In agriculture, watering crops can be done through irrigation or rain. Since rain can sometimes be unreliable due to climate change, most farmers rely on irrigation to cultivate plants. The type of irrigation a farmer chooses depends on factors such as soil type, type of crop, land topography and weather patterns. The following are the main types of irrigation.
- Surface Irrigation
This type of irrigation relies on gravity flow to distribute water. It is the most commonly used irrigation methods and is well suited to mild slopes as well as regular slopes. Surface irrigation also works best in soil with fine texture with medium to minimum infiltration rate. It requires plenty of groundwater and adequate workforce since it operates without the use of advanced technology. There are various methods of irrigation under surface irrigation. They include;
- Basin Irrigation: This type of surface irrigation waters crops of flat land called basins, enclosed with bunds. It involves flooding a flat area with water, and the bunds help to avoid the flow of water to nearby fields. This irrigation, therefore, serves crops such as rice that are cultivated in flat areas.
- Furrow Irrigation: This irrigation involves the construction of parallel channels called furrows that allows water to flow to the rest of the field by gravity flow. This method is suitable for row crops.
- Border Irrigation: Also known as border strip, border irrigation waters land structured as long strips with bunds in separating these sloping strips. Water flows to these borders through siphons or gates. This irrigation is appropriate for large farms that are cultivated by machines.
Surface irrigation has various advantages.
- It is cost effective as it can be used on small pieces of land and does not require advanced machinery and technology.
- Its minimum filtration rate makes leaching of salts in soil possible and easy.
- It makes good use of rainwater, and therefore it is not affected by heavy rains.
- Draining excess water from basins is difficult.
- Due to the soil’s texture and infiltration rate, crops can be covered by water over long periods.
- It requires only flat and level land.
2. Sprinkler Irrigation
Sprinkler Irrigation involves spraying crops with water by use of permanently or temporarily set tools. Water is pumped through pipes and sprinkled to crops like drops of rain from the spray heads. Sprinklers are effective for both small and large farms and are suitable for any slope, and they can irrigate any field crop and row crop. Some sprinklers, however, release large water droplets that destroy vegetables like lettuce and are therefore not suited for such plants. This irrigation is fit for most types of soil, especially those with high infiltration. Clean water devoid of any solid substance should be used to avoid blockage on the sprinklers. There are two main categories of sprinklers, namely, rotor sprinklers and spray sprinklers. These sprinklers differ on how they distribute water. Spray heads sprinkle water like shower nozzles. Sprinkler nozzles have different patterns and cover different radii depending on the size and structure of the farm. Rotor sprinklers, on the other hand, consist of sprinklers that spin or rotate when watering an area. Rotator nozzles are the latest and most popular sprinklers on the market. When choosing a sprinkler, consider its application rate and its drop sizes. The application rate measures the amount of water sprinkled in mm/hr. Factors such as pressure, the spacing between sprinklers, and the nozzle size determine the application rate. Ensure that your sprinkler application rate is not above the soil’s infiltration rate for the water to be well absorbed. The operating pressure and the nozzle also determined by the size of the water droplets. Large drops should be avoided, as they not only damage crops, but the soil as well. Find a sprinkler with a small nozzle diameter that functions under normal pressure to prevent crop damage.
- This irrigation is convenient for any slope; land leveling is therefore not necessary
- Sprinklers are easy to operate. Hence, no skilled personnel are required
- It is effective for uniform distribution of pesticides, water and fertilizers
- Conserves water and improves the quality and quantity of farm produce
- Sprinkler irrigation is expensive
- Water distribution is affected by high temperatures and strong winds
- It consumes a lot of energy
3. Drip Irrigation
Drip irrigation involves the use of pipes with small openings called drippers. These drippers, also known as emitters, trickle water at low rates on the soil. This type of irrigation only waters, soil that closely surrounds a plant to keep it moist. It is appropriate for row crops and trees where each dripper supplies water to its plant. The crops, planted in lines along the pipes, will each receive adequate water. Drip irrigation is fit for any slope. Emitters can be set up to drip water on different rates depending on the type of soil. For example, lower rates will be used to water clay soil as compared to sandy soil. Drip irrigation is then fit for any soil. Emitters, having very small diameters, are prone to blockage by tiny sediments. It is, therefore, essential to ensure that your irrigation water is free of any insoluble substances.
- Since water is directly applied to each crop, chances of weed growing are low.
- It boosts yield and seed germination.
- It is very convenient for fertilizer application.
- Drip irrigation saves water.
- Setting up this irrigation system is very expensive.
- Since emitters are prone to blockage, filters, and regular, cleaning of the pipes is required.
- It requires skilled personnel, especially in the water management area.
4. Subsurface Irrigation
Subsurface irrigation waters crops from below the ground. Pipes placed beneath the soil surface supply water to the roots of plants. There are various methods used for this irrigation depending on how deep the water table lies. Tillage methods are a significant factor in subsurface irrigation as some cultivation practices can destroy the irrigation system. This irrigation is suitable for dry and windy areas as it limits the loss of water through evaporation. Water should be filtered to avoid blockage in the pipes. Subsurface irrigation can be set up to water any crop on any farmable slope. They are used mostly on high value crops, especially vegetables and strawberries.
- Saves water and minimizes water loss through evaporation
- Allows crops to grow uniformly and improves yield
- It is not labor intensive and therefore cuts the costs of hiring employees.
- Setting up and maintaining this irrigation system is expensive.
- Cars, tractors, and machines can easily damage this irrigation system.
- Root hairs can block the drippers in the pipes and sometimes destroy them.
In conclusion, it is crucial to put all the important factors such as slopes, soil type, and climate into consideration before choosing an irrigation method. Smart farming means understanding your crop’s needs and your environment.