scholarly journals An Irrigation Scheduling Model for Turnip Greens

1993 ◽  
Vol 118 (6) ◽  
pp. 726-730 ◽  
Author(s):  
Eric H. Simonne ◽  
Doyle A. Smittle ◽  
Harry A. Mills
Keyword(s):  
Irrigation System ◽  
Irrigation Scheduling ◽  
Leafy Vegetables ◽  
Pan Evaporation ◽  
Class A ◽  
Soil Water Tension ◽  
Scheduling Model ◽  
Leaf Yield ◽  
Scheduling Irrigation ◽  
Water Tension

An irrigation scheduling model for turnip (Brassica rapa L.) was validated using a line-source irrigation system in a 2-year field trial. The model used a water balance, a variable root length, and a crop factor function of plant age (i). Evapotranspiration was computed daily as class A pan evaporation times a crop factor [CF(i) = 0.365 + 0.0154i-0.00011i2]. Irrigation according to the model maintained soil water tension at <25 kPa at a 30-cm depth. When rainfall amounts were less than water use, leaf yields responded quadratically to irrigation rates, from 0% to 160% of the model rate, and the highest leaf yield with the lowest water applications corresponded to the model rate. Therefore, this model could replace the “feel or see” methods commonly used for scheduling irrigation of leafy vegetables grown in the southeastern United States.

scholarly journals Water Budgets to Schedule Irrigation for Vegetables

1992 ◽  
Vol 2 (1) ◽  
pp. 54-59 ◽  
Author(s):  
Doyle A. Smittle ◽  
W. Lamar Dickens
Keyword(s):  
Water Use ◽  
Soil Depth ◽  
Irrigation System ◽  
Irrigation Scheduling ◽  
Pan Evaporation ◽  
Model Soil ◽  
Soil Water Tension ◽  
Summer Squash ◽  
Daily Water ◽  
Water Tension

Instrumented rainfall- and groundwater-protected irrigation shelters were used to establish relationships (daily crop factors) between pan evaporation and daily water use for several vegetables. Use of these daily crop factors (water use/pan evaporation) and pan evaporation data for scheduling irrigations are described. Snap bean (Phaseolus vulgaris L.) is used to illustrate irrigation scheduling by this method. A table of the model output with columnar headings of age, root depth, date, pan evaporation, crop factor, daily water use, cumulative water use, allowable water use, rainfall, and irrigation is presented. When irrigation was applied according to the model, soil water tension was held below 25 db at 6-inch (15-cm) soil depth. With varying irrigation rates under a line-source irrigation system, marketable pod yields were maximized at 100% of the model rate. Marketable yields of summer squash also were maximized when irrigation was applied at 100% of the model rate. Marketable yields of sweetpotato were not affected by irrigation rates ranging from 1% to 177% of the model rate.

scholarly journals Irrigation Regimes Affect Leaf Yield and Water Turnip Use by Mustard

HortScience ◽  
1992 ◽  
Vol 27 (4) ◽  
pp. 308-310 ◽  
Author(s):  
Doyle A. Smittle ◽  
W. Lamar Dickens ◽  
James R. Stansell ◽  
Eric Simonne
Keyword(s):  
Soil Water ◽  
Water Use ◽  
Regression Equations ◽  
Pan Evaporation ◽  
Soil Water Tension ◽  
Irrigation Regimes ◽  
Leaf Yield ◽  
Daily Evapotranspiration ◽  
Daily Pan Evaporation ◽  
Water Tension

Turnip (Brassica rapa L.) and mustard (Brassica juncea L.) were grown in drainage lysimeters under controlled soil water regimes during 2 years. Irrigation regimes consisted of water applications when the soil water tension at a 10-cm depth exceeded 25,50, or 75 kPa throughout growth of the two crops on two soil types during spring and fall production seasons. Leaf yield and water use were highest when irrigation was applied at 25 kPa soil water tension. Regression equations are presented to describe the relationships of daily pan evaporation and water use to plant age, and to compute daily evapotranspiration: pan evaporation ratios (crop factors) during spring and fall production seasons.

scholarly journals Soil Water Tension, a Powerful Measurement for Productivity and Stewardship

HortScience ◽  
2011 ◽  
Vol 46 (2) ◽  
pp. 178-185 ◽  
Author(s):  
Clinton C. Shock ◽  
Feng-Xin Wang
Keyword(s):  
Soil Water ◽  
Irrigation System ◽  
Irrigation Scheduling ◽  
Plant Performance ◽  
Vegetable Crops ◽  
Crop Species ◽  
High Productivity ◽  
Soil Water Tension ◽  
Water Tension

