DRY-FARMING.pptx

Pandit jawaharlal nehru college of agriculture and research institute –
karaikal 609603
COURCE TITLE: agron 501 Modern concepts in crop production (3+0)
COURCE TEACHER: Dr.R. MOHAN
TOPIC: dry farming
BY,
R.VIMALRAJ

Topics for discussion
 Dryland agriculture
 Definition of dry farming, dry land and rainfed farming
 Why dry farming is important?
 Characters of dry farming
 Problems of crop production in dry farming
 Benefits of dry farming
 Moisture stress and effects of moisture stress

 Mechanisms to conserve water
 Mechanism to improve water uptake
 Drought tolerance
• Resource development and utilization
• Dryland farming techniques
• Dry farming practices
• Conclusion

Dryland agriculture
• Growing of crops entirely under rainfed conditions is known as
dryland agriculture.
• Depending on the amount of rainfall received, dryland
agriculture can he grouped into three categories;
Dry
farming
Dryland
farming
Rainfed
farming

Dry farming
• Dry farming is cultivation of crops in regions with annual
rainfall less than 750 mm.
• Crop failure is most common due to prolonged dry spells
during the crop period.
• These are arid regions with a growing season (period of
adequate soil moisture) less than 75 days.
• Moisture conservation practices are necessary for crop
production

Why dry farming is important?
• Dry farming is an important agricultural practice in areas that
lack sufficient water resources or are prone to drought.
• It can help increase crop yields and reduce the amount of water
needed to grow crops.
• It also can help preserve the land while minimizing soil erosion.

Dryland farming
• Dryland farming is cultivation of crops in regions with annual
rainfall more than 750 mm.
• In spite of prolonged dry spells crop failure is relatively less
frequent.
• These are semi-arid tracts with a growing period between 75
and 120 days.
• Moisture conservation practices are necessary for crop
production.
• However, adequate drainage is required especially for
vertisols.

Rainfed farming
• Rainfed farming is crop production in regions with annual
rainfall more than 1150 mm.
• Crops are not subjected to soil moisture stress during the crop
period.
• Emphasis is often on disposal of excess water.
• These are humid regions with growing period more than 120
days

• United nations economic and social commission for Asia
and the pacific distinguished dryland agriculture mainly into
two categories: dryland and rainfed farming.
• The distinguishing features of these two types of farming are
given below.

Present status
• If 69.5 per cent is dryland and rainfed area. This area
contribute about 42% of the food grains.
Class Area (m ha) Percentage of
total arable land
Total arable 143.8 100
Dryland 34.5 24.0
Rainfed 65.5 45.5
Irrigated 43.8 30.5

The concept
• In modern concept, dryland areas are those where the balance
of moisture is always on the deficit side.
• In other words, annual evapotranspiration exceeds precipitation.
• In dryland agriculture there is no consideration of amount of
rainfall.
• It may appear quiet strange to a layman that even those areas
which receive 1100 mm or more rainfall annually fall in the
category of dryland agriculture under this concept.

• To be more specific, the average annual rainfall of Varanasi is
around 1100 mm and the annual potential evapotranspiration is
1500 mm.
• Thus the average moisture deficit so created comes to 400
mm.
• This deficit in moisture is bound to affect the crop production
under dryland situation, ultimately resulting into total or partial
failure of crops.
• Accordingly, production is either low or extremely uncertain and
unstable which are the real problems of dryland in India.

• Success of crop production in these areas depends on the
amount and distribution of rainfall, as these influences the
stored soil moisture and moisture used by crops.
• Amount of water by crop and stored in soil is governed by
water balance equation
ET= P-(R+S)
• When balance of the equation shifts towards right,
precipitation (P) is higher then ET, so that there be waterlogging
or it may even lead to runoff (R) and flooding.
• On the other hand, if the balance shift to left, ET becomes
higher then precipitation, resulting in drought.

Characters of dry farming
• Uncertain, ill-distributed and limited annual rainfall.
• Occurrence of extensive climatic hazards like drought, flood
etc.
• Undulating soil surface
• Practice of extensive agriculture i.e. Prevalence of mono
cropping etc..
• Very low crop yield.
• Poor marketing facility for the produce.
• Poor health of cattle as well as farmers.

