Benefits of Irrigation in Agriculture
Without agriculture, man can’t live and without irrigation man can’t have agriculture.
Food is essential for human beings as well for animals for their sustenance. Before irrigation, man satisfied his hunger by eating fruits from the forest and drinking water from natural streams. Slowly his demands grew and he felt the need of different types of food. He started cultivating and grew crops. Agriculture was his sole occupation. He depended mainly on rainwater to water the crops, but nature did not favor him always. Occasionally droughts were severe and there was a consequent lack of harvest. There was a need for irrigation and he started to use water from ponds, streams and rivers for agriculture.
Irrigation is defined as the supplementation of precipitation by storage and transportation of water to the fields for the proper growth of agricultural crops. Archaeological studies have revealed that irrigation benefits in agriculture was in vogue even during prehistoric times as sufficient water was not available from the rain.
The Sumerians of Mesopotamia were the first to use irrigation for agriculture. They utilized the waters drawn from the Tigris and Euphrates rivers. In Persia, presently Iran, the Kareze irrigation system was developed about 3000 years ago. Crop rotation was also practiced at that time in which crops were yearly alternated on the same field. The purpose was to restore nutrients that had been used and depleted. In North America, Spanish and Americans built canals along the Rio Grande. With the development of agriculture, irrigation became more pronounced in the Indus Valley, presently India and Pakistan. Egyptians utilized water from the Nile River for irrigation.
Today 689 million acres of agricultural land are equipped with irrigation facilities across the whole world. Out of this, 68% of irrigated land is in Asia, 17% in North America, 9% in Europe, 5% in Africa and 1% in Oceania.
Types of Irrigation
There are different types of irrigation, which one used depends on the source and method of the distribution of water.
Water flows under gravity and is spread over the area. The water then infiltrates to the subsoil. Quite often, land gets flooded, however. This is called, flood irrigation. Dikes are constructed to control the water level.
Water is distributed through a network of pipes under low pressure. Drip irrigation, bubble irrigation, and spray irrigation all come under this category.
Water is spread drop by drop onto the root of the plants. The advantage of this method of irrigation is that losses due to runoff and evaporation are reduced to a considerable extent.
Water is distributed through high pressure sprinklers. These sprinklers are located in one or more central locations. The sprinklers can also be mounted onto moving platforms.
This is labor intensive. In this, buckets and water cans are used to carry and distribute water.
Augmentation of irrigation and the concomitant expansion of an irrigated area will bring many direct and indirect benefits, such as:
*Irrigation helps to increase agricultural production. The yield for irrigated crops are expected to be two to three times higher.
*It helps to utilize land for agriculture.
*Diversification of crops like corn, beans, peas and so on can be harvested.
*High valued cash crops like tobacco, or sugar cane are grown as annual crops with the help of ground water irrigation.
*From the irrigated fields, the yields are stable and reliable. Assured production targets can be met.
*Reduces fluctuations in the year-to-year yields and the risk of crop failure due to drought.
*Allows for continuous cultivation.
*As pumps and other ancillary equipment are required, there is an increased demand for irrigation equipment.
Irrigation is required to supply water for the proper growth of crops. Water is supplied at regular intervals depending on the type of crop, nature of soil and the amount of precipitation. Water from a reservoir is transported through canals and distributaries.
1.Textbook of Irrigation Engineering by Dahigaonkar J P , 2008, Asian Books (P) Ltd, India
2. Elementary Irrigation Engineering by Asawa G L, 1999, New Age International (P) Ltd, India
3. Irrigation Technology- Theory and Practice by Rao Y P , 2008, Agroteck Books, India