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Papers by Edward Martin
Onion production in Arizona has remained relatively stable since 2001, varying from 1000-2000 pla... more Onion production in Arizona has remained relatively stable since 2001, varying from 1000-2000 planted acres, with an average yield of 487 cwt./acre. Market prices have continued to grow over the years from 8.80in2004,8.80 in 2004, 8.80in2004,12.00 in 2007 to
Transactions of the ASAE, 2001
A mobile weighing system was designed in 1994 to weigh small lysimeters to measure water use by s... more A mobile weighing system was designed in 1994 to weigh small lysimeters to measure water use by shallow-rooted crops. Using a reconditioned pesticide sprayer, a hoist, and a weighmeter, small lysimeters were weighed in the 1995, 1996, and 1997 growing seasons. The lysimeters were constructed of 4.8-mm hot-rolled steel and were 0.91 × 1.02 × 0.61 m in size with an internal area of 0.929 m 2. The weight of a lysimeter containing only moist soil was 1,110.27 kg. At the beginning of each season of use, several tests were conducted on the weighing system to determine if it was sensitive enough to give adequate results of crop water use. In 1995, tests were conducted on linearity, repeatability, thermal shift, and creep errors. The values were ±0.062 kg, ±0.12 kg,-0.007 kg/ °C, and-0.242 kg, respectively. The terminal linearity was 0.082 kg (1996) and 0.043 kg (1997). The measurement uncertainty decreased as the number of lifts increased. The results showed that the system was capable of producing adequate results for determining crop water use.
The world supply of quality water for irrigation of crops is being depleted. Growers in the arid ... more The world supply of quality water for irrigation of crops is being depleted. Growers in the arid and semi-arid regions of the world, where irrigation is a requirement for crop production, are looking for ways to conserve their water use and increase their irrigation efficiency. One tool that has been useful in helping growers reduce their irrigation water inputs is computerized irrigation scheduling programs. This study is part of a joint project between the government of Egypt (National Agricultural Research Project), USA1D and The University of Arizona. Working together, researchers from Egypt and Arizona are developing water management tools that will help both countries better use their scarce water resources in arid environments. The main thrust of this segment of the project is to develop water use data on vegetables grown in both regions. These data will then be used to develop crop coefficient data to be used in AZSCHED, a computerized irrigation scheduling program developed at the University of Arizona. Using a subsurface drip irrigation (SDI) system, carrots, cauliflower, head lettuce, and tomatoes were grown to determine water use patterns and develop basal crop coefficients. Water use data were collected using a neutron moisture gauge and a time domain reflectometer (TDR). Soil water data were collected 1 day following an irrigation and just prior to the next irrigation. Additionally, three different watering regimens were employed using available water content in the rootzone as a trigger to initiate irrigation (20 %, 30% and 40% depletion). The carrots, cauliflower and lettuce were planted in early October, 1993, using a randomized block design. Yield data showed no significant differences between treatments for any of the vegetables. Also, the soil moisture data did not indicate water stress in the treatments. In March of 1994, tomato transplants were planted and the irrigation treatments were altered to 30 %, 40% and 50% depletion, in an attempt to get significant differences between treatments. The results for all four vegetables showed high variability in soil water data between replications, although an initial determination of basal crop coefficients was possible. Additional data will be required to better refine the crop coefficients.
Revista Brasileira de Engenharia Agrícola e Ambiental, 2005
A two year field study (1996/97 and 1997/98 growing seasons) was carried out at the Maricopa Agri... more A two year field study (1996/97 and 1997/98 growing seasons) was carried out at the Maricopa Agricultural Center (33º04'07" N; 111º57'18" W) of the University of Arizona, USA, to investigate the water use and to derive Kc's for subsurface drip-irrigated head lettuce grown in small weighable lysimeters. Measurement periods ranged from 480 to 1100 ºC-day (96/97) and from 439 to 1098 ºC-day (97/98). These intervals corresponded essentially to the second half of the crop cycle which amounted to a 1100 ºC-day, on average. The lysimeters were weighed periodically and the computation of the water balance revealed an average water use of 117 mm. Basal crop Kc was expressed as a function of cumulative growing degree days following a multiple linear regression procedure in which the data were fitted with a Fourier sine series model with up to six coefficients. Two-year Kc curves were obtained based on the Hargreaves, FAO Penman and FAO Penman-Monteith equations and compa...
