farm size, irrigation practices, and on-farm irrigation efficiency

IRRIGATION AND DRAINAGE

Irrig. and Drain. 54: 43–57 (2005)

Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/ird.148

FARM SIZE, IRRIGATION PRACTICES, AND ON-FARMIRRIGATION EFFICIENCYy

R. K. SKAGGS* AND Z. SAMANI

New Mexico State University, Las Cruces, NM 88003, USA

ABSTRACT

Relationships between farm size, irrigation practices, and on-farm irrigation efficiency in the Elephant Butte

Irrigation District, New Mexico, USA are explored using 2001 water delivery data supplied by the irrigation

district. The study area is experiencing rapid population growth, development, and competition for existing water

supplies. It is conventionally assumed that in the future water will be transferred from agriculture to other uses.

Analysis of pecan orchard water delivery data, fieldwork, and interviews with irrigators found extremely long

irrigation durations, inefficient irrigation practices, inadequate on-farm infrastructure, and lack of interest in

making improvements to the current irrigation system or methods on the smallest farms. These findings are

attributed to the nature of residential/lifestyle or retirement agriculture. Irrigation practices on large, commercial

orchards are notably different from the smallest farms: irrigation event durations are shorter, less water is applied,

and the producers are commercially oriented. With respect to future increases in the efficiency of irrigation

water usage, large, commercially oriented producers already have a high level of physical efficiency. Small

producers appear to view irrigation as a consumptive, recreational, social, or lifestyle activity, rather than

an income-generating pursuit, thus the cost of inducing changes in their practices may be extremely high.

Copyright # 2005 John Wiley & Sons, Ltd.

key words: agricultural structure; efficiency; irrigation; off-farm work; technology adoption; water transfer

RESUME

Les rapports entre superficie des expolitations, pratiques et efficacite de l’irrigation a la parcelle sont explores en

utilisant les donnees d’apport d’eau de 2001. Les donnees sont fournies par la Zone d’Irrigation d’Elephant Butte

du Nouveau Mexique aux Etats-Unis. Dans cette region on observe une croissance rapide de la population, et un

developpement accompagne d’une concurrence accrue pour les reserves en eau. L’eau agricole devrait dans le futur

y etre transferee a d’autres utilisations. L’analyse de donnees de fourniture d’eau a des vergers de noyers de pecan,

de travaux de terrain, et d’entrevues avec des agriculteurs a mis en evidence des durees extremement longues

d’irrigation, des pratiques inefficaces d’irrigation, des infrastructures parcellaires insatisfaisantes, et des petits

agriculteurs ne s’interessant pas aux ameliorations du systeme et des methodes d’irrigation.

Ces resultats sont attribues au style de vie residentielle ou a la nature d’agriculture pour les gens en retraite. Les

pratiques d’irrigation sur les grands vergers commerciaux sont notoirement differentes des plus petites fermes. Les

durees d’irrigation y sont plus courtes et des quantites d’eau moindres sont appliquees. L’efficacite de l’utilisation

de l’eau d’irrigation, y est donc elevee. Pour petits producteurs par contre, l’irrigation est surtout une activite de

consommation, de recreation, de culture, ou de style de vie, et non une affaire profitable. Dans ces conditions, le

Received 13 November 2003

Revised 6 March 2004

Copyright # 2005 John Wiley & Sons, Ltd. Accepted 23 August 2004

*Correspondence to: R. K. Skaggs, Agricultural Economics and Agricultural Business, Box 30003, MSC 3169, New Mexico State University,Las Cruces, NM 88003, USA. E-mail: [email protected] de ferme, pratiques d’irrigation, et efficacite d’irrigation sur ferme.

cout des changements de leurs pratiques sera sans doute extremement eleve. Copyright # 2005 John Wiley &

Sons, Ltd.

mots cles: structure agricole; efficacite; irrigation; travail outre de la ferme; adoption de technologie; transfert de l’eau

INTRODUCTION

The structure of agriculture1 in the United States is dualistic and will likely become more so in the future. This dual

structure is one where approximately 8% of farms (with annual sales over $250 000) produce more than 72% of the

total value of output, while 92% of farms are responsible for the remaining 28% of output (US Dept. of

Agriculture, 1999). A ‘‘farm’’ is defined by the US Census of Agriculture as any place from which $1000 or more

of agricultural products were produced and sold, or normally would have been sold, in a given year. In 1997, the

United States had 1.9 million farms comprising an extremely diverse farm sector. Approximately 50% of all US

farm operators do not consider farming to be their principal occupation and 55% of farms report some off-farm

work (US Dept. of Agriculture, 1999).

A new farm typology developed by the US Department of Agriculture’s Economic Research Service classifies

farms with less than $250 000 in annual sales as small farms (Hoppe and McDonald, 2001). This typology further

categorizes small farms as limited resource, retirement, residential/lifestyle, and farming occupation operations.

Of all US farms, 54% are retirement or residential/lifestyle operations, which account for 7.8% of the value of US

agricultural production (Hoppe, 2001).

Almost three-fourths of all US farms sell less than $50 000 worth of goods yearly (US Dept. of Agriculture,

1999). The 1.4 million farms in the lower sales categories tend to have chronic negative net farm incomes, and

many have no intention of earning a living from farming. For many of these people, crop or livestock production is

a consumption activity which must be subsidized with off-farm earnings. For example, residential/lifestyle farms

had an average 1998 total household income of $72 081 with average annual farm earnings of �$4309 (Hoppe,

2001). Average operator household earnings from farming activities as a percentage of average operator household

income in the United States has been less than 10% since 1999, and is expected to decline to 6.6% in 2003 (US

Dept. of Agriculture, 2003). The off-farm share of total farm household income for farms with annual sales

between $250 000 and $499 999 averaged 40.4% in 1999, and 106.3% for farms with sales less than $50 000 in the

same year (Mishra et al., 2002). These data illustrate the tendency for smaller farms to subsidize farm activities

with off-farm income.

