AGM Training for Debre Zeit regnal

AGROMETEOROLOGY AND IT’S IMPORTANCE FOR
EFFECTIVE DRM ACTIVITIES
By
Almaz Demessie
M.Sc. IN TROPICAL AGRICULTURAL DEVELOPMENT(Uk)
Senior Agro meteorologist and Early Warning expert, UNDP/GEF LDCF project Focal Person
Disaster Risk Management and Food Security Sector
Office tel: +251-114430578, Mobile tel: +251 -911-197120
E-mail: demessiead@gmail.com
Strengthening the existing Early Warning Activities in terms of data collection, interpretation and information dissemination in order to
establish timely response mechanism”, organized by DRMFSS and supported by UNDP/GEF LDCF project December 4 – 5, 2015, Debre
Zeit

INTRODUCTION
 Agrometeorology is the application of
meteorological knowledge, information
and data to weather sensitive
problems in agriculture. Amongst other
things this includes problems dealing
with the effect of weather, climate and
their variability.

Introduction cont’d….
• An agrometeorological service is of great
importance for countries with a primary
agricultural economy. It supplies forecasts
of adverse weather conditions like frost,
heavy rainfall, drought, late onset and early
cessation of rainfall, erratic distributing of
rainfall, extreme maximum and minimum
temperatures, strong wind, excess moisture
and could cover, and information, which is
important for sowing, application of
pesticides, for harvesting, etc.

• Agricultural meteorology deals with the
interaction between meteorological and
hydrological factors, on the one hand, and
agriculture in the widest sense, including
horticulture, animal husbandry and forestry, on the
other. Its objective is to discover and define such
effects, and then to apply knowledge of weather to
practical agricultural use. Its field of interest
extends from the soil layer of deepest plant and
tree roots, through the air layer near the ground in
which crops grow and animals live, to the higher
levels of the atmosphere of interest in aerobiology,
the latter with particular reference to the effective
transport of seeds, spores, pollen and insects.

• In addition to natural climate and its local
variations, agricultural meteorology is also
concerned with modifications in the
environment.

The services which meteorologists can provide to
agriculturists
It may be grouped broadly as
follows: -
a. To co-operate with and seek advice from agricultural services
in all matter of common interest;
b. To supply as far as practicable, any available meteorological
data required by agricultural scientist in their research experimental
and advisory work;

The services which meteorologists Cont’d…
c.To advice on the best utilization of weather
and climate data in attaining such objective
as improving agricultural production
introducing new species of plants and
animals and increasing the area in efficient
farming use;

d. To assist agricultural and allied interests in
combating unfavorable weather and climate.
eg. - artificial modification of climate
- wind breaks, shelter-belts,
irrigation and glass house
- afforestation (by planting trees)

e. To assist in the fight against agricultural pests
and diseases by considering both the
environmental factors during their life histories
and the meteorological factors which may
influence the effectiveness of the protective
measures taken;
f. To advise on the protection of agricultural
products, in storage and in transit, against
damage.

The services which agriculturists can provide
to meteorologists
It may be grouped broadly as follows:-
a) To co-operate with and seek advice from
Meteorological Services in all matters of
common interest;
b) To supply meteorologists with such
ecological data on the life-histories of plants
and animals, and of the pests, as may serve a
guide for preparing corresponding weather
forcasts and for formulating climatological
advice on such matters as the introduction of
new plants and animals;

c) To encourage the implementation of continuous
and comprehensive national surveys of
important agricultural pests, so that their
relationships with weather factors in different
regions may be studied further;
d) To supply, as far as practicable, statistical data
on crop yields, etc, adequate for investigation of
reliable crop-weather relationships;
e) To co-operate with Meteorological Services in
establishing standard agrometeorlogical stations
and in collecting other relevant data.

Joint services by meteorologists and
agriculturalists
Meteorologists and agriculturists should co-operate
towards making meteorological and climatological
information “an operational tool” in every farmer’s
day to day activities and in his weekly, seasonal and
long-range planning. This jointly developed and
furnished services should include:
a) Operationally useful forecasts of meteorological
variables that are important to current farming
operations together with an agricultural interpretation
of such forecasts;

b) Education programmes for farmers to
demonstrate the usefulness of weather
information for agricultural planning and
operations;
c) Joint research projects on agriculture-weather
relationships and their applications to farming
practices.

The six main points governing relationship
between weather and agriculture
1. Soils
Weather is important factor in creating and
determining the nature of soil
Climate and weather affect
i. Chemical physical and mechanical properties of
the soil
ii. The organism it contains.
iii. Its capacity for retaining and giving up heat.
Iv Types of nutrient (e.g Rainfall not only adds
chemical contents to soil and washes soil
nutrients).
V State of soil ( it is affecting cultivation, pest control
and harvesting).

2. Plants
Development and growth of plants depend on
environmental condition at every stage. Un
understanding of inter relation between the
environment(ground cover, surface slop, degree
of shelter, ect) and the local micro climate, in the
crop and around the crop may result actions
aimed at the long term improvement of the growth
situation .
Even before planting the influence of weather
should be considered in terms of seed quality and
viability.

