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Costs and Benefits of More Efficient Irrigation Systems for Florida Chipping Potato Production1

Jenna Rogers, Tatiana Borisova, Lincoln Zotarelli, Kelly Grogan, Jeffrey Ullman, Jessica Bertine, and Kelly Morgan 2

Acknowledgment

We are appreciative of the assistance provided by Serhat Asci, research fellow, Center for Agricultural Business, California State University Fresno, Fresno, CA.

Introduction

The goal of this article is to help producers and other interested parties understand how alternative irrigation systems can affect economic outcomes in agricultural operations. We used chipping potato production in the Hastings area in northeast Florida as an example to discuss factors to consider when selecting an irrigation system.

Investing in more efficient irrigation systems can provide significant advantages for producers. In a survey of 31 US eastern states, more than half of the surveyed farms that had improved their irrigation systems between 2003 and 2008 reported improved yield/quality (68%), reduced energy costs (57%), and/or reduced water applied (54%) (Table 1). These statistics presented a regional perspective on irrigation systems. In 2013, researchers at the University of Florida conducted a survey of Florida producers specifically on irrigation systems. The results of this survey generally complied with the regional data. More information can be found in a study by van Dijl (2013).

Changes in the regulatory framework guiding water use (e.g., monitoring requirements, water fees, and reduction in water use permits) and possible reductions in water availability due to weather/climate conditions provide additional incentives for agricultural producers to invest in water conservation and water-efficient irrigation technologies.

In this article, we focused on chipping potato production in the Hastings area in northeast Florida (Figure 1). We first reviewed existing Florida-specific studies that identified the costs and benefits of switching to a subsurface drip irrigation system in potato production. Then we combined those cost and benefit estimates with the UF/IFAS chipping potato production budget to identify whether it is economically justifiable for producers to switch from a seepage irrigation system to a drip irrigation system or a tile drain irrigation system. Specifically, we estimated the value of switching irrigation systems over a ten-year period to enable producers to make better decisions regarding the long-term costs and benefits of alternative irrigation systems and water use.

Figure 1. Counties in northeast Florida TCAA [Credit: Mossler and Hutchinson (2014)]
Figure 1.  Counties in northeast Florida TCAA [Credit: Mossler and Hutchinson (2014)]

Alternative Irrigation Systems for Florida Potato Production

The irrigation methods typically used in Florida potato production are described below.

Seepage irrigation is an irrigation system in which ground water is pumped from wells and delivered to furrows. These irrigation furrows are usually spaced 60 feet apart (the furrows set the boundaries to every bed, and each bed contains 16 potato rows). The furrow water seeps laterally across the rows. Growers use water retention structures to hold the water back in ditches to raise the water table (Reyes-Cabrera et al. 2014; Figure 2). The furrows, along with the cross-cuts, are also used to remove the water from the fields during high precipitation events (Zotarelli et al. 2013). Because historically most of the Florida potato fields were set up to use seepage irrigation, this system is the most familiar to the producers, and it is the least costly to operate. However, depending on the system management, irrigation efficiency with this system can be low (Table 2). Note that in the years with sufficient rainfall, irrigation may not be needed at all because the water table will be high enough to water plants effectively.

Figure 2. Traditional seepage irrigation system used to manage the water table for a potato crop in Hastings, Florida [Credit: L. Zotarelli, UF/IFAS]
Figure 2.  Traditional seepage irrigation system used to manage the water table for a potato crop in Hastings, Florida [Credit: L. Zotarelli, UF/IFAS]

Drip irrigation is a micro-irrigation system that uses drip tapes placed either on the surface of the soil or four to five inches below the surface to supply water directly to the root zone (Reyes-Cabrera 2014; Figure 3). This method seeks to keep the water table low and to only place water needed for plant growth at the plants' roots with one drip tape per potato row. Furrows between the beds are still required to remove excess water from the fields after rain. The advantages of the system are significant potential reductions in water use (Table 2) and opportunities for fertigation (with potential reduction in the use of fertilizers). A disadvantage is the high cost of maintenance (the drip tapes generally need to be replaced annually). For more information on drip irrigation, see Dukes et al. (2008).

