Directory UMM :Data Elmu:jurnal:A:Agricultural Water Management:Vol46.Issue3.2001:
Agricultural Water Management 46 (2001) 241±251
Assessment of drip and ¯ood irrigation on water and
fertilizer use ef®ciencies for sugarbeets
F. Cassel Sharmasarkar, S. Sharmasarkar*, S.D. Miller,
G.F. Vance, R. Zhang
Department of Plant Sciences and Renewable Resources, College of Agriculture, University of Wyoming,
P.O. Box 3354, Laramie, WY 82071-3354, USA
Accepted 7 February 2000
Abstract
Mismanagement of nitrogenous fertilizers has caused serious nitrate (NO3) contamination in
many ¯ood-irrigated regions of the western US. Low-volume irrigation practices, such as drip
irrigation, can offer an alternative approach for controlling NO3 leaching and agricultural water use.
The objectives of this study were to compare NO3 movement through soils under ¯ood and drip
irrigation practices for sugarbeet production, and to evaluate the agronomic feasibility of
implementing drip irrigation. A ®eld experiment was conducted during the sugarbeet (Beta vulgaris
L.) growing seasons of 1996 and 1997 in southeastern Wyoming, where NO3 contamination is a
continued concern and sugarbeet is a major cash crop. Three drip irrigation regimes, corresponding
to 20, 35, and 50% water depletion of ®eld capacity (designated as D1, D2, and D3, respectively),
were compared against ¯ood irrigation. The irrigation plots were treated with 112, 168, and 224 kg
N haÿ1 (designated as F0, F1, and F2, respectively). Sugarbeet (SB) yields and sugar contents under
drip irrigation were higher (3±28%) than those with ¯ood irrigation; yields and sugar contents for
the drip systems were in the order of D1>D2>D3. For all of the irrigation applications, there was an
increasing trend in yields with increasing fertilizer rates. Drip regime resulted in greater residual
soil NO3 (RSN) for both 1996 and 1997 seasons as compared to ¯ood practices. Values of RSN in
both years followed the trend: F2>F1>F0. Soil NO3 in all three drip regimes was higher (1.6±2.4
times) than that with ¯ood irrigation. In the overall root zone, NO3 concentrations between D1 and
D2 were comparable, whereas both of those levels were lower than D3. Greater NO3 concentrations
with D3 were observed at all depths. The amount of applied irrigation water with the drip system
was lower than that for ¯ood irrigation. Agronomic water use ef®ciency (WUE) and fertilizer use
ef®ciency (FUE) for drip irrigation were always higher than those for ¯ood irrigation. In 1996,
WUE and FUE maintained an order of D1>D2>D3. There was a decreasing pattern in FUE values
with increasing fertilizer rates. The overall results indicated that SB production could be sustained
*
Corresponding author. Present address: California State University, Department of Plant Science, H/S
AS-72, 2415E. San Samon Avenue, Fresno, CA 93740-8033. Tel.: 1-559-278-2904; fax: 1-559-278-7413.
E-mail address: ssharmas@csuffesno.edu (S. Sharmasarkar).
0378-3774/01/$ ± see front matter # 2001 Elsevier Science B.V. All rights reserved.
PII: S 0 3 7 8 - 3 7 7 4 ( 0 0 ) 0 0 0 9 0 - 1
242
F. Cassel Sharmasarkar et al. / Agricultural Water Management 46 (2001) 241±251
with lower water and fertilizer use by using drip irrigation. The p-values (0.05), based on both Ftest (pf) and two-tailed student's t-test (pt), suggested a signi®cant difference between the yield
means obtained under drip and ¯ood irrigation practices. As compared to the ¯ood irrigation, the
least p-values were obtained with D1 followed by D2 and D3, respectively, thus, con®rming that D1
was the most effective treatment. The p-values for SB yields under comparative fertilizer treatments
and same drip application showed no signi®cant difference between the means, thus, suggesting the
feasibility of using lower fertilizer rate while sustaining the targeted yield under drip irrigation. The
comparative estimation of water losses by drainage between ¯ood and drip irrigation suggested that
the later practice reduced the quantity of water leaching beyond the root zone. Among the three drip
treatments, the lowest drainage amount was observed with D1 as a result of its higher irrigation
frequency and smaller quantity of water input during each application. # 2001 Elsevier Science
B.V. All rights reserved.
