Civil Engineering Department
SEMESTER – 4THSUBJECT – HYDRAULICS & IRRIGATION ENGINEERING
TOPIC – WATER REQUIREMENTS OF CROPS
BY
ER. SASMITA GOCHHAYAT
(HOD, CIVIL ENGG. Dept.)
AY-2021-2022
IRRIGATION :-��
》Irrigation is the agricultural process of applying Controlled amount of Water to land to assist In the Production of crops .
》With crops as well as to grow landscape plants and lawns , where it may be known as watering.
》Irrigation has been a central feature of agricultural for over 5,000 years and has been developed independently by many cultures across the globe.
(Irrigation of agricultural fields )
NECESSITY OF IRRIGATION:-
》If rainfall is less than the demand for plants, irrigation is necessary to fulfill the water requirement for plants .
》Through out the crop period adequate quantities of water os required near the root zone of the plants for their growth .
》Improvement of perennial crops.
》Development of agriculture in desert area .
BENEFITS OF IRRIGATION:-
》Irrigation helps to grow agricultural crops , maintain lands capes.
》Irrigation also has other uses in crop production, including frost protection, suppressing weed growth in grain fields and preventing soil consolidation.
》It also used for cooling livestock ,dust suppression, disposal of sewage, and in mining .
TYPES OF IRRIGATION:-
》There are 5 types of irrigation methods .
1) SURFACE IRRIGATION:-
》Surface irrigation known as gravity irrigation.
》It is the oldest form of irrigation and has been use for thousands of years .
》In surface irrigation systems, water moves across the surface of an
agriculture lands , in order to wet it land infiltrate in to the soil.
(Surface irrigation)
2) MICRO IRRIGATION:-
》Micro irrigation sometimes called localized irrigation, low volume irrigation.
》It Is a system where water is distributed under low pressure through a piped network in a pre-determined pattern.
(Micro irrigation)
3) DRIP IRRIGATION:-
》Drip irrigation also known as trickle irrigation function a its name suggested.
》In this system , water is delivered at or near the root zone of plants , one drop at a time .
(Drip irrigation)
SPRINKLE IRRIGATION:-
》In sprinkle irrigation or overhead irrigation, water is piped to one or more central locations with in the field and distributed by overhead high-pressure sprinklers or guns .
》It operates very high pressures of 275 to 900 Kia and flows of 3 to 76 liter per second.
(Sprinkle irrigation)
CENTER PIVOT :-
》Center pivot is a form of sprinkler irrigation utilizing several segments of pipe joined together and supported by trusses , mounted.
》The system moves in a circular pattern and is fed with water from the pivot point at the center of the area .
(Center pivot )
CROP SEASON :-
》Crop season means a season is a decision of the year maked by changes in weather ecology and the amount of day light .
》There are three main cropping season in India – kharif, Rabi and Zaid .
DUTY, DELTA AND BASE PERIOD THEIR RELATIONSHIP:-
DUTY :-
It is the area of land that can be irrigated with a unit volume of water supplied across the base period .
DELTA :-
It is the depth of water required to raise a crop over a unit area across the base period .
BASE PERIOD :-
It is defined as the total time between the first watering done for preparation of land for sowing a crop and the last watering done before its harvesity.
OVERLAP ALLOWANCE:-
》The time period in days for which crop of previous season overlaps the new sown crop is known as overlap allowance.
》 Water percentage in overlap allowance is 5-10 .
KHARIF AND RABI CROPS :-
》The crops that are shown in rainy season are called Kharif crops.
》The crops that are shown in winter season are called rabi crops .
》The kharif crops are rice , maize , sorghum , bajra , finger ragi , pulses etc .
》The rabi crops are wheat , barley , oats, pulses , mustars etc.
GROSS COMMAND AREA :-
》The gross command area is the total area bounded with in the irrigation boundary boundary of the project that can be irrigated economically with out bothering about the limitation of quantity of water available.
》The gross command area includes the cultivable area and un-cultivable area .
CULTURABLE COMMAND AREA IN IRRIGATION:-
》Culturable command area is the area in which a crop is grown at a practicalar time or crop season .
》It is denoted by CCA .
》Uncultivable areas are excluded from GCA to obtain CCA .
INTENSITY OF IRRIGATION:-
》Intensity of irrigation is defined as the percentage of culturable commanded area that can be irrigated during a given season.
》It is the ratio of gross irrigated area to the net irrigated area expressed as a percentage.
IRRIGABLE AREA :-
》Irrigation area is the maximum area which could be irrigated in the reference year using the equipment and the quantity of water normally available on the holding.
》Irrigable means suitable for Irrigation.
TIME FACTOR :-
》It is defined as the rational of actual operating operating period of a distributary to the crop period.
CROP RATIO :-
》It is the ratio of the areas irrigated in rati and Khalifa seasons.
》The ratio between kharif and rabi is 1:2 .