Figure 3. Surface drip irrigation for potato production [Credit: L. Zotarelli, UF/IFAS]
Figure 3.  Surface drip irrigation for potato production [Credit: L. Zotarelli, UF/IFAS]

Subsurface drip irrigation for water table management (WTM) is a system for which water is delivered under pressure through polyvinyl chloride (PVC) pipes (i.e., subsurface drip irrigation tape) buried two feet below the surface (Figure 4). The walls of the pipes are permeable, allowing water to enter the soil. These pipes are placed every fourth row in the field (or three to four drip tapes per a 60-foot-wide bed of 16 potato rows). Like seepage irrigation, subsurface drip irrigation for WTM allows for lateral seepage of water to raise the water table. In comparison with the seepage system, this system can result in water savings by eliminating water evaporation from the furrows during irrigation. However, compared to seepage irrigation, subsurface drip irrigation for WTM requires higher energy use to pressurize the water and pump it through the pipes. This system also requires annual cleaning, as well as daily spigot operation and maintenance. In addition, like seepage irrigation, subsurface drip irrigation for WTM requires furrows every 60 feet and cross-cuts in the field for drainage (Zotarelli et al. 2013).

Figure 4. Installation of subsurface drip irrigation tape at a depth of 24 inches below the soil surface in a potato field in Hastings, Florida [Credit: L. Zotarelli, UF/IFAS]
Figure 4.  Installation of subsurface drip irrigation tape at a depth of 24 inches below the soil surface in a potato field in Hastings, Florida [Credit: L. Zotarelli, UF/IFAS]

Tile Drain (aka Irridrain or subsurface tile) uses corrugated 3- to 4-inch PVC pipes with permeable walls buried three feet deep every 20 to 25 feet (Figure 5). The pipes both irrigate and drain the field. The primary advantage of the tile drain irrigation system is the increased yield per area that is achieved by removing furrows to gain 11–12% more plantable ground. Another advantage is that the system decreases evaporation. Since this irrigation system does not require pressurized water pumping, energy use is comparable to seepage irrigation.

Figure 5. Title drain system [Credit: Illinois NRCS (2013)]
Figure 5.  Title drain system [Credit: Illinois NRCS (2013)]

In addition to irrigation efficiency, a variety of system characteristics are important for growers' choice of irrigation systems. Past studies have explored the changes in production costs and yields that can be attributed to replacing seepage irrigation with alternative irrigation systems (Table 3). The estimates vary widely among the studies, partially because of the different irrigation systems considered, the potato varieties examined, and the sizes of the farms analyzed. The previous studies highlight the variability in costs and benefits of alternative irrigation systems which is important for a producer to consider. Note, however, that these studies do not consider cost-share funding available from the USDA Natural Resources Conservation Service (USDA/NRCS) to reduce installation costs. The USDA/NRCS cost-share payment rate is provided to participating producers as part of the Environmental Quality Incentive Program (EQIP) that addresses natural resource concerns. A 75% cost-share rate is given to those who are farming within the designated USDA/NRCS Tri-County Agricultural Area (TCAA) to implement more efficient irrigation systems.

In this study, we specifically focus on the economics of two of the alternative irrigation systems: subsurface drip for WTM and tile drainage. We do not consider surface/subsurface drip irrigation systems because no Florida-specific studies evaluate the changes in input costs due to fertigation, which is a main advantage of these systems.

Methods and Data

To compare the economic performance of the irrigation systems, we estimated a ten-year net present value ($/acre) for each system. We disregard the costs of preparing the field for the use of the seepage irrigation system since such systems are installed on most Florida potato farms. The ten-year net present value, NPV, is estimated, where annual net returns are based on yields, prices, and production and harvesting costs. The year of irrigation system installation is assumed to be 2011. Because potato yield and price vary from year to year, 500 samples of ten-year period yields and prices are generated, and a distribution of NPV for each irrigation system type is generated using Simetar© Excel Add-In (Richardson 2001).

