Drip Irrigation

Compiled by:
Beat Stauffer (seecon international gmbh)

Executive Summary

Drip irrigation is a technique in which water flows through a filter into special drip pipes, with emitters located at different spacing. Water is distributed through the emitters directly into the soil near the roots through a special slow-release device. If the drip irrigation system is properly designed, installed, and managed, drip irrigation may help achieve water conservation by reducing evaporation and deep drainage. Compared to other types of irrigation systems such as flood or overhead sprinklers, water can be more precisely applied to the plant roots. In addition, drip can eliminate many diseases that are spread through irrigation water. Drip irrigation is adaptable to any farmable slope and is suitable for most soils. In contrary to commercial drip irrigation, simple self-made systems are cheap and effective.

In Out

Freshwater, Urine or Yellowwater, Fertigation Water, Treated Water, Energy

Food Products

Introduction

With drip irrigation, water is conveyed under pressure through a pipe system to the fields, where it drips slowly onto the soil through emitters or drippers which are located close to the plants. Compared to other types of irrigation (sprinkler irrigation or surface irrigation), only the immediate root zone of each plant is wetted. Therefore this can be a very efficient method of irrigation. Drip irrigation is sometimes called trickle irrigation (FAO 1988).

Drip irrigation can be a very technical irrigation system for food or plant production fields. But compared to other technical systems (e.g. sprinkler irrigation) it is a low-technique solution. Furthermore it is possible to combine this system with a water treatment plant (e.g. non-planted filter or constructed wetlands (horizontal flow or vertical flow) and use the treated water as irrigation water.

Drip irrigation requires little water compared to other irrigation methods. About 40-80 litres per day are needed per 100-200 plants (INFONET-BIOVISION 2010). The small amount of water reduces weed growth and limits the leaching of plant nutrients down in the soil. In organic fertiliser or urine tea can be applied efficiently to the plants through the drip system (INFONET-BIOVISION 2010).

Basic Design Principles

Commercial Drip Irrigation System

 INFONET-BIOVISION (2010)

Schematic design of a commercial drip irrigation system. This includes technical components such as filters, pumps and hydraulic control valves. Source: INFONET-BIOVISION (2010)

Expensive commercial drip irrigation systems are employed in highly technical and industrial farming. The used systems are very expensive and needs expert design and maintenance (INFONET-BIOVISION 2010).

Most large drip irrigation systems employ some type of filter to prevent clogging of the small emitter flow path by small waterborne particles. New technologies are now being offered that minimise clogging. Some residential systems are installed without additional filters since potable water is already filtered at the water treatment plant. Virtually all drip irrigation equipment manufacturers recommend that filters be employed and generally will not honour warranties unless this is done. Last line filters just before the final delivery pipe are strongly recommended in addition to any other filtration system due to fine particle settlement and accidental insertion of particles in the intermediate lines. Drip systems often mix liquid fertiliser with the irrigation water. This is called fertigation and chemigation (application of pesticides and other chemicals to periodically clean out the system) (WIKIPEDIA 2011).

 

Small Scale and Self-Made Drip Irrigation Systems

 STANDISH (2009) and INFONET-BIOVISION (2010)

A self-made irrigation system in Africa with a bucket as a water reservoir and simple plastic hoses for the distribution. If bamboo is available, it can be used as distribution pipes. Source: STANDISH (2009) and INFONET-BIOVISION (2010)

For a relatively low initial investment a small-scale farmer can buy and set up a drip-irrigation system. If used to grow crops for market, this investment will pay itself within the first season and lead to increased household food production, especially during extended dry periods (INFONET-BIOVISION 2010). Apply correct design (that might need training of the farmers), very simple drip systems can be built with local available material. Using buckets or barrels as water reservoir and bamboo or PVC tubes as distribution pipes, everyone can construct a very efficient irrigation system. If wastewater is used, a filtration unit after the treatment plant is recommended to avoid clogging of the emitters. Read more about simple manual irrigation methods here.

 

Design of a Simple Drip Irrigation System

A simple drip can consist of a 20 litre bucket with 30 metres (100 feet) of hose or drip tape connected to the bottom of the tank. The bucket is placed at least 1 metre (3 feet) above the ground so that gravity provides sufficient water pressure to ensure even watering for the entire crop. Clean water is poured into the bucket daily through a filter/ strainer. The water in the bucket fills the drip tape and is evenly distributed to 100 watering points. A multi-chambered plastic drip tape is engineered to dispense water through openings spaced at 30cm (12 inches). The bucket kit is the smallest type of drip irrigation technique (Adapted from RCSD 2008). A filter after the control valve can be installed, to prevent blockages (e.g. a screen) or an even more developed filter to improve the water quality.

