Water is an essential element for survival. About seventy per cent of the human body consists of water while plants contain almost 90 per cent of water. Still, we have to depend on some outside sources to fulfil the water requirements of our body.Similarly, crops require water for their growth and development. The process of supplying water to the crops is known as irrigation.
Soil irrigation is the process by which we can use water that is supplied to any land according to their need for various purposes. It is the controlled application of water for agricultural purposes through man-made systems to supply water requirements not satisfied by rainfall. Crop irrigation is vital throughout the world in order to provide the world’s ever-growing populations with enough food.There are a lot of methods for irrigation but the main point of this is to give water to the plant effectively and efficiently.
The different types of irrigation systems for agriculture each come with advantages and disadvantages, and some are more appropriate for certain crops than others.There are 4 different types of irrigation systems for agriculture are follows.
Surface irrigation is arguably the easiest and the most commonly used type of irrigation. It uses gravity to draw water from a higher area of land to the fields. The slopes need to be steep enough to allow the water to flow, but not too steep as to flood the field. The main advantage of this type of irrigation is that it requires no advanced technology to work.Currently, surface irrigation is the most commonly used type of irrigation system for agriculture, accounting for 85% of the world’s irrigated land.
The primary advantage of surface irrigation is that it requires the lowest capital investment and little or no technical know-how. It is also the most energy-efficient method on sloping fields because there is no need for electrical pumps or factory-made pieces and parts. Where the soil drains freely, surface irrigation techniques may allow for some of the water to filter back down into underground aquifers. In this case, the soil structure, roots, and rocks underground work to filter the water naturally.
Surface irrigation is the most water-intensive type of irrigation system for agriculture, as only a small percentage of the water reaches the roots while the rest flows past through the system of furrows. The temporary saturation of the soil reduces the soil’s ability to absorb water, making intermittent applications of water a far more efficient approach. The other main disadvantage compared to drip irrigation in a vineyard, field, or orchard is the potential for contamination. If the water source or plants uphill are contaminated or diseased, these problems may spread to the plants in the rest of the field.
Sprinkler irrigation uses a series of pipes to move water from the source to specially designed spray heads. The water must be pumped through the pipes to gain the right pressure, which needs to be controlled so the fields are not over watered.
Advantages Sprinkler irrigation system uses far less water than surface irrigation and can be used on a greater variety of terrains. The grower can also program the sprinkler head to turn on and off at certain intervals to maximize filtration and reduce the amount of water used. Disadvantages
While sprinklers may be helpful for irrigating row crops, they are not a particularly helpful kind of irrigation for fruit trees as the trunks block the path of the spray. Water applied with sprinkler irrigation is also highly vulnerable to evaporation as a large percentage falls (and subsequently evaporates) off the leaves.
Subsurface irrigation uses a series of pipes to water the crops under the surface of the soil. This allows more effective hydration of the plant roots which is especially important with high-value crops that are expensive to grow.
Once this type of irrigation is installed, it takes only a small amount of maintenance, so there is a cost-saving on employees. It is also highly efficient because water doesn’t evaporate like other forms of irrigation. Disadvantages
The cost of installing this type of irrigation is high, and the small pipes in the soil can be damaged by farm machinery and get clogged by the plant roots.
Drip irrigation works in a similar way to the subsurface system, but the pipes are located on the surface of the soil. The pipes are only designed to water the plants immediately near them, so they are best suited to rows of crops.
Drip irrigation in a vineyard or orchard can increase efficiency significantly compared to a basin-and-furrow irrigation system. It also prevents diseases from being passed from one plant to the next, as the water is supplied directly to each plant. If liquid fertilizers are used on the crop, these liquids can be mixed in with the irrigation water to the correct ratios and supplied directly to the soil where needed.
Compared to sprinklers and surface irrigation, micro-irrigation is the most high-tech type of irrigation system for agriculture and requires the most capital to set up. It also needs a skilled person to manage the water being used, which will cost more long-term. Filters and regular cleaning of the pipes is also needed to prevent blockages.
Which Irrigation Method Is Suitable For Your Farm ?