Seepage Irrigation, Baseline. This scenario is based on the chipping potato production budget (IATPC 2008/09) indexed to 2011 (US Bureau of Labor Statistics 2013). Information regarding average yield and price for chipping potatoes in Hastings, Florida, was obtained from the USDA for years 1984–2010 (Table 5). To forecast yields and prices for years 2011–2020, a simple regression model was used.

Subsurface drip irrigation for WTM. In this scenario, we assume that the producer installs a subsurface drip irrigation system for WTM in 2011. Note that the previous studies report a range of possible costs and benefits incurred by installing this irrigation system. In this study, we selected the following scenario, and the baseline budget for potato production was modified as follows:

  • 70% increase in pumping costs (based on Smajstrla 2000)

  • 25% increase in labor costs due to pipe cleaning and spigot maintenance (based on Casey 1996)

  • Additional irrigation system depreciation, assuming a ten-year life span of the system and using straight-line depreciation methods

The installation costs for this system are estimated at $705 per acre based on the USDA/NRCS cost modeling procedure, with a $528.50 cost-share rate. Note that the scenario assumes an increase in production costs compared to the baseline seepage system. We also assume that expected potato yields remain the same as for the seepage irrigation system. Actual producer experiences in the field can differ.

Tile drain (Irridrain). The installation costs are estimated to be approximately $2,316 per acre based on a cost modeling procedure for determining cost-share amounts from the USDA/NRCS. In Hastings, Florida, potato producers could receive $1737 per acre for a tile drain irrigation system, which is approximately 75% of the estimated total installation cost. Also, the following modifications were made to the baseline budget (i.e., budget for the seepage irrigation method):

  • 50% decrease in pumping costs (based on the data from one of the farms in Hastings, Florida, implenting tile drains)

  • Additional irrigation system depreciation assuming a thirty-year life span of the system and using straight-line depreciation method

Because the system eliminates furrows and therefore allows for an 11–12% increase in plantable area as compared to a seepage system, for this scenario, we assumed a 10% increase in yields. Note that this specification ignores possible effects of increased potato yields and harvests on the potato sale price. This specification also assumes that the increase in the harvestable area does not affect yearly variability in yield.

Results and Discussion

Based on the information presented above, the ten-year NPV per acre for different irrigation systems is shown in Figure 6 and is summarized below:

  • Seepage irrigation, baseline: ten-year NPV per acre, ranging from $1,729 to $20,671/acre, centered on an average NPV of $6,911/acre

  • Subsurface drip irrigation for WTM: ten-year NPV per acre, ranging from $2,996 to $19,404, centered on an average NPV of $5,645

  • Tile drain (Irridrain): ten-year NPV per acre, ranging from $1,155 to $21,289, centered on an average NPV of $9,209

Figure 6. Ten-year NPV distributions of three irrigation systems [Credit: Authors' illustration]
Figure 6.  Ten-year NPV distributions of three irrigation systems [Credit: Authors' illustration]

Given the assumptions about the costs and benefits of the tile drain irrigation system, the financial analysis shows that Hastings potato producers can benefit by switching from a traditional seepage irrigation system to a tile drain irrigation system. The primary advantage of the tile drain irrigation system is the increase in plantable land area, and hence yields that offset the investment cost and the increase in operation and maintenance costs. As seen in Figure 6, the tile drain irrigation system represents the highest mean ten-year NPV.