Keywords: Drip irrigation; Water use; Drainage; Fertilizer management; Sugarbeet production
1. Introduction
Mismanagement of nitrogenous fertilizers has caused serious agricultural contamination in many regions throughout the US (U.S. Department of Agriculture, 1991). High
concentrations of NO3 in drinking water can cause health problems (Environmental
Protection Agency, 1990). In the southeastern region of Wyoming, where sugarbeet (SB)
production is intensive and fields are mainly flood irrigated, levels surpassing the critical
EPA limit of 10 mg lÿ1 NO3-N have been detected in several well waters (Baker and
Associates Consulting Engineers, 1989; Wyoming Hydrogram, 1995). A way of
managing NO3 pollution is to introduce an alternative irrigation method that reduces
chemical transport through soils, as well as agricultural water demand. A low-volume
irrigation practice, such as drip irrigation, can offer such a technology (Bucks et al., 1982;
Caswell, 1991).
Field studies are necessary to determine the efficacy of this new irrigation system in
Wyoming, where flood (furrow) is the major irrigation practice. Benefits of drip irrigation
have been documented by different researchers. In a study involving NO3 transport to
groundwater, Geleta et al. (1994) compared drip and flood irrigation, and concluded that
drip irrigation resulted in lower NO3-N loss. Based on a groundwater quality assessment
research in the delta Wadi El-Arish area of Egypt, Bihery and Lachmar (1994) also
recommended that flood irrigation practice be replaced by drip irrigation system,
especially in arid environments. In another study comparing drip and flood irrigation
practices, Roth et al. (1995) observed that reduced water use did not affect the yield and
quality of orange fruits. Drip irrigation practices are widely used on coarse-textured soils,
and for high-value crops in FL, CA, Europe and Israel where water is scarce or expensive
(Gregory, 1990).
Many SB growing areas in Wyoming are characterized by semi-arid climate and sandy
soils in which NO3 causes serious contamination problems. Sugarbeet is a major cash
crop within the eastern Rocky Mountain region, including Wyoming, and contributes
more than US$ 48 million in annual income to the state (Wyoming Agricultural Statistics
F. Cassel Sharmasarkar et al. / Agricultural Water Management 46 (2001) 241±251
243
Service, 1998). Use of drip irrigation for SB production is yet to be tested in Wyoming.
Therefore, the objective of this study was to compare drip and flood irrigation regarding
water and fertilizer use efficiencies for SB production.
2. Materials and methods
A field experiment was conducted during the SB (Beta vulgaris L.) growing seasons of
1996 and 1997 (seeding: first week of April, harvesting: first week of October) at the
Torrington Research and Extension Center (elevation>1200 m), located in southeastern
Wyoming, where NO3 contamination is a continued concern and SB is a major cash crop
(Wyoming Agricultural Statistics Service, 1998). The soil is classified as Daily sandy
loam (sandy, mixed, mesic, Torriorthentic Haplustoll) with less than 1% organic matter
within the root zone. This soil series was formed predominantly in alluvium and winddeposited and reworked sand which originated from noncalcareous sandstone.
The experimental design was a split-plot, where each irrigation plot was factorially
arranged for three rates of post-emergence nitrogen (N) fertilizer (urea ammonium
nitrate, UAN) applications: control (0 kg haÿ1), half-dose (56 kg haÿ1), and full-dose
(112 kg haÿ1). Earlier in the season, a basal pre-plant dose of 112 kg N haÿ1 was also
applied. Thus, a total quantity of 112, 168, and 224 kg N haÿ1, designated henceforth as
F0, F1, and F2, respectively, was used during the growing season. Weeds were controlled
with two post-emergence herbicide applications (Nortron: 2.13 kg haÿ1, and Betamix:
1.70 kg haÿ1). Additional plot care was ensured by hand-picking of weeds throughout the
growing season. SBs were irrigated using two different methods: conventional flood and
surface drip irrigation. Both flood and drip irrigation applications were initiated in July
and continued until harvesting. Prior to irrigation treatment initiation, the soil profile was
watered to field capacity with flood irrigation to refill a depth of 1.2 m and ensure
moisture content homogeneity in the experimental field. Three irrigation regimes,
corresponding to 20, 35, and 50% water depletion of field capacity (designated as D1:
drip1, D2: drip2, and D3: drip3, respectively), were used for drip irrigation in 1996.
