Irrigation is the artificial application of water to plants. It had started as long as human beings started growing the plants. Earlier, people have buckets to apply the water to plants. This method of watering the plants is still in action, but also other methods have been invented. Out of these, some methods are traditional which are used mostly at common level and some are modern irrigation method.
1. Traditional irrigation methods:
(i) Check Basin Method.
(ii) Furrow Irrigation Method.
(iii) Strip Irrigation Method.
(iv) Basin Irrigation Method.
2. Modern irrigation methods:
(i) Sprinkler Irrigation Method.
(ii) Drip Irrigation Method.
(iii) Pot Irrigation Method.
In this present situation, there is shortage of water everywhere. So, we should adopt those irrigation methods which were helpful in reducing this water shortage crisis by suitable water management.
Here, we will describe only modern irrigation methods.
SPRINKLER IRRIGATION METHOD
In present times, it is the simplest and easiest method of irrigation. In this method, water is supplied to the field from source thorough pipes. This method is used in areas where there is more scarcity of water and in high temperature regions, to maintain the humidity. It is mostly used in sandy soils and in uneven ground level regions. By this method irrigation efficiency may increase from sixty to ninety percent.
This method is installed in three ways.
• Permanent.
• Semi-permanent.
• Temporary.
In permanent installation, the pipes are installed permanently in the field. After, installation, these pipes cannot be shift from its installed place. If the pipelines are installed underground, then they may remain safe, while in case of above ground pipes there is chance of breakage. Permanent installation is suitable in canal irrigated areas, where water is available for short time.
In semi-permanent installation, main pipelines are fixed below the ground while branch pipelines are above the ground so that the whole land is irrigated by changing the place of branch pipelines. In temporary installation, the pipelines are fixed temporarily and their position can be changed according to the requirement. In this method less investment is required.
However, there are some disadvantages like that this system is expensive. The crops can be damaged by changing the pipes again and again. The water in the pipes should be clean, otherwise pipes may damage more quickly. In spite of some disadvantages, this method is adopted more and more in water scarcity condition.
DRIP IRRIGATION
A new irrigation system is developed which is known to be drip irrigation or trickle irrigation. This method was developed in Israel and after that it became popular in water scarcity areas. This method is mostly used for irrigation in fruits and vegetables. This method can also be used on uneven soils.In this method water is applied in the form of drops through nozzles which are attached to tubes to irrigate limited area around the plant. The water may be saved by up to seventy per cent as compared to flooding. Weeds may not grow because water is applied only to the crops. We can also apply fertilizers and pesticides by this method through fertilizer tank, and can saves the fertilizers from thirty to sixty percent.
There are two types of drip irrigation. Surface and sub-surface drip irrigation. Surface drip irrigation use water is less efficient than the sub-surface. Surface is a short-life span system while sub-surface is long-life span. In surface drip irrigation, mechanical harvesting is not easier while in sub-surface mechanical harvesting is easier.
There are some disadvantages of this system such as it is more expensive. This method is not suitable for all the crops, it requires technical knowledge and plants may get nutrients in a limited amount.
POT IRRIGATION METHOD
The pot irrigation method may be considered as an alternative of the drip irrigation system. It was originated in North Africa and Iran. This method is more suitable in areas of low rainfall. In saline soils where flow irrigation is not suitable, this method is used.
In this method first of all pitchers are fixed in the ground up to the neck. These pitchers are filled with water. Holes are made in these pitchers and water is applied to the nearest soil through these holes by seepage. However, many factors affect the distribution of the humidity around the pitcher. These factors may include type of soil, size of the pitcher and seepage of water from hole. Distance between the two pitchers also affects the humidity distribution. Normally, the distance between the pitchers should be kept in such a way that the humid area of pitchers may not join.
There are some advantages of this method such as by this method only area near the pitcher gets moisture. Evaporation losses are decreased. Seepage of the water below the ground remains minimal. This method is less technical. Once the pitchers are fixed in the soil then they may remain in soil for six years. This method is best for horticultural crops and vegetables.
However, there are also some disadvantages such as it is not suitable for all the crops. Water in the pitchers should be clean otherwise it may block the holes. Only a limited area comes under humidity.