In contrast, given the assumptions about the increase in energy and labor costs, the subsurface drip irrigation for the WTM system does not yield as much of a benefit to the producers. In fact, it performs worse than the seepage irrigation system. Note the analysis is conducted using limited data, and hence does not account for all benefits that producers could experience from the system. For example, we did not have any information about the potential changes in yields due to potentially more effective water management provided by a subsurface drip irrigation for WTM system. To illustrate the importance of this assumption, we examined an alternative scenario for a subsurface drip irrigation for WTM system. Specifically, we assumed that the system increases yield and reduces pumping costs:

  • 10% increase in yield

  • 41% decrease in pumping costs (Casey 1996)

  • 25% increase in labor costs due to pipe cleaning and spigot maintenance (Casey 1996)

  • Additional irrigation system depreciation, assuming a ten-year lifespan of the system and using straight-line depreciation method

These modified assumptions significantly improved the performance of the subsurface drip irrigation for WTM system, making the ten-year NPV comparable with the baseline seepage irrigation system (despite the investment costs and potential increase in labor costs) (Figure 7): modified subsurface drip irrigation for WTM system, with ten-year NPV per acre, ranging from $1,768 to $19,438, centered on an average NPV of $9,338.

Figure 7. Ten-year NPV distributions of three irrigation systems, WTM example [Credit: Authors' illustration]
Figure 7.  Ten-year NPV distributions of three irrigation systems, WTM example [Credit: Authors' illustration]

A summary of simulation results for the three irrigation systems is presented in Table 4. In addition, summary tables for the historic potato yields and prices (Table 5), as well as estimated average cost and revenue information for the three irrigation systems (Table 6) are provided.

Conclusions

Using an example of chipping potato production in the Hastings area of northeast Florida, we discussed the factors to be considered in selecting an alternative irrigation system. Based on the handful of existing studies, we developed scenarios to describe the potential benefits and costs of tile drain irrigation systems and subsurface drip irrigation for WTM systems, and compared these systems with the traditional seepage irrigation system.

Our analysis shows that changes in energy and labor costs can affect producers' decisions to invest in alternative irrigation systems. However, the potential increase in yields is the primary determinant of the profitability of more water-efficient irrigation systems. For example, a 10% increase in plantable area and a corresponding 10% increase in yields would make the tile drainage irrigation system out-perform the seepage irrigation system by approximately $2,000 per acre over a ten-year period. Similarly, a 10% increase in yield would make the financial performance of the subsurface drip irrigation for WTM systems comparable with the traditional seepage irrigation system, despite a potential increase in labor costs and depreciation. It is also important to mention that the USDA/NRCS cost-share covers approximately 75% of the investment costs of more water-efficient systems, improving the financial performance for such systems.

Changes in the regulatory framework guiding water use (such as water-use monitoring requirements, water fees, or reduction in water-use permits), along with the possible reduction in available water due to weather/climate conditions, provide additional incentives for producers to invest in water conservation and water-efficient irrigation technologies. Furthermore, salinity concerns are significant in northeast Florida, as well as in other parts of the state. The tile drain irrigation system or the sub-surface drip irrigation for WTM system could be beneficial for reducing saltwater intrusion, and hence reducing/delaying the effect of salinity on yields.

References

Casey, F., P. Byrne, and R. Weldon. 1996. The economic feasibility of automated sub-drip irrigation for potato production in Florida. Florida's Water website. ftp://secure.sjrwmd.com/technicalreports/SP/SJ97-SP9.pdf

Dukes, M., D. Haman, R.O. Evans, G.L. Grabow, K. Harrison, A. Khalilian, W.B. Smith, D.S. Ross, P. Tacker, D.L. Thomas, R.B. Sorensen, E. Vories, and H. Zhu. H. 2008. "SDI considerations for North Carolina growers and producers." Subsurface Drip Irrigation (SDI). North Carolina Cooperative Extension, Raleigh, NC. https://content.ces.ncsu.edu/sdi-considerations-for-north-carolina-growers-and-producers

