Drip irrigation............


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Drip irrigation............

  1. 1. Contents Introduction Advantages Disadvantages Comparison with other irrigation system Components of drip irrigation system Design of drip irrigation system Design procedure Example of designing Benefits for farmer
  2. 2. Introduction Irrigation is an artificial application of water to the soil through various systems of tubes, pumps, and sprays.  Irrigation is normally used in areas where rainfall is inconsistent or dry conditions or drought is expected.
  3. 3. Drip Irrigation  Drip irrigation is a micro irrigation method in which the rate of water application is very low and without any pressure. i.e., drop by drop  Drip irrigation is based on the basic concept of irrigation only the roots zone of crop , rather than the entire land surface on which the crop is grow.
  4. 4.  Water flows from the emission points through the soil by capillarity and gravity.  The soil moisture content of the crop root zone is maintain at near optimum level to facilate optimum crop growth and production.
  6. 6. Drip irrigation is useful for crop…..  Fruit crops :  Banana, Grapes, Citrus, Pomegranate, Papaya, Pineapple, Watermelon, Sweet lime, Mango, Kinnow, Mosambi.  Vegetable crops :  Cabbage, Cauliflower, Okra, Tomato, Potato, Onion, Chillis, Radish, Brinjal, Bottle grown, French been, Capsicum, Bhindi, Beans, Baby corn, Carrots, Cucumber, Bitter gourd, Bottle gourd, Ashgourd, Gherkins.  Commercial crops :  Sugarcane, Cotton, Ground nut, Chickpea.
  7. 7. Advantages of Drip Irrigation         Less requirement of irrigation water Water supply at optimum level. Water logging is avoided High yield Over irrigation is avoided Variation in application rate Reduced labour cost Weed control
  8. 8.  Increase in net irrigable area  Highly uniform distribution of water i.e., Controlled     by output of each nozzle No soil erosion Suitable for any topography Maintenance of high surface temperature Improved disease and pest control Tolerance to windy atmospheric condition
  9. 9. Disadvantages of drip irrigation  High cost :  drip irrigation systems are expensive because of there requirements of large quantity of piping & filtration equipment to clean the water.  Expense:  Initial cost can be more than overhead systems.  Waste:  The sun can affect the tubes used for drip irrigation, shortening their usable life. Longevity is variable.  Clogging:  If the water is not properly filtered and the equipment not properly maintained, it can result in clogging.  Drip tape causes extra cleanup costs after harvest. You'll need to plan for drip tape winding, disposal, recycling or reuse.  This method is not suitable for closely planted crops such as wheat
  10. 10. COMPARISON Drip method Flood method Water saving High, between 40 and 100 % Less. High rates of evaporation, surface run off and percolation Irrigation efficiency 80 – 90 % 30 - 50 % Weed problem Diseases and pests Efficiency of fertilizer use High Even saline water can be Only normal water can be used Suitable water Almost nil used Relatively less High Very high since supply is regulated Heavy losses due to leaching
  11. 11. Drip method Water logging Water control Flood method Nil High Can be regulated easily Cost benefit ratio (additional Excluding water savings: 1.3 - amount in rupees for every 13.3, Including water savings: rupee invested) Not much control 2.8 - 30.0 Capital cost/ha Yield increase Rs 15,000 to 40, 000 20 - 100 % higher than flood method Between 1.8 and 3.9 depending –– on crop spacing Less compared to drip
  12. 12. Crops: Drip versus Flood irrigation
  13. 13. Components of Drip Irrigation system  Pumping set  Filters  Mainlines  Sub-main  Laterals  Drippers/emitters
  14. 14.  Pumping set: To create a pressure about 2.5 Kg/sq cm to regulate the amount of water to be supplied. • Filter : To filter the water in Order to remove the suspended impurities from water.
  15. 15.  Main lines:  It is a Distribution system in drip irrigation. Rigid PVC and high density polyethylene pipes are used as main pipes to minimized corrosion and clogging.  Pipes of 65 mm diameter and with pressure rating of 4 to 10 kg/sq. cm  Sub Main:  It is usually connected to the main lines through a control valve assembly.  The function of its to distributes water uniformly to a number laterals.
