Irrigation is an artificial system of applying water to the soil. This system is very useful in areas where there is very little rainfall and during dry seasons. Irrigation is also used to prevent soil consolidation, suppress the growth of weeds in grain fields, and to protect plants against frost. There are different systems of irrigation, each with its advantages and disadvantages.
Surface irrigation is an irrigation system in which gravity flow is applied to move water across the land in order to infiltrate and wet it. Surface irrigation is further classified as borderstrip, basin or furrow irrigation. Surface irrigation is the most commonly used method of irrigation and represents as much as 95 per cent of common irrigation activity today. The most obvious advantage of surface irrigation is that it is the most widely understood method of irrigation due to its popularity. Surface irrigation conserves water, as it applies water only down to the depths required to refill the root zone. It is especially handy in cases where there are water shortages. Surface irrigation is comparatively cheap to develop, and requires minimal investment on the part of the farmer. Surface irrigation is not affected by climatic and water quality characteristics. The major disadvantage of surface irrigation is that it tends to lead to waterlogging and soil salinity if there are no provisions for adequate drainage. Another disadvantage is that it tends to be labour intensive.
Sprinkler or overhead irrigation is an irrigation system in which water is distributed throughout the field by the aid of high-pressure sprinklers. The idea is to simulate rainfall during dry weather. The advantages of sprinkler irrigation systems include their more even distribution of water when different soil types are found within one irrigation scheme. Sprinkler irrigation systems are better than surface irrigation in leaching out salts from the soil, and they are not affected by uneven land distribution. The disadvantage of sprinkler systems is that they are affected by windy conditions which disturb the even distribution of water from the sprinklers.
Drip irrigation is an irrigation system in which water is delivered at the root of the plant, drop by drop. It is also known as trickle irrigation. The main advantage of drip irrigation is that it is the most water-efficient method of irrigation. The disadvantages are that it is the most expensive and least aesthetically pleasing method because of all the plastic lines which have to be installed close to each other on the ground.