Journal of Irrigation and Drainage Engineering, 2004
A key component in the calculation of reference crop evapotranspiration (ETr) is the weather data... more A key component in the calculation of reference crop evapotranspiration (ETr) is the weather data. If the weather data have been collected from a station under nonreference conditions, the data itself may contain errors, which will in turn yield inaccurate ETr estimates. It was proposed by Allen in 1996 that data used for evapotranspiration be scrutinized by comparing daily minimum temperature (Tmin) and the daily average dew point temperature (Tdew). If the difference between Tmin and Tdew is greater than 3°C, then the site is considered to be arid (nonreference) and adjustments are recommended for temperature and dew point data. In Arizona, normal weather conditions often occur where Tmin and Tdew do not approach each other. This study examined the appropriateness of applying the conditions set forth by Allen to temperature data collected in central Arizona. Two weather stations were set up in a 35.5ha alfalfa field in central Arizona to measure dry bulb and wet bulb temperatures. Additionally, plant te...
Agronomy Journal, 2006
The Unified Animal Feeding Operation Strategy requires that field application of animal waste, a ... more The Unified Animal Feeding Operation Strategy requires that field application of animal waste, a common fertilization and disposal practice, may not exceed crop nutrient needs. Additional guidelines set forth by the Arizona Department of Environmental Quality state that animal waste applications on agricultural fields in designated Confined Animal Feeding Operations (CAFOs) must be made in a manner such that the total N applied to the field cannot exceed the uptake from the crop grown. Because alfalfa is grown year round and can take up large quantities of N, many operators of CAFOs apply animal waste to their production alfalfa fields as method of waste disposal. In this research, fresh and composted dairy manure was applied to plots in a production alfalfa (Medicago sativa L.) field to determine the impact on alfalfa yield, soil nitrogen (N), phosphorus (P), and electrical conductivity (EC) levels and the potential for nitrate (NO 3) and phosphate (PO 4) leaching. Unfertilized plots were maintained as controls. Fresh and composted manure was applied to fertilized plots after each harvest at a rate intended to replace N removed from the previous cutting. After 1.5 yr and 13 cuttings, soil analysis down to 150 cm depth showed no significant difference in soil N between treatments. At study end, NO 3-N made up 1.1% of total N in the fertilized plots but only 0.6% in control plots. Changes in soil N were not significant. Soil P content increased in fertilized plots but remained stable in control plots. Final soil PO 4 measurements were 16, 99, and 116 kg ha 21 in the control, manure-treated, and compost-treated plots, respectively. Leachate from three drainage lysimeters contained no detectable NO 3 or PO 4 from any of the treatments. LSD showed no difference in EC between the beginning and the end of study, and alfalfa yield did not vary among treatments.
Applied Engineering in Agriculture, 1997
he citrus-growing regions of the world are widely distributed between 20°and 40°of latitude. The ... more he citrus-growing regions of the world are widely distributed between 20°and 40°of latitude. The climate of these areas ranges from humid tropic to arid subtropic. In the U.S., there exists a variety of subtropical climates ranging from arid deserts to humid tropics. In the Florida peninsula, citrus grows under humid conditions with an annual rainfall of 1250 to 1550 mm. By contrast, the arid regions of Arizona and California produce citrus under irrigation where the mean annual rainfall is less than 125 mm. In these arid regions, the determination of crop water use is critical to assure good fruit quality and high yields. Much of the irrigation in the western U.S. is done using some method of scheduling, including computerized scheduling programs, to determine when to irrigate and how much water to apply. One such program that is being used in Arizona is AZSCHED, AriZona irrigation SCHEDuling program (Fox et al., 1992). AZSCHED uses a checkbook balance approach to help growers schedule irrigation on a variety of crops including cotton, wheat and several vegetable crops. A unique aspect of AZSCHED is that all crop coefficient (kc) data are heat unit-based. AZSCHED calculates heat units using the sinusoidal approach described by Snyder (1985). Heat units (HU), also termed growing degree days (GDD), are widely used to measure plant phenological events and the growth and development of crop pests. In irrigation scheduling, heat unit-based kc data allow for differences in temperatures from year to year. In Arizona, the determination of heat units is difficult because the lower temperature threshold (LTT) and the upper temperature threshold (UTT) must both be determined. This concept is further complicated in grapefruit production because there is no dormant period in Arizona. Many other researchers have attempted to delineate the LTT and UTT for citrus crops. Reuther (1967) gave an overview of the development of the citrus industry. He stated that as early as 1927, Oppenheim studied stomatal changes in grapefruit. Although