    

Schematic design of a low-cost drip irrigation system. Source: (RCSD 2008)  

Costs considerations

As already mentioned, commercial systems for industrial production are very expensive. Small scale farmers can buy a drip irrigation system for relatively low initial costs (US$15 to $85) or construct it with local available material (buckets, bamboo or plastic pips)(INFONET-BIOVISION 2010). In general, it is more costly than manual irrigation, but has improved yields and decreased water/ operating costs.

Operation and Maintenance

For perennial crops, the drip hose should be lifted periodically if a drip hose system is used on the soil surface, so that leaves, soil, and debris do not cover the hose. If the drip hose is not lifted, roots can grow over the hose, anchor it to the ground, and eventually pinch off the flow of water. Leaks can occur unexpectedly as a result of damage by insects, animals, or farming tools. Systematically monitor the lines for physical damage. It is important to fix holes as soon as possible to prevent uneven irrigation. If the rate of water flow progressively declines during the season, the tubes or tape may be slowly plugging, resulting in severe damage to the crop. Once a month, flush the drip lines by opening the far ends of a portion of the tubes at a time and allowing the higher velocity water to flush out the sediment (INFONET-BIOVISION 2010). If poorly treated wastewater is used, soil quality can be degraded over time (e.g. accumulation of salts) (TILLEY at al. 2008).

Health Aspects

(Adapted from TILLEY et al. 2008)

If wastewater is used for the irrigation process, there are potential health risks if water is not properly pre-treated (i.e. inadequate pathogen reduction). If poorly treated wastewater is applied. Appropriate pre-treatment should precede any irrigation scheme to limit health risks to those who come in contact with the water. As well, depending on the degree of treatment that the effluent has undergone, it may be contaminated with the different chemicals that are discharged into the system. When effluent is used for irrigation, households and industries connected to the system should be made aware of the products that are and are not appropriate for discharging into the system. Drip irrigation is the only type of irrigation that should be used with edible crops, and even then, care should be taken to prevent workers and harvested crops from coming in contact with the treated effluent. Despite safety concerns, irrigation with effluent is an effective way to recycle nutrients and water (see also waterborne diseases pathogens and contaminants).

At a Glance

Working Principle

With drip irrigation, water is conveyed under pressure through a pipe system to the fields, where it drips slowly onto the soil through emitters or drippers, which are located close to the plants.

Capacity/Adequacy

It is applicable to almost every crop prediction, especially in arid, dry areas.

Performance

High

Costs

Commercial system for industrial production is very expensive. Small-scale or self-made systems are inexpensive

Self-help Compatibility

Expert design is required for commercial systems. Small-scale drip systems can be operated by trained farmers.

O&M

Flush piping system once a month to prevent clogging and check if the pipes are not covered by soil/foliage or damaged.

Reliability

Very reliable if operated and maintained well.

Main strength

High water application efficiency.

Main weakness

Water must be well settled and particle-free because of the high risk of clogging.

Applicability

Generally, drip irrigation is the most appropriate irrigation method; it is especially good for arid and drought prone areas. Drip and subsurface drip irrigation is used almost exclusively when using recycled municipal wastewater. Regulations typically do not permit spraying water through the air that has not been fully treated to potable water standards (WIKIPEDIA 2011). Furthermore, this system can be very technical for industrial crop production but also a simple small-scale irrigation method, which farmers can construct by themselves.

Advantages

  • High water application efficiency and lower labour costs
  • Minimised fertiliser/nutrient loss due to localised application and reduced leaching
  • Ability to irrigate irregular shaped fields. Levelling of the field not necessary
  • Allows safe use of recycled (waste-) water
  • Moisture within the root zone can be maintained at field capacity and minimised soil erosion
  • Soil type plays less important role in frequency of irrigation
  • Highly uniform distribution of water i.e., controlled by output of each nozzle
  • Usually operated at lower pressure than other types of pressurised irrigation, reducing energy costs

Disadvantages

  • Expensive initial cost can be more than overhead systems (commercial system)
  • The sun can affect the tubes used for drip irrigation, shortening their usable life
  • If the water is not properly filtered and the equipment not properly maintained, it can result in clogging
  • Drip irrigation might be unsatisfactory if herbicides or top dressed fertilisers need sprinkler irrigation for activation
  • Waste of water, time & harvest, if not installed properly
  • Systems require careful study of all the relevant factors like land topography, soil, water, crop and agro-climatic conditions, and suitability of drip irrigation system and its components
  • Without sufficient leaching (most drip systems are designed for high efficiency, meaning little or no leaching fraction), salts applied with the irrigation water may build up in the root zone

References Library

INFONET-BIOVISION (Editor) (2010): Water for Irrigation. Zürich: Biovision. URL [Accessed: 02.08.2010].