Much of the residential/lifestyle and retirement agricultural activity occurs on the urban fringe and in rural areas

just beyond the urban fringe.2 In the arid western United States, retirement and residential/lifestyle farming is often

located in irrigated river valleys, which also tend to be rapidly growing in population and increasing in economic

diversity. Agricultural irrigation accounted for 92% of total consumptive water use in the 11 western states in 1995,

and market transfers of water from agriculture are viewed as the most likely way to accommodate growing

municipal and industrial demands for water supplies (Gollehon, 1999). It is often assumed that improving low

irrigation efficiencies will release water from agriculture to other uses, while at the same time allowing agricultural

production to continue. The economic, lifestyle, environmental, open space, and preservation values of urban

fringe agriculture could thus be maintained.

Increased irrigation efficiency implies a change in technology (e.g. adoption of drip irrigation, canal lining),

management practices (e.g. irrigation scheduling), or both. It is usually assumed that incentives to increase

irrigation efficiency will work because agricultural water users have traditional business-like objectives (e.g.

1The structure of agriculture refers to the number and size of farms, ownership and control of resources, and the managerial, technological, andcapital organization of farming (Knutson et al., 1995).2‘‘Urban fringe’’ is defined as the rural parts of metropolitan counties not settled densely enough to be called urban, while ‘‘beyond the urbanfringe’’ refers to the rural countryside beyond the edge of existing urban areas in metro counties and often in adjacent nonmetro counties(Heimlich and Anderson, 2001).

44 R. K. SKAGGS AND Z. SAMANI

Copyright # 2005 John Wiley & Sons, Ltd. Irrig. and Drain. 54: 43–57 (2005)

increased revenues and profits, and reduced costs). However, a significant percentage of farm operators throughout

the United States and in the West are not strongly motivated by business or commercial objectives.

New Mexico’s Lower Rio Grande Valley is experiencing rapid population growth, development of the rural

countryside, and decreasing municipal groundwater supplies. Plans are underway to transfer some of the surface

water from agriculture to municipal and industrial use in Dona Ana County, where most of the Elephant Butte

Irrigation District (EBID) is located. Lifestyle agriculture is widespread in the county, where the number of

irrigated farms increased by 70% between 1974 and 1997 (US Dept. of Commerce, 1981; US Dept. of Agriculture,

1999). Irrigated acreage in the EBID has been stable over that period of time (approximately 75 000 acres or

30 352 ha), while numbers of farms in the smallest acreage categories grew dramatically as a result of land splits.

For instance, there were 150 farms between 1 and 9 acres (0.41–3.64 ha) in 1974 and 691 of these farms in 1997

(US Dept. of Commerce, 1981; US Dept. of Agriculture, 1999).

Conveyance efficiency (e.g. diversion/farm delivery) in the EBID is estimated to be 54%, while district-wide on-

farm irrigation efficiency (e.g. consumptive irrigation requirement/farm delivery) is estimated to be 83%

(Magallanez and Samani, 2001). Although most of the District is irrigated by traditional basin or basin-furrow

methods (with no runoff from the end of the field), on-farm efficiency (crop consumptive use relative to farm

delivery) is high as a result of deficit irrigation3 practices on much of the crop acreage. Samani and Al-Katheeri

(2001) used on-site flow measurement and chloride tracing and found basin and basin-furrow irrigation efficiency

to be as high as 95% for pecans. Pecans typically have high efficiency because of the high consumptive demand

which makes it difficult to overirrigate. Deras (1999) found efficiencies ranging from 88 to 98% in alfalfa, 88–97%

in cotton, 79–94% in pecans, and 83–94% in chile peppers (Salameh Al-Jamal et al., 1997). The efficiency studies

that support EBID’s aggregate assessments have been conducted on a small number of relatively large, commercial

farming operations; thus while they represent a large percentage of irrigated EBID lands, they reflect the irrigation

practices of a very small percentage of total irrigators and farms.

Crop yields in the region vary dramatically between farms of different sizes. For example, large, commercial

pecan orchards (i.e. those achieving the high irrigation efficiencies) typically yield more than 2000 pounds of nuts

per acre (2242 kg ha�1), while it is not uncommon for smaller orchards to yield well under 1000 pounds per acre

(1121 kg ha�1). Pecan industry contacts report that small orchard owners do not want to incur the expenses of

pruning, pest and water management, and fertilization. Thus, the large yield differences. Quality can also be lower

for nuts produced in the smaller orchards, with industry contacts reporting a tendency for a lower ratio of meat to

shell for pecans produced in noncommercially oriented orchards.

The large, commercial farms in the region are motivated by very different factors than those of smaller, lifestyle

farms. Yet, all farms (regardless of size) are facing short-term irrigation water shortages due to drought, and long-

term competition for existing surface water supplies. The impact of the structure of local agriculture on farm

management practices generally, and irrigation practices specifically, has not been previously examined. Potential

responses to incentives for improved irrigation efficiency or water marketing have not been explored, although the

structure of local agriculture could be an important variable affecting water use and transfers in the future.

This paper reports on recent research to evaluate water use in the EBID using water delivery data recently made

available by the EBID. This research sought to identify parameters which affect irrigation practices and on-farm

irrigation efficiency on different-sized farms. The results provide insight into the effect of farm size on irrigation

water management, and potential responses to water marketing or incentives for improved irrigation efficiency.

TECHNOLOGICAL CHANGE AND AGRICULTURAL STRUCTURE

Technological change in US agriculture has been dramatic over the past century. The adoption of new technologies

has driven down real commodity prices, increased productivity, reduced production costs, and changed agricultural

structure. What Cochrane (1958) called the ‘‘technological treadmill’’ is credited with mass migration of people

out of the US agricultural sector, reduced numbers of farms in the US, increased average farm size, rural

3Deficit irrigation is an irrigation practice whereby water supply is reduced below maximum levels and mild stress is allowed with minimaleffects on yield (Food and Agriculture Organization, 2002).

