Drip irrigation and fogging system under protected structure

Discuss drip irrigation and a fogging system. The importance of these systems on the protected structure and how it could help farmers.

1. DRIP IRRIGATION AND FOGGING SYSTEM UNDER PROTECTED STRUCTURE COLLEGE OF AGRICULTURE, OUAT, BHUBANESWAR

2. INTRODUCTION Also known as trickle irrigation or micro irrigation To apply sufficient moisture to the root of the crops- prevent water stress . A major difference between drip system and most other systems is that the balance between crop evapotranspiration and applied water Drip irrigation system delivers water to the crop using a network of mainlines, sub-mains and lateral lines with emission points spaced along their lengths .

3. WHAT IS DRIP IRRIGATION? In this system, water is delivered directly to the soil near the roots of the plant through a special outlet device called an emitter or dripper Water is supply drip by drip at very slow rate 2-10 ltr /hr. The water applied near the root zone spread laterally as well as vertically due to Capillary action in the soil

4. Why consider drip irrigation? Drip irrigation can help you use water efficiently. Agricultural chemicals can be applied more efficiently through drip irrigation. No water to runoff or evaporation. It reduces water contact with crop leaves, stems, and fruits.

5. Drip delivers water directly to plants Ideal for fine tuning water and fertilizer applications Laterals Submain

6. Fig.- Drip under plastic mulch in strawberry

7. advantages of drip irrigation Maximum use of available water. No water being available to weeds. Maximum crop yield High efficiency in the use of fertilizers. Low labour and relatively low operation cost. No soil erosion. No runoff of fertilizers into ground water. Less evaporation losses of water as compared to surface irrigation. Improves seed germination.

8. disadvantages to drip irrigation Initial investment costs per acre may be higher than those of other irrigation options. Management requirements are somewhat higher. Delaying critical operation decisions may cause irreversible crop damage. Frost protection is not possible with drip systems; if it is needed, sprinkler systems are necessary. Rodent, insect, and human damage to drip lines are potential sources of leaks. Water filtration is necessary to prevent clogging of the small emitter holes. Compared to sprinkler irrigation, water distribution in the soil is restricted.

9. ARRANGEMENT FOR DRIP SYSTEM

10. Drip irrigation system components Pumping set Filters Mainlines Sub-main Laterals Drippers/emitters

11. 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.

12. 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 SubMain : 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.

13. Types of Irrigation Filters

14. 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 .

15. System management and maintenance Flow of water Watch for leaks Chlorine clears clogged emitters Chemigation Fertilizer Placement of tape Timing and rates Standard maintenance

16. 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

17. 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

18. Typical ingredients of a drip system

19. TECHNICAL ASPECTS Design Parameters Area to be irrigated, type of plants, their spacing and numbers per hectare. Peak water requirement of a plant per day. For estimation of total water requirement for a given area, the number of emitters required per plant, amount of water discharged per hour through each emitter and the total number of hours water is available should be known/estimated. Design of Main and Lateral Drip Lines. This depends upon friction head loss which in turn is governed by the type of plantation/crop and field configuration. Water required to be pumped from the well. This depends upon hydrogeological conditions in the area and water requirement of plants/crop. Horse Power of Pump set depends upon discharge and total head including friction losses over which water is to be lifted/pumped. Unit cost.

20. Command Area - A command area map giving systems layout is necessary to plan and design a drip irrigation system. It may not be necessary to have a detailed contour plan but it is helpful if a plan showing the highest and lowest points along with well location is given in the scheme. This enables proper design of main line and laterals to suit the spacing and number of plants. The recommended spacing and population of some of the important plants/crops are given in the Table 1.

21. Table 1 : Spacing and Plant Population of Important Plants/Crops

22. Water Requirement of crops/plants - Water requirement of crops (WR) is a function of surface area covered by plants, evaporation rate and infiltration capacity of soil. At first, the irrigation water requirement has to be calculated for each plant and thereafter for the whole plot based on plant population for the different seasons. The maximum discharge required during any one of the three seasons is adopted for design purposes. The daily water requirement for fully grown plants can be calculated as under.

