Irrigation engineering

Irrigation engineering : in agriculture, artificial watering of the land. Although used chiefly in regions with annual rainfall of less than 20 in. (51 cm), it is also used in wetter areas to grow certain crops, e.g., rice. Estimates of total irrigated land in the world range from 543 to 618 million acres (220 to 250 million hectares), almost half of them in India, Pakistan, and China. The United States had almost 60 million acres (23.8 million hectares) of irrigated farmland in 1991.

In Irrigation engineering Methods of applying water include free-flooding of entire areas from canals and ditches; check-flooding, in which water flows over strips or checks of land between levees, or ridges; the furrow method, in which water runs between crop or tree rows, penetrating laterally to the roots; the surface-pipe method, in which water flows in movable slip-joint pipes; sprinklers, including large-scale center-pivot and other self-propelled systems; and a variety of water-conserving drip and trickle systems. In many cases irrigation is correlated with drainage

 to avoid soil salinity, leaching, and waterlogging. Irrigation may also involve preliminary clearing, smoothing, and grading of land. Especially in areas of high evaporation rates, intensive irrigation can result in excessive quantities of salts accumulating in the upper layers of the soil as water evaporates from the surface, rendering the soil unfit for crop production.

Since prehistoric times water has been diverted from waterways to fields by ditching. Early improvements for raising water included counterbalanced poles with attached water vessels, and adaptations of the wheel and of a pump called the Archimedes’ screw. The use of canals, dams, weirs, and reservoirs for the distribution, control, and storage of water was probably initiated in ancient Egypt. A system of gently sloping underground tunnels (qanats) to deliver water from a subterranean source to distant areas where it is accessed through shafts was developed in ancient Persia and has been widely used elsewhere. In modern times pumps have facilitated the use of underground as well as surface water, but overuse of water in aquifers can exhaust their usable water. Large-scale 20th-century irrigation projects commonly also include water supply, hydroelectric power, and flood control.

 

Subsurface irrigation or simply subirrigation method

Subsurface irrigation or simply subirrigation method Subsurface irrigation or simply subirrigation method is the practice of applying water to soils directly under the surface. Moisture reaches the plant roots through capillary action. The conditions which favour Subsurface irrigation or simply subirrigation method are as follows (i) Impervious subsoil at a depth of 2 metres or more, (ii) A very permeable subsoil, (iii) A permeable loam or sandy loam surface soil, (iv) Uniform topographic conditions, and (v) Moderate ground slopes. In Subsurface irrigation (or simply subirrigation) method, water is distributed in a series of ditches about 0.6 to 0.9 metre deep and 0.3 metre wide having vertical sides. These ditches are spaced 45 to 90 metres apart. Sometimes, when soil conditions are favourable for the production of cash crops (i.e., high-priced crops) on small areas, a pipe distribution system is placed in the soil well below the surface. This method of…

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Methods of irrigation surface irrigation

Methods of irrigation  surface irrigation Surface irrigation Uncontrolled flooding, Border strip,Check,Basin,Furrow method. In all the surface methods, Surface irrigation Uncontrolled flooding, Border strip,Check,Basin,Furrow method. of irrigation, water is either ponded on the soil or allowed to flow continuously over the soil surface for the duration of irrigation. Although surface irrigation, Surface irrigation Uncontrolled flooding, Border strip,Check,Basin,Furrow method. is the oldest and most common method of irrigation, it does not result in high levels of performance. This is mainly because of uncertain infiltration rates which are affected by year-to-year changes in the cropping pattern, cultivation practices, climatic factors, and many other factors. As a result, correct estimation of irrigation efficiency of surface irrigation is difficult. Application efficiencies for surface methods may range from about 40 to 80 per cent. (i) Surface irrigation which includes the following: (a) Uncontrolled (or wild or free) flooding method, (b) Border strip method, (c) Check method, (d)…

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Methods of Irrigation and its subsystems