Plants contd
Post harvest operation, such as drying of
grains and other crops, and the capacity to
maintain the quality of harvested fruit,
vegetable and other farm products
affected by seasonal weather. Weather
and climate are important in the
occurrence forest, bush and grass fires,
knowledge of them is important for the
defence against such hazards.

3.Farm animals
Weather affects animals in the following
ways:-
a.direct
b.crops on which they feed
c. soil on which they are kept
d.their geographical distribution
e.yield and quality of animal product
f. preparing these products and their
capacity for storage and transport

4. Diseases and pests of crops and
animals
a.weather influences susceptibility of plants
and animals to attack by pests and
diseases
b.nature, number, spread and activity of
pests and diseases
c. has impact upon the effectiveness of
control measures
d.on the amount and toxicity of spray on
harvested crops

5. Farm buildings and equipment
a. weather conditions should be considered
while planning farm buildings particularly
designing animal housing and storage
space for agricultural products
b. It also influences the choice, up-keep and
best use of farm machinery.

6.Artificial modification of meteorological
and hydrological regimes
 Irrigation, mulching, wind breaks and
shelter belts.

Agrometeorological observations
The effect of weather on agriculture can not
be determined by observing only the weather.
In addition to meteorological observation
therefore, agrometeorologists began observing
plants, soils domestic animals, the occurrence
of pests and disease etc. Modern
agrometeorology needs and uses data from
both observations of the weather and of
agriculture.

Agrometeorological observations
- Plant development (phenology)
- State of the plant
- Plants yield
- Plants height
- Damage from adverse meteorological phenomenon
- Extent of weeds
- Soil moisture in the field of crops
- State of soil surface
- Health of domestic animals
- Productivity of domestic animals
- Occurrence of diseases etc.

Depending upon their applicability and use, the
agro-meteorological observations can be divided
into two main groups:-
a. Observations made for specific research
projects.
b. Observations used as permanent (routine) in a
network of agro-metrological stations

Observations to be carried out at agro-
meteorological stations.
I. Observations of the physical environment
a) Temprature and humidity of the air;
b) Wind;
c) Sunshine and radiation;
d) Clouds, hydrometeors and other water-
balance factors(including hail, dew, fog, soil
and water evaporation, plant transpiration,
runoff and water table);

e) Evaporation and water-balance
measurements
f) Soil temperature.
g) Soil moisture
Additional observations contribute towards
better understanding of soil-moisture
conditions:
- Field capacity of the soil;
- Permanent wilting point; and
- Depth of the groundwater

II. Phenological Observation
In the developmental process from the
germination of seeds, plants show several
visible external changes, which are a result of
the environmental conditions. These external
changes are called phenological phases (stages)
of plant development and the observations are
called phenological observations.

- Definitions and methods of observation of
individual phenological phase
Eg.
Sprouting:-This is defined as when seeds
have developed shoots and the first leaves
have unfolded in different spots on the plots,
the sprouting stage has begun. Uniformly of
emergence is described qualitatively by the
following criteria.
Good - over 90% of the entire field is uniformly
emerged.
Fair - below 90% but above 75% of the entire
fields is Uniformly emerged.
Poor - below 75% of the entire field is uniformly
emerged.

Selection of fields for phenological observation
 Phenological observations should not be
made on crops involved in agricultural
experiments, such as testing fertilizers
irrigation experiments etc. The
phenological observations however can
be performed in the control plots of such
experiments, where all conditions are the
same as in the surrounding area.

Times of phenological observation
 The phenological observations should be
performed three times a week. If one of the
selected days is an official holiday, the
observations should be performed a day earlier
or later.
Method of phenological observation
 The method of performing phenological
observations depends on the way a crop is
cultivated.

III. OBSERVATIONS ON THE STATE OF THE CROPS
A. General assessment of the state of the plant
- Excellent stae:- the plants are strong, healthy, well rooted and
well-developed. The density the sowing area is optimal for the local
conditions, and there are no missing plants. All parts of the plants, and
especially the reproductive ones, are in excellent condition. There are no
weeds. Such a state is typical for years with very good meteorological
conditions and a yield much higher than normal years is to be expected;
- Very good state:- the state could not be assessed as excellent
only because of some minor shortcomings-some plants are not too
healthy or strong; there are missing plants in some parts of the field; there
are some weeds; there is slight damage from adverse meteorological
phenomena, pests. Neverthless, the expected yield from the crops is still
above average for the area;
- Normal state:- a normal yield is expected;
- Unsatisfactory state:- a yield below normal is to be expected;
- Bad state:- a very poor yield is to be expected.