FARM SIZE, IRRIGATION PRACTICES, AND ON-FARM IRRIGATION EFFICIENCY 45


depopulation, and the current dual-farm structure. The impact of technology on agricultural structure has been

examined extensively (Hallam, 1993 provides an overview), as have the factors which influence the likelihood and

extent of technology adoption by producers (Rogers, 1962, 1983 are seminal works). Individual characteristics

usually associated with technology adoption include farmer age, length of time in farming, educational attainment,

off-farm employment, level of involvement in farm organizations, wealth status, and risk orientation.

The adoption of conservation practices has also been studied using the theoretical approach applied to the

adoption of other agricultural technologies. Research has shown that educational attainment, farm organization

involvement, and willingness to accept risk tend to be positively associated with adoption of conservation

practices, that off-farm employment is negatively related to conservation practices, and mixed results for the

relationship of farmer age and length of time farming to adoption of conservation practices (Clearfield and Osgood,

1986 provide a summary of this research). With respect to farm structure variables, adoption of conservation

practices also tends to be positively related to farm size, farm income, and family participation in farming, while

associations between farm tenure status, use of credit, and degree of farm specialization with conservation are not

consistent (Clearfield and Osgood, 1986).

Extensive research has been conducted on the off-farm labor supply of farmers and determinants of farm family

off-farm work decisions (Lass et al., 1991 provide a review). Much of this research has been based on the

presumption that participation in the off-farm labor market is a response to underemployment of labor on the farm,

and that off-farm work is a residual activity undertaken only after farm work and farm management activities have

been accomplished (Phimister and Roberts, 2002). Researchers have often been interested in the on-farm

adjustments to farm operators taking off-farm jobs in order to generate livable household incomes (Carlin and

Bentley, 1991). These traditional views of off-farm job holding were more useful in understanding conditions in

the US farm sector during the decades when large numbers of marginal farms were transitioning away from full-

time farming and complete dependence on farm incomes. They are less helpful in an era where the dual-farm

structure is well established, with lifestyle/residential and retirement farms growing in numbers as a result of new

entrants with significant off-farm incomes into farming.

Some research has been conducted into the effects of off-farm employment on farm production decisions;

however, attention has been limited (Phimister and Roberts, 2002). Anosike and Coughenour (1990) found that

farm diversification was negatively and significantly associated with off-farm work. Carlin and Ghelfi (1979)

concluded that part-time farmers must adjust their farm enterprises to off-farm labor requirements and do so by

adopting less labor-intensive farm enterprises. These authors indicated that operators of animal specialty farms,

livestock enterprises, fruit and tree nut farms, and meadow production all have higher levels of off-farm

employment and that these enterprises are all better suited to part-time farming than other crops or enterprises.

The adoption of new agricultural technologies has been examined in the context of busy farm families that need

to save time doing farm work due to the demands of off-farm employment (Smith, 2002). Smith (2002) notes that

some recently introduced technologies (e.g. genetically engineered insect-resistant and herbicide-tolerant crops)

have been adopted at extremely rapid rates, while the adoption of technologies such as integrated pest management

and bovine somatotropin has been limited. She concludes that convenient technologies that are not management

intensive and which take no extra thought are most likely to be adopted by small farm operators engaged in

multiple income-generating activities. This author also posits that management intensity of agricultural technol-

ogies may be a source of scale bias, with larger farming operations much more likely to adopt management-

intensive technologies. Fernandez-Cornejo and Hendricks (2003) support this observation with their findings that

off-farm work is positively associated with the adoption of herbicide-tolerant soybeans (a management-saving

technology).

Phimister and Roberts (2002) have hypothesized that the provision of environmental services by agriculture and

farm households in Western Europe may be negatively impacted by off-farm work. Their observation is

particularly relevant in regions where agriculture plays a variety of roles beyond simply being a source of food

and fiber commodities. The multifunctionality of agriculture is often defined around the environmental services

and landscape values provided by agricultural land uses. Many technologies and management practices are

available to reduce agriculture’s impact on the environment, increase the level of environmental services, and

enhance the landscape amenities provided by the sector. Tools and techniques are available to improve water

conservation, increase irrigation efficiencies, and ultimately release water from agriculture to other uses; however,



adoption levels will ultimately be determined by individual farm operators—many of whom are residential or

lifestyle farmers.

DATA AND METHODS

As stated above the objective of this research is to examine irrigation practices and efficiency across a broad cross-

section of farms in the EBID. This district is currently in the process of water rights adjudication, is facing rapid

population growth, economic diversification, and increased competition for water resources. The larger munici-

palities in the area (Las Cruces, New Mexico and El Paso, Texas) are transitioning to surface water for municipal

and industrial use as a result of decreasing groundwater supplies. EBID is a quasi-governmental organization,

which currently irrigates �75 000 acres (30 352 ha) in almost 8300 parcels of land.4 Thirty-eight percent of the

irrigated parcels are less than 2 acres (0.81 ha) in size, while another 28% are between 2 and 5 acres (0.81–2.02 ha),

with both these parcel categories accounting for 12% of the District’s irrigated lands. In comparison, irrigated

parcels of more than 100 acres (40.47 ha) comprise less than 2% of EBID’s irrigated parcels, but account for almost

28% of irrigated land. Larger, commercially oriented farms often operate on numerous parcels, which are usually

not contiguous.

EBID irrigators do not directly pay for water applied to their farms; they pay for the delivery of water to which

they already own the right to beneficial use. The irrigation district charges landowners an annual fee which

includes general, operating and maintenance, and reservoir charges. This fee has been approximately $50.00 per

water-righted acre ($123 ha�1) for the past several years. In a full allocation year, irrigators will receive 2 acre-feet

per water-righted acre (6096m3 ha�1) in return for their fixed annual fee, with the opportunity to acquire a third

acre-foot per acre for $25.00. For a 500-acre (202 ha) commercial farm served by the District, the cost of irrigation

water in a full allocation year is approximately 5% of all cash and fixed expenses (Libbin and Hawkes, 2004).