FAO (Editor) (1988): Irrigation Water Management: Irrigation Methods. (= Training manuals - 5). Rome: Food and Agriculture Organization of the United Nations (FAO). URL [Accessed: 12.07.2010].

STANDISH, S. (2009): How to Irrigate On A Shoestring. Portland: Global Envision. URL [Accessed: 23.06.2011].

TILLEY, E.; LUETHI, C.; MOREL, A.; ZURBRUEGG, C.; SCHERTENLEIB, R. (2008): Compendium of Sanitation Systems and Technologies. Duebendorf, Switzerland: Swiss Federal Institute of Aquatic Science and Technology (EAWAG) and Water Supply and Sanitation Collaborative Council (WSSCC). URL [Accessed: 15.02.2010]. PDF

See document in FRENCH

WIKIPEDIA (Editor) (2011): Drip Irrigation. URL [Accessed: 23.06.2011].

Further Readings Library

Reference icon

FAO (Editor) (1988): Irrigation Water Management: Irrigation Methods. (= Training manuals - 5). Rome: Food and Agriculture Organization of the United Nations (FAO). URL [Accessed: 12.07.2010].

This report — the full version only available on-line — shortly explains various irrigation techniques and contains pictures of all the different methods.


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IMAS, P. (2005): Fertigation: Optimizing the Utilization of Water and Nutrients. (= Fertigation Proceedings: Selected papers presented at the joint IPI-NATESC-CAU CAAS International Symposium on Fertigation Optimizing the utilization of water and nutrients Beijing). URL [Accessed: 13.08.2010]. PDF

The papers in these proceedings demonstrate the many uses of fertigation and highlight the opportunities created by effectively managing water and nutrients.


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NEIBLING, H.; ROBBINS, J.A. (n.y.): Equipment Selection and Sizing for Sprinkler and Drip Irrigation. Idaho: University of Idaho. URL [Accessed: 21.06.2011]. PDF

This document describes small-scaled sprinkler and drip systems and also discusses the technical aspects.


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SHOCK, C. (2006): Drip Irrigation: An Introduction. Corvallis: Oregon State University. URL [Accessed: 23.06.2011]. PDF

A document about drip irrigation system including components, design advices, management of the system and additional resources.


Reference icon

TILLEY, E.; LUETHI, C.; MOREL, A.; ZURBRUEGG, C.; SCHERTENLEIB, R. (2008): Compendium of Sanitation Systems and Technologies. Duebendorf, Switzerland: Swiss Federal Institute of Aquatic Science and Technology (EAWAG) and Water Supply and Sanitation Collaborative Council (WSSCC). URL [Accessed: 15.02.2010]. PDF

This compendium gives a systematic overview on different sanitation systems and technologies and describes a wide range of available low-cost sanitation technologies.

See document in FRENCH


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RCSD (Editor) (2008): Low Cost Drip Irrigation Manual. Assam: Resources Centre for Sustainable Development (RCSD). URL [Accessed: 01.01.1970]. PDF

This two-page paper manual describes the low-cost drip irrigation.


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GENSCH, R. ; MISO, A.; ITSCHON, G. (2011): Urine as Liquid Fertilizer in Agricultural Production in the Philippines. Cagayan de Oro: Sustainable Sanitation Center Xavier University (XU), the Philippine Sustainable Sanitation Knowledge Node, the Philippine Ecosan Network, and the Sustainable Sanitation Alliance (SuSanA). URL [Accessed: 04.05.2011]. PDF

This field guide has been developed to accommodate the ever-increasing demand for more detailed and scientifically backed information on how to use urine in agricultural production. It is intended primarily for practitioners and experts in the water, sanitation, planning, and agriculture sectors, as well as local and national government officials from the various sectors, NGO and individuals interested and working in the field of agriculture and sustainable sanitation in the Philippines and the wider Southeast Asian region.


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IDE (Editor) (n.y.): Technical Manual for Ideal Micro Irrigation Systems. Golden: International Development Enterprises. URL [Accessed: 30.11.2011]. PDF

This manual features comprehensive parts lists and instructions for assembling low-cost drip irrigation systems.