23. WR = A X B X C X D X E.................Equation (1) Where: WR = Water requirement ( lpd /plant) A = Open Pan evaporation (mm/day) B = Pan factor (0.7) C = Spacing of crops/plant (m 2 ) D = Crop factor (factor depends on plant growth for fully grown plants = 1) E = Wetted Area (0.3 for widely spaced crops and 0.7 for closely. spaced crops) The total water requirement of the farm plot would be WR x No. of Plants The daily water requirement pf various crops per plant for different pan evaporation readings are given in Table 2.

24. Table 2: Water requirement of Crops/Plants on the Basis of Pan Evaporation Data Crops Spacing (m) Pan Evaporation ( mm/day )       2 4 6 8 10 Tomato/Brinjal/Chillies 1.3 x 1.3 0.5 3.3 5.0 6.6 8.3 Grapes 3.0 x 3.0 3.7   7.6   11.3   15.1 . 18 Mango/Sapota 10.0 x 10.0   42   84.0   126.0   168.0   210.0 Oranges   5.0 x 5.0   10.5   21.0   31.5   42.0   52.5 Coconut   6.0 x 6.0   15.1   30.2   45.4   60.5   75.6 Banana   7.5 x 7.5   24.2   48.5   72.8   97.0   121.3 The water requirement for different seasons can be calculated using Equation 1 given in previous slide. The maximum discharge required during any one of the three seasons is adopted for design purposes.

25. Design and Performance of emitter - The design, number of emitters required for plant and their discharge are important factors in designing a drip irrigation system. Various emitters are designed for controlled release of water to the plants. It is necessary for manufactures of drip system to state optimum operating pressure and discharge and the emitter is so selected that application rate equals to the absorption rate of soil so that no water stagnation takes place on the surface of the soil. In some systems a short length of flexible plastic tubing of small diameter is used as emitter. This tubing is generally of 0.96mm diameter and is inserted through holes in walls of the laterals. This is commonly known as micro tube system.

26. Performance of Emitter - Water from emitters fall on ground and is absorbed by soil. The wetted area depends upon the soil type and rate at which water comes out of emitters. The infiltration rate for various types of soil and the surface area wetted due to drippers at various flow rates. In orchards having widely spaced plants, two or more line of laterals may be required for each row. Sometimes a loop with 3 to 4 emitters is placed around each plant to provide the required wetted area. This should be away from the plant stem.

27. No. of emitters – The number of emitters is based on the volume of wetting for each plant. Generally, 30-70 percent of the area is wetted dependent upon plant spacing, nature & development of root zone. The number of emitters required per plant is estimated as the ratio of rate of irrigation requirement to the emitter discharge. If single emitter is provided, it must be placed 15-30 cm. from the base of the plant.

28. 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 Almost nil High Suitable water Even saline water can be used Only normal water can be used Diseases and pests Relatively less High Efficiency of fertilizer use Very high since supply is regulated Heavy losses due to leaching Water logging Nil High Water control Can be regulated easily Not much control Yield increase 20 - 100 % higher than flood m ethod Less compared to drip

29. Benefits to Farmers More than 70% of Indian farmers are small scale operators cultivating plots less than one hectare. Erratic rainfall pattern play havoc into the livelihoods of the small farmers who do not have any alternate supply of water.

30. 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

31. FOGGING SYSTEM UNDER PROTECTED STRUCTURE

32. FOGGING SYSTEM The fog system is based on spraying the water as small drops (in the fog range, 2-60 µm in diameter) in order to increase the water surface in contact with the air. The free-fall velocity of the droplets is slow and the drops are easily carried by the air streams inside the greenhouse. This result in a high efficiency of water evaporation combined with keeping the foliage dry (ASHRAE, 1972 and Frenkel , 1986).

