Micro irrigation in Sugarcane

Dr.Kanchan Nainwal,G.B.P.U.A.&T.,Pantnagar 

The water availability for agricultural production is a limitation and therefore, judicious use of water is essential. Micro-irrigation techniques are now being used to mitigate water scarce situation in the water scarce sugarcane growing areas of the country in a big way.

What exactly micro irrigation is

Micro irrigation is the frequent application of small quantities of water on, above or

below the soil surface, by surface drip, subsurface drip, micro sprayers or micro

sprinklers. Water is applied as discrete or continuous drops, tiny streams or miniaturesprays through emitters or applicators placed along a water delivery line near the plant.

Benefits of Micro irrigation

• Low flow rate
• Long duration irrigation and frequent irrigation
• Water applied near or into the root zone of plants and low pressure delivery

systems.

 Components of micro irrigation system

Different components used in a typical micro irrigation system may be classified in

three groups:

1. Head control unit

2. Water carrier system

3. Water distribution system

• 1. Head control Unit-This unit includes pump, air release valve, vacuum gauge,

pressure gauge, filtration unit (Gravel/Hydro cyclone/Disc/Screen), fertigation

unit, throttle valve, water meter, other fittings and accessories.

• 2. Water Carrier system-This unit includes PVC pipeline for main and sub-main,control valve and flush valve.
• 3. Water Distribution System-This unit includes lateral pipe and drippers, spagetthi(for connecting emitter to lateral), barbed connecter, grommet, nipple, start connector, and end cap.

Selection of the appropriate components depends on

• crop condition (row to row and plant to plant spacing)
• environmental demand for water, water quality
• availability of labour.

Why to use micro irrigation

• Improved plant response
• Increased irrigation efficiency
• Minimized deep percolation due to more precise water control
• Enhanced uniformity of water application
• For sugarcane crop, water utilization efficiency can be improved from 50-60% in flooding method to 90-95% in micro irrigation method. Due to water saving, 40 to 60 per cent more land can be irrigated with the same amount of irrigation water.
• The consumption of fertilizers and chemicals can be reduced by up to 30 per cent, by using micro irrigation system since these are applied through water directly at the root zone of the plant in a uniform and effective way. Since water is applied directly to the base of the plant, weed germination between plants and plant rows is less to the extent of 50% Since less water is pumped for micro irrigation, energy requirements are reduced. By irrigating one hectare sugarcane crop with microirrigation, 1059 kwh energy is saved when compared to flood method. Micro irrigation can be used on steep or undulating topography and on soils that have low infiltration rates or low water holding characteristics. Saline soils and saline water can also be used for irrigation.

Maintenance

Occasional maintenance should be carried out on all micro irrigation systems. To do this, it is needed to inspect the emitters, flush the lines by opening the end cap, and clean the filter. Depending on water quality, the frequency of filter cleaning may vary.The design of the system using filtration and quality emission components will make maintenance a simple annual task. Visual inspection of the system is the best way to observe performance. Injection of 30 per cent HCl is recommended for removal of precipitated calcium salts on the inner surface of the drip system. When the source of irrigation water is river, canal, open well etc., chlorination at the rate of 1 ppm is recommended to kill bacteria, algae etc. The frequency of acid treatment and chlorination depends on the quality of irrigation water.

Pump's suction pipe is elevated above bottom of water source (Float the foot valve 45 to 60 cm below the water surface.) Water source should not contain excessive amounts of algae. If so, then treat with a non-phytotoxic algaecide like chlorine. Record water meter reading because decreased flow mean blockage and increased flow means leakage. Once the pipes filled up, check all gauges.

 Check pressure reading on gauges on either side of primary sand filters and if the difference in pressure is 0.35 kg/cm2 or greater, the filters need to be backwashed.Check pressure reading on gauges on either side of the secondary filter.