1. WATER MANAGEMENT IN
HORTICULTURE CROPS
INTRODUCTION
The suitability of an irrigation water system
depends upon several factors such as water
quality, soil type, plant characteristics,
irrigation method, drainage, climate and
local conditions. The integrated effect of
these factors on suitability can be expressed
by the relationship given below:
where
suitability of irrigation = QSPCD
Q = quality of irrigation of water i.e total
salt concentration etc.
2. S = soil type, texture, structure,
permeability, fertility, type of clay mineral
etc.
P = salt tolerance, characteristics of the crop
to be grown, its variety and growth stage.
C = climate i.e total rainfall, its distribution
and evaporation characteristics
D = Drainage conditions, depth of water
table, nature of soil profile etc.
Factors affecting the suitability of
irrigation method
1. TOPOGRAPHY
2. SOIL TYPE
3. CLIMATE
4. WATER AVAILABILITY AND WATER
CONSUMPTION
3. 5. TYPES OF CROPS TO BE IRRIGATED
6. ECONOMIC FACTOR AND LABOUR
7. COSTS AND BENEFITS
TOPOGRAPHY
Topography is the slope of the ground and
how much uneven or leveled it is. The
irrigation method is selected accordingly.
Topography is a major factor affecting
irrigation, particularly surface irrigation. Of
general concern are the location and
elevation of the water supply relative to the
field boundaries, the area and configuration
of the fields, and access by roads, utility
lines (gas, electricity, water, etc.), and
migrating herds whether wild or domestic.
5. SLOPE TOPOGRAPHY
SOIL TYPE
When a variety of different soil types is
found within one irrigation scheme,
sprinkler or drip irrigation are
6. recommended as they will ensure a more
even water distribution.
Sandy soils typically have high intake rates
and low soil moisture storage capacities and
may require an entirely different irrigation
strategy than the deep clay soil with low
infiltration rates but high moisture-storage
capacities. Sandy soil requires more
frequent, smaller applications of water
whereas clay soils can be irrigated less
frequently and to a larger depth.
TYPE OF SOIL AND ROOTING DEPTH
OF CROPS
7. CLIMATE
Ground level irrigation methods are directly
affected by climate. The sprinkler system of
irrigation is most suitable for such climate.
Dryness, humidity and speed of air affect
the methods of irrigation.
Strong wind can disturb the spraying of
water from sprinklers. Under very windy
conditions, drip or surface irrigation is
8. suitable. Sprinkler or drip irrigation may be
more suitable than surface irrigation
because of their flexibility and adaptability
to varying irrigation demands on the farm.
WATER AVAILABILITY AND WATER
CONSERVATION
Water application efficiency is generally
higher with sprinkler and drip irrigation
than surface irrigation and so these
methods are preferred when water is in
short supply. However, it must be
remembered that efficiency is just as much
a function of the irrigator as the method
used.
Water conservation is the demand of the
day when the whole world is facing water
crisis. Hence, such a method of irrigation
should be adopted which uses minimum
9. water but provides maximum humidity to
the plants. Sprinkler method and drip
irrigation method are the best from the
view point of water conservation.
TYPE OF CROPS TO BE IRRIGATED
Surface irrigation can be used for all types
of crops. Sprinkler and drip irrigation,
because of their high capital investment per
hectare, are mostly used for high value
crops, such as vegetables and fruit trees.
Drip irrigation is suited to irrigating
individual plants or trees or row crops such
as vegetables. It is not suitable for close
growing crops.
11. ECONOMIC FACTORS AND LABOUR
While selecting any method of irrigation, the
economic condition must be kept in mind as
many irrigation methods require heavy initial
investment but lesser investment later on.
Surface irrigation methods require continuous
investment. Along with investment, availability
of labour is also an essential factor. As
12. compared to sprinkler method, check basin
method of irrigation requires more labour
Sprinkler and drip irrigation require little land
leveling. System operation and maintenance
are less labour intensive.
COSTS AND BENEFITS
Before choosing an irrigation method, an
estimate must be made of the costs and
benefits of the available options. On the cost
side not only construction and installation, but
also the operation and maintenance (per
hectare) should be taken into account. These
costs should then be compared with the
expected benefits (yields). It is obvious that
farmers will only be interested in implementing
a certain method if they consider this
economically attractive.