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SIJALI, I.V. (2001): Drip Irrigation Options for Smallholder Farmers in Eastern and Southern Africa. Stockholm: Sida's Regional Land Management Unit. URL [Accessed: 29.02.2012]. PDF

Smallholder farmers in the semi-arid regions of eastern and southern Africa have to depend on erratic, unreliable and low rainfall for their livelihoods. Subsistence staple food crops are generally grown under rainfed conditions. Consequently there is a growing interest in complementing this risky rainfed food production with cultivation of high-value vegetable crops and fruits. But in most cases this means these small-scale vegetable gardens and orchards must be irrigated in order to assure an economic return. Drip irrigation methods minimize the non-productive water losses associated with conventional irrigation, e.g. from evaporation and soil runoff, and thus can make more efficient use of the already minimal water supplies in these arid areas. But until recently drip irrigation technology had been associated with costly investments available only to large commercial farmers. Now there is growing interest in the technique and many efforts are being made around the world to develop low-cost, simple, drip irrigation systems suitable for smallholder farmers. This handbook presents some of these drip irrigation options that can be promoted by extension officers in eastern and southern Africa. It describes the most interesting small-scale low-cost drip irrigation methods of which the author and the other contributors have practical experience. It also gives a brief overview of methods that have been used successfully in other parts of the world with details of how to obtain further information about them or order equipment.


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ALEMEHAYU, T.; DEMISSIE, A.; LANGAN, S.; EVERS, J. (2011): Irrigation Practice and Policy in the Lowlands of the Horn of Africa. Rome: Food and Agriculture Organization of the United Nations (FAO). URL [Accessed: 26.03.2012]. PDF

The drought of 2011 and the famine that followed in politically instable Somalia highlighted the vulnerability of the lowlands of the Horn of Africa. It is a story revisited with high frequency – 2000, 2005, and 2008. Climate variability is easily mentioned as the main attributing factor. Clearly it is – but there is also extensive land use change, because of the widespread invasion of invasive species (prosopis in particular) and the decimation of natural wood stands for charcoal production (particularly in Somalia). 2011 was a crisis year – but even in a normal years food insecurity is common. In the Afar lowlands in Ethiopia food aid has become part of the livelihoods, with most of the people dependent on it – including reportedly middle class families. There is a growing realization that water resource development – appropriate to the context – has to have a place in addressing food insecurity in the Horn of Africa. This paper focuses on irrigation policy and practice in the arid lowlands of the Horn that have been hit hardest and most frequent in the drought episodes


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RODDA, N.; CARDEN, K.; ARMITAGE, N.; PLESSIS, H.M. du (2011): Development of Guidance for Sustainable Irrigation Use of Greywater In Gardens and Small-Scale Agriculture in South Africa. Pretoria: Water Research Commission (WRC). URL [Accessed: 11.05.2012]. PDF

There are presently no formal guidelines for the use of greywater in South Africa. This paper presents the rationale and framework of a guidance document for the sustainable use of greywater to irrigate gardens and small-scale agriculture in South Africa, developed under the auspices of the Water Research Commission.


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DRECHSEL, P. (Editor); SCOTT, C.A. (Editor); RASCHID-SALLY, L. (Editor); REDWOOD, M. (Editor); BAHRI, A. (Editor) (2010): Wastewater Irrigation and Health. Assessing and Mitigating Risk in Low-Income Countries. London: Earthscan. URL [Accessed: 15.05.2012]. PDF

This book is written for practitioners, researchers and graduate students in environmental and public health, sanitary and agricultural engineering, and wastewater irrigation management in developing countries. In particular, it should be useful for all those working to assess and mitigate health risks from the use of wastewater and faecal sludge in agriculture, under conditions where wastewater treatment is absent or inadequate to safeguard public health. In this respect, the book builds on and complements the international Guidelines for the Safe Use of Wastewater, Excreta and Greywater published in 2006 by the World Health Organization in collaboration with the Food and Agriculture Organization of the United Nations and the United Nations Environment Programme.


Case Studies Library

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ANDERSSON, L. (2005): Low-Cost Drip Irrigation. On Farm Implantation in South Africa. Lulea: Lulea University of Technology . URL [Accessed: 23.06.2011]. PDF

Small-scale rural farmers’ perceptions, attitudes and preferences of low-cost drip irrigation systems were investigated through a series of interviews conducted before, during and following their use of such systems. Responses were analysed to determine the technological, socioeconomic and cultural suitability of the systems.