Major problems of dryland
A. Vagaries of monsoon
B. Soil constraints
C. Lack of suitable varieties
D. Heavy weed infestation
E. Socio-economic constraints

A. VAGARIES OF MONSOON
• Based on average annual rainfall, the country can be divided
into three zones: low (less than 750 mm), medium (750-1,150
mm) and high (more than 1,150 mm) rainfall zones.
• Dryland area is nearly equally distributed among the three.
Areas with less than 1,150 mm (arid and semiarid) are the
problem areas for crop production.
• Main characteristics (features) of rainfall influencing crop
production are its variability, intensity and distribution, late onset
and early withdrawal of monsoon and prolonged dry spells
during the crop period.

Variable rainfall
• Annual rainfall varies greatly from year to year. Generally,
higher the rainfall, less is the coefficient of variation. In
otherwords, crop failures due to uncertain rains are more
frequent in regions with lesser rainfall.

Intensity and distribution
• In general, more than 50 per cent of total rainfall is usually
received in 3 to 5 rainy days.
• Such intensive rainfall results in substantial loss of water due to
surface runoff.
• This process also accelerates soil erosion.
• Distribution of rainfall during the crop growing season is more
important than total rainfall in dryland agriculture.

Late Onset and Early Cessation of Rains
 Due to late onset of monsoon, sowing of crop is delayed resulting in
poor yields.
 Sometimes the rain may cease very early in the season exposing the
crop to drought during flowering and maturity stages which reduces
the crop yields considerably.

Prolonger dry spells during the crop
period
• Long breaks in the rainy season are important features of
Indian monsoon.
• These intervening dry spell when prolonged during crop
period reduces crop growth and yield and when unduly
prolonged crop fails.

B. SOIL CONSTRAINTS
• Alluvial soils occupy the largest area in dryland agriculture.
• Problems of crop production are so acute in these soils as they are in
black and red soils.
• Major problems are encountered Vertisols, Alfisols and related soils
and associated soils are mesh distributed in central and south India.
• The coastal areas have Alfisols, laterite and lateritic soil.

Alluvial soils
Poor crop stand due to crusting and rapid drying of surface soil.
Poor crop growth due to unreliable soil moisture supply, low
moisture storage capacity due to shallow depth and drought
spells during crop season.
Low soil fertility due to low organic matter, poor nutrient statu.
Land degradation from soil erosion and crusting.

Vertisols soil
• These soils commonly called as black soils are characterized by
high clay content (30-70%).
• Physical constraints such as narrow range of soil water content
for tillage, tendency to become waterlogged and poor
trafficability.
• Low soil fertility due to low N and available P.
• Land degradation from soil erosion and salt accumulation,
especially in low-lying areas.

Inceptisols and Entisols
• These are commonly termed as alluvial soils.
• They have low water holding capacity and low nutrient holding
capacity.
• Management of these soils for crop production is relatively easy
compared to red and black soils. Soil erosion is, however, a
problem leading to land degradation.

Heavy weed infestation
• This is the most serious problem in dryland areas.
• Soil environment ideal for crop growth is also congenial for
weed growth.
• Weed seeds germinate earlier than crop seeds and suppress
the crop growth.
• Weed infestation is severe in dryland agriculture due to
continuous rains and acute labour shortage.
• Since crop performance under dryland farming is unpredictable,
farmers hesitate to investment money for weed management
leading to heavy loss in crop yield.

Socio-economic constraints
• The socio-economic status of dryland farmers, generally, will not
permit them in adopting the recommended dryland technology.
• Major socio-economic constraints are:
Lack of capital, support price for the produce, marketing and credit
facilities make the farmers hesitate to invest on recommended
technology.
Most of the resource poor farmers opt for avoiding risk in dryland
agriculture.
Poor organisational structure for input supply in dryland areas.

Benefits of Dry Farming
Allows farmers to produce crops in areas with limited water
resources.
Helps conserve water in the environment.
Helps reduce soil erosion and increase water infiltration into
the soil.
Reduction in costs associated with irrigation.

Drought or moisture stress
• An extended period of deficient rainfall compared to normal rainfall
of the region is called drought.
• Depending on the criteria used, drought is called as meteorological,
agriculture or hydrological drought.
Meteorological drought – It refers to substantial deficit of rainfall
relative to average of the region.
Indian Meteorological Department defines meteorological drought as a
situation when there is a 25% decrease in the average rainfall for a
given period in a region.

Agricultural drought – It refers to extended dry period in which
lack of rainfall results in insufficient moisture in the root zone of
the soil causing adverse effects on crops.
Hydrological drought – It is extended dry period leading to
marked depletion of surface water and consequent drying up of
reservoirs, lakes, streams, rivers, cessation of spring flows and
fall in groundwater levels.
Dry spell is a rainless period more than 10 days in light soil areas
and 15 days in heavy soil areas. Drought is prolonged dry spell
resulting wilting or drying of crops. Severe from drought is called
famine.