In periods of drought, allocations can be less than 2 acre-feet per acre; however, irrigators must pay the full

annual fee per water-righted acre even if they receive only a fraction of the full allocation. When extra water (i.e. in

excess of 3 acre-feet per acre or 9026m3 ha�1) is available, irrigators can purchase additional water from the

District’s ‘‘conservation pool’’ for $25.00/acre-foot ($20 1000m�3). Some water is in the conservation pool as a

result of water rights being removed from land that has been permanently urbanized. The conservation pool water

cannot currently be applied to any use other than crop production.

EBID water rights are appurtenant to land. A mechanism has been established for the transfer of agricultural

water to nonagricultural use by a city, county, university, or mutual-domestic water provider. These entities must

own land to which water rights they own are appurtenant. At present, no nonagricultural entity in the District has

the capacity to treat surface water, and until they develop the capacity, the water to which they hold rights goes into

the District’s conservation pool, where it is put to agricultural use.

Alfalfa, pecans, cotton, chile peppers, and onions are the primary crops produced in the District, with over 750

pecan orchards covering approximately 21 000 acres (8499 ha).5 Results of analysis of 2001 water delivery and

billing data recorded by EBID for pecans are reported here. Data for alfalfa and cotton have also been analyzed but

are only briefly discussed here. Data were obtained in raw form in ExcelTM spreadsheet files from the District and

had never been subjected to any systematic analysis. The data files included number of irrigations, acres for which

water was ordered, amount of water delivered to the farm turnout, and exact times when the water was turned on

and off at the farm turnout. The data were restricted to farms which had only one field for which irrigation water

was ordered, to avoid (as much as possible) situations where water is ordered for one field, but applied to another.

Fields 2 acres (0.81 ha) and larger are classified as farm accounts and receive water on demand, as opposed to

smaller fields which must be irrigated on a schedule established by the irrigation district.6 The key structural

4The Elephant Butte Irrigation District data are reported in acres for land area and acre-feet for water applied. US customary units are usedthroughout this paper so as to be consistent with the structure of the available data. Metric conversions are presented throughout.5With the exception of cotton, there are no state or federal price or income subsidies provided to the producers of these crops.6US customary units reflect the structure of the EBID, particularly in the distinction between ‘‘flat-raters’’ or ‘‘small tract irrigators’’ (farms ofless than 2 acres), and ‘‘farm accounts’’ (farms 2 acres and larger). Flat-rate irrigators are not represented on the District’s Board of Directors,and cannot vote on district policies.



variable available in the data set is farm size. Unfortunately, there are currently no data available to test some of the

more interesting hypotheses explored above in the review of literature.

Figure 1 shows the distribution of the 340 pecan farms for which data were analyzed. Almost two-thirds of the

340 pecan farms analyzed were irrigating less than 5 acres (2.02 ha) of trees. The pecan data received from EBID

represent approximately 13% (2716 acres; 1099 ha) of total irrigated pecan acreage in the District, and almost half

of total orchards. The size distribution of pecan farms in the data set is very similar to the size distribution of all

pecan farms in the District. Water delivery data for the 340 pecan farm accounts were analyzed using ExcelTM and

SASTM, with the objective of identifying patterns in on-farm irrigation efficiencies and water use. Field visits were

conducted in order to ground-truth findings of the data analysis, observe actual irrigations, and meet the producers.

FINDINGS

Prior to data analysis, it was hypothesized that differences in amounts of irrigation water applied and time spent

irrigating would exist between farms of different sizes. Differences in soil types and irrigation water turnouts were

also assumed to be factors that would influence water applied and time spent irrigating. Prior field observations had

led to the hypothesis that smaller farms were applying more water per acre and using more time to irrigate each

acre of land.

Pecan consumptive use is 4.9 acre-feet per acre (14 935m3 ha�1) for mature trees, yielding on average 2000

pounds per acre (2242 kg ha�1) (Miyamoto, 1983). Figure 2 presents acre-feet per acre of water applied to pecans

relative to farm size, and shows a high degree of variability in water applied across all farm sizes. Based on analysis

of the irrigation district’s 2001 records, approximately 18% of the pecan farms analyzed applied water in excess of

the 4.9 acre-feet per acre (14 935m3 ha�1) consumptive use requirement. By comparison, 70% of the 524 alfalfa

farms analyzed were applying water in excess of consumptive use (i.e. more than 3.5 acre-feet per acre

(10 668m3 ha�1)). The District’s 2001 accounting of water delivered does not reflect actual measurements. The

quantities of water are based on ditch riders’7 subjective assessments of how much water went onto the parcels for

which water was requested. There exist numerous opportunities for under- or overdelivery under this system of

water accounting.

Figure 1. Pecan farm size distribution (2001, n¼ 340)

7Ditch riders are employed by the irrigation district and are responsible for overseeing canal operations and water deliveries in designated areasof the irrigation district.



District average pecan and alfalfa irrigation on-farm efficiencies (consumptive irrigation requirement/farm

delivery) have been estimated to be 87 and 76%, respectively (Samani et al., 2003). Analysis of the District’s 2001

water delivery data reveals that 8% of the pecan parcels and 36% of the alfalfa parcels had less than average on-

farm irrigation efficiencies. These results show potential for reduced water use in both pecans and alfalfa.