Oppenheim did not specify threshold temperatures, he did report that the fruit growth slowed at 12.5°C and declined rapidly below 8°C. Furthermore, he suggested that growth and development of the tree would be inhibited at temperatures higher than 30°C. Other researchers have also attempted to determine the threshold temperatures in citrus. Bain (1949) proposed temperature thresholds of 12.2°C and 36.1°C for 10-yearold "Marsh" grapefruit trees. Mendel (1969) reported the temperature thresholds were between 12.5°C and 13°C for the LTT and 37°C and 39°C for the UTT. Mendel also estimated that an annual accumulation of heat units between 1000°C and 1500°C would represent slow growth while a range of 5000°C to 6000°C would represent optimum growth. Other researchers (Newman et al., 1967; Cassin et al., 1967) also estimated LTT between 12°C and 13°C and an UTT in the mid-30°C range. Traditionally, sap flow meters have been used as a measure of direct transpiration. Steinberg et al. (1990) found that sap flow in pecan trees in a 24-h period closely corresponded to canopy transpiration (+8%). They also found that trunk and branch sap flow began concurrently. Weibel et al. (1992) compared stem flow balance, gravimetric and leaf transpiration methods to measure water loss in mangosteens. They reported close agreement in the results from the three methods. Lascano et al. (1992), Devitt et al. (1993), Dugas et al. (1993), and Ansley et al. (1994) also successfully used sap flow gauges and the stem heat balance (SHB) method.
This information has been reviewed by university faculty. cals.arizona.edu/pubs/water/az1329.pdf ... more This information has been reviewed by university faculty. cals.arizona.edu/pubs/water/az1329.pdf MEASURING WATER FLOW IN SURFACE IRRIGATION DITCHES AND GATED PIPE Measuring water in surface irrigation systems is critical for peak efficiency management. Without knowing the amount of water being applied, it is difficult to make decisions on when to stop irrigating or when to irrigate next. A good irrigation manager should know the flow rate of the irrigation water, the total time of the irrigation event and the acreage irrigated. From this, the total amount of water applied can be determined, which will help determine whether the irrigation was adequate and when the next irrigation should be. Irrigation management decisions should be made based on the amount of water applied and how this relates to the consumptive use demands of the plants and the soil water holding capacity. Units of Measuring Water There are many ways to express water volume and flow. The volume of water applied is usually expressed in acre-inches or acre-feet for row crops or gallons per tree in orchards. Flow rate terminology is even more varied. Flow rate is expressed as cfs (cubic feet per second), gpm (gallons per minute) and in some areas, miner's-inches. Below is a description of each. Acre-inch (ac-in.): An acre-inch is the volume of water required to cover an acre of land with one inch of water. One acre-inch equals about 3,630 cubic feet or 27,154 gallons. Acre-foot (ac-ft): An acre-foot is the volume of water required to cover an acre of land with 1 foot of water. One acre-foot equals about 43,560 cubic feet, 325,848 gallons or 12 acre-inches. Cubic feet per second (cfs): One cubic foot per second is equivalent to a stream of water in a ditch 1foot wide and 1-foot deep flowing at a velocity of 1 foot per second. It is also equal to 450 gallons per minute, or 40 miner's-inches. Gallons per minute (gpm): Gallons per minute is a measurement of the amount of water being pumped, or flowing within a ditch or coming out of a pipeline in one minute. Miner's inches: Miner's-inches was a term founded in the old mining days. It is just another way of expressing flow. Some areas in the West still use this measurement unit. Caution needs to be taken because there are Arizona miner's-inches, California miner's-inches and probably some that are locally used. Approximately 40 Arizona miner's-inches equals 1 cfs or 450 gpm. Pressure or Head (H): People often use the phrase "head of water." A foot of head usually implies that the water level is one foot above some measuring point. However, head can also mean pressure. For example, as the level of water rises in a barrel, the pressure at the bottom of the barrel increases. One foot of water exerts 0.43 pounds per square inch (psi) at the bottom of the barrel. Approximately 2.31 feet of water equals 1 psi. Thus, if a tank of water were to be raised 23.1 feet (2.31 x 10) in the air with a hose connected to it, the pressure in the hose at the ground would be about 10 psi. Area: The cross sectional area of a ditch is often required to calculate flow. Some ditches are trapezoids and others or more like ellipses. To find the area of a trapezoid (Fig. 1a), measure the width of the bottom (b) and the width of the ditch at the water surface (s) and add them together. Divide that number by 2 and then multiply by the height (h) of the water. If the ditch is more elliptical in shape (Fig. 1b), take the depth of the water (h), multiply it by the width of the ditch at the surface (s), divide by 4 and then multiply by PI (3.14). To calculate the cross-sectional area of a pipe, the formula is PI x r 2 , where PI is 3.14 and "r" is the radius of the pipe. NOTE: All measurements should be in feet.
