IRRIGATION ENGINEERING PREPARED BY BIPASHA RAY

 Irrigation is any process, other than natural precipitation, which supplies water to crops for their successful growth.  Irrigation is the artificial application of water to the soil to meet the crop water needs for its vegetative development and for production.  Irrigation is the science of artificial application of water to the land, in accordance with the crop requirements throughout the crop period for full nourishment of the crops.

o Irrigation is needed for a continuous and reliable water supply to the different crops in accordance with their different needs. o The factors for which irrigation is necessary are :- i.inadequate rainfall ii.uneven distribution of Rainfall iii.increasing the yield of the crops iv.growing a number of crops v.to insure against drought. vi.to grow perennial crops.

 Add water to soil to supply the moisture essential for plant growth.  Provide crop insurance against short duration droughts.  Cool the soil and atmosphere, there by making more favorable environment for plant growth.  Reduce the hazard of frost.

 Wash out or dilutes salts in the soil.  Reduce the hazard of soil piping  Soften tillage pans and clods  To enhance fertilizer application.

 Irrigation helps to maintain the condensation of the loam.  It provides mineral as well as other nutrition by the assimilation from the mold.  Irrigation is one of the most feasible ways to grow cash crops like sugarcane, tobacco, etc.  As people are dependant on irrigation channels, there is now an extensive irrigation system which people are using as a mean of their communication.  It helps to preserve the structure of the topsoil

 By eliminating the deficiency of water, Irrigation manages to give fast manufacturing.  The more production rate intensifies, the more living standard of the farmer increases.  Canal and irrigation water seeps through the soil and elevates the water table. This is desirable in desiccated and semiarid zones.  At many places, the irrigation serves as the only water source.  Irrigation helps to make the cash flow of a country profound with the massive production of crops.  It helps the landowners by the monetary increment of fertile lands.

 Irrigation sometimes creates unrestrained excretion and percolation of water throughout the whole passage.  The overflowing irrigated water gives insects a place to make their habitat which is harmful to surroundings giving rise to various diseases.  As irrigated water helps to lessen the inversion, sometimes it turns the area into a wet and sweaty surface. Immoderate irrigation clogs specific area by raising the water

 While constructing the colossal irrigation waterways, people lose their residential and commercial lands.  Not every time irrigation is affordable. The embryonic value of irrigation is quite inflated, and people end up paying a lot of imposed taxes.  Irrigation becomes an obstacle in the path of free devours during the rainy season.  Careless and over-irrigation can lead to salt efflorescence

IRRIGATION SURFACE SUB SURFACESPRINKLER DRIP

Surface irrigation is defined as the group of application techniques where water is applied and distributed over the soil surface by gravity.

 Irrigation management is very easy and does not require modern technology and can largely build on local traditional knowledge;  Adapts well to small land holdings and does not require high financial input;  Adapts easily to flat topography and can function without outlet drainage facilities;  Works well with short-term water supplies;  Irrigation allows full utilization of rainwater and can achieve high application efficiencies;  Adapts well to moderate to low infiltration rates and allows easy leaching of salts.

 Requires level land to achieve high efficiencies (maximum land elevation fluctuation should not be greater than half the applied irrigation depth);  Soils with high infiltration rates require small field sizes, which interferes with mechanization.  Difficulty to apply small irrigation quantities, excess water is difficult to evacuate, particularly during times of excess rainfall.  Plants are partly covered with water sometimes over extended periods.  Small basins require extensive delivery channels and are not easily adaptable to tractor mechanization.

Subsurface irrigation uses a network of polyethylene pipes located just under the ground's surface to apply disinfected effluent in the root zone of plants, preventing airborne drift and minimising runoff.

 It costs less to water plants more fully. Less water is lost in the process and there’s no run-off.  Subsurface irrigation systems can free up above ground space. This can increase the amount of crops produced and less equipment required.  Crops grown in these conditions may grow more uniformly. The water is evenly distributed across all plants, improving overall growth level. More so, there is less of a need for fertilizer use, which is both good for the environment and for budgeting.  With less water remaining on the leaves, there is a lowered risk of excessive moisture damage.

 Driving vehicles over a subsurface irrigation system will likely damage piping.  Storage facilities for effluent must exist for extended periods of time when the ground for subsurface irrigation systems is wet or frozen.  Wind obstructions may be necessary with a subsurface irrigation system to prevent off-site air transportation of effluent.

An Irrigation sprinkler is a device used to irrigate agricultural crops, lawns, landscapes, golf courses, and other areas.

 Expansive land leveling or terracing is not required;  No loss of cultivable area due to channel construction;  Suitable for almost all soil types;  Water saving irrigation intensity can be changed in accordance with the infiltration capacity of soil and crop water requirements;  High efficiency due to uniform water distribution, crop water management can be adapted to growth stage and conditions;  Possibility of adding fertilizers or pesticides to irrigation water in an economic way.

High initial capital costs (investment in equipment - sprinklers and pipes) and high operation costs due to energy requirements for pumping and labor costs. Sensitivity to wind, causing evaporation losses (under high wind condition and high temperature distribution and application efficiency is poor); Unavoidable wetting of foliage in field crops results in increased sensitivity to diseases; Highly saline water causes leaf burning when temperature higher than 35 degrees (Celsius). Debris and sediments in irrigation water can cause clogging of sprinkler nozzles.

Drip irrigation is a type of micro-irrigation system that has the potential to save water and nutrients by allowing water to drip slowly to the roots of plants, either from above the soil surface or buried below the surface.

 Fertilizer and nutrient loss is minimized due to a localized application and reduced leaching.  Water application efficiency is high if managed correctly.  Field leveling is not necessary.  Fields with irregular shapes are easily accommodated.  Recycled non-potable water can be safely used.  Moisture within the root zone can be maintained at field capacity.

DISADVANTAGE OF DRIP IRRIGATION  Initial cost can be more than overhead systems.  The sun can affect the tubes used for drip irrigation, shortening their lifespan.  The PVC pipes often suffer from rodent damage, requiring replacement of the entire tube and increasing expenses.  Drip irrigation systems cannot be used for damage control by night frosts.  Drip irrigation might be unsatisfactory if herbicides or top dressed fertilizers need sprinkler irrigation for activation.  Drip tape causes extra cleanup costs after harvest. Users need to plan for drip tape winding, disposal, recycling or reuse.