Descriptive statistics for acre-feet per acre of water applied for the 340 pecan farms are presented in Table I. As

might be expected from observation of Figure 2, the acre-feet per acre means were not dramatically different

across the four farm size acreage groups (i.e. 2� acres< 5; 5� acres< 10; 10� acres< 20;� 20 acres).8 Mean

separation tests confirmed that the means were not significantly different; however, the range of water applied does

vary by farm size. The range of water applied across all quantiles is 5.30 acre-feet per acre (16 154m3 ha�1) for the

smallest farm size, which is more than three times larger than the second highest range. The irrigation district data

included no information about supplemental groundwater applied to the orchards, and farms which received

surface water less than five times during the irrigation season were not included in the analysis in an effort to

Figure 2. Pecan acre-feet per acre water applied by farm size (2001, n¼ 340)

Table I. Quantile analysis and descriptive statistics for pecan water use relative to farm size (2001, n¼ 340)

Farm size category

2� acres< 5 5� acres< 10 10� acres< 20 � 20 acres

Quantiles0% Minimum acre-feet/acre water applied 1.85 2.18 2.47 2.2725% 3.04 3.11 3.37 3.2850% Median acre-feet/acre water applied 3.78 3.67 4.01 4.4975% 4.53 4.37 4.95 4.9880% 4.72 4.51 5.35 5.0985% 4.97 4.61 5.61 5.2090% 5.44 5.09 5.63 5.7995% 6.09 5.59 5.64 5.9599% 6.45 5.99 5.70 6.23100% Maximum acre-feet/acre water applied 7.15 5.99 5.70 6.23Descriptive informationNumber of farms 223 65 24 28Mean acre-feet/acre 3.91 3.79 4.12 4.23Standard deviation (acre/feet/acre) 1.05 0.94 0.99 1.09Range (all quantiles) (acre-feet/acre) 5.30 1.26 1.58 1.70Range (75–100%) (acre-feet/acre) 2.62 1.62 0.75 1.25

82� acres< 5 (0.81� ha< 2.02); 5� acres< 10 (2.02� ha< 4.05); 10� acres< 20 (4.05� ha< 8.09); � 20 acres (� 8.09 ha).



eliminate farms which apply primarily groundwater. Nevertheless, it is curious to see the low levels of surface

water applications in the 25% of the farms using the least amount of water in each farm size category. It may thus

be more appropriate to compare the ranges of water applied for the highest 25% of water users in each farm size

category, to reduce the likelihood of supplemental groundwater use. Examination of the ranges of water applied for

the highest 25% of water users again shows the largest range of acre-feet per acre water applied in the smallest

farm size group.

Another indicator of irrigation efficiency in the District is the duration of irrigation (i.e. hours per acre per

irrigation). A long duration can be caused by several factors, including lack of attention to irrigation practices, lack

of knowledge of crop consumptive use, highly permeable soils, small and/or unlined farm ditches, small farm

turnouts, several users on a single delivery ditch attempting to irrigate simultaneously, and low water discharge at

the farm turnout. The low discharge can be due to both poor water delivery infrastructure at the farm turnout and

insufficient flows, a single factor, or a combination of several factors. Prior fieldwork and recent observations

throughout the District by the authors have resulted in the empirical guideline of 0.5 h per acre per irrigation

(1.24 h ha�1 per irrigation). Regardless of soil type (e.g. sand, loam, clay), it has been found that irrigations on

large, commercially oriented farms typically require about 30min of water flow per acre through the farm turnout

onto the field. This guideline reflects typical lengths of run for the water in the fields, normal water flows at the

farm turnouts, and adequately sized on-farm turnouts. On heavy, clay soils, 0.2 h per acre per irrigation (0.49 h ha�1

per irrigation) have been observed. Very long irrigations usually indicate that on-farm irrigation efficiency will be

reduced as a result of deep percolation losses at the front end of the field.

The relationship between duration of irrigation and farm size for the 340 pecan farms analyzed is shown in

Figure 3. The figure reveals large differences in irrigation duration between small and large farms. Figure 3 has

also been adjusted such that several data points in the range of 12–26 h per acre per irrigation (29.65–64.25 h ha�1

per irrigation) are not shown on the figure. Outlying and other data points were confirmed by field observation of

irrigation events in 2002 and 2003. As shown in Figure 3, irrigation duration drops off at approximately 20 acres

(8.09 ha), and remains close to the empirical guideline of 0.5 h per acre per irrigation (1.25 h ha�1 per irrigation) for

all larger farm sizes. Irrigation durations for farms less than 20 acres are highly variable, lasting several hours in

many cases. Average hours per acre per irrigation are shown by acreage category in Figure 4.

Several fields with long irrigation durations were visited during the 2002 and 2003 irrigation seasons to gain a

better understanding of the conditions which led to the lengthy irrigation periods. Most fields were visited while

irrigations were underway. A common reason for long durations was the condition of the farm delivery ditches and

the size of the on-farm turnouts. In several cases, the water was moving so slowly through the farm delivery ditches

toward the on-farm turnouts that flow measurements could not be taken with a digital propeller meter. The water

was released from the District’s larger canal via partially open 24-inch gates into the farm delivery ditch, and then

through very small on-farm turnouts onto the fields. These small turnouts were usually round 4-inch pipes. In other

cases, the on-farm turnouts were not really structures; instead, they were more like controlled breaks in the farm

Figure 3. Pecan hours per acre per irrigation vs. farm size (2001, n¼ 340)



delivery ditch. When asked about the length of time spent irrigating their fields, several individuals complained

about the bad condition of the on-farm delivery ditch from which they take their water. The irrigation district has

no responsibility or authority for maintaining these ditches, and the irrigators noted that weeds, trash, rodents, and

breaks were factors that resulted in long irrigation durations. In the case of one of the long-duration fields, a fallow

lot approximately 40m wide by 40m long was being used as a channel through which the water flowed

uncontrolled before it reached the small pecan orchard actually being irrigated. Complaints about neighbors’

unwillingness to grant easements for improving irrigation water delivery, or allow modifications to easements for

the purpose of increasing the size of the on-farm delivery infrastructure, were often heard.

Conversations with the irrigators conducted during the field visits revealed some common themes. One theme

can be summarized by one older man’s comment regarding the fact that it took him almost two days to irrigate his

�3 acre (1.21 ha) pecan orchard. He said, ‘‘I’m retired, what else have I got to do?’’ Other comments revolved

around the view that irrigation was a family tradition, that irrigating often meant the involvement of members of

extended families, that irrigation was a social undertaking, that irrigation was a peaceful, meditative, enjoyable

task. Overall, the levels of irrigation technology and water management found on field visits to small farms were

extremely low, and often a consequence of inadequate irrigation design. The principal design problem found was

narrow-diameter farm turnouts which cannot physically deliver to the field the minimum flow necessary to rapidly

push the water across the field, thus reducing both the time spent irrigating and infiltration losses during the

irrigation process. The level of involvement by some water users in the practice of irrigation also appeared to be

quite low, and a relatively high degree of resentment toward other users of the same farm delivery ditches was

noted among those interviewees (e.g. ‘‘Nobody else does anything to maintain the ditch, why should I?’’). Many of

the long-duration irrigators complained about their neighbors’ unwillingness to improve the mutual on-farm

delivery ditch (i.e. that part of the delivery system not maintained by the District).

