MICRO IRRIGATION

• Micro irrigation is a modern method of irrigation; by this method water is irrigated through drippers, sprinklers, foggers and by other emitters on surface or subsurface of the land. Major components of a micro irrigation system is as follows.

Water source, pumping devices (motor and pump), ball valves, fertigation equipments, filters, control valves, PVC joining accessories (Main and sub main) and emitters.

• In this system water is applied drop by drop nearer the root zone area of the crop.
  The drippers are fixed based on the spacing of crop.  Many different types of emitters are available in the market. They are classified as Inline drippers, on line drippers, Micro tubes, Pressed compensated drippers.
• Drip irrigation is most suitable for wider spacing crops. Micro sprinkler irrigation system is mostly followed in sandy or loamy soils.  This system is most suitable to horticultural crops and small grasses. In this method water is sprinkled in a lower height at various directions.
• Portable micro sprinklers are also available. They distribute slightly more water than drippers and micro sprinklers. They spray water in not more than one meter. It is used for preparing nursery and lawns in soils with low water holding capacity. 

Advantages of drip irrigation system

• Water saving and higher yield
• High quality and increased fruit size
• Suitable for all types of soil
• Easy method of fertigation and chemigation
• Saving in labour and field preparation cost

Disadvantage of drip irrigation system

• High initial investment
• Clogging of emitters
• Possible damage of system components due to animals, etc.,

Investment cost mostly differs based on spacing of the crops

• Generally, the reasons for clogging are solid particles (sand, rust), soft dirt (organic matter, algae, micro organism, salt), sediments (salt in the fertilizers).
• Filtration is the main key factor to the success or failure of the system. The main of filtration is to stop dirt particles which damage any components of the system.
• To remove salt encrustation, 30 per cent commercial hydrochloric acid can been used at the rate of one liter per one m3 area. (One part HCl mixed with 5 parts of water) 
• To remove algae and fungal clogging 5 to 500 ppm sodium hydrochloride (10 per cent chlorine) can be used.

Maintenance of drip system

• Back washing and sand filters has to be cleaned
• Frequent cleaning of emitters and drippers
• Flushing at every irrigation
• Cleaning of sub main and main pipes
• Cleaning of PVC pipes and laterals and acid or chlorine may be used to remove clogging.

Water used and yield of crops in micro and conventional irrigation methods 

Crop	Methods of irrigation	Water requirement (cm)	% water saving	Yield kg ha-1	% increase in yield	Water use efficiency (kg ha mm-1)
Banana	Drip	97.00	45.00	87500	52.00	90.20
	Surface	176.00	-	57500	-	32.67
Sugarcane	Drip	94.00	56.00	170000	33.00	180.85
	Furrow	215.00	-	128000	-	59.53
Grapes	Drip	27.80	48.00	32500	23.00	116.90
	Surface	53.20	-	26400	-	49.62
Cotton	Drip	28.00	66.27	3250	25.00	116.10
	Furrow	83.00	-	2600	-	31.33
Beetroot	Drip	17.70	79.34	887	55.34	50.11
	Surface	85.70	-	571	-	6.66
Radish	Drip	10.80	75.72	1186	13.49	109.80
	Surface	46.40	-	1045	-	22.52
Papaya	Drip	73.88	67.89	23490	69.47	0.32
	Surface	225.80	-	13860	-	0.06
Mulberry	Drip	20.00	60.00	71400	3.03	3570
	Surface	50.00	-	69300	-	1386
Tomato	Drip	18.40	39.00	48000	50.00	260.86
	Surface	30.00	-	32000	-	106.66

(WTC Annual Reports 1985-2003)

Affordable micro irrigation systems
            Affordable micro irrigation system is mostly suitable to kitchen garden, nursery and ornamental crops.

1.  Bucket kit system
            Bucket kit system is defined for kitchen garden suitable for women, marginal and small farmers. It consists of a bucket (15 lit.) 10 metre long lateral (12mm) fitted with drippers  (4 LPH), which can irrigate about 100 plants in approximately 15 m2 area.  The bucket is placed at a height of 1m (3 feet) and water is filled for 4 to 5 times daily.

2.  Drum kit system
            This system is ideally suitable to kitchen garden and small commercial vegetable growers. The drum is having 200 liter capacity which would supply water approximately 500 plants by filling the drum twice daily. It consists of lateral (16mm and 12mm). One number of 16mm lateral and five 12mm laterals are used. This system could cover an area of 120 m2 (3 cents).

3.  Micro sprinkler system
            Micro sprinkler kit is suitable for farmers with access to pressurised water. It is very useful for groundnut, vegetables, nurseries home gardens, and lawns etc. It can be connected with a tap from an overhead tank or a domestic water pump. It consists of 15 micro sprinklers with pipes irrigating an area of 250 m2 (6 cents). Fertigation can also be done through this method.

Sl.No.	Item	Selling Cost/Unit	Area covered by the kits
1.	Bucket Kit (Drip system)	Rs.225	20 m2 (0.5 cent)
2.	Drum Kit  (Drip system)	Rs.600 (Excluding Drum Cost)	120 m2 (3.0 cents)
3.	Micro sprinkler kit	Rs.900	240 m2 (6.0 cents)