In the recent past, many scientific and technical
research efforts have proven quite meaningful in developing suitable
irrigation for different countries for growing vegetable or other
suitable crops. Many methods and techniques have been designed, planned,
developed and applied successfully in the agricultural fields/gardens
etc. for the profitable marketing agriculture. Versatile and powerful
sprinkler irrigation technique can be used economically under various
topographic conditions, because it requires least land development.
Initially sprinkler irrigation method was used on high-value plantation
crops such as coffee, tea, cardamon and orchards, but now it is gaining
popularity on most of the food crops, orchards and cotton. Sprinkling is
suitable for sandy soils or any other soil, where surface irrigation may
be inefficient or expensive or where erosion may be particularly
hazardous. In this system, quite low rates and amounts of water may be
applied as the low amount of water is required for seed germination,
delay of fruit budding, and cutting of crops in hot weather. The
important agricultural input such as fertilizers may be dissolved in the
water and applied efficient through the irrigation system. Sprinkles
technique is classified according to principles of operation, pressure
discharge, and material from which they are made. Sprinklers
manufactured from bronze materials are considered to be resistant and
longer lasting than those prepared completely or in part from aluminium.
Different types include whirling, propeller, mini and micro. Others may
be (i)
low angle jets - under canopy sprinklers, (ii)
giant sprinklers - irrigation of cereals and fodder crops, wide spacing
covering large areas, (iii)
part circle sprinklers, for part irrigation of marginal areas to prevent
water wastage and wetting of roads, (iv)
pop-up sprinkler for lawns and house gardens, (v)
regulated sprinklers.
With micro-sprinklers, the water jet fitted in the
system strikes a bearing with one or two channels causing the sprinklers
to rotate quickly and distribute the water. When selecting a sprinkler,
suitable reliable workable factors such as crop, soil, quality of
irrigation water, irrigation schedules, water availability or supply
conditions such as pressure, discharge, labour, manpower, economic
evaluation etc. must be taken into consideration. The sprinkler
characteristics must also be considered, such as quality of water
application pressure and discharge range and sensitivity to wind etc.
Medium-pressure sprinklers are the most widely used ones. If operated at
a correct pressure and spacing appropriate to the nozzle, they give good
uniformity of water application with little risk of damage to crop or
soil except in sensitive cases. An irrigation system of sprinkler type
is planned so that the correct amount of water will be applied
efficiently at the right time. The system should be selected after
aicomplete evaluation of planning considerations such as crop
requirement for irrigation schedules, soil types, available water,
infiltration rate, climate, precipitation, wind velocity and
evaporation, water quality, water supply conditions, discharge, pressure
and proper time, landscape topography and shape of the field, existing
irrigation network and labour and economic factors. The basis of good
and sound planning generally depends upon the provision of exact and
reliable recorded data of the crop yields by the surrounding field
farmer to the planner. This will include the topographical scale map
with details of border, paths, direction of tillage and row and existing
network, ditches, electricity lines, crop irrigation timing, water
supply conditions, and water source, soil analysis, agro-technical
considerations etc. Wise and honest planning will definitely provide
efficient and long-term solutions and will also strike a balance between
crop requirements and the desires of the growers, and technical
engineering and economic possibilities regular inspection of screens and
filters is worthwhile for continuing efficiency of the system.
The main advantages of sprinkler irrigation, (i)
expensive land leveling is not required, (ii)
water saving-irrigation intensity can be changed in accordance with the
infiltration capacity of soil, (iii)
high efficiency due to uniform water distribution, (iv)
no special skills-trained personal can operate the system reasonably
well, (v)
easy and uniform application of fertilizers and pesticides through
irrigation system, (vi)
possibility of applying a minute quantity of water for germination and
other irrigation systems, (vi)
frequent and light irrigation is possible, giving better response from
the crops, (vii)
increase in yield and quality, early ripening, water conservation and
alternative value of specific periods, saving of labour, machinery,
fertilizers and pesticides, (viii)
soil moisture is maintained at optimum level by sprinkler irrigation and
20 higher yields are obtained in some crops. The quality of the products
is also good.
Fertilizers and pesticides can be mixed, hence the
efficiency of these inputs for crop production is more compared to
surface irrigation. Fertilizer can also be applied through sprinkler
system, which saves labour. By introducing this system, there will be no
soil erosion problem, no compaction of soil during irrigation. In recent
years, sprinkler irrigation has become widespread irrigation method in
cereal or tree crops as a result of numerous improvements both in the
sprinklers and in the adaptation of the irrigation method to specific
local conditions. Although, sprinkler irrigation system is used
primarily for the application of water to crops, it is a multipurpose
system with a wide range of uses. There are certain disadvantages in the
use of sprinkler system, and these are: (i)
higher initial cost, (ii)
high and continuous energy requirement for operation, (iii)
under high windy condition and high temperature, distribution
and application efficiency is poor, (iv)
highly saline water 76 mmhos/cm causes leaf burning, when temperature is
higher than 95°F, (vi)
when lands have been already leveled and developed for surface or other
irrigation methods, sprinkler irrigation is not so economical, (vi)
loss of water due to evaporation from the area during irrigation, (vii)
above canopy sprinkling may cause washing of spray, materials and
aggravate the incidence of pests and diseases.
During irrigation a stable water supply is needed for
the most introducing sprinklers irrigation technique for certain crops
and certain locations. Such system can be made operative in the desert
areas of the country. Areas of Balochistan, Thal, Thar, Cholistan and
other sandy and barren areas of Pakistan are suitable for cultivation of
vegetable crops. The sprinkler irrigation system is very much profitable
in Middle East countries and other barren areas of the world. Sprinkler
irrigation has immensely helped in developing UAE's agriculture and
forestry projects. The success rate could be judged from the fact that
up to early eighties, the UAE used to import about 90-95 per cent of its
total fruits and vegetable requirements from abroad, but only that
figure has drastically reduced to less than 30 per cent. In some areas,
they have surplus farm products, fruits and vegetables for exports to
the neighbouring countries as well as to European countries and USA.
This situation has also helped to improve the weather conditions and
environments to the extent that top summer temperatures have been
reduced over a period of 25 year or so by 5-7 degrees centigrade. As the
water supply in the world becoming lesser and lesser with each passing
day, I must eulogize that the sprinkler irrigation system is the key to
the development of agriculture and forestry projects all over the world.
The world, including our country, especially in drought-hit areas,
sprinkler irrigation would enable our farmers to produce maximum
possible crop yield with minimum possible water supply from the
reservoir.
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