Agronomy Journal, 2000
Detasseling is the operation that consists of removing the tassels of the female plants prior to ... more Detasseling is the operation that consists of removing the tassels of the female plants prior to silk emergence CERES-Maize, which was designed for simulation of hybrid maize and pollen shed to prevent self-pollination. During this (Zea mays L.), cannot be applied directly to seed-producing inbred maize because of specific field operations and physiological traits of operation, several leaves are generally removed from inbred maize plants. We developed CERES-IM, a modified version the plants. Though male-sterile inbreds have also been of CERES-Maize 3.0 that accommodates these inbred-specific operaused to avoid detasseling of seed-bearing female plants, tions and traits, using a set of phenological measurements conducted most maize inbreds planted in the USA are not malein Nebraska (NE), and further tested this model with a set of field sterile and require mechanical detasseling (Wych, 1988; data from Michigan (MI). Detasseling (i.e., removal of the tassels J. Wei, personal communication, 1999). Detasseling is from the female plants) was conducted prior to silking. Male rows an important field operation that modifies the plant were removed approximately 10 d following 75% silking. The thermal canopy. The number of leaves removed by detasseling time from emergence to the end of the juvenile phase (P1) and the depends on plant morphology, the time of detasseling potential number of kernels per plant (G2) were assessed from field relative to the time of tassel emergence, pollen shed data, and were the only two coefficients allowed to vary according to the inbred line. Rate of leaf appearance of the inbreds was accurately and silk emergence, and the settings of the mechanical simulated using a measured phyllochron interval of 54 degree-days detasseling machines (Wilhelm et al., 1995b). Removal (؇Cd). Simulation of detasseling and male-row removal improved grain of the tassel alone was reported to augment maize grain yield simulation for inbreds. For a set of 35 inbred-site-year simulayields by increasing the amount of light available to the tions, the model simulated grain yield with satisfactory accuracy top leaves (Duncan et al., 1967; Hunter et al., 1969). (RMSE ϭ 429 kg ha Ϫ1). Average grain yields were 4556 and 4721 kg Leaf removal associated with detasseling induces a linha Ϫ1 for the measured and simulated values, respectively. CERESear decline in grain and stover yields proportional to IM simulations suggest that the effect of male-row removal on grain the number of leaves removed (Wilhelm et al., 1995b). yield is extremely sensitive to the precise date at which this operation Stover biomass was reduced by 4 to 18% when one to is conducted. This would explain the inconsistent effect of male-row three leaves were removed with the tassel (Wilhelm et removal on female grain yields reported in the literature. al., 1995b). Inbred maize plants differ from grain-producing hybrids in size and potential grain yield. The canopy of
Agronomy Journal, 2000
... Crop Sci. 34:7683. WHEAT Durum Grain Quality as Affected by Nitrogen Fertilization nearAnthe... more ... Crop Sci. 34:7683. WHEAT Durum Grain Quality as Affected by Nitrogen Fertilization nearAnthesis and Irrigation During Grain Fill ... Applications of that N fertilizer application near anthesis has a primary influence on N fertilizer near anthesis are more efficient at increasing ...
Un método que se usa comúnmente para determinar cuándo regar es monitorear la disminución de agua... more Un método que se usa comúnmente para determinar cuándo regar es monitorear la disminución de agua en el suelo. Cuando una planta crece, utiliza el agua del suelo alrededor de su zona de raíces. A medida que las plantas utilizan el agua, la humedad en el suelo baja hasta un nivel en el cual se requiere aplicar un riego o el cultivo comienza a estresarse por falta de agua. Si no se aplica agua, la planta continuará haciendo uso de la poca humedad que queda hasta que finalmente utilice toda el agua disponible en el suelo y muera de sed.