B. Density of the sowing area
C. Height of the plants

D. Observation of damage to plants by
unfavorable weather phenomena
i. Unfavorable weather phenomena to plants
The following are the main weather factors that adversely
affect crops.
a. Abnormal rainfall condition.
Direct damage to fragile plant organs, like flowers; soil erosion;
water logging; drought and floods; land slides; impeded and
drying of agricultural product; conditions favorable to crop and
livestock pest development; negative effect on pollination and
pollinators etc.

b. Abnormal wind condition.
 Physical damage to plant organs or whole
plants(e.g. defoliation, particularly of
shrubs and trees); soil erosion; excessive
evaporation. Wind is an aggravating factor
in the event of bush or forest fires.

c. Abnormal air moisture.
 High values create conditions favorable to
pest development; low values associated
with high evaporation and often one of the
most determinant factors in fire outbreaks.

d. High tempratures
 Increased evaporation; induced sterility in
certain crops. High temperatures at night
are associated with increased respiration
loss. “Heat waves”, lengthy spells of
abnormally high temperatures are
particularly harmful.

e. Low temperatures
– Destruction of cell structure(frost); desication;
slow growth, particularly during cold waves;
cold dews.
f. High cloudiness
 Increased incidence of diseases; poor
growth.

g. Hail
 Hail impact is usually rather localized, but
the damage to crops particularly at critical
phenological stages may be significant. Even
light hail tends to be followed by pest and
disease attacks.
h. Lightning
 Lightning causes damage to buildings and the
loss of farm animals. It is also one of the causes
of wildfire.

i. Snow
 Heavy snowfall damages woody plants. Un-
seasonable occurrence particularly affects
reproductive organs of plants.
j.Volcanic eruptions, avalanches and
earthquakes
 The events listed may disrupt infrastructure
and cause the loss of crops and farmland,
sometimes permanently. A recent example of
carbon dioxide and hydrogen sulphide emissions
from a volcanic lake in Cameroon caused
significant loss of human life and farm animals.

k. Air and water pollution
 Air pollutants affect life in the
immediate surrounding of point sources.
In combination with fog, some pollutants
have more marked effect on plants and
animals. Occurrences of irrigation water
pollution have been reported.

E. Damage from Plant pathogens
i) Plant pathogens
 Plant diseases are caused by different
pathogens in groups of viruses, fungi,
nematodes, bacteria etc like organisms.
 Meteorological conditions influence
not only the development of an epidemic
over a single growing season, but also the
survival of the pathogen until the next
season.

ii) The influence of climate on pest and disease
Climate determines the distribution of pest like the distribution of
vegetation over the area. In other word climate sets the limits of
occurrence of pest. The development of pest depends upon three
factors that are environment, host and pathogen.
Disease triangle or disease triode
P- Pathogen H- Host
Time
E- Environment

iii) Classification of plant disease: -
Based on the severity of the
occurrence or intensity of attack the
plant disease classified as follows
- Sporadic
- Endemic
- Epidemic

iv) Role of weather in the development of pest
 Temperature - influence all metabolic (physiological or
biochemical) reactions
- Influence incubation period (time interval between infection and first
appearance of disease symptom in the host)
E.g. Wheat stem rust
Temperature Incubation period
24°C 5 days
13°C 12 days
4.5°C 21 days

 Humidity –temperature and humidity
together influences the process of infection,
incubation period, and sporulation and
determines the number of disease cycles in
one crop-growing season.
 Rainfall - if it is little with sunny intervals it
would create favourable condition for
decease whereas if it is heavy it is not
favourable for disease development, it
washed out the spores.

 Wind -if it is calm and the rainfall
occurs, it would favour the disease but
if it is strong it dried the leaf no
condition for germination.
 Light - intense light condition is not
favorable for fungi but deem and moist
condition is favourable.

Insect pests responses to climate variability
Examples
African armyworm (spodoptra exemta)
 The first outbreaks in east Africa are often in Tanzania at the end of
the year, and later outbreaks are further and further north, reaching
Ethiopia by the middle of the year (The infestation period at
different areas of the country is mid-April-July). Downwind
displacement would take moths towards and into the Inter Tropical
Convergence Zones(ITCZ), so that most of the insects, whether
caterpillars or moths would be near the ITCZ, where rains fall and
grasses grow. Moreover, the following generations would move with
the ITCZ as shown by catches from a network of moth traps over
east Africa.

Locusts
 Over most parts of the African Savanna, grasshoppers
and locusts destroy many farmlands every year. The
locusts generally originate in the Sahara desert margins
where there is enough moisture for breeding and for
vegetative growth to feed the larvae. The locusts fly in
swarm’s southwards with the northeasterly winds during
the day when temperatures are between 20 and 40°C.
Locusts find it impossible to hold to a course if the wind
speed exceeds 16 to 20 Km/hour.

Quelea
 The red-billed quelea is mainly distributed in the Ethiopian rift
valley where sorghum is grown abundantly. The depredation
of sorghum by the red-billed quelea at its milky stage is very
high.
 The seasonal movement patterns of queleas for breeding are
influenced by rainfall. Queleas are dependent on ripening grass
seeds for breeding and these become available six to eight
weeks after the onset of the main rains.

AGM Training for Debre Zeit regnal

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