14: Microirrigation
- Page ID
- 44310
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)- 14.1: Introduction
- This page discusses microirrigation as an effective irrigation method for high-value crops, highlighting its efficiency, especially in difficult soil types. Key factors for farmers include cost-effectiveness, emitter clogging prevention through filtration, and proper emitter selection. Benefits include enhanced plant growth and reduced energy usage; however, challenges include high initial costs and ongoing maintenance needs.
- 14.2: History and Impact
- With the addition of appropriate additives, such as carbon black, antioxidants, and stabilizers, clear plastic could be converted into a black, durable and economical pipe, well suited for microirrigation. The first survey of microirrigation in the U.S. in 1974 (Irrigation Journal, 1974) reported about 70,000 acres of microirrigation. California had more than half of the national total
- 14.3: System Types
- Microirrigation includes trickle, drip, subsurface, bubbler, and spray irrigation systems (ASABE, 2019). Trickle and drip irrigation are often considered synonymous and we will refer to it as drip irrigation in this book. Here we differentiate these systems into four major types based on installation method, emitter design, or mode of operation.
- 14.4: System Components
- Water discharge, in most systems, is controlled by adjusting the pressure or by regulating the flow at the manifold inlets. The regulators used for this purpose are usually preset for a given pressure or flow rate and are not adjustable. From the mainline, water is distributed through manifolds to laterals where water application occurs. Water discharge, in most systems, is controlled by adjusting the pressure or by regulating the flow at the manifold inlets.
- 14.5: Preventing Clogs
- Clogging of emitters is one of the major concerns for microirrigation. Obviously, the smaller the orifice or the longer the capillary section, the more prone the emitter is to clogging. Emitters can be clogged by particles, bacterial slimes, algae, water-borne organisms, or precipitation of various chemicals. Filtering to prevent mineral and organic particles from entering the system or chemical injections to prevent mineral precipitation or the growth of slime are the normal management schemes
- 14.6: Uniformity
- The primary objective of a microirrigation system is to supply the prescribed amounts of water and chemicals to each plant at frequent intervals and in small volumes. For maximum uniformity the variation in discharge from the various water applicators must be acceptably low. Uniformity of manufacturing is critical when selecting emitters for a microirrigation system.
- 14.7: Management
- The success of any irrigation system, particularly microirrigation, depends on management. Irrigating by small quantities frequently is quite different from sprinkler and surface irrigation methods where larger, less frequent applications are normal. With microirrigation, precise information on crop water requirements is required to determine the appropriate irrigation amount.
- 14.8: Summary
- The necessity and selection of equipment at the control station are presented along with the procedures to select the appropriate diameter of the various sections of the pipeline. A major concern with microirrigation is the potential for clogging the emitters. The types of filters normally recommended are described and the types of materials that lead to clogging are discussed
- 14.9: Questions
- What environmental and/or economic factors give microirrigation an advantage when selecting an irrigation system? What is the present land area under microirrigation in the U.S.? How does this compare with the total irrigated area in the U.S.? Do you think microirrigation will increase in the future? Why? From a water sample of your choice, evaluate the potential for the water to clog a microirrigation system.
- 14.10: References
- ASABE Standards (2019). ASAE EP405.1 APR1988 (R2019): Design and installation of microirrigation systems. St. Joseph, MI: ASABE. Bucks, D. A., Nakayama, F. S., & Gilbert, R. G. (1979). Trickle irrigation water quality and preventive maintenance. Agric. Water Manag, 2, 149-196. Bucks, D. A., Nakayama, F. S., & Warrick, A. W. (1982).