La estimación acertada de la cantidad de agua aplicada a una parcela es crítica para cualquier es... more La estimación acertada de la cantidad de agua aplicada a una parcela es crítica para cualquier esquema de manejo del riego. Muy a menudo, los agricultores aplican agua para hacer que la parcela y los surcos “se vean bien” (oscurecer las camas de los surcos) o continuan regando hasta que el agua llega al final de cada surco. Sin embargo, con frecuencia no tienen una idea precisa de cuanta agua han aplicado. Cuando los agricultores no toman en cuenta la eficiencia de sus sistemas de riego, pueden estar aplicando demasiada o muy poca agua. Muy poca agua ocasiona un estrés hídrico innecesario y puede resultar en reducciones de rendimiento. Demasiada agua puede causar estancamiento del agua, pérdida de nutrientes por excesiva infiltración y puede resultar en una pérdida de la cosecha.
La conversión de sistemas de riego por gravedad a sistemas por goteo requiere más que la inversió... more La conversión de sistemas de riego por gravedad a sistemas por goteo requiere más que la inversión de capital. Los agricultores y regadores deben adaptar sus estrategias de manejo para dar acomodo al nuevo sistema de riego. En particular, los sistemas por goteo no están diseñados para aplicar las grandes candidades de agua de riego que la mayoría de los sistemas por gravedad sí son capaces de aplicar. Dependiendo del diseño y distribución del sistema por goteo, este sistema puede tomar varias horas para aplicar una pulgada de agua a la parcela, mientras que la mayoría de los sistemas por gravedad pueden aplicar de 4 a 8 pulgadas en 12 horas. Debido a esta diferencia, los agricultores que utilizan sistemas por goteo necesitan monitorear muy de cerca la condición de humedad del suelo de sus campos regados por goteo y regar apropiadamente. Existen varias publicaciones sobre el uso del agua en cultivos, la calendarización del riego, el monitoreo del agua en el suelo, la medición del flu...
Proper water management involves two basic considerations: when and how much irrigation water to ... more Proper water management involves two basic considerations: when and how much irrigation water to apply. The timing of an irrigation event (the when) involves utilizing information on plant needs and soil water conditions. How much depends primarily on the soil’s water holding capacity, the depletion level and the rooting depth of the crop. Once you have calculated how much water to apply, how can you be sure that you have accurately applied that amount? Or, if you miss your target amount, how do you determine how much water you actually applied? The amount of water applied to a field is a function of time, flow and area. The time of an irrigation is easily recorded. The amount of area irrigated is also easily calculated. However, estimating flow rate in an open ditch is often guess work, at best. In this bulletin we shall discuss ways to measure water flow in an open ditch.
is an equal opportunity, affirmative action institution. The University does not discriminate on ... more is an equal opportunity, affirmative action institution. The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.
An irrigation scheduling trial was implemented on both long and short staple cotton on the Saffor... more An irrigation scheduling trial was implemented on both long and short staple cotton on the Safford Agricultural Center in 1993. It is a continuation of studies initiated in 1991, where plots were irrigated when they reached 40 %, 50% and 60% soil water depletion level as predicted by the AZSCHED software. Results for this study are given as well as a summary of the three year study. Introduction AZSCHED software has been used on the Safford Agricultural Center to schedule irrigations on all of the cotton fields using 50% depletion level to trigger irrigations.. Varying the depletion level at which irrigations are scheduled does not affect the calculated evapotranspiration (ET) values used by the software, only the timing at which the irrigations are applied. In the 1992 trial the 50% depletion level on long staple cotton yielded lower than the 40% and 60% depletion levels, so it was felt necessary to perform the experiment another time to look at long term effects. Materials and Methods The experiment was set up in the same manner as the two previous trials (references 1 and 2), the ground was prepared, rowed -off, planted and watered up. The fields were then marked off with each four rows separated from the adjacent plot with a border to prevent seepage from one plot to another. The treatments were applied to plots in a randomized complete block design. Weather data was downloaded from the AZMET bulletin board each Monday and the fields in the computer were updated for irrigations and rainfall received during the week. A print -out with the scheduled irrigations were given to the farm manager who in turn discussed the