Water Management in Horticultural Crops

Introduction

• Drip irrigation is sometimes called trickle irrigation and involves dripping water onto the soil at very low rates (2-20 litres/hour) from a system of small diameter plastic pipes fitted with outlets called emitters or drippers. Water is applied close to plants so that only part of the soil in which the roots grow is wetted, unlike surface and sprinkler irrigation, which involves wetting the whole soil profile. With drip irrigation water, applications are more frequent (usually every 1-3 days) than with other methods and this provided a very favorable high moisture level in the soil in which plants can flourish.
• A typical drip irrigation system consists of the following components:
• Pump unit
• Control head
• Main and sub mainlines
• Laterals
• Emitters or drippers
• The pump unit takes water from the source and provide the right pressure for delivery into the pipe system.
• The control head consists of valves to control the discharge and pressure in the entire system. It may also have filters to clear the water. Common types of filter include screen filters and graded sand filters which remove fine material suspended in the water. Some control head units contain a fertilizer or nutrient tank. These slowly add a measured dose of fertilizer into the water during irrigation. This is one of the major advantages of drip irrigation over other methods.