Literature Review

Water is very essential for plant growth. The two main mechanisms through which water is supplied to plants are: direct rainfall and irrigation (Centers for Disease Control and Prevention, 2016). Direct rainfall is an easy and cost effective method of watering plants but it is inefficient due to its inability to ensure that plants get the right quantity of water at the right time. This problem escalates when the rainfall is insufficient, such as during drought seasons or in arid and semi-arid areas. Irrigation is a method of watering plants artificially using irrigation systems. These systems are very useful in areas with irregular rainfall patterns, in dry areas or during drought seasons. Through irrigation systems, farmers are able to water their plants appropriately thus improving their growth and development.

As stated by Irrigation Australia (2016), irrigation started being practiced during 6000 BC in Egypt and Iran & Iraq (known as Mesopotamia by then). This was done using flood water from River Nile and Euphrates/Tigris. The flood water was diverted into fields and directed back to the river later. In 3100 BC, the Egyptians started diverting River Nile’s flood water into a new lake known as Moeris. Several techniques of irrigation were developed thereafter, not only in Egypt and Mesopotamia but also in different parts of the world. Some of the irrigation techniques, devices and systems that were developed include: cement pipe, irrigation shaduf, Noria, hanging gardens of Babylon, Qanat, Persian water wheel, Archimedes screw, windmills, irrigation canal/furrow, residential sprinkler, residential hose nozzle, etc. In 1800 AD, the total acreage under irrigation worldwide reached 19.76 million acres (Irrigation Australia, 2016).

Since the ancient days, there are numerous types of irrigation systems that have been developed. These include: surface irrigation systems, localized irrigation systems, lateral move irrigation systems, centre pivot irrigation systems, manual irrigation systems, sub-irrigation systems, drip irrigation systems, and sprinkler irrigation systems. Surface irrigation systems supply water to the designated points by gravity flow. These systems deliver water through open channels (lined or unlined), or low-head pipes. These methods have been in use for thousands of years starting from Egypt, India, China and Middle East. The surface irrigation systems are still being used all over the world. In the U.S., for example, over 61 million acres of land is under surface irrigation (James, 2012). The four main categories of surface irrigation systems are: basin irrigation system, uncontrolled flooding system, furrow irrigation system, and border irrigation system (National Resources Management and Environment Department, (n.d.)). Figures 1, 2 and 3 below show three main types of surface irrigation systems (Stauffer and Spuhler, 2011)

 

Localized irrigation systems are those that apply water directly to the root zone or only the desired surface area. These systems have very high efficiency rates and prevent a lot of water loss. Examples of localized irrigation system are trickle or drip irrigation system, perforated plastic sleeves, porous pipes and porous clay pots (Akvopedia, 2017). Lateral move irrigation systems are self-driven devices that apply water to crops from a canopy by moving over the filed. The key advantages of these systems are: reduced variability, accurate application, reduced labour requirements, less requirement for landforming, and suitable for fertigation (State of Victoria, 2015; Queensland Government, 2011). Figure 4 below shows an example of a lateral move irrigation system

Historical Background of Irrigation Systems

 

Figure 4: Lateral move irrigation system

Subirrigation systems water plants from under the surface of the soil, as shown in Figure 5 below. These systems deliver water to the root zone from below the surface then the water is absorbed upwards. Subirrigation systems are very environmental friendly and they have attracted many users. Manual irrigation systems are very simple but require a lot of labor inputs. Some of these systems include use of watering cans, simple drip irrigation system, pitcher irrigation, bottle irrigation, sectioned and porous pipes and perforated plastic sleeves. Figure 6 below shows examples of manual irrigation systems

 

Figure 7 below shows the trend of land under rainfed and irrigated cropping from 1961 to 2008. According to the graph, the amount of land under irrigation has been increasing over the last five decades and this can be attributed to improved irrigation systems, among other reasons. Statistics show that the average large under irrigation between 1961 and 2009 has increased by 171% (from 130 Mha to 301 Mha) while that under rain feeding has reduced by 0.2% (from 1229 Mha to 1226 Mha) over the same period (FAO, 2011). Irrigation systems are also being used to mitigate various environmental factors that are reducing agricultural yields, such as irregular rainfall patterns and drought (Dowgert, 2010). As a result, these systems have played a major role in increasing food production for the rapidly growing global population.