The extreme differences in irrigation duration relative to farm size are shown in Figure 3. Descriptive statistics

for irrigation event durations are presented in Table II. As expected from examination of Figure 3, mean irrigation

duration is greatest for the smallest farms, and declines with increasing orchard size. Ranges of irrigation durations

across the quantiles are also much broader for the smaller orchards, and the median duration for the smallest farm

size group is more than three times larger than the median of the � 20 acres (8.09 ha) group. Mean irrigation

durations for the four farm size groups were significantly different overall. The 340 observations were also divided

into four equal quartiles based on average hours per acre per irrigation, and a chi-square test of differences in

proportions was conducted. The chi-square analysis found significantly more small orchards with the longest

irrigation durations, and significantly more large orchards with the shortest irrigation durations. Field analysis on

selected farms in 2002 and 2003 consistently found that the amount of water applied to a field is strongly and

positively related to irrigation duration per acre.

Figure 4. Pecan average hours per acre per irrigation (2001, n¼ 340)



Both fieldwork and examination of the irrigation district’s data also lead to the conclusion that in general there is

little relationship between seasonal water demand and applied water for the farms studied. Lack of knowledge

about, and inattention to, irrigation scheduling based on actual crop water demands also contribute to low on-farm

water use efficiency. Traditional irrigation timing practices (i.e. every 7–14 days throughout the irrigation season)

contribute to overwatering at the beginning and end of the irrigation season, plant stress at peak crop water use

periods, and result in reductions of both nut yields and nut quality (e.g. lower ratios of pecan meat to shell). The

average hours per acre per month irrigation duration and maximum pecan evapotranspiration (ETm, in feet) are

shown in Figure 5. The measurement scales for irrigation duration and Etm are very different, although as stated

above, a strong, positive relationship between irrigation duration and water applied was found. The consistency of

irrigation practices over the course of the irrigation season for the smallest size farms (2� acres< 5), and

relatively little variability in irrigation duration for the other three farm size categories, is illustrated in Figure 5. It

is also interesting to see that when pecan evapotranspiration is steeply increasing during April and May, many

irrigators are reducing their irrigation durations (e.g. 5� acres< 10; � 20 acres). These same two farm categories

and farms between 2 and 5 acres also increase irrigation durations in July and August (a period for which

maximum evapotranspiration steeply decreases).

DISCUSSION

This research effort employed data that were not collected for the purpose of examining the relationship of farm

size to irrigation practices and efficiencies. The primary objective of these data is for billing irrigators for water

delivered; prior to the 2003 drought period actual quantities of water delivered to farms were not physically

measured by the EBID. Results of recent field measurements have been intriguing, and usually at odds with the

District’s water delivery data, which record 6 acre-inch per acre (1524m3 ha�1) deliveries for most irrigations.

Field measurements taken in 2002 and 2003 have found a large range of actual water deliveries to farms, and some

patterns have emerged. Results tend to show underdelivery (i.e. less than 6 acre-inches per acre) and subsequent

overcharges to larger fields, while smaller fields (i.e. less than 10 acres or less than 4.05 ha) tend to receive more

than 6 acre-inches per acre per irrigation. Smaller farms are thus undercharged for their irrigation water.

Table II. Quantile analysis and descriptive statistics for pecan irrigation durations (hours/acre/irrigation) relative to farm size(2001, n¼ 340)

Farm size category

2� acres< 5 5� acres< 10 10� acres< 20 � 20 acres

Quantiles0% Minimum hours/acre/irrigation 0.35 0.46 0.28 0.9125% 0.98 0.70 0.52 0.2850% Median hours/acre/irrigation 1.25 0.82 0.65 0.3875% 1.71 1.17 0.92 0.4680% 1.80 1.24 0.97 0.5385% 1.95 1.48 1.01 0.5390% 2.14 1.65 1.40 0.8195% 2.73 1.74 1.44 0.8399% 7.54 2.05 2.01 1.09100% Maximum hours/acre/irrigation 25.6 2.05 2.01 1.09Descriptive information

Number of farms 223 65 24 28Mean hours/acre/irrigation 1.57 0.97 0.76 0.42Standard deviation (hours/acre/irrigation) 1.93 0.40 0.40 0.21Range (all quantiles) (hours/acre/irrigation) 25.25 1.59 1.73 0.90Range (75–100%) (hours/acre/irrigation) 23.89 0.71 0.64 0.63



Overdelivery of water is related to the excessively long irrigation durations discussed above, with reasons for

overdelivery including long fields (i.e. irrigation runs in excess of 1200 ft or 366m), rough field surfaces, low

flows, and small turnouts to the farm. During fieldwork many water deliveries ranging from 8 to 12 acre-inches

(2032–3048m3 ha�1) were measured on alfalfa and pecan fields. The fields receiving the water were generally

smaller, although not exclusively so. Deliveries in the range of 2–4 acre-inches (508–1016m3 ha�1) on larger fields

were also measured. These fields tended to be intensively managed (evidenced by surface smoothness and absence

of weeds), and were part of large, commercial farming operations. These fields also tended to be located near the

larger delivery canals, irrigated through large turnouts, and receive high flows of water during most irrigation

events. The water rapidly moved across the fields, and due to the common practice of shutting off the water when it

reaches the end of the field, underdelivery occurred. Prior to this research effort, in the process of testing flumes

and training students in their use, the authors also found underdelivery of irrigation water to larger farms.

