Complete Design of an Automated Drip Irrigation System for citrus (Including Drawings)
The system is designed for one (1) hectare of land, for citrus and the water source is pumped water from.
There are two major phases of the design. But I will not go into the technical details required to arrive at them. So let’s just go straight to the relevant details.
Important to know however is that there are two specific phases of the design, first the drip irrigation system design itself, then secondly, its automation.
1) Stage 1. Drip irrigation system design
There are two distinct, but operationally dependent, sections of the complete drip irrigation system:
(i) The head control:
This is comprise of the water source, mechanism pump unit and irrigation water treatment mechanism such as the filtering, and fertilizer tanks, control valves.
Figure (i). Head Control
Depending on the water source such as well or lake, system capacity has to be computed to ensure that water is enough to meet the crop water requirement.
Knowledge of this is crucial guide in the sizing of the main pipe that leads water to the field. The fertilizer tank, sand and gravel filters ensure good quality treated water that will not block the tiny-holed drippers.
ii) Field pipe layout
This is comprised of the pipe orientation and field block arrangement.
Figure (ii) Field Block Layout
The one (1) Hectare field was divided into eight (8) blocks (B1, B2, B3, B4, B5, B6, B7 and B8), each of size 25m*50m.
1) Stage 2. Automation of the Designed Drip Irrigation System
Components to actualize the automation of the irrigation system include among others,
(i) The microcontroller which is the brain of the system (one)
(ii) The valves which are solenoid valves (these were 8, one for each of the 8 field blocks)
(iii) The field devices such as the sensors that continuously measure soil moisture levels (8).
The choice of the design approach of the automation system was based upon two functional needs, namely.
a) To completely minimize human intervention,
b) And to guarantee the most efficient use of water;
Therefore, a closed loop control system approach was chosen as befitting the required demands.
In this closed loop system, feedback from the eight (8) field blocks would be gathered from the eight (8) sensors each strategically deployed in each of the eight (8) blocks
The closed loop system confers the following advantages:
(i) Measures moisture directly from the root zone
(ii) Eliminates the need for end-user intervention and this reduces human error
(iii) Eliminates the need for seasonal clock adjustments employed in related systems.
In summary: From the automated irrigation design results
a) A total of eight (8) solenoid sensors were needed so that each sensor would be placed per the eight blocks,
b) Eight solenoid valves (8) each at the manifold and controlling water entry into specific blocks amongst the eight blocks,
c) One (1) master valve to actuate the release of water from the tank and act as a buffer in case of any accidental irrigation regimes.
The complete designed automation system consisted of the following components:
(i) Pump,
(ii) Water meter,
(iii) Flow meter,
(iv) Control valves,
(v) Chemical units,
(vi) Moisture Sensors
(vii) And the microcontroller.
The components most crucial to the system are:-
a) the microcontroller which is the brain of the entire system,
b) the sensors
c) and the valves.
The microcontroller selected that suited the calculated parameters was the ‘ATmega16’ microcontroller characterized by 8 input pins in the analogue to digital converter.
As such, the eight blocks/networks could be operated by the single microcontroller.
3) Brief description of automated irrigation system operation
Overall, the automated irrigation system includes three basic stages of operation:
- A wired communication between the sensors and the micro-controller to give in real time, the status of moisture levels in the soil.
- The decision making by the micro-controller on the irrigation action to take, depending on whether or not the moisture level reported by the sensor is the required amount (the micro-controller compares to a pre-set moisture level threshold)
- Finally, the wired communication between the micro-controller and zonal valves, where the controller communicates the decision to either open and permit water entry, if the moisture amount reported by the sensor is below the pre-set threshold amount, and/or to close and stop water entry, if the moisture level reported by the sensor is higher than the pre-set threshold amount.
4) The microcontroller operates in three major related stages.
Figure (iii) Stages of Operation of Microcontroller
The desired soil in-put stage which shows the set parameter both climatic and soil.
Second stage is the stage of the in-put variables which are parameters that determine the making of decisions.
Thirdly, the control stage in which desired inputs are measured with measured variable inputs.
The automated control unit consists of moisture sensors, signal conditioning unit, digital to analogue converter (ADC), Local crystal display (LCD) module, and relay driver and solenoid valves.
Figure (iv). Microcontroller unit
5) Operation of the Automated Drip Irrigation System
Application of the automated drip irrigation system to the field and mapping the area orientation of the system.
The sensors strategically located on the field continuously send signals that are boosted to required levels by corresponding amplifier stages.
Amplified signals are fed to the analogue to digital converter of the desired resolution to obtain the digital form of sensed input for microcontroller use.
The LCD monitors current sensor readings and current status of respective block solenoid valves which are controlled by the microcontroller through relays
Figure (v) Arrangement of Application of the Automated System to the Field
Now the Area orientation of the system, incluidng all parts.
Figure VI. Map of the Area Orientation of the System
6) What the designed automated irrigation system does (Advantages)
(i) It drastically cuts down on labor costs that would otherwise be required to run the system, especially on large acreages.
(ii) It also eliminates the need for end-user intervention as is characteristic of manual set-ups, and thus reduces the probabilities of human error.
(iii) Through continuous and consistent monitoring of moisture levels, the automated system achieves high levels of water application precision and efficiency of water and chemical use.
(iv) the automated system also releases the farmer and allows him to apportion time for other ventures, and he/she does not have to be present to operate the irrigation system.
7) Conclusion
The focus of research in agriculture has now shifted to the recent concept of agric-technology that seeks to widen modern agricultural horizons by incorporating the use of Information and Communication Technologies (ICT).
These shifts in the focus of irrigation system design toward the new concept of hardware and software synergies is promulgated on many benefits, but above all, on the requirement to give the farmer complete control of the water requirement of the crop.
Overall, the above designed system serves to reduce water consumption, reduce human involvement and associated operational labor costs.
The designed system uses a real-time, closed-loop control to measure the soil moisture and turn the valves on and off. The system - best suited to commercial agricultural production - guarantees sober economies of scale.
All drawings unless cited, are my own, drawn using AutoCAD 2007
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