Application of flood irrigation was maintained at 65% water depletion of field capacity in
consistency with the local farming practices. Therefore, a total of four irrigation
treatments was used for the field experiment. Eight SB rows (10 m length0.76 m
standard spacing) were allocated for each irrigation treatment, separated by four furrows
(10 m length0.76 m width) as bordering-buffer-zones to prevent the influence of one
treatment on another. A spacing of 3 m was also maintained as a bordering-zone at both
ends of the rows. Thus, the experimental plot area totaled 600 m2 in which each of the
four irrigation treatments covered an area of 150 m2 and comprised three replicates.
Along the SB rows, furrow irrigation water was delivered from gated pipes connected
to the main water supply. Furrows were fitted with flumes at the beginning and end of
each row to calculate water flow rates. The furrows for flood irrigation were scheduled
for 2 h bi-weekly watering at a rate of 7.00 l hÿ1. Flood irrigation (designated as Fl) was
applied when the soil moisture reached a level of 65% water depletion of field capacity.
The drip irrigation system consisted of PVC pipe laterals (19.05 mm i.d., 10 m length)
and spaced at 0.76 m intervals. Each drip line was equipped with 20 emitters spaced at
244
F. Cassel Sharmasarkar et al. / Agricultural Water Management 46 (2001) 241±251
0.55 m intervals. The drip water was supplied through a pump connected to the main
water source. Each drip system was operated by a control valve at a discharge rate of
3.78 l hÿ1 with an application efficiency of 92%. For D1, D2, and D3, water applications
were scheduled to coincide with 20, 35, and 50% water depletion of field capacity,
respectively. The water depletion, caused by evapotranspiration (ET), was replenished
with irrigation water.
The amounts of water estimated to refill the plant-root zone to field capacity were
computed using the following equations for drip irrigation: SWRCWUÿP; and
DDWHCRZPwf. The soil water requirement (SWR) was calculated based on the
crop water use (CWU) and precipitation (P). The CWU was determined from the
moisture loss due to crop ET. Throughout the growing season at Torrington Research and
Extension Center, daily P data were recorded and the sugarbeet ET values were
calculated based on a modified Penman method (Doorenbos and Pruitt, 1977). The design
depth (DD) indicated the water depletion level between irrigation events and was
determined from soil water holding capacity (WHC), crop rooting depth (RZ), water
depletion factor (f), and percentage of wetted soil surface (Pw) maintained at 70%
according to a FAO guideline for drip irrigation (Vermeiren and Jobling, 1984). Each
irrigation event for D1, D2, and D3 was scheduled at DD values calculated with 20, 35,
and 50% water depletion of field capacity, respectively (f values). Irrigation water was
applied when cumulative value of the daily SWR equaled DD for each drip regime. The
range of f values was consistent with the FAO guideline for drip irrigation (Vermeiren and
Jobling, 1984). The DD with lower f value corresponded to a higher frequency of
irrigation events and smaller quantity of water input during each application.