Moisture stress
• Soil moisture is the most limiting factor in dry farming and
dryland farming situation.
• Stress is the result of action of external factors of an organism.
Moisture stress indicates the action of lack of or excess of water
on plants.
• The term moisture stress is generally used for deficit moisture
conditions through it is applicable to excess moisture also.
• Moisture stress is most prevalent under dryland farming
conditions.

Development of Moisture Stress
• Water deficits occur in the plant whenever transpiration exceeds
absorption.
• It may be due to excessive water loss, reduced absorption of
water from soil or both.
• After irrigation or rain, water deficits develop gradually and only
for a very short period in the beginning.
• Though there is sufficient amount of soil moisture, water deficits
develop due to higher transpiration than absorption especially
on hot middays.
• This temporary wilting is known as incipient wilting or midday
depression.

• Under such conditions, stomata are open for a short period in
the morning and evening and partially closed during the rest of
the day.
• Stomatal closure occurs when leaf water potential approaches
about -1.0 to 1.2 MPa in soybean.
• When the soil moisture reaches about -15 bars, plants show
wilting symptoms most of the day, but do not die and it is known
as permanent wilting point.
• Plants recover when irrigation is given or rain is received. If the
soil moisture is further allowed to deplete to a level of - 6 MPa,
plants die permanently and this is known as ultimate wilting
point.

Drought tolerance
• Due to different drought avoidance mechanisms, plants are able
to maintain favorable water balance and adverse effect of
reduced water potential are not felt by the plants.
• In drought tolerance, water potential of plant is reduce and it
adverse effects are felt.
• Drought tolerance can be defined as tolerance of the plants to a
level of stress at which 50% of the cells die.
• The performance of higher plants depends upon the integrated
function of may cells which is disturbed by drop.
• Drought tolerance is either by mitigating stress or by showing
high degree of tolerance.

MOISTURE CONSERVATION IN DRYLANDS
• Annual rainfall in several parts of drylands is sufficient for one or
more crops per year.
• Erratic and high intensity storms leads to runoff and erosion.
• The effective rainfall may be 65 per or sometimes less than 50
per cent.
• A number of simple technologies have been developed to
prevent or reduce water losses and to increase water intake.
Tillage
Fallowing
Mulching
In situ moisture conservation

Tillage
• The surface soil should be kept open for the entry of water through
the soil surface.
• Offseason shallow tillage aids in increasing rain water infiltration
besides decreasing weed problems.

Fallowing
• Leaving the land fallow during rainy season and raise crops
only during postrainy season on profile stored soil moisture.
• The main intention of fallowing is to provide sufficient moisture
for the main postrainy season crops.

Mulching
• Mulching is a practice of covering the soil surface with organic
materials such as straw, grass stones, plastics etc, to reduce
evaporation, to keep down weeds and also to moderate diurnal soil.

In situ moisture conservation
I. Bunding
The first essential step in dry farming is bunding. The land is
surveyed and level contours determined every hundred feet.

II. Broad Beds and Furrows (BBF)
• These are effective on black soils.
• Beds of 120-180 cm separated by furrows on grade are
effective for in situ water conservation.
• Beds function as minibunds at a grade normally less than the
maximum slope of the land.
• When runoff occurs, its velocity is reduced and infiltration
opportunity time increased.
• Excess water is removed in a large number of small furrows.
Crops are sown on broad beds

III. Compartmental Bunds
• They convert the area into small square/rectangular blocks.
• They are useful for temporary impounding water and improving
the moisture status of soil.
• These can be made with bund formers or country plough.
• Size of bunds depend on inter bunded land area.
• Areas having a slope of 1 per cent or less suitable for
compartmental bunding.

III. Dead Furrows
• Dead furrows on contour at 2.4 to 3.6 m are effective in shallow
red soils of Anantapur (AP) for increasing the groundnut yield.
• Dead furrows are formed between two rows of the crop before
start of heavy rains (September-October).
• They increase infiltration opportunity time besides reducing soil
erosion.

IV. Opening Ridges and Furrows
• Ridges and furrows are opened before onset of monsoon so
that the flow of water may be reduced and erosion may be
controlled to minimum.
• During rainy season, crops like maize, sorghum, pearl millet etc
may be grown in the furrows and legumes like soybean,
pigeonpea, greengram, blackgram, cowpea etc may be grown
on the ridges.