farm needs with the chief irrigator. Water was applied to the plots as near to the dates specified as possible, but it should be noted that availability of water, or other scheduling pressures sometimes delayed application. When an irrigation was to be applied, the irrigator set the siphon pipes and allowed the water to run until the furrows were filled. At that time the siphons were stopped and the time was recorded. Thus, the amount or water applied was dictated by how much water the furrows could hold, not what the software indicated was needed to bring the soil back to field capacity. The way that the plots were managed is described in the following crop histories. Crop history Pima: Soil type: Pima clay loam variant (est. water holding capacity, 7.9 inches in 5 feet) Previous crop: Wheat Planting date: i April 1993 Rate: 25 pounds /ac Herbicide: Treflan, pre -plant incorporated Fertilizer: 108 lbs /ac of urea side dressed on 10 June 229 Insecticides: Pyrethroids applied twice, organophosphate applied once; pink boll worms and aphids Pix/Prep: None Defoliants: None Harvest dates First pick: 1 November Second pick: 23 November Crop history upland: Soil type: Grabe clay loam (est. water holding capacity, 7.9 inches in 5 feet) Previous crop: Cotton Planting date: 2 April 1993, the stand was not adequate so it was replanted 29 April and watered up 3 May Rate: 25 pounds /ac Herbicide: Treflan, pre -plant incorporated Fertilizer: 108 lbs /ac of urea side dressed on 10 June and on 16 August Insecticides: Pyrethroids applied twice, organophosphate applied once; pink boll worms and aphids Pix/Prep: None Defoliants: None Harvest dates First pick: 28 October Second pick: 23 November At harvest time the center two rows out of each plot was picked using a IH 782 two -row cotton picker and weighed using a basket scale. Results and Discussion Figure 1 shows the percent soil moisture depletion, as calculated by AZSCHED, throughout the season for the long staple trial. The bar graphs indicate when and how much irrigation water was applied. Some drops can be seen in the percent depletion curve, which are not associated with an irrigation application, these drops were caused by rainfall, which had a total of 6.4 inches during the growing season. Figure 2 shows similar information for the short staple trial. In Figure 1, it can be seen that the percent depletion exceeded it target values about 30 days on both the 40% and 50% depletion graphs during the middle of the season. And in fact, these plots may have undergone more moisture stress than the 60% depletion treatment. This probably explains why the 60% depletion plot had a higher yield than the other treatments as shown in Table 1. Table 1 shows yields and other agronomic data from the long staple trial. The 50% depletion treatment, apparently lost fruit in its high stress period between 60 and 75 days. This caused it to grow taller and mature later as shown by the data. The 60% depletion treatment had less water applied, produced no leaching and had the highest `efficiency'. In an area such as Safford, where soils and irrigation water are salty, this efficiency may come at a high cost. Leaching water through the soil profile to reduce salts is probably of more importance to growers in the area than having a highly `efficient' harvest. The 50% depletion…
One method commonly used to determine when to irrigate is to follow soil moisture depletion. As a... more One method commonly used to determine when to irrigate is to follow soil moisture depletion. As a plant grows, it uses the water within the soil profile of its rootzone. As the water is being used by the plants, the moisture in the soil reaches a level at which irrigation is required or the plant will experience stress. If water is not applied, the plant will continue to use what little water is left until it finally uses all of the available water in the soil and dies.
Timely information on crop water needs is essential for any effective irrigation scheduling strat... more Timely information on crop water needs is essential for any effective irrigation scheduling strategy. Use of historical or average weather data may suffice in the short term, but often causes significant errors in crop water use estimates when used over long periods of time. AZSCHED (AriZona Irrigation SCHEDuling) program utilizes real-time weather data from the AZMET (AriZona METeorological) database to estimate reference crop evapotranspiration (ET o ). These data are then combined with crop coefficient data (K c ) to estimate daily crop water use for 28 different crops grown in Arizona and the Southwest. AZSCHED V1.0 is already available on the Internet and has been downloaded to over 300 users. This new version allows for the use of tree crops and incorporates many new features that can be used with drip and micro sprinkler systems. This paper discusses some of the new features and how the new V2.0 system operates.