Once the comparative assessment of different drip and flood irrigation treatments was
established in 1996, a similar experiment was repeated during the 1997 season using one
drip irrigation treatment (analogous to D1 of 1996) along with flood irrigation for the
purpose of verifying the patterns of our previous findings. The SBs from each plot were
harvested in October and analyzed for yield and sugar content by the Holly Sugar
Company, Torrington, Wyoming. Soil samples, collected from the rooting depth (0±45,
45±90, 90±135, 135±150 cm), were stored at 48C until analyzed. The samples were airdried, finely ground (
Assessment of drip and ¯ood irrigation on water and
fertilizer use ef®ciencies for sugarbeets
F. Cassel Sharmasarkar, S. Sharmasarkar*, S.D. Miller,
G.F. Vance, R. Zhang
Department of Plant Sciences and Renewable Resources, College of Agriculture, University of Wyoming,
P.O. Box 3354, Laramie, WY 82071-3354, USA
Accepted 7 February 2000
Abstract
Mismanagement of nitrogenous fertilizers has caused serious nitrate (NO3) contamination in
many ¯ood-irrigated regions of the western US. Low-volume irrigation practices, such as drip
irrigation, can offer an alternative approach for controlling NO3 leaching and agricultural water use.
The objectives of this study were to compare NO3 movement through soils under ¯ood and drip
irrigation practices for sugarbeet production, and to evaluate the agronomic feasibility of
implementing drip irrigation. A ®eld experiment was conducted during the sugarbeet (Beta vulgaris
L.) growing seasons of 1996 and 1997 in southeastern Wyoming, where NO3 contamination is a
continued concern and sugarbeet is a major cash crop. Three drip irrigation regimes, corresponding
to 20, 35, and 50% water depletion of ®eld capacity (designated as D1, D2, and D3, respectively),
were compared against ¯ood irrigation. The irrigation plots were treated with 112, 168, and 224 kg
N haÿ1 (designated as F0, F1, and F2, respectively). Sugarbeet (SB) yields and sugar contents under
drip irrigation were higher (3±28%) than those with ¯ood irrigation; yields and sugar contents for
the drip systems were in the order of D1>D2>D3. For all of the irrigation applications, there was an
increasing trend in yields with increasing fertilizer rates. Drip regime resulted in greater residual
soil NO3 (RSN) for both 1996 and 1997 seasons as compared to ¯ood practices. Values of RSN in
both years followed the trend: F2>F1>F0. Soil NO3 in all three drip regimes was higher (1.6±2.4
times) than that with ¯ood irrigation. In the overall root zone, NO3 concentrations between D1 and
D2 were comparable, whereas both of those levels were lower than D3. Greater NO3 concentrations
with D3 were observed at all depths. The amount of applied irrigation water with the drip system
was lower than that for ¯ood irrigation. Agronomic water use ef®ciency (WUE) and fertilizer use
ef®ciency (FUE) for drip irrigation were always higher than those for ¯ood irrigation. In 1996,
WUE and FUE maintained an order of D1>D2>D3. There was a decreasing pattern in FUE values
with increasing fertilizer rates. The overall results indicated that SB production could be sustained
*
Corresponding author. Present address: California State University, Department of Plant Science, H/S
AS-72, 2415E. San Samon Avenue, Fresno, CA 93740-8033. Tel.: 1-559-278-2904; fax: 1-559-278-7413.
E-mail address: ssharmas@csuffesno.edu (S. Sharmasarkar).
0378-3774/01/$ ± see front matter # 2001 Elsevier Science B.V. All rights reserved.
PII: S 0 3 7 8 - 3 7 7 4 ( 0 0 ) 0 0 0 9 0 - 1
242
F. Cassel Sharmasarkar et al. / Agricultural Water Management 46 (2001) 241±251
with lower water and fertilizer use by using drip irrigation. The p-values (0.05), based on both Ftest (pf) and two-tailed student's t-test (pt), suggested a signi®cant difference between the yield
means obtained under drip and ¯ood irrigation practices. As compared to the ¯ood irrigation, the
least p-values were obtained with D1 followed by D2 and D3, respectively, thus, con®rming that D1
was the most effective treatment. The p-values for SB yields under comparative fertilizer treatments
and same drip application showed no signi®cant difference between the means, thus, suggesting the
feasibility of using lower fertilizer rate while sustaining the targeted yield under drip irrigation. The
comparative estimation of water losses by drainage between ¯ood and drip irrigation suggested that
the later practice reduced the quantity of water leaching beyond the root zone. Among the three drip
treatments, the lowest drainage amount was observed with D1 as a result of its higher irrigation
frequency and smaller quantity of water input during each application. # 2001 Elsevier Science
B.V. All rights reserved.