METHODS OF IRRIGATION Methods of Irrigation and its subsystems Any irrigation system or Methods of Irrigation and its subsystems would consist of the following four subsystems : (i) The water supply subsystem which may include diversion from rivers or surface ponds or pumped flow of ground water. (ii) The water delivery subsystem which will include canals, branches, and hydraulic structures on these. (iii) The water use subsystems, which can be one of the four main types, namely, (a) surface irrigation, (b) subsurface irrigation, (c) sprinkler irrigation, and (d) trickle irrigation. (iv) The water removal system i.e., the drainage system. In this section, the water use subsystems have been described. Water Use Subsystems Irrigation water can be applied to croplands using one of the following irrigation methods : (i) Surface irrigation which includes the following: (a) Uncontrolled (or wild or free) flooding method, (b) Border strip method, (c) Check method, (d) Basin…

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Main crops of Rabi season are wheat, barley and gram

Crops of Rabi Season Main crops of Rabi season are wheat, barley and gram, Rabi season starts earlier in the western part and continues until the sun attains equatorial position.Rabi’ season (October to March).  Wheat In terms of production, wheat occupies the first place among the food crops in the world. In India, it is the second most important food crop, next only to rice. The Indo-Gangetic plains form the most important wheat area. The cool winters and hot summers are conducive to a good crop of wheat. Well-drained loams and clayey loams are considered good soils for the cultivation of wheat. However, good crops of wheat can be raised in sandy loams and black soils also. Wheat crop requires a well-pulverized but compact seedbed for good and uniform germination. Under irrigated conditions, the first fortnight of November is considered the optimum time for sowing the medium to long-duration wheats…

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Crops of Kharif Season are Rice,Maize,Jawar,Bajra.

Crops of Kharif Season Crops of Kharif Season are Rice,Maize,Jawar,Bajra.The crops of  Kharif season is characterized by a gradual fall in temperature, larger number of rainy days, low light intensity, a gradual shortening of the photo period, high relative humidity, and cyclonic weather.The Kharif season starts earlier in the eastern part of the country because of the earlier arrival of the monsoon and continues until the withdrawal of the monsoon. Crops of Kharif Season are Rice,Maize,Jawar,Bajra,Groundnut and cotton Rice crops of kharif season Rice cultivation in India stretches from 8°N latitude to 34°N latitude. Rice is also grown in areas below the sea level (as in the Kuttanad region of Kerala) as well as at altitudes of about 2000 m (as in parts of Jammu and Kashmir). High rainfall or assured irrigation is essential for areas of rice cultivation. Rice crop requires about 30 cm of water per month during…

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Weather for Kharif seasons and Rabi seasons

Content of this article: Learn about weather, weather for Kharif season,weather for Rabi season Weather Weather is the state of the atmosphere, describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloudy. Most weather phenomena occur in the lowest level of the atmosphere, the troposphere,just below the stratosphere. Weather refers to day-to-day temperature and precipitation activity, whereas climate is the term for the averaging of atmospheric conditions over longer periods of time. When used without qualification, "weather" is generally understood to mean the weather of Earth. Weather for kharif season Weather for kharif season : At the end of May or beginning of June, there should be some rainfall so that the fields can be ploughed. Towards the end of June, heavy rainfall is required for thorough wetting of the land. This must be followed by a period of…

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Major crops and crop seasons of India

Content of this article: Learn about crop seasons,Rabi crop,Kharif crop,Zaid crop and five agricultural regions. Activities relating to crops go on continuously throughout the year in India. In north India,there are two main crop seasons. These are ‘Kharif’ (July to October) and ‘Rabi’ (October to March). Crops grown between March and June are known as ‘Zaid crop’. In other parts of the country there are no such distinct seasons but some kind of classification of crop seasons exists every where. The Kharif season is characterised by a gradual fall in temperature, larger number of rainy days, low light intensity, a gradual shortening of the photoperiod, high relative humidity, and cyclonic weather.The Kharif season starts earlier in the eastern part of the country because of the earlier arrival of the monsoon and continues until the withdrawal of the monsoon. On the other hand, bright sunshine, near absence of cloudy days, and…

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