A fundamental way to schedule irrigation is through the monitoring and management of soil water tension (SWT). Soil water tension is the force necessary for plant roots to extract water from the soil. With the invention of tensiometers, SWT measurements have been used to schedule irrigation. There are different types of field instruments used to measure SWT, either directly or indirectly. Precise irrigation scheduling by SWT criteria is a powerful method to optimize plant performance. Specific SWT criteria for irrigation scheduling have been developed to optimize the production and quality of vegetable crops, field crops, trees, shrubs, and nursery crops. This review discusses known SWT criteria for irrigation scheduling that vary from 2 to 800 kPa depending on the crop species, plant product to be optimized, environmental conditions, and irrigation system. By using the ideal SWT and adjusting irrigation duration and amount, it is possible to simultaneously achieve high productivity and meet environmental stewardship goals for water use and reduced leaching.

scholarly journals An Irrigation Scheduling Model for Summer Squash

1992 ◽  
Vol 117 (5) ◽  
pp. 717-720 ◽  
Author(s):  
Doyle A. Smittle ◽  
W. Lamar Dickens ◽  
M. Jane Hayes
Keyword(s):  
Cucurbita Pepo ◽  
Irrigation System ◽  
Irrigation Scheduling ◽  
Pan Evaporation ◽  
Water Application ◽  
Scheduling Model ◽  
Summer Squash ◽  
Marketable Fruit ◽  
N Rates ◽  
Nitrogen Rates

An irrigation scheduling model for summer squash (Cucurbita pepo L.) was developed and validated during 1986, 1987, and 1989. The model is represented by the equation: 12.7(i - 4) × 0.5ASW = Di-1 + [E(0.14 + 0.015) - P - I]i, where crop age in days is i; effective root depth is 12.7(i - 4) with a maximum of 381 mm; usable water (cubic millimeter per cubic millimeter of soil) is 0.5ASW, deficit on the previous day is Di-1; evapotranspiration is pan evaporation (E) times 0.14 + 0.015i; rainfall (in millimeters) is P; and irrigation (in millimeters) is I. The model was validated during the three years using a line-source irrigation system with irrigation depths ranging from 5% to 160% of the model rates. Nitrogen rates were 50%, 100%, and 150% of the recommended rate. Marketable fruit yields increased as the irrigation depths increased up to the model rate then decreased with greater water application depths. Marketable fruit yields increased as the N rate increased in 1987 and 1989, but yields were similar at all N rates in 1986. The shelf life of marketable fruits was not influenced by irrigation or N rates.

scholarly journals Effects of Irrigation on Sweetpotato Yields

HortScience ◽  
1998 ◽  
Vol 33 (4) ◽  
pp. 606b-606
Author(s):  
Eric Simonne ◽  
James Bannon ◽  
Marvin Ruf
Keyword(s):  
Soil Water ◽  
Irrigation Scheduling ◽  
Pan Evaporation ◽  
Limited Effect ◽  
Class A ◽  
Drought Tolerant ◽  
Scheduling Model ◽  
Ipomea Batatas ◽  
Temporary Water ◽  
Class A Pan

Sweetpotato (Ipomea batatas L.) is a drought-tolerant crop mostly produced without irrigation. Consequently, sweetpotato may be exposed to temporary water stress. In 1997, an irrigation scheduling model using a water balance and class A pan evaporation (Ep) was evaluated with `Beauregard' on a loam sandy soil. The model was (12.7 DAT + 76) 0.5 ASW = DDAT-1 + [Ep (0.12 + 0.023 DAT – 0.00019 DAT2) – RDAT – IDAT], where DAT is days after transplanting (DAT = 0 on 20 June), ASW is available soil water (15%), D is soil water deficit (mm), R is rainfall (mm), and I is irrigation (mm). Root depth expanded at a rate of 13 mm/day to a maximum depth of 305 mm. Irrigation rates ranging between 0 and 145% of the model rate were created with sprinklers. The model scheduled 10 irrigations between DAT = 26 and 116 (harvest). Irrigation did not alter storage root quality, but did influence all the marketable grades (P < 0.01; R2 > 0.87). However, between 0 and 129% yield increases were linear and small, suggesting that the model overestimated sweetpotato water use. Thus, deficit irrigation between 50% to 70% of the model would have a limited effect on sweetpotato yields.

scholarly journals 213 A COMPARISON OF STRATEGIES FOR SCHEDULING IRRIGATION OF VEGETABLES

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 460a-460
Author(s):  
Eric H. Simonne ◽  
Joseph M. Kemble ◽  
Doyle A. Smittle
Keyword(s):  
Irrigation Scheduling ◽  
Weather Data ◽  
Pascal Program ◽  
Planting Dates ◽  
Soil Water Tension ◽  
Scheduling Method ◽  
Complete Calculation ◽  
Scheduling Irrigation ◽  
Water Tension ◽  
Moldboard Plow

