List and explain the forms of irrigation?

Sprinklers
Sprinkler systems distribute water in the air, much like rain falling from the sky. The sprinklers are connected to an underground system of pipes that distribute water at the desired times. Although sprinkler systems are efficient when properly installed, they require regular inspection and may not be as cost efficient when the sprinkler heads are not placed properly. For best results, sprinkler heads should be at a right angle to the soil surface, rather than tilted, which can cause dry spots.

Drip Systems
If you want an efficient watering system, drip irrigation may be the way to go. Drip irrigation is over 90 percent efficient, as compared to sprinkler systems, which are approximately 50 to 70 percent efficient. Drip-irrigation systems deliver the water very slowly and closer to the soil line, which minimizes runoff and water loss. Since drip-irrigation systems work so slowly, however, it can be difficult to tell if they're actually working. Consider using an indicator device to make sure your irrigation system delivers an adequate amount of water to plants.

Surface Systems
Some irrigation systems apply water at the ground level and allow it to flow over the soil surface. Examples of surface methods include flood irrigation and furrows. It can be difficult to distribute water evenly over the soil surface, and soils that have a high sand and rock content are not well suited for this method. Surface systems have an efficiency rate of 45 to 60 percent, although well-planned surface methods may perform at a 70 to 85 percent efficiency rate, according to the Washington State University Extension.

Subirrigation
Subirrigation systems, also known as zero-runoff systems, water the root zone from below and are commonly used in container planting. Instead of seeping into the soil and down into the root zone, the water is absorbed upwards from beneath the plant root zone. Subirrigation is commonly used in greenhouses due to its efficiency. Fertilizers can also be applied to the root zone via subirrigation. Several types of subirrigation methods are available, including capillary-mat, trough, flood-floor and ebb-and-flow systems.