Flood, drip, and mechanized are all common types of irrigation that are used in agriculture. If you’re looking to add irrigation to your dry land, it’s important to understand the benefits and drawbacks of each type in order to make the right decision for your fields. Before you decide on your method(s), you need to fully understand your field’s topography, soils, available water, and crop type(s). When you have a complete understanding of your field’s layout and composition, you’re ready to begin searching for the right method of irrigation.
The suitability of the various irrigation methods, i.e. surface, sprinkler or drip irrigation, depends mainly on the following factors:
– natural conditions
– type of crop
– type of technology
– previous experience with irrigation
– required labour inputs
– costs and benefits.
The natural conditions such as soil type, slope, climate, water quality and availability, have the following impact on the choice of an irrigation method:
Sandy soils have a low water storage capacity and a high infiltration rate. They therefore need frequent but small irrigation applications, in particular when the sandy soil is also shallow. Under these circumstances, sprinkler or drip irrigation are more suitable than surface irrigation. On loam or clay soils all three irrigation methods can be used, but surface irrigation is more commonly found. Clay soils with low infiltration rates are ideally suited to surface irrigation.
When a variety of different soil types is found within one irrigation scheme, sprinkler or drip irrigation are recommended as they will ensure a more even water distribution.
Sprinkler or drip irrigation are preferred above surface irrigation on steeper or unevenly sloping lands as they require little or no land levelling. An exception is rice grown on terraces on sloping lands.
Strong wind can disturb the spraying of water from sprinklers. Under very windy conditions, drip or surface irrigation methods are preferred. In areas of supplementary irrigation, sprinkler or drip irrigation may be more suitable than surface irrigation because of their flexibility and adaptability to varying irrigation demands on the farm.
Surface irrigation is preferred if the irrigation water contains much sediment. The sediments may clog the drip or sprinkler irrigation systems.
If the irrigation water contains dissolved salts, drip irrigation is particularly suitable, as less water is applied to the soil than with surface methods.
Sprinkler systems are more efficient that surface irrigation methods in leaching out salts.
TYPE OF CROP
Surface irrigation can be used for all types of crops. Sprinkler and drip irrigation, because of their high capital investment per hectare, are mostly used for high value cash crops, such as vegetables and fruit trees. They are seldom used for the lower value staple crops.
Drip irrigation is suited to irrigating individual plants or trees or row crops such as vegetables and sugarcane. It is not suitable for close growing crops (e.g. rice).
TYPE OF TECHNOLOGY
The type of technology affects the choice of irrigation method. In general, drip and sprinkler irrigation are technically more complicated methods. The purchase of equipment requires high capital investment per hectare. To maintain the equipment a high level of ‘know-how’ has to be available,. Also, a regular supply of fuel and spare parts must be maintained which – together with the purchase of equipment – may require foreign currency.
Surface irrigation systems – in particular small-scale schemes – usually require less sophisticated equipment for both construction and maintenance (unless pumps are used). The equipment needed is often easier to maintain and less dependent on the availability of foreign currency.
PREVIOUS EXPERIENCE WITH IRRIGATION
The choice of an irrigation method also depends on the irrigation tradition within the region or country. Introducing a previously unknown method may lead to unexpected complications. It is not certain that the farmers will accept the new method. The servicing of the equipment may be problematic and the costs may be high compared to the benefits.
REQUIRED LABOUR INPUTS
Surface irrigation often requires a much higher labour input – for construction, operation and maintenance – than sprinkler or drip irrigation. Surface irrigation requires accurate land levelling, regular maintenance and a high level of farmers’ organization to operate the system. Sprinkler and drip irrigation require little land levelling; system operation and maintenance are less labour-intensive.
Before choosing an irrigation method, an estimate must be made of the costs and benefits of the available options.Surface irrigation is by far the most widespread irrigation method. It is normally used when conditions are favourable: mild and regular slopes, soil type with medium to low infiltration rate, and a sufficient supply of surface or groundwater. In the case of steep or irregular slopes, soils with a very high infiltration rate or scarcity of water, sprinkler and drip irrigation may be more appropriate. When introducing sprinkler and drip irrigation it must be ensured that the equipment can be maintained.