The loss of 46% of EBID’s diverted water before deliveries to the farm turnouts is often cited by critics as an

example of extreme inefficiency. However, the research described here has led to skepticism about the 54%

diversion-to-delivery efficiency estimates. It is likely that at least part of the loss claimed to occur from diversion at

Elephant Butte Dam to delivery on farms is water actually applied to fields and not accounted for, with the excess

applications most likely to occur on smaller fields. It is also likely that carriage water requirements are larger for

the smaller water deliveries to the smaller fields. Irrigation infrastructure on the smaller fields limits the rate at

which water can be diverted to farms, resulting in deep percolation, runoff, and excess carriage water losses.

Necessary infrastructural improvements are unlikely to occur as a result of limited financial resources, easement

disputes, disagreements between local irrigators, and lack of urgency or interest on the part of many irrigators.

Field observations have led the authors to conclude that many water users appear to place a low priority on

agricultural production. Yields for pecans in southern New Mexico vary greatly relative to orchard size, with

orchards between 2 and 5 acres (0.81–2.02 ha) having an average yield of 636 pounds per acre (713 kg ha�1) while

1754 pounds per acre (1966 kg ha�1) is the average yield for orchards of at least 100 acres (40.47 ha) (US Dept. of

Agriculture, 1999). These yields were reported in the 1997 Census of Agriculture, and while members of the local

pecan industry contacted in the course of this research do not dispute the range of yields between small and large

orchards, they cite an average of �850 pounds per acre (953 kg ha�1) for small orchards and at least 2000 pounds

per acre (2242 kg ha�1) in large, commercial, well-managed orchards. Reasons industry members give for low

yields on small orchards include inadequate pruning, and limited fertility, pest, and irrigation management. Similar

Figure 5. Pecan average irrigation duration by farm size (by month, 2001, n¼ 340) and maximum evapotranspiration



variations in alfalfa management practices and yields are reported to exist; however, alfalfa is produced throughout

New Mexico, and census data for alfalfa do not provide clear information about yield differences relative to farm

size in the EBID (where 75% of New Mexico’s pecan production occurs).

A summary of orchard size distribution (using US Census of Agriculture farm size classes), total irrigation water

deliveries, average yields, and average nut production per unit of water delivered for the 340 farms analyzed is

shown in Table III. The total amount of water recorded as delivered to these farms by the EBID in the 2001

irrigation season was almost 11 022 acre-feet (13.59Mm3). The distributions of acres and volume of water applied

across farm sizes are remarkably similar, and reflect the record-keeping assumption of approximately 9 acre-inches

per acre (2286m3 ha�1) delivered by the District to the farm turnouts for the first irrigation of the season, and

approximately 6 acre-inches per acre (1524m3 ha�1) for all subsequent irrigations. Average yields per acre in

Table III are from the 1997 Census of Agriculture. Multiplying average yields per acre (H) by total acres (D) gives

the total production by farm size class for the farms analyzed (I). Comparison of the distribution of farms (C) with

distribution of production (J) across farm sizes illustrates the concentration of production on a small number of

farms which characterizes New Mexico’s overall pecan industry. Given the disparity in yields reported in the 1997

Census of Agriculture, nut production per acre-foot of water delivered (K) ranges from 161 pounds per acre-foot

(59.2 kg 1000m�3) for the smallest orchards to almost 300 pounds per acre-foot (110.3 kg 1000m�3) for the

largest orchards. The value of nut production per unit water applied (L) was calculated using 2001 season average

prices.

The results in Table III are based on the EBID’s accounting of how much water was delivered in a typical, full-

supply irrigation season (e.g. 2001). The findings of fieldwork over the last two years lead to the tentative

conclusion that nut production per acre-foot is probably less than presented in Table III for the smaller orchards,

and greater than the results in Table III for the larger orchards. Columns (K) and (L) are not measures of the

marginal productivity or marginal value of water in pecan production, but the information does provide insight into

the physical efficiency and gross value of irrigation water used by pecan producers relative to orchard size.

The ability to identify structure effects on irrigation practices and irrigation efficiency in the EBID is currently

limited by data availability. This research did reveal some interesting patterns, particularly with respect to farm

size and irrigation duration. Fieldwork has been helpful in developing a better understanding of structure effects,

but much work remains to be done. The current drought, continued adjudication of surface water in the EBID,

ongoing or threatened litigation between various water-using entities in the region, and a recent appeals court

decision forcing the US Bureau of Reclamation to release water for endangered silvery minnows on the Rio Grande

north of the EBID are factors which make it difficult to ask and receive answers for many socioeconomic questions.

It has been relatively easy and nonthreatening for water users to provide information to the current study, as

engineering research is apparently not perceived to be as intrusive as socioeconomic research.

Throughout the process of conducting the research reported here, we have hypothesized that many farm owners

will not be inclined to improve their irrigation infrastructure, increase irrigation efficiency, and reduce the time

spent irrigating because it is not financially rewarding to do so. Many of the water users encountered over the last

two years did not appear to be concerned about their relatively low pecan yields, or the physical efficiency of

irrigation water used in pecan production. Many small-scale pecan producers also appear to be deriving significant

utility from current irrigation practices and technologies.

CONCLUSIONS

It is commonly assumed by many observers and critics of the EBID that the irrigation practices of the large,

commercial farms must be improved in order to release water for other uses. However, the results of this and earlier

research, the prevalence of deficit irrigation practices and other techniques or technologies currently used on large

farms to increase the physical efficiency of irrigation water indicate that marginal increases in efficiencies on many

large farms are likely to be small and come at a high cost. And the price at which many small farm operators will be

inclined to change their irrigation practices may be extremely high, because for them, irrigation appears to be a

recreational, social, or lifestyle activity, rather than an income-generating pursuit. Furthermore, the common

property nature of those segments of the water delivery system not owned by the EBID creates a disincentive for



Table

III.

