Drip, or trickle irrigation, is the system in which water is frequently and slowly applied directly on the crop root zone. The concept of this irrigation system is to irrigate only the root zone instead of the entire field surface, thus making water content of the crop root zone at the optimum level.
In a drip irrigation system, water is applied under the pressure, dripping one drop at a time through the small emitters. Water can also be sprayed as a fine mist over a portion of field’s surface or bubbled onto the soil in small streamlets.
Although drip systems irrigate only a portion of the soil, the amount of wetted soil depends on soil characteristics, the length of the irrigation period, emitter discharge, and number and spacing of emitters.
Drip Irrigation System Types
According to emitters which control the quantity and rate of water discharge, trickle or drip irrigation systems can be divided into four types:
- Point-source emitters (drip bubbler)
- In-line drip emitter
- Basin bubblers
- Micro spray sprinkler
Although emitters have many common characteristics, they all differ in size and shape, as well as in internal design.
Drip irrigation is one of the most efficient types of irrigation systems. The efficiency of applied and lost water as well as meeting the crop water need ranges from 80 to 90%. What does this mean? Well, its efficiency is the result of only two factors;
- Applying of water drop by drop, the soil soaks it before it evaporates
- Water is applied on the crop root zone (localized) where it is needed most
Sub-surface Drip Irrigation
The drip hose can be placed above ground or buried in the ground, which is called sub-surface drip irrigation. Sub-surface irrigation has the advantage of nearly zero evaporation. However, it can be harder to tell if an emitter becomes plugged or damaged.
Why Use Drip or Trickle Irrigation System?
In providing water to plants according to plant water requirements, drip irrigation systems create no pollution and no runoff and very little evapotranspiration. By using this system, a farmer can certainly ensure good water management. Utilization of a drip irrigation system type provides other benefits to both the farmer and crop production:
- Simple implementation of existing soil sensors
- Management of soil moisture level; crops are irrigated immediately when soil moisture drops below threshold
- Application of fertilizers and pesticides combined with irrigation
- Reduced weed growth and facilitated management of farm activities in the field due to localized soil wetting
- Irrigation can be stopped at any moment (if rain occurs) which prevents overirrigation
- Easy to install, design, and it can be very inexpensive
- Possible to implement on almost any terrain, soil, and crop type; especially suitable for high-value row crops
Drip irrigation system is a great solution on crop productions with dry, saline, low drainage soils and on soils where moisture maintenance may result in high insect pests and disease incidence.
Limitations in Using Drip Irrigation System
Despite many benefits, drip system has also limitation factors for successful implementation on crop production:
- Clogging of emitters due to small outlets, caused by soil particles, chemicals, fertilizers or organic materials
- Damage on plastic pipe caused by rodents
- Uniformity of water distribution due to elevation differences on unleveled field
- Potential salt accumulation in crop root zone between two irrigation cycles
- Plants are more susceptible to stress if drip irrigation system fails
Drip Irrigation = Smart Irrigation
Drip irrigation is the most efficient and appropriate irrigation system. Instead of wetting the whole field surface, water is applied only to the plant root zone. The primary goal of drip irrigation is to apply water at the time when plants need it most and in rates needed for proper plant growth. Moreover, it provides a very favorable moisture level in the soil in which plants can flourish.
Although a drip irrigation system is the best solution for smart irrigation, its implementation is not that simple and can take time. To ensure good water management and maintenance, a farmer needs to first understand crop needs and field properties.