Irrigation plays a vital role in the success of high-density plantation systems and is one of the important aspects of orchard management. International Water Management Institute (IWMI) reports that around 50 per cent of the increase in demand for water by the year 2025 can be met by increasing the effectiveness of irrigation. Drip irrigation is one of the most perceptual ways of irrigating fruit crops, mainly due to the great water economy with complete automation of the irrigation process. Drip Irrigation offers high water application efficiencies since there is reduced surface evaporation, less surface runoff, as well as minimal deep percolation. Drip irrigation consists of a permanent system of plastic pipes that use emitters for localizing the application of water near the individual plants using high-frequency applications and low discharge rates. Moreover, a drip irrigation system can easily be used for fertigation, through which crop nutrient requirements can be met accurately. Because of a very high level of conveyance and application efficiency and low water moisture evaporation, the overall water use efficiency is very high (80-90 percent). It has the potential to increase crop yield even with reduced irrigation water application. Also, drip irrigation can help to irrigate hilly terrains or texturally non-uniform fields. It also allows farming on flat lands to save labor and operating cost of land leveling, making furrows, and ridges.
Just like people, plants like to get their water and nutrients in a balanced way. Nobody wants to eat a month’s worth of food in one day, and the same goes for plants which is why drip irrigation applies water and nutrients frequently and in small doses, ensuring optimal growing conditions that helps produce the highest yields possible. With the adoption of this technology, it is always possible to have water and air in the root zone as much as the plant needs. In the flood irrigation method, there is a lack of air in soil pores due to excess water in the first days of the irrigation and a water shortage in the root zone before the second irrigation. Drip systems help to improve the irrigation systems in the orchard as they offer to deliver the water and nutrients directly to the root zone. Flood irrigation creates anaerobic conditions in the early days of watering. Likewise, waterlogged conditions also result in Zn deficiency. Drip irrigation methods are also efficient in terms of reducing weed growth. The drip method helps in saving irrigation water, increasing water-use efficiency, decreasing tillage requirement, producing higher quality products, increasing crop yields, and higher fertilizer-use efficiency.
Major Components of drip irrigation system include: Pump station, By pass assembly, control valves, filtration system, fertilizer tank/venturi, pressure gauge, Mains/Sub-Mains, Laterals, Emitting devices/Emmitters, and Micro-tubes. There are a number of factors to take into account when deciding what type of drippers you want to use in your production line. To pick the best one, one needs to consider a few variables such as; grimy or hard water, elevation changes, and fluctuating water requirements in the length of a drip line. In light of all that, you need to understand the similarities as well as the differences of these drippers and seek an expert advice from orchardly. There are Non-pressure compensating emitters, pressure compensating emitters, inline drippers and adjustable drippers.
Non-pressure compensating emitters use a turbulent flow action which provides greater durability and longevity along with clogging resistance and low maintenance. Non-pressure compensating drippers will have varying output flow at varying inlet pressures. Therefore the flow will vary along uneven terrain, and each dripper will emit a different amount of water depending on its location on the supply line. The pressure to a drip emitter can vary due to the slope of the land and the length of the supply tube. If an irrigation system is installed down a slope, there will be higher water pressure at the bottom of the slope than at the top, and non-compensating drippers at the bottom will emit more water than those at the top.
Pressure Compensating Emitters allow long runs with equal flow from each dripper at any pressure between 10 and 50 psi. They are self-cleaning and utilize a silicone diaphragm which moves up and down as pressure fluctuates to control the flow. Large water passage reduces clogging. Great when elevation is an issue as they provide the same amount of water at the top of a hill as they do the bottom.
In inline dripper irrigation, the drippers are pre-inserted along the length of the pipe during the extrusion process at fixed intervals. So in order to operate efficiently, inline drippers are ideal for equally spaced plants in order to avoid a lot of connections with plain pipe. Since the dripper insertion process is done during the extrusion process, inline drippers can be installed quickly and easily, and begins dripping reliably as soon as one end of the pipe is connected to a water supply. The inline drippers are also cost effective and easy to clean.
In online drip irrigation, the PE pipe is supplied without any drippers inserted and typically requires manual insertion of the drippers to the outside wall of the pipe. The advantage of this method is that it can work with plants that are not equally spaced, since drippers are manually inserted exactly at the point needed. However, these drippers usually face issues of clogging and cleaning. The manual adjustment of each dripper flow is also cumbersome at times.
Intelligent IoT-based Automated Irrigation system is an addition to a precision drip system with advanced sensor-based irrigation management that involves the application of water & fertilizers to the plant on the basis of its water requirement at different stages, soil type, climate etc. with the help of micro irrigation, sensors & controllers. In this Moisture and Temperature sensors are deployed in the orchards to capture the data for watering the field. Now based on information gathered by the gateway unit from the sensor, information is sent to the control unit for analysis of information extracted from the sensor for actuating the pump for watering the field. This information on data analyzed is recorded in a Cloud server which allows the farmers to access it from their mobile handset. Irrigation decisions can be executed according to signals from the sensors like Soil Moisture Sensor, Tensio-meter, Solar Radiation, Vapor Pressure Deficit, Evapo Transpiration (ET) etc. The IoT based drip irrigation management system is fast growing technology for orchards like high density plantation systems.