Irrigation
Definition: irrigation is artificial application of water to soil for the purpose to access the crop production. It is supplied supplementary to water available from rainfall & ground water.
Types of irrigation – (classification)
1. Flood
2. Surface
3. Sub surface
4. Sprinkle
5. Drip irrigation.
Surface irrigation:
Water is applied directly to the soil from channel located at upper ridge of the field proper land preparation adequate control of water is necessary for uniform distribution of water border. The entire field is divided into strips separated by low ridge of the strip to lower in form of sheet guided by the low ridges. Border should have uniform gentle slope in direction of irrigation. Each strip is independently by turning stream of water at upper ridge. Suitability-suitable for close growing crops some row crop & orchards under favorable soil & topographic condition. Not recommended for extremely low or extremely high infiltration rate soils.
Advantage:
Easy construct & operate
Person can irrigation more compares to check basin.
If properly designed use uniform distribution & high water use efficiency.
Large streams can be effectively used.
If can provide excellent drainage (surface) if have proper outlet facility at the lower end.
Disadvantages:
Required precise land leveling
Required large irrigation streams.
Check basin:
It is used in extreme condition of soil. It is well known method generally used for heavy soils with low infiltration rate or high permeable soil like deep sand. Used for orchards grain & folder production.
Disadvantages:
Labor requirement for land preparation is high.
Operation cost is more.
The ridges cause hindrances to implements by field operations.
Furrow method:
Furrow is preferably used for row crops like maize, sugarcane, potato, groundnut & other vegetable crops. Water is applied in small furrows betureoil the row crops. Water infiltrated into soil & spread within the root zone. Large as well as small sized stream can be effectively used for irrigation. It also acids for safe disposal of excess water i.e. facilitates drainage. Only 1/5 to ½ of land surface is in contact with water (wet). There by reducing the evaporation losses. Method is specially situated to crops like maize which are sensitive to water in contact with their strength. The cost of land preparation is reduced & there is no wastage of land under field channels. In clay or deep clay soils shadow furrow are made along with guiding ridge to take care of soil cracking behavior such furrow are called corrugated furrow.
Subsurface irrigation:
Water is applied below the ground surface by maintaining artificial water table at some depth depends upon the soil characteristic & root zone of crop. Water moves through capillaries within soil to meet plant requirement deep trenches & underground piper are the two ways for sub-surface irrigation.
Adaptability: Soils having low W.H.C. soil having very high-high infiltration rate. Soils surface method is not possible where sprinkle method of irrigation proves to be expensive.
Advantage:
1) Evaporative losses are minimum.
Disadvantage:
1) Salty water can not be used.