Dukes, M., D. Haman, R.O. Evans, G.L. Grabow, K. Harrison, A. Khalilian, W.B. Smith, D.S. Ross, P. Tacker, D.L. Thomas, R.B. Sorensen, E. Vories, and H. Zhu. H. 2008. "Site selection for SDI systems in North Carolina." Subsurface Drip Irrigation (SDI). North Carolina Cooperative Extension, Raleigh, NC. https://content.ces.ncsu.edu/site-selection-for-sdi-systems-in-north-carolina

Dukes, M., D. Haman, R.O. Evans, G.L. Grabow, K. Harrison, A. Khalilian, W.B. Smith, D.S. Ross, P. Tacker, D.L. Thomas, R.B. Sorensen, E. Vories, and H. Zhu. H. 2008. "Design and installation of SDI systems in North Carolina." Subsurface Drip Irrigation (SDI). North Carolina Cooperative Extension, Raleigh, NC. https://content.ces.ncsu.edu/design-and-installation-of-sdi-systems-in-north-carolina

Dukes, M., D. Haman, R.O. Evans, G.L. Grabow, K. Harrison, A. Khalilian, W.B. Smith, D.S. Ross, P. Tacker, D.L. Thomas, R.B. Sorensen, E. Vories, and H. Zhu. H. 2008. "Critical management issues for SDI systems in North Carolina." Subsurface Drip Irrigation (SDI). A Series of four Extension Publications by North Carolina Cooperative Extension, Raleigh, NC. https://content.ces.ncsu.edu/critical-management-issues-for-sdi-systems-in-north-carolina

Ehmke, T. 2013. "Improving water and nutrient use efficiency with Drainage Water." Crops & Soils, July–August 2013. https://www.agronomy.org/publications/cns/pdfs/46/4/6

Haman, D.Z., A.G. Smajstrla, and D.J. Pitts. 2005. Efficiencies of irrigation systems used in Florida nurseries. EDIS #AE087. UF/IFAS Extension.

Howell, T.A. 2003. "Irrigation Efficiency." Encyclopedia of Water Science. https://www.researchgate.net/profile/Terry_Howell4/publication/43256707_Irrigation_Efficiency/links/566ec91c08aea0892c52a91c/Irrigation-Efficiency.pdf

IA Drip-Micro Common Interest Group Market Development Subcommittee. 2008. Drip-Micro Irrigation Payback Wizard. Website at http://www.dripmicrowizard.com

IATPC. 2008/09. UF/IFAS budgets for various crops in various areas of Florida. International Agricultural Trade and Policy Center, University of Florida, Gainesville, FL. http://www.fred.ifas.ufl.edu/iatpc/ibudgets09.php

Mossler, M.A., and C. Hutchinson. 2014. Florida Crop / Pest Management Profile: Potatoes. EDIS CIR 1237. UF/IFAS Extension, Gainesville, FL. https://edis.ifas.ufl.edu/pi030

Pitts, D.J., A.G. Smajstrla, D.Z. Haman, and G.A. Clark. 2002. Irrigation costs for tomato production in Florida. EDIS #AE074. UF/IFAS Extension, Gainesville, FL.

Richardson, J.W. 2001. Simulation for Applied Risk Management: With an Introduction to the Software Package Simetar: Simulation for Excel to Analyze Risk. College Station, TX: Texas A&M University.

Reyes-Cabrera, J., L. Zotarelli, D.L. Rowland, M.D. Dukes, and S.A. Sargent. 2014. "Drip as a alternative irrigation method for potato in Florida sandy soils." American Journal of Potato Research. doi:10.1007/s12230-014-9381-0.