Keywords: Drip irrigation; Water use; Drainage; Fertilizer management; Sugarbeet production
1. Introduction
Mismanagement of nitrogenous fertilizers has caused serious agricultural contamination in many regions throughout the US (U.S. Department of Agriculture, 1991). High
concentrations of NO3 in drinking water can cause health problems (Environmental
Protection Agency, 1990). In the southeastern region of Wyoming, where sugarbeet (SB)
production is intensive and fields are mainly flood irrigated, levels surpassing the critical
EPA limit of 10 mg lÿ1 NO3-N have been detected in several well waters (Baker and
Associates Consulting Engineers, 1989; Wyoming Hydrogram, 1995). A way of
managing NO3 pollution is to introduce an alternative irrigation method that reduces
chemical transport through soils, as well as agricultural water demand. A low-volume
irrigation practice, such as drip irrigation, can offer such a technology (Bucks et al., 1982;
Caswell, 1991).
Field studies are necessary to determine the efficacy of this new irrigation system in
Wyoming, where flood (furrow) is the major irrigation practice. Benefits of drip irrigation
have been documented by different researchers. In a study involving NO3 transport to
groundwater, Geleta et al. (1994) compared drip and flood irrigation, and concluded that
drip irrigation resulted in lower NO3-N loss. Based on a groundwater quality assessment
research in the delta Wadi El-Arish area of Egypt, Bihery and Lachmar (1994) also
recommended that flood irrigation practice be replaced by drip irrigation system,
especially in arid environments. In another study comparing drip and flood irrigation
practices, Roth et al. (1995) observed that reduced water use did not affect the yield and
quality of orange fruits. Drip irrigation practices are widely used on coarse-textured soils,
and for high-value crops in FL, CA, Europe and Israel where water is scarce or expensive
(Gregory, 1990).
Many SB growing areas in Wyoming are characterized by semi-arid climate and sandy
soils in which NO3 causes serious contamination problems. Sugarbeet is a major cash
crop within the eastern Rocky Mountain region, including Wyoming, and contributes
more than US$ 48 million in annual income to the state (Wyoming Agricultural Statistics
F. Cassel Sharmasarkar et al. / Agricultural Water Management 46 (2001) 241±251
243
Service, 1998). Use of drip irrigation for SB production is yet to be tested in Wyoming.
Therefore, the objective of this study was to compare drip and flood irrigation regarding
water and fertilizer use efficiencies for SB production.
2. Materials and methods
A field experiment was conducted during the SB (Beta vulgaris L.) growing seasons of
1996 and 1997 (seeding: first week of April, harvesting: first week of October) at the
Torrington Research and Extension Center (elevation>1200 m), located in southeastern
Wyoming, where NO3 contamination is a continued concern and SB is a major cash crop
(Wyoming Agricultural Statistics Service, 1998). The soil is classified as Daily sandy
loam (sandy, mixed, mesic, Torriorthentic Haplustoll) with less than 1% organic matter
within the root zone. This soil series was formed predominantly in alluvium and winddeposited and reworked sand which originated from noncalcareous sandstone.
The experimental design was a split-plot, where each irrigation plot was factorially
arranged for three rates of post-emergence nitrogen (N) fertilizer (urea ammonium
nitrate, UAN) applications: control (0 kg haÿ1), half-dose (56 kg haÿ1), and full-dose
(112 kg haÿ1). Earlier in the season, a basal pre-plant dose of 112 kg N haÿ1 was also
applied. Thus, a total quantity of 112, 168, and 224 kg N haÿ1, designated henceforth as
F0, F1, and F2, respectively, was used during the growing season. Weeds were controlled
with two post-emergence herbicide applications (Nortron: 2.13 kg haÿ1, and Betamix:
1.70 kg haÿ1). Additional plot care was ensured by hand-picking of weeds throughout the
growing season. SBs were irrigated using two different methods: conventional flood and
surface drip irrigation. Both flood and drip irrigation applications were initiated in July
and continued until harvesting. Prior to irrigation treatment initiation, the soil profile was
watered to field capacity with flood irrigation to refill a depth of 1.2 m and ensure
moisture content homogeneity in the experimental field. Three irrigation regimes,
corresponding to 20, 35, and 50% water depletion of field capacity (designated as D1:
drip1, D2: drip2, and D3: drip3, respectively), were used for drip irrigation in 1996.