  16. 16.  Drippers/emitters:  It is fitted to a drip irrigation lateral and intended to emit water in the form of drops or continuous flow at emitter rates not exceeding 15 liters/hr.  Drippers function as energy dissipated, reducing the inlet pressure head in the lateral, which generally range from 0.3 to 1.5 atmosphere .
  17. 17. Design of Drip irrigation system  Data collection  Types of soil  Infiltration characteristics of soil  Types of crop  Consumptive use of water by crops  Water quality  Climate condition  Availability of funds  Contour map
  18. 18. Design procedures  Prepare on inventory of available resources & operating conditions  Determine the water requirement to be met by the drip system  Determine the appropriate type of system  Determine the type and design of emitters  Determine the capacity of pumping system  Decide on the economic sizes of the pumping system  Determine the maximum and minimum operating pressure and the minimum efficiency required  Determine the appropriate filtering system  Determine the requirement of the fertilization system  Plan field evaluation  Prepare drawings, specification, cost ,schedules, installation, operations ,maintenance.
  19. 19. Emitter Selection  The efficiency Of Drip irrigation system depends mainly on the selection of the type of emitter and its design.  Characteristic of emitter that influence the efficiency of irrigation system is Discharge rate  Critical items in emitter selection are the % area wetted(Pw) and the emitter reliability.  The density of emission points required to obtain Pw ≥ 33% .
  20. 20.  Manufacturing Variation in Emitter: Cv = S/Q = (q₁²+q₂²….+ qn ²-n(q) ²)⅟2 / q(n-1) ⅟ 2 In Which, Cv = emitter coefficient of manufacturing variation, q₁, q₂… qn = individual emitter discharge rate values, N = Number of emitter in sample, Q = Average discharge rate of the emitters sampled, S = Standard deviation of the discharge rates of the sample.
  21. 21.  Recommended rangers of Cv (emitter coefficient of manufacturing variation) <0.05 Excellent 0.05 to 0.07 Average 0.07 to 0.11 Marginal 0.11 to 0.15 Poor > 0.15 unacceptable
  22. 22. Discharge of Drippers q= khx In which, q = Discharge of the dripper, volume/time P= operating pressure, force/area X= constants for specified emitters
  23. 23. Irrigation water requirement Vm = Kc x Kp x Cc x Ep x A In which Vm = Monthly Irrigation water requirement, Kc = Crop co efficient Cc = Canopy factor Kp= Pan evaporation factor (0.8) Ep = Normal monthly evaporation A = Area to be irrigated, m2
  24. 24. Capacity of drip irrigation system Q = Vd x T (na x t) In which Q = Capacity of drip system, Vd = Daily water requirement, T = Irrigation interval days na = Water application efficiency t = Duration Qp = Q/n Qp = Discharge per plant n = Number of plant
  25. 25.  Numbers of Laterals required:  For vegetable crops – 1 lateral for each slop.  For orchards – 1 to 2 /each row  Number of drippers per plant: (% total area shaded by the tree x area per tree) / (effective area wetted by a single emitter).
  26. 26.  Area irrigated by a dripper :  Ai = (L x S x P) / (100 x Ne ) Ai = Area irrigated, m2 L = Spacing between adjacent plant rows, m S = Spacing between emission points, m P = % of cropped area to be irrigated Ne = Numbers of drippers at each emission point
  27. 27. Benefits to Farmers :  More than 70% of Indian farmers are small scale operators cultivating plots less than one hectare. Irratic rainfall pattern play havoc into the livelihoods of the small farmers who do not have any alternate supply of water.
  28. 28. CONCLUSION • Drip irrigation system is an economical and very efficient system of irrigating for vegetables, row crops etc. • Drip irrigated crops use less water compared to overhead irrigated crops. • Drip irrigation increase yields
  29. 29. Thank you