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BELDER, P.; ROHRBACH, D.; TWOMLOW, S.; SENZANJE, A. (2007): Can Drip Irrigation Improve the Livelihoods of Smallholders? Lessons Learned from Zimbabwe. Bulawayo: International Crops Research Institute for the Semi-Arid Tropics (ICRISAT). URL [Accessed: 23.06.2011]. PDF

The survey focuses on the determinants of success and failure and identifies knowledge gaps that influenced either adoption or disadoption by beneficiaries. A cost-effectiveness analysis is also undertaken to compare drip kits with traditional bucket irrigation. Finally, the study draws some conclusions and lessons that can be extrapolated beyond Zimbabwe to ensure that interventions aimed at smallholder-irrigated gardens have more sustainable impacts.


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BURNEY, J.; WOLTERING, L.; BURKE, M.; NAYLOR, R.; PASTERNAK, D. (2009): Solar-powered Drip Irrigation Enhances Food Security in the Sudano–Sahel. Washington, DC: Proceedings of the National Acedemy of Sciences of the United States (PNAS). URL [Accessed: 23.06.2011]. PDF

This paper analyses solar-powered drip irrigation as a strategy for enhancing food security in the rural Sudano–Sahel region of West Africa.


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PALANISAMI, K.; RAMAN, S. (2012): Potential and Challenges in Up-scaling Micro-irrigation in India. Experiences from Nine States . (= Water Policy Research Highlight, 20). Gujarat, India: IWMI-Tata Water Policy Program. URL [Accessed: 15.01.2013]. PDF

This paper aims to fill a research gap in India by focusing on adoption patterns of micro irrigation and the economic impacts on farm households.This study is based on primary and secondary data collected from nine states. It seeks to establish a relationship between landholding size, area under micro-irrigation, and net benefits. Farmers' suggestions for making micro irrigation more accessible are also noted.


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PULLABHOTLA, H.K.; KUMAR, C.; VERMA, S. (2009): Micro-irrigation Subsidies in Gujarat and Andhra Pradesh. Implications for market dynamics and growth. (= Water Policy Research Highlight, 43). Gujarat, India: IWMI-Tata Water Policy Program. URL [Accessed: 15.01.2013]. PDF

Despite its proven benefits, micro-irrigation has been slow to realise its potential in India. Following the recommendations of the Micro-irrigation task force in 2004, a tiered set of subsidies was put into place for micro-irrigation. The models set up in Andhra Pradesh and Gujarat have been considered the most successful. This paper compares these two models using several parameters and comes up with a set of recommendations for replication elsewhere.


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BAMUTAZE, A.B.N.; BABIRYE, V. (2013): Drip Irrigation and Fertigation Prospective. A Case Study of Cabbage Growing at the ATC, Mukono District. Mukono: Appropriate Technology Centre (ATC) for Water and Sanitation. URL [Accessed: 21.10.2013]. PDF

The study aimed at assessing the feasibility of using urine as a fertilizer and drip irrigation technology to address food scarcity that has hit Uganda as a country of late. The study revealed high rates of return for a farmer who chooses to practice drip irrigation and fertigation. This however gives best results with effective disease control.


Training Material Library

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IDE (Editor) (n.y.): Simple Drip Irrigation. Golden: International Development Enterprises. URL [Accessed: 30.11.2011]. PDF

This PDF-presentation shows photos of drip system components and installations in Nepal.


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PALADA, M.; BHATTARAI, S.; WU, D.; ROBERTS, M.; BHATTARAI, M.; KIMSAN, R.; MIDMORE, D. (2011): More Crop Per Drop. Using Simple Drip Irrigation Systems for Small-scale Vegetable Production. Shanhua, Tainan: AVRDC - The World Vegetable Center. URL [Accessed: 18.01.2012]. PDF

Simple low-cost drip irrigation is practical and affordable for smallholder farmers. It has been successfully used in India and is becoming more popular in other southeast Asia and sub-Saharan Africa. It can reduce both water and labor use by as much as 20-50%. Yield of vegetables also can be increased by at least 10%. Our farm trials in Cambodia showed yield increases of 20-50% compared to traditional hand watering. Low pressure irrigation is also a key component of the African Market Garden concept jointly developed in west Africa with ICRISAT. This 10-chapter drip irrigation manual provides basic, step-by-step procedures for installing simple drip irrigation systems for different crops, climates, and soils.


Important Weblinks

http://www.fao.org/ [Accessed: 23.06.2011]

This website is an attempt to distil current information on irrigation methods that might be appropriate, and to offer some ideas on the possible adoption and adaptation of such methods by small-scale farmers in the semi-arid areas of sub-Saharan Africa.

http://www.infonet-biovision.org

Water for irrigation: different irrigation techniques and tips for using water for irrigation

www.ideorg.org [Accessed: 30.11.2011]

The website of International Development Enterprises (IDE) contains many (technology-)documents, photos and information about the water and agricultural section in developing countries.