Application of flood irrigation was maintained at 65% water depletion of field capacity in
consistency with the local farming practices. Therefore, a total of four irrigation
treatments was used for the field experiment. Eight SB rows (10 m length0.76 m
standard spacing) were allocated for each irrigation treatment, separated by four furrows
(10 m length0.76 m width) as bordering-buffer-zones to prevent the influence of one
treatment on another. A spacing of 3 m was also maintained as a bordering-zone at both
ends of the rows. Thus, the experimental plot area totaled 600 m2 in which each of the
four irrigation treatments covered an area of 150 m2 and comprised three replicates.
Along the SB rows, furrow irrigation water was delivered from gated pipes connected
to the main water supply. Furrows were fitted with flumes at the beginning and end of
each row to calculate water flow rates. The furrows for flood irrigation were scheduled
for 2 h bi-weekly watering at a rate of 7.00 l hÿ1. Flood irrigation (designated as Fl) was
applied when the soil moisture reached a level of 65% water depletion of field capacity.
The drip irrigation system consisted of PVC pipe laterals (19.05 mm i.d., 10 m length)
and spaced at 0.76 m intervals. Each drip line was equipped with 20 emitters spaced at
244
F. Cassel Sharmasarkar et al. / Agricultural Water Management 46 (2001) 241±251
0.55 m intervals. The drip water was supplied through a pump connected to the main
water source. Each drip system was operated by a control valve at a discharge rate of
3.78 l hÿ1 with an application efficiency of 92%. For D1, D2, and D3, water applications
were scheduled to coincide with 20, 35, and 50% water depletion of field capacity,
respectively. The water depletion, caused by evapotranspiration (ET), was replenished
with irrigation water.
The amounts of water estimated to refill the plant-root zone to field capacity were
computed using the following equations for drip irrigation: SWRCWUÿP; and
DDWHCRZPwf. The soil water requirement (SWR) was calculated based on the
crop water use (CWU) and precipitation (P). The CWU was determined from the
moisture loss due to crop ET. Throughout the growing season at Torrington Research and
Extension Center, daily P data were recorded and the sugarbeet ET values were
calculated based on a modified Penman method (Doorenbos and Pruitt, 1977). The design
depth (DD) indicated the water depletion level between irrigation events and was
determined from soil water holding capacity (WHC), crop rooting depth (RZ), water
depletion factor (f), and percentage of wetted soil surface (Pw) maintained at 70%
according to a FAO guideline for drip irrigation (Vermeiren and Jobling, 1984). Each
irrigation event for D1, D2, and D3 was scheduled at DD values calculated with 20, 35,
and 50% water depletion of field capacity, respectively (f values). Irrigation water was
applied when cumulative value of the daily SWR equaled DD for each drip regime. The
range of f values was consistent with the FAO guideline for drip irrigation (Vermeiren and
Jobling, 1984). The DD with lower f value corresponded to a higher frequency of
irrigation events and smaller quantity of water input during each application.
Once the comparative assessment of different drip and flood irrigation treatments was
established in 1996, a similar experiment was repeated during the 1997 season using one
drip irrigation treatment (analogous to D1 of 1996) along with flood irrigation for the
purpose of verifying the patterns of our previous findings. The SBs from each plot were
harvested in October and analyzed for yield and sugar content by the Holly Sugar
Company, Torrington, Wyoming. Soil samples, collected from the rooting depth (0±45,
45±90, 90±135, 135±150 cm), were stored at 48C until analyzed. The samples were airdried, finely ground (