 

Figure 7: Trend of rainfed and irrigate land

With the availability of a wide range of irrigation systems, the process of selecting the most suitable system may be quite challenging. However, this process can be made easier by considering various important factors, including: availability of water; type and location of water source; quality of water; type of crop being irrigated; type of soil; weather patterns and climate of the area; topography of the area; shape and size of the field; availability of fuel and cost; labour requirements; and initial, operating and maintenance cost of the irrigation system.

For many years, irrigation systems have been used for various purposes including: prevention of weeds and diseases, conservation of water and time, preservation of structure and nutrients of soil, and improvement of gardening flexibility (SFGate.com, (n.d.)). Development of irrigation systems have been driven by several factors including: lower rainfall than the amount of water needed by plants; increased global population that have augmented food demand; rainfall’s improper spatial distribution; rainfall’s improper temporal distribution; and availability of modern technology (Civil Engineers Forum, 2016). The importance of these irrigation systems are: they increase agricultural production certainty; increase crop production; allow production of multiple crops; increase land under cultivation; stabilize agricultural produce levels; create employment opportunities; and generates income for farmers and revenue for governments (Seth, 2016).

There are two main categories of irrigation systems: manual irrigation systems and modern or automated irrigation systems. Manual irrigation systems are usually traditional systems that involve drawing water from the source manually and pouring it in the farming field or where the crops are planted. This method is cheap but it consumes a lot of time, has low efficiency, results to uneven water distribution, and has greater water loss. Automated irrigation systems are the modern irrigation systems that overcome almost all the drawbacks of traditional methods. The main types of modern methods are drip irrigation system and sprinkler irrigation system. Automated irrigation systems ensure that optimal use of water, which improves plant growth and development.

Types of Irrigation Systems

Development of automated irrigation systems have greatly revolutionized irrigation. Today, there are different types of irrigation systems that make it possible to irrigate nearly any type of crop in any place. These systems comprise of various components, including sensors that detect temperature, light, water and humidity levels in the environment where the plants are. These components are integrated and controlled by a computer program, which determines the necessity of each of the key requirements of plant growth and development (Dilluvio, 2015). Automated irrigation systems usually use mechanical appliances, including sensors, timers, computers, and actuators, thus requiring very minimal manual intervention (Stauffer and Spuhler, 2011). These irrigation systems has numerous benefits, including the following: reduced labor, reduced costs, reduced water and nutrient runoff, more precise cut-off, more well-timed irrigation, better management of greater water flow rates, improved plant growth, and improved lifestyle, among others (Victoria State Government, 2015). According to Gutierrez et al. (2013), automated irrigation systems can save up to 90% of water compared with manual irrigation systems. These systems have made it very easy to water crops, and this has not just stopped in outdoor applications. Instead, various irrigation systems have also been designed particularly for indoor plants.

Indoor plants are the major components of interior landscaping. The interior landscaping industry started growing in 1990s after several studies found that there are numerous benefits of indoor plants to humans. At the start of 21^st century, many homes and business premises started investing in interior landscaping. Majority of them planted indoor plants to beautify their homes or workplaces. These plants have continued to be used for creating beautiful and relaxing indoor environments. The indoor plants are now found in many places including living rooms, bedrooms, reception areas, hotel rooms, banking halls, hospitals, and offices (John Mini Distinctive Landscapes, 2017). Indoor plants together with other elements have continued to expand the indoor landscaping industry. Today, there are many commercial and residential property owners who spend a lot of money paying indoor landscapers to maintain their indoor plants. As argued by Davis (2013), indoor landscaping is a billion-dollar industry and it is continuing to grow very quickly as more people want to create green spaces in their homes, offices and business premises.    