V. Inter-row Water Harvesting
• under this system, furrows of about 30-40 cm width (15 cm deep) are
alternated by ridges of 60-70 cm .
• It reduces runoff and water is conserved in furrows.
• It is, particularly, suitable for heavy textured soils. In light soils, crops
are grown in furrows whereas in heavy soils, planting is usually on
ridges to eliminate the problem of waterlogging.

Mechanism to improve water
uptake
• Drought avoidance is promoted by well-developed deep root
system with high efficiency to extract water from deeper layers
of the soil.
• This mechanism is desirable if there is sufficient soil moisture
in deeper layers for extraction.
• Water uptake can be improved by several mechanisms such
as:
Efficient root system
Root-shoot ratio
Increase in liquid phase
Osmotic adjustment

Efficient root system
• Deep, well branched and rapidly growing root
system helps in absorbing more moisture by
exploiting higher volume of soil.
• It is an important morphological adaptation that
helps in. drought resistance without losing
productivity
• Variation in root length between varieties is
related to differences in drought resistance.
Genetic variability in root length is observed in
soybean, wheat and tomato.

Root-shoot ratio
• If the roots are more compared to
transpiring shoots, water balance can be
maintained. Seedling establishment is
particularly important in semiarid
environments and root growth takes
precedence over shoot during this stage.
• Drought increases root growth and root-
shoot ratio which is an important
mechanism of drought avoidance.

Increase in liquid phase
• To maintain high water potential in plants, not only uptake is
important, but also conductance.
• Lowering of resistance to water can be achieved by increasing
either diameter of xylem vessels or their number.

Mechanisms to conserve water
• Stomatal mechanism
• Increase photosynthetic efficiency
• Liquid deposits on leaves
• Reduction in leaf area and Leaf surface
• Effects of awns
• Water storage in plants

Resource development and
utilization
• Important natural resources are rainfall, soil and plants.
• Resource development are their efficient use are two important
aspects to achieve good and stable yield under dryland
condition.
• The rainfall received in arid and semi-arid regions is to be stored
either on the soil or in the soil.

Soil resources are developed by:
• Understanding the soil by proper grouping or classification.
• Rectifying the defects of the soil either by leveling, application of
amendments.
• Increasing storage capacity of the soil.
• Plant resources are developed by selecting or breeding drought
resistant varieties suitable for arid and semi-arid environments.

Dryland Farming Techniques
Increase Water Absorption
Prevent a crust at the soil surface.
The beating action of raindrops tends to break down clods
and disperse the soil.
 By tillage, create a rough, cloddy surface which lengthens
the time necessary for the rain to break down the clods and
seal the surface.
For seed bed preparation in general, small seeds should
have a finer, mellower bed than large seeds.

Reduce the Runoff of Water
• To the extent that waterlogging is not a problem, the runoff of
water an attendant erosion must be stopped.
• Cropland should be as level as possible.
• All tillage and plantings must run across (or perpendicular to) the
slope of the land. Such ridges will impede the downward
movement of water.

Reducing the Loss of Soil Moisture
Reducing Soil Evaporation
Water in the soil exists as a continuous film surrounding each grain. As
water near the surface evaporates, water is drawn up from below to
replace it, thinning the film. When it becomes too thin for plant roots to
absorb, wilting occurs.
Shelter belts of trees or shrubs reduce wind speeds and cast
shadows which can reduce evaporation 10 to 30 percent by itself and
also reduce wind erosion.
Mulching reduces the surface speeds of wind and reduces soil
temperatures.

Reducing Transpiration
All growing plants extract water form the soil and evaporate it from their
leaves and stems in a process known as transpiration.
Weeds compete not only for soil nutrients, but water as well and so their
control is critical.
Selection of crop is significant as well. Dwarf varieties have less surface
and so lose less water.
In dry farming, the number and spacing of plants is reduced so that fewer
plants compete for soil moisture. The exception to this occurs when
allowances for insect, bird, and rodent loss must be made at planting.

Conclusion
• Dryland agriculture requires different management practices
than irrigated agriculture because of rainfalls variable and
often unreliable nature.
• Crop must withstand long periods without water, followed by
periods of heavy rains that can cause soil erosion. With careful
consideration of soil type, crops and irrigation techniques,
anyone with access to arable land can get into dry farming.

Reference
• John A WIDTSOE (n.D.) Dry farming for sustainable agriculture.
• T. yellamanda reddy (n.D) Principles of agronomy, dryland
agriculture.
• S.R. reddy (n.D) Principles of agronomy, dryland agriculture.

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