33. Fogging systems are a system used in dozens of areas; it serves different purposes such as humidification, dust suppression, disinfection, deodorization, etc., especially in cooling by lowering the temperature of the environment. Nowadays, greenhouse cultivation is a closed cultivation process in a certain humidity and temperature level . Greenhouse humidification , which helps achieve target production by increasing efficiency, increases efficiency by reducing water consumption while increasing greening by cooling effect.

34. DIFFERENT METHODS FOE GENERATING FOG DROPLETS Twin-fluid nozzles provide a combination of air and water under appropriate pressure and flow rates, enabling droplets of the desired size to be generated. The main drawback of this system is that the compressor requires high electrical power (an order of magnitude greater than that needed for a high-pressure pump), greatly increasing the costs of the system and its operation (Montero et al., 1990).

35. With the spinning cage , water is supplied to the centre of a spinning disk and centrifugal force drives it to the periphery, from where it is flung off in the form of droplets. This system is expensive, since each disk is operated separately, and clogging occurs as a result of poor water quality ( Lemeshkina , 1984). Systems based on high-pressure nozzles are characterized by low cost in comparison with those described above. Using such nozzles requires pretreatment of the water in order to prevent clogging, since the diameter of the orifice of each nozzle is 0.1-0.3 mm. In addition, incorrect operation of the system can promote conditions leading to salt accumulation on the foliage, wetting of the foliage, and subsequently to disease outbreaks and leaf scalding (Willits, 1993; Press, 1984; Giacomelli and Krass , 1985).

36. Fig.- Fogging System

37. Fig.- Greenhouse Humidification Fogging System

38. BENEFITS FROM FOGGING SYSTEM Provide more uniform humidification and cooling Improve energy efficiency Decrease water consumption and need for chemicals Improve indoor and outdoor air quality and comfort Help minimize brittleness and static electricity Increase germination and propagation Diminish the risk of respiratory infections Control unwanted odors Enhance surroundings Minimize damage to equipment and materials in a fire

39. DISADVANTAGE OF FOGGING SYSTEM The cost of installing an air compressor of adequate size, and the cost of running compressed air lines in addition to water lines, is generally considered excessive Providing uniform distribution of the water droplets throughout the space so that uniform cooling is achieved. Generally, the fogging nozzles are spaced along the water lines 4 feet or less apart. The water lines are then run the full length of the house with 2 or more runs per house section. When high pressure systems are used, each line is sometimes controlled separately to provide a discrete difference in the misting rate. Another disadvantage with fogging type systems is that any minerals carried in the water are related when evaporation occurs. These minerals settle out on the plant surfaces, causing a white discoloration of the plant foliage .

40. REFERENCE ASHRAE. Handbook of Fundamentals, Chapter 10. pp. 177-186. New York: ASHRAE, 1972. Giacomelli G A; Krass A E Greenhouse fog evaporative cooling using a movable boom. American Society of Agricultural Engineers, 1985, 85, 4530-4545. Press T F Propagation: fog not mist. Combined Proceedings, International Plant Propagators’ Society, 1984, 33, 100-109. Montero J I; Anton A; Beil C; Franquet A Cooling of greenhouses with compressed air fogging nozzles. Acta Horticulturae , 1990, 281, 199-209. Willits D H Greenhouse cooling. North Carolina Flower Growers’ Bulletin, 1993, 38(2), 15-18. Lemeshkina E M Reducing excessive air temperature in greenhouses. Mekhanizatsiya i Elektrifikatsiya Sel’skogo Khozyaistva , 1984, 9, 60-61 (in Russian) Frenkel H Pesticide application, technique and efficiency. In: Advisory Work in Crop Pest and Disease Management. ( Palti J; Ausher R eds ), pp. 132-160. New York: Springer, 1986. Website - OSU Extension Service Catalog (http://extension.oregonstate.edu/catalog/) Website - Maintenance of microirrigation systems (http://ucanr.org/sites/Microirrigation) Website - http://vikaspedia.in/agriculture/agri-inputs/farm-machinary/drip-irrigation-system Website - http://www.cropinfo.net/water/dripIrrigation.php