, yeast, molds
Bacteria –
aerobic/
anaerobic
-
autotrophic/heterotrophic
Actinomycetes

A

Flora

118
Q

■ Burrowing – channels for drainage and aeration,
entry of other animals, entry of water, nutrients, roots
■ Mix the soil, “plows” the soil
■ Incorporates crop residues
■ Contribute to OM
■ Humus enrichment
■ Improves soil structure
■ Control pests (e.g., leaf miner pupa, scub pathogen)
■ Nutrient recycling

A

Benefits from Earthworms

119
Q

■ – channels for drainage and aeration,
entry of other animals, entry of water, nutrients, roots

A

Burrowing

120
Q
  • whether the land is flat or sloping
  • a major parameter in delineating lowlands
    and uplands
    ■ in the Philippines, the slope of the land is
    used as the major determinant.
    i.e., uplands - > 18% slope
  • in crop production, topography is critical in:
    ✓
    irrigation and drainage
    ✓soil conservation
A

Topography

121
Q
  • whether the land is flat or sloping
  • a major parameter in delineating lowlands
    and uplands
    ■ in the Philippines, the slope of the land is
    used as the major determinant.
    i.e., uplands - > 18% slope
  • in crop production, topography is critical in:
    ✓
    irrigation and drainage
    ✓soil conservation
A

Topography

122
Q

■ in flat lands, the problem can be in drainage.
■ in sloping lands, the problem can be in how to bring
water up for irrigation.
■ poor drainage can result into soil fertility problems.
■ in sloping lands, soil erosion can be a major problem
especially if crop production practices do not
consider soil and water conservation strategies.
■ to a great extent, CEC is an indicator of soil fertility
because most nutrients are taken up by plants in
cation form.
■ the soil can also exchange anions
■ roots of plant also have their own CEC – the
exchange thereforedepends on the interaction of soil
and root CEC.

A

Topography

123
Q
  • all living elements in the environment that
    can affect crop production
  • includes: beneficial organisms pests
    1. Beneficial organisms
    ■ provide beneficial effects on crop
    production
    includes:
    ■ Pollinators
    ■ important role in the preservation of species and in
    biodiversity conservation
A

BIOTIC FACTORS

124
Q
  • all living elements in the environment that
    can affect crop production
  • includes: beneficial organisms pests
A

BIOTIC FACTORS

125
Q

■ provide beneficial effects on crop
production

A
  1. Beneficial organisms
126
Q
  1. Beneficial organisms
    ■ provide beneficial effects on crop
    production
    includes:
    ■ ___________________
    ■ important role in the preservation of species and in
    biodiversity conservation
A

Pollinators

127
Q

■
■ an important part in the food chain which is related to
energy flow in a crop production system.
■ a trophic level, usually consisting soil microorganisms
(soil biotic factors)
■ specifically important in the maintenance of soil organic
matter

A

Decomposers

128
Q

■ provide balance in a crop production system particularly
in the control of pests
■ as bio-control agents against pests

A

■ Natural pest enemies

129
Q

■ a collective term that includes insect
pests, diseases, weeds, invertebrates and
vertibrates
■ has always been a major limiting factor
in crop production!
■ Damage can go as high as 100%

A

1.1 Pests

130
Q

Include all factors internal to the plant

A

GENETIC FACTORS

131
Q
  1. – the genetic design of a
    plant which dictates the ceiling of how
    much a variety/cultivar can yield.
    Genome – sets the ultimate limit for
    plant variation
A

Genotype

132
Q

:
✓The choice of variety is one of the most critical
decisions in crop production.
✓ Technologies required in growing a certain
crops are dependent on the characteristics
of a particular variety especially:
✓growth characteristics
✓quality of the product
✓market acceptability

A
  1. Selection indices of major Philippine crops
133
Q

■ the latest development in biotechnology in
relation to crop improvement.
■ in countries like the USA, Argentina, Canada
and China, transgenic crops have been
commercialized.
■ global area of transgenic crops in 1999 is
about 39.9 million hectares
■ transgenic crops: corn, tomato, soybean,
cotton, potato

A

Genetically Modified Organisms
(GMOs)

134
Q

The issue:
■ Genetic engineering is vastly different from
other methods used by breeders. While all
other processes for breeding rely on natural
functions of organisms, GE moves genes
from one organism to another in ways that
could never be possible in nature. The
science is not precise and the interactions
between the GMO and the surrounding
environment are unpredictable

A

GMO’s

135
Q

Concerns:
■ possible transfer of trans gene to other
microorganisms like soil microorganisms
■ possible effects of products on non target
organisms
■ possible faster pest adaptation
■ possible production of allergenic and/or toxic
substances
■ possible effects of transgenic products
themselves

A

GMO’s

136
Q

■ often overlooked but probably the most critical of all
factors
■ from a system perspective, it is not only a factor,
rather it is the core of the system itself (it is the
reason for crop production, for farming)
1. Farmer’s preference re: crop type, variety
■ ideally based on farmer’s objectives and aspirations
■ however, in the Philippines, this is often dictated by
external factors, i.e., ✓market ✓
government policies

A

Human factors

137
Q
  1. Farmer’s capability
    ■ depends on: ✓
    resources ✓
    knowledge
    ■ most Filipino farmers are resource-poor
    ■ our culture is very rich in indigenous
    knowledge particularly about farming
  2. Management
    ■ a result of 1 and 2
    ■ goes along with eco-social-political realities
A

Human factors

138
Q

■ depends on: ✓
resources ✓
knowledge
■ most Filipino farmers are resource-poor
■ our culture is very rich in indigenous
knowledge particularly about farming

A
  1. Farmer’s capability
139
Q

■ a result of 1 and 2
■ goes along with eco-social-political realities

A
  1. Management
140
Q

■ ideally based on farmer’s objectives and aspirations
■ however, in the Philippines, this is often dictated by
external factors, i.e., ✓market ✓
government policies

A
  1. Farmer’s preference re: crop type, variety

Cropsci (2 decks)

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