The history of indoor plants can be traced back over 3,000 years ago. In about 1,000 B.C.E., indoor plants were already being used by ancient Chinese as ornamental features to symbolize wealth and keep the indoor environment green regardless of the extreme temperatures outdoors. During Victorian era in 1800s, houseplants were grown during British’s dreary and cold months. Besides creating beautiful interiors, people also chose houseplants that produced more oxygen and required less light. Therefore the health benefits of indoor plants also started many years ago. During those early days, indoor plants were watered using manual irrigation systems. This was largely done by pouring water in the pots or containers where the plants were grown. Failure to water the plants would cause stunted growth or permanent death of these plants. Just like any other manual irrigation system, the techniques used to water indoor plants during the ancient days had high water inefficiency rates and great labour requirements.   

Factors to Consider When Choosing an Irrigation System

Some of the benefits of indoor plants include: improve indoor air quality, improve mental health, boost sleep, reduce background noise, improve performance and productivity of people in the building, enhance aesthetic value of the room, reduce stress, create natural scent, boost mood, reduce risk of falling sick, improve wellbeing, and sharpen focus, memory and concentration (Healthline, 2016; Ambius, 2017; Ellard, (n.d.)). These benefits result from the fact that indoor plants purify air by removing toxic substances, release oxygen into the air at night, humidify air, and eliminates mold from air (Bayer Advanced, 2017). Therefore indoor plants improve the quality of people’s lives. There are different types of indoor plants but one common thing about them is that they have the same needs for proper growth and development. The key needs are: water, temperature, light and relative humidity (Pennisi, 2017; West Coast Nurseries Group, 2016).

However, there are several challenges of growing and maintaining indoor plants. The major challenges are environmental conditions, insects, diseases, nutrient deficiencies (Dong, (n.d.)). This project has focused on the problem of environmental conditions because it probably the leading problem associated with indoor plants. Examples of environmental conditions problems are: overwatering, insufficient water, sunburn, inadequate light, too dry air, and high ambient room temperature (Deardorff, 2009; Gardening ABC, 2015). The demand for water, light, temperature and humidity by indoor plants keeps on fluctuating due to varying indoor and outdoor environmental conditions, making it more challenging to ensure proper conditions. However, automated watering systems are now available to overcome these challenges. These systems are able to detect water, temperature, light and humidity requirements of indoor plants using specialized sensors and activate appropriate components to attain the needed conditions. In this project, the main focus is how to water indoor plants automatically using raspberry pi. This is a technologically driven watering system with very high water efficiency rates because it only waters the plants when they need the water.

An indoor plant watering system helps in ensuring that indoor plants are supplied with the right quantity of water at any given time (Pearson, 2017). This simply means that the system automates the entire indoor plant watering process thus making it hassle-free to maintain these plants (Klosowski, 2012). This irrigation system comprises of sensors, actuators, timer and computer, among others. Sensors are used to detect the water/moisture in the soil, relative humidity in the air, room temperature and light intensity. The signal from the sensors is transmitted to actuators, which activate the right function to meet the plant requirement. For example, if the room temperature is too low, the actuator activates the heating and when the soil moisture is low then the actuator activates the watering system. Timers are used to activate the system automatically so as to provide the set plant requirement after a pre-determined period. Computer is where the appropriate software or program is installed so as to analyze the signal received from the sensors and initiate the action triggered by the actuator. This project used raspberry pi 3 to develop the indoor plant watering system. With this system, there is very minimal manual intervention in watering indoor plants. In fact the system can continue watering the indoor plants even if the homeowner is away for several days or weeks. This irrigation system is undoubtedly among the modern watering systems that are revolutionizing the indoor landscaping industry. 

References

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