The effect of irrigation scheduling method (variable crop factor, 1; constant crop factor, 2; empirical, 3), soil water tension (25, 50, 75kPa SWT), tillage (disc arrow, DA, moldboard plow, MP) and planting dates (PD) on total irrigation (TI), number of irrigations (NI), useful (UR) and lost rainfall (LR) was studied using a Pascal program that simulated water budgets of 720 crops of snap bean over 10 years. NI and TI were significantly (p<0.01) lower with met.1. Met.3 had the lowest LR and highest UR, but did not allow the complete calculation of the water balance. TI was significantly higher at 25kPa. MP tillage requested fewer NI and less TI, had lower LR and higher UR. Early PD requested fewer NI and TI, and had higher LR. Hence, when water supply was not limiting and weather data were available, a combination of Met.1, MP at any PD provided a continuous supply of water to the crop while controlling water deficit.

scholarly journals An Irrigation Scheduling Model for Snap Bean

1990 ◽  
Vol 115 (2) ◽  
pp. 226-230 ◽  
Author(s):  
Doyle A. Smittle ◽  
W. Lamar Dickens ◽  
James R. Stansell
Keyword(s):  
Phaseolus Vulgaris ◽  
Nitrogen Fertilization ◽  
Line Source ◽  
Irrigation System ◽  
Irrigation Scheduling ◽  
Root Depth ◽  
Pan Evaporation ◽  
Snap Bean ◽  
Fertilization Rates ◽  
Scheduling Model

An irrigation scheduling model for snap bean (Phaseolus vulgaris L.) was developed and validated. The irrigation scheduling model is represented by the equation: 12.7(i - 4) × 0.5ASW = Di-1 + [E(0.31 + 0.01i) - P - I]i, where crop age is i; effective root depth is 12.7(i - 4) with a maximum of 400 mm; usable water (cm3·cm-3 of soil) is 0.5 ASW, deficit on the previous day is Di-1; evapotranspiration is pan evaporation (E) times 0.31 + 0.01i; rainfall (mm) is P, and irrigation (mm) is I. The model was validated using a line source irrigation system with irrigation depths ranging from 3% to 145% of tbe model rate in 1985 and from 4% to 180% of the model rate in 1986. Nitrogen fertilization rates ranged from 50% to 150% of the recommended rate both years. Marketable pod yields increased as irrigation rate increased in 1985. Irrigation at 4%, 44%, 65%, 80%, 150%, and 180% of the model rate produced yields that were 4%, 39%, 71%, 85%, 92%, and 55% as great as yields with the model rate in 1986. Marketable pod yields increased as N rate increased when irrigation was applied at 80%, 100%, or 150% of the model rate in 1986, but pod yields varied less with N rate when irrigation was applied at 4%, 44%, 65%, or 180% of the model.

Development and use of a variable-speed lateral boom irrigation system to define water requirements of 11 turfgrass genotypes under field conditions

2007 ◽  
Vol 47 (1) ◽  
pp. 86 ◽  
Author(s):  
D. C. Short ◽  
T. D. Colmer
Keyword(s):  
Water Conservation ◽  
Irrigation System ◽  
Water Status ◽  
Irrigation Scheduling ◽  
Variable Speed ◽  
Leaf Water Status ◽  
Area Index ◽  
Class A ◽  
Irrigation Requirements ◽  
Class A Pan

Improved irrigation scheduling is one strategy by which water management can be improved in turfgrass systems. The development and testing of a variable-speed lateral boom irrigation system for use in field-based irrigation trials is reported. Christiansen’s coefficient of uniformity was greater than 92% and the efficiency of irrigator discharge was greater than 90% for application depths (mm/unit land area) of 0.5–13 mm. The minimum irrigation requirements were determined for 11 turfgrass genotypes from a summer irrigation dose–response field trial that applied daily treatments of 100 (control), 80, 60, 40 and 20% of the previous day’s net evaporation measured using a US Class A pan. Responses of several shoot parameters, including clipping production, green leaf area index, leaf chlorophyll and leaf water status were evaluated to define minimum irrigation requirements for the turfgrasses. Minimum irrigation requirements (as defined by declines of 10% in several shoot responses) for C3 and C4 turfgrasses were 64–94% and 32–78% of US Class A pan, respectively. Variability in irrigation requirements within C3 or C4 types was due mainly to variations in estimates based on the different shoot parameters. The results demonstrate the opportunity for water conservation by using C4 rather than C3 turfgrasses in locations with hot dry summers (and mild winters) typical of a Mediterranean-type climate.

