Water Saving Technique

Introduction

Water is a vital natural resource available on earth. The utilizable water resources in India are not enough to irrigate the cultivable area, hence efforts are needed to maximize the use of water. Different water saving techniques like use of advanced irrigation methods like sprinkler, drip , microirrigation, watershed management approach, water harvesting and recycling etc. are to be used to conserve water and thereby increase water use efficiency.

Advanced Irrigation Method

• Sprinkler irrigation

Water is applied as a spray or rain drops over the corp. In this method saving of water ranges from 25 to 50% for different crops. As the application rate is less than intake rate of soil, surface runoff does not occur. Soil moisture is maintained at optimum level.

• Low Energy Precision Application (LEPA) system

LEPA system is a modification of sprinkler system in which water is applied directly to the furrow at very low pressure through drop tubes and orifice controlled emitters. Water is not sprayed with pressure as in sprinkler system. The system is used in conjunction with furrow designed to retain all applied water.

Micro Irrigation Technique

Micro irrigation is the latest and most efficient method of water utilization for crop growth. It has high water use efficiency. This advance method of irrigation has an efficiency up to 70 to 75%. Water is applied to the crop area near the root zone on a daily basis and as there is no water/moisture stress, the crop growth is not affected at all.

• Microjet irrigation

This gives throw distance of 1 to 4 m with a correspondingly larger wetted area of ground. The water discharge of the jets is 5 to 160 litres per hour.

• Microsprinkler irrigation

The discharge in micorsprinklers currently available varies from 28 to 223 litres/hour, operating pressure 0.8 to 4.0 bar and throw distance 0.9 to 4 metres.

• Bubbler Irrigation

Bubbler irrigation, a relatively new system, is designed to reduce energy requirements through inexpensive, thin walled, corrugated plastic pipe with a diameter that even the low pressure head from a surface ditch might suffice. The disadvantages in drip irrigation i.e. high energy consumption to pump water with pressure for distribution, clogging of drip emitters and damages to delicate screen filters, are all avoided.

Features

• Water is applied at low rate,
• Water is applied over a long period of time,
• Water is applied at frequent intervals,
• Water is applied directly into the plant root zone, and
• Water is applied via a low-pressure delivery system.

Use of Irrigation Water Control Devices

• Canvas dam

The canvas dam is a portable devices, which is used to regulate the water level in an open irrigation channel. Regulation of water level can serve to divert the water into ditches or to raise the water level so that water can be taken from the ditch. The canvas dam consists of a waterproof canvas tied to bamboo pole with a role.

• Spiles

Spiles are outlets in the side of channel to deliver water to individual furrows or corrugations. Spiles are short hollow tubes made of either bamboo, baked clay or steel. The rate of discharge depends on the diameter of spiles, which ranges from 50 to 75 mm.

• Siphon tubes

Siphon tubes are curved pipes, which are used to take water from supply channel into the field. Siphon tubes are made of rubber, plastic or PVC. The normal length of Siphon tubes in 2 m and diameter ranges from 12 to 50 mm.

• Gated pipe

Gated pipe is a portable pipe with a number of small gates or outlets along one side through which water can be run into furrows, corrugations or border strips. The rate of flow can be controlled by adjusting the opening of the outlet.

Use Of Water Conservation Methods

• Management practices

Strip cropping,

Mulching,

Crop rotation,

Contour cultivation,

Planting of grasses for stabilizing bunds,

Planting of trees and afforestation,

Cashewnut plantation, and

• Mechanical practices

Bunding,

Terracing,

Gully or nala control,

Control of stream and rive banks.

• In situ soil conservation measures

In order to increase the entry of rainwater into root profiles, several approaches have been made they include Off-season tillage, and Land treatment with different configurations.

Run-off Recycling

The measures available now are structures for water recycling (i. Farm ponds, ii. Embankment type reservoirs and iii. Conservation ditching) and structures for recharging ground water (Percolation tanks).

Watershed Management Programme

This programme along with agro-horticultural and silvipastoral systems helps improve the water use efficiency and managed the arable crop lands.