Pecan

orchardsize

distribution,totalirrigationwater

deliveries,pecan

yieldsandproductionforallfarm

sanalyzed(2001,n¼340)

Farm

size

class1

Farms2

%Farms

Acres

2%Acres

Acre-feet2

%Acre-feet

Mean

Nut

%Production

AverageNut

ValueofNut

(A)

(B)

(C)

(D)

(E)

(F)

(G)

yieldsper

production

(J)

Productionper

Productionper

acre

3(H

)(I)

Acre-foot(K)

Acre-foot4(L)

2–5ac

223

65.6

648

23.9

2567.5

23.3

636lb

206.1

tons

18.2

161lb

$103.04

(0.81–2.02ha)

(262.2ha)

(3.17Mm

3)

(712.84kg/ha)

(186.97mt)

(0.059kg/m

�3)

($0.08m

�3)

5–14.9

ac82

24.1

584

21.5

2293.5

20.8

623lb

181.8

tons

16.0

159lb

$101.76

(2.02–6.03ha)

(236.3ha)

(2.83Mm

3)

(698/27kg/ha)

(164.93mt)

(0.058kgm

�3)

($0.08m

�3)

15–24.9

ac13

3.8

247

9.1

991.1

9.0

881lb

108.7

tons

9.6

219lb

$140.16

(6.07–10.08ha)

(100.0ha)

(1.22Mm

3)

(987.45kg/ha)

(98.61mt)

(0.081kgm

�3)

($0.11m

�3)

25–49.9

ac14

4.1

467

17.2

1777.5

16.1

852lb

198.9

tons

17.6

224lb

$143.36

(10.12–20.19ha)

(189.0ha)

(2.19Mm

3)

(954.94kg/ha)

(180.44mt)

(0.082kgm

�3)

($0.12m

�3)

50–99.9

ac5

1.5

324

11.9

1515.5

13.8

1022lb

165.6

tons

14.6

218lb

$139.52

(20.23–40.43ha)

(131.1ha)

(1.87Mm

3)

(1145.48kg/ha)

(150.23mt)

(0.080kgm

�3)

($0.11m

�3)

100–249.9

ac3

0.9

446

16.4

1876.6

17.0

1220lb

272.1

tons

24.0

290lb

$185.60

(40.47–101.13ha)

(180.5ha)

(2.31Mm

3)

(1367.40kg/ha)

(246.85mt)

(0.107kgm

�3)

($0.15m

�3)

Total

340

100

2716

100

11021.7

100

—1133.2

tons

100

——

(1099.1ha)

(13.6Mm

3)

(1028.03mt)

1Farm

size

classesusedin

thistable

arethose

usedin

the1997USCensusofAgriculture

forNew

Mexicopecan

producers.

2From

ElephantButteIrrigation2001irrigationseasonwater

deliverydata.

3From

1997USCensusofAgriculture.

4Theseasonaverageprice

forpecanswas

$0.64per

pound($1.41kg�1)in

2001(N

ewMexicoAgriculturalStatistics,2001).



investment and improvements by individual water users. We currently hypothesize that many smaller water users

have minimization of the costs or risks of operating their small farms (regardless of the impacts on irrigation water

productivity, nut yields, or total production) as their primary objective. Many also seem to have maximizing their

utility or satisfaction from the small farm generally (and irrigation activities in particular) as a key objective.

Again, these objective functions do not seem very compatible with the notion that water users will be interested in

increasing irrigation efficiency through changes in technology, increases in management intensity, and responding

to financial incentives to release surface water from agriculture for other competing uses.

Previous researchers have concluded that the adoption of conservation practices is affected by farm structure

characteristics. The research results reported here support the conclusions of other authors (e.g. Clearfield and

Osgood, 1986; Smith, 2002; Fernandez-Cornejo and Hendricks, 2003). We have found that small residential/

lifestyle farms tend to employ lower levels of irrigation technology, and are characterized by less intensive

irrigation management. At this point, we can make no conclusions regarding causation links, and the principal

contribution of the current research is an explicit illustration of the heterogeneity in irrigation practices and on-

farm efficiencies that currently exists among farms of different sizes in the study region. The irrigation

technologies in use and current irrigation practices vary greatly relative to farm size. Based on this research,

we conclude that the adoption of on-farm irrigation technologies is subject to scale bias, with larger farming

operations more likely to use management-intensive technologies.

This research has provided previously unavailable insight into relationships between current farm structure and

irrigation technology in the EBID. The EBID is not unique, with numerous formerly rural irrigation districts in the

western United States experiencing similar trends in population growth and urbanization. The number of irrigated

farms in the EBID has increased over the last several decades, due to splitting larger farms into smaller parcels. The

ramifications of this for on-farm irrigation, delivery efficiencies, irrigation infrastructure, and irrigation system

management are serious and underappreciated. When the majority of irrigators are not commercially oriented, do

not engage in intensive irrigation management, and are not motivated to increase ‘‘crop per drop’’, what is the

future for increasing irrigation efficiency? While it might be tempting to conclude that water marketing will

provide an incentive for irrigators to adopt technology that increases efficiency or to simply stop irrigating, the

nature of residential/lifestyle agriculture in the EBID (and elsewhere) leaves us skeptical that many irrigators will

be willing to give up their irrigation pasttime. Future research will attempt to further understand and describe the

objective functions of residential/lifestyle and commercial pecan producers. What may appear on the surface to be

perverse economic behavior by residential or lifestyle farms is likely to be extremely rational behavior within a

theoretical framework which accurately captures their consumption objectives.

One final conclusion of this research concerns relationships between engineering and socioeconomics . . . . Theirrigation structures (e.g. ditches, gates, turnouts) designed for the agricultural structure (i.e. numbers and

distribution of farms by size and type) which characterized the EBID in the early twentieth century are currently

a source of significant inefficiencies. The degree of reinvestment necessary to make irrigation structure compatible

with agricultural structure is surely very large. Furthermore, agricultural structure in the region will continue to

evolve with additional land splits, urbanization, population growth, and economic development.

ACKNOWLEDGEMENTS

This research was supported by the New Mexico Agricultural Experiment Station and the Rio Grande Basin

Initiative (a joint project of the Texas A&MUniversity System Agriculture Program and the College of Agriculture

and Home Economics at New Mexico State University).

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