scholarly journals Measurement and Estimation of Annual Variability of Water Loss at Njuwa Lake Using Class ‘A’ Pan Evaporation Method

2020 ◽  
pp. 11-21
Author(s):  
A. A. Sadiq
Keyword(s):  
Water Loss ◽  
Irrigation Scheduling ◽  
Water Volume ◽  
Pan Evaporation ◽  
Morphometric Characteristics ◽  
Average Width ◽  
Evaporation Method ◽  
Class A ◽  
Annual Variability ◽  
Class A Pan

Aim: To measure and estimate the annual variability of water loss at Njuwa Lake using Class ‘A’ Pan Evaporation Method. Place and Duration of Study: Njuwa Lake in Yola South LGA, Adamawa State Nigeria between November, 2019 and May, 2020. Methodology: Direct measurements of morphometric characteristics of the lake were adopted using simple bathymetric method. Evaporation rates data and other related weather variable for the periods of ten (2007-2016) years were obtained from Upper Benue River Basin Development Authority located near the lake where the volume of water in the lake and the annual water loss were estimated using FAO estimate of water requirement procedures. Results: The results revealed that Njuwa Lake has morphometric characteristics of 1, 325 m average length, 180m average width, average depth 3.4 m, 238, 500 m2 of  surface area, 1,445 m shoreline length and 0.834 m shoreline development with an estimated water volume of  810, 900 m3 respectively. Similarly, highest Class ‘A’ Pan evaporation rates were found in the year 2011, 2007 and 2008 with the corresponding total annual values of 2688.06 mm, 2403.64 mm and 2389.63 mm having an estimated values of water lost from the lake of 641, 102.310 m3 (79.07%), 573, 268.140 m3(70.7%) and 569, 926.755 m3 (70.29 %) correspondingly. Conversely, the year 2013,2012 and 2014 were found with the lowest measured Pan evaporation rates (1585.00 mm, 1611.54 mm and 1663.27 mm) with an estimated water lost on the lake of about  378, 022.500 m3 (46.6 %), 384, 352.290 m3 (47.4 %) and 396, 689.895 m3 (48.9 %). Conclusion: The rate of water loss was through evaporation was estimated to be greater than the stored water in the Lake in most of the years under study which led to untimely drying of the lake thereby affecting the irrigation farming in the area. Valuable strategies of water use efficiency and irrigation scheduling for effective utilization of the limited stored water in the lake for sustainable food production should be therefore adopted. The research work, however, need further work to make a comparison between the class ‘A’ Pan method and other empirical models method to revalidate the reliability.

scholarly journals 533 Monitoring Soil Water Content in Tropical Fruit Orchards in Southern Florida with Multi-sensor Capacitance Probes and Tensiometers

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 487C-487 ◽  
Author(s):  
R. Nuñez-Elisea ◽  
B. Schaffer ◽  
M. Zekri ◽  
S.K. O'Hair ◽  
J.H. Crane
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Volumetric Soil Water Content ◽  
Tropical Fruit ◽  
Soil Water Tension ◽  
Scheduling Irrigation ◽  
Southern Florida ◽  
Fruit Orchards ◽  
Water Tension

Tropical fruit trees in southern Florida are grown in porous, oolitic limestone soil that has very low organic matter content and water-holding capacity. Thus, trees require frequent irrigation during dry periods. In these soils, a quantitative basis for monitoring soil water content to determine when and how much to irrigate has been lacking. Multi-sensor capacitance probes (EnviroSCAN™, Sentek, Australia) were installed in commercial carambola, lime, and avocado orchards to continuously monitor changes in soil water content at depths of 10, 20, 30, and 50 cm. Eight probes were installed per orchard. Volumetric soil water content was recorded at 15-min intervals with a solar-powered datalogger. Results were downloaded to a laptop computer twice a week. Monitoring the rate of soil water depletion (evapotranspiration) allowed irrigation before the onset of water stress. The time at which soil reached field capacity could be determined after each irrigation (or rain) event. Soil water tension was recorded periodically using low-tension (0–40 cbars) tensiometers placed adjacent to selected capacitance probes at 10- and 30-cm depths. Soil water tension was better correlated with volumetric soil water content at a 10-cm depth than at 30-cm depth. Using multi-sensor capacitance probes is a highly accurate, although relatively expensive, method of monitoring soil water content for scheduling irrigation in tropical fruit orchards. Whereas tensiometers require periodic maintenance, the multi-sensor capacitance probe system has been virtually maintenance free. The correlation between soil water content and soil water tension obtained in situ indicates that tensiometers are a less precise, but considerably cheaper, alternative for scheduling irrigation in tropical fruit orchards in southern Florida.

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