Schaible G. and M. Aillery. 2012. Water conservation in irrigated agriculture: Trends and challenges in the face of emerging demands. USDA Economic Information Bulletin No. EIB-99. Economic Research Services, United States Department of Agriculture (ERS/USDA), Washington, D.C. (September). https://www.ers.usda.gov/webdocs/publications/44696/30956_eib99.pdf

Simmone, E., R. Hochmuth, J. Breman, W. Lamont, D. Treadwell, and A. Gazula. 2008. Drip-irrigation systems for small conventional vegetable farms and organic vegetable farms. EDIS #HS388. UF/IFAS Extension, Gainesville, FL. https://edis.ifas.ufl.edu/hs388

Smajstrla, A.G., B.J. Boman, G.A. Clark, D.Z. Haman, D.S. Harrison, F.T. Izuno, D.J. Pitts, and F.S. Zazueta. 2002. Efficiencies of Florida agricultural irrigation systems. EDIS #BUL247. UF/IFAS Extension, Gainesville, FL.

Smajstrla, A.J., S.J. Locascio, D.P. Weingartner, and D.R. Hensel. 2000. "Subsurface drip irrigation for water table control and potato production." Applied Engineering in Agriculture 16(3): 225–229. https://elibrary.asabe.org/abstract.asp?aid=5147&t=2&redir=&redirType

United States Bureau of Labor Statistics (USBLS). 2013. Producer Price Index Industry Data. Series ID: PCUBNEW—BNEW. Washington, D.C.

United States Geological Survey (USGS). 2005. Estimated use of water in the United States county-level data for 2005. USGS: data files for estimated use of water in the United States, 2005. Reston, VA. http://water.usgs.gov/watuse/data/2005/index.html

United States Geological Survey (USGS). 2014. Irrigation: How Farmers Irrigate Fields. Reston, VA. https://water.usgs.gov/edu/irquicklook.html

United States Geological Survey (USGS). 2014. Water Science Glossary of Terms. Reston, VA. https://water.usgs.gov/edu/dictionary.html

United States Geological Survey (USGS). 2014. U.S. Geological Survey: Water-use Terminology. Reston, VA. http://water.usgs.gov/watuse/wuglossary.html

Van Dijl, E. 2013. Determinants of Drought Adaptation among Field Vegetable Growers in Florida and Limburg. M.S. Thesis. Food and Resource Economics, University of Florida.

Zotarelli, L., L. Rens, C. Barrett, D. J. Cantliffe, M. D. Dukes, M. Clark, and S. Lands. 2013. Subsurface Drip Irrigation (SDI) for Enhanced Water Distribution: SDI—Seepage Hybrid System. HS1217. Gainesville: University of Florida Institute of Food and Agricultural Sciences. https://edis.ifas.ufl.edu/hs1217

Tables

Table 1. 

Responses to a nationwide farm survey.

Table 2. 

Irrigation efficiency of alternative irrigation systems.

Table 3. 

Summary of previous studies of drip irrigation for Florida vegetable production.

Table 4. 

Summary of simulation results for three irrigation systems (seepage, subsurface drip for WTM, and tile drain).

Table 5. 

Historical information of yield and price for potatoes in Hastings, FL.

Table 6. 

Estimated costs and returns for chipping potato production in Hastings, Florida ($/acre), given alternative irrigation systems (assumed yield is 274 cwt/acre, price is $14.42/cwt, and indexing the 2008/09 budget to year 2011).

Footnotes

1. This document is FE953, one of a series of the Food and Resource Economics Department, UF/IFAS Extension. Original publication date August 2014. Reviewed March 2018. Technical revision (correct broken links): June 2019. Visit the EDIS website at https://edis.ifas.ufl.edu.
2. Jenna Rogers, former graduate student, Food and Resource Economics Department; Tatiana Borisova, assistant professor, Food and Resource Economics Department; Lincoln Zotarelli, assistant professor, Department of Soil and Water Sciences; Kelly Grogan, assistant professor, Food and Resource Economics Department; Jeffrey Ullman, assistant professor, Department of Agricultural and Biological Engineering; Jessica Bertine, state agricultural economist, United States Department of Agriculture; and Kelly Morgan, associate professor, Department of Soil and Water Sciences; UF/IFAS Extension, Gainesville, FL 32611.

Publication #FE953

Date: 6/4/2019

  • Program Area: Agriculture Water
Fact Sheet
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