Onion production in Arizona has remained relatively stable since 2001, varying from 1000-2000 pla... more Onion production in Arizona has remained relatively stable since 2001, varying from 1000-2000 planted acres, with an average yield of 487 cwt./acre. Market prices have continued to grow over the years from 8.80in2004,8.80 in 2004, 8.80in2004,12.00 in 2007 to
Transactions of the ASAE, 2001
A mobile weighing system was designed in 1994 to weigh small lysimeters to measure water use by s... more A mobile weighing system was designed in 1994 to weigh small lysimeters to measure water use by shallow-rooted crops. Using a reconditioned pesticide sprayer, a hoist, and a weighmeter, small lysimeters were weighed in the 1995, 1996, and 1997 growing seasons. The lysimeters were constructed of 4.8-mm hot-rolled steel and were 0.91 × 1.02 × 0.61 m in size with an internal area of 0.929 m 2. The weight of a lysimeter containing only moist soil was 1,110.27 kg. At the beginning of each season of use, several tests were conducted on the weighing system to determine if it was sensitive enough to give adequate results of crop water use. In 1995, tests were conducted on linearity, repeatability, thermal shift, and creep errors. The values were ±0.062 kg, ±0.12 kg,-0.007 kg/ °C, and-0.242 kg, respectively. The terminal linearity was 0.082 kg (1996) and 0.043 kg (1997). The measurement uncertainty decreased as the number of lifts increased. The results showed that the system was capable of producing adequate results for determining crop water use.
The world supply of quality water for irrigation of crops is being depleted. Growers in the arid ... more The world supply of quality water for irrigation of crops is being depleted. Growers in the arid and semi-arid regions of the world, where irrigation is a requirement for crop production, are looking for ways to conserve their water use and increase their irrigation efficiency. One tool that has been useful in helping growers reduce their irrigation water inputs is computerized irrigation scheduling programs. This study is part of a joint project between the government of Egypt (National Agricultural Research Project), USA1D and The University of Arizona. Working together, researchers from Egypt and Arizona are developing water management tools that will help both countries better use their scarce water resources in arid environments. The main thrust of this segment of the project is to develop water use data on vegetables grown in both regions. These data will then be used to develop crop coefficient data to be used in AZSCHED, a computerized irrigation scheduling program developed at the University of Arizona. Using a subsurface drip irrigation (SDI) system, carrots, cauliflower, head lettuce, and tomatoes were grown to determine water use patterns and develop basal crop coefficients. Water use data were collected using a neutron moisture gauge and a time domain reflectometer (TDR). Soil water data were collected 1 day following an irrigation and just prior to the next irrigation. Additionally, three different watering regimens were employed using available water content in the rootzone as a trigger to initiate irrigation (20 %, 30% and 40% depletion). The carrots, cauliflower and lettuce were planted in early October, 1993, using a randomized block design. Yield data showed no significant differences between treatments for any of the vegetables. Also, the soil moisture data did not indicate water stress in the treatments. In March of 1994, tomato transplants were planted and the irrigation treatments were altered to 30 %, 40% and 50% depletion, in an attempt to get significant differences between treatments. The results for all four vegetables showed high variability in soil water data between replications, although an initial determination of basal crop coefficients was possible. Additional data will be required to better refine the crop coefficients.
Revista Brasileira de Engenharia Agrícola e Ambiental, 2005
A two year field study (1996/97 and 1997/98 growing seasons) was carried out at the Maricopa Agri... more A two year field study (1996/97 and 1997/98 growing seasons) was carried out at the Maricopa Agricultural Center (33º04'07" N; 111º57'18" W) of the University of Arizona, USA, to investigate the water use and to derive Kc's for subsurface drip-irrigated head lettuce grown in small weighable lysimeters. Measurement periods ranged from 480 to 1100 ºC-day (96/97) and from 439 to 1098 ºC-day (97/98). These intervals corresponded essentially to the second half of the crop cycle which amounted to a 1100 ºC-day, on average. The lysimeters were weighed periodically and the computation of the water balance revealed an average water use of 117 mm. Basal crop Kc was expressed as a function of cumulative growing degree days following a multiple linear regression procedure in which the data were fitted with a Fourier sine series model with up to six coefficients. Two-year Kc curves were obtained based on the Hargreaves, FAO Penman and FAO Penman-Monteith equations and compa...
Journal of Irrigation and Drainage Engineering, 2004
A key component in the calculation of reference crop evapotranspiration (ETr) is the weather data... more A key component in the calculation of reference crop evapotranspiration (ETr) is the weather data. If the weather data have been collected from a station under nonreference conditions, the data itself may contain errors, which will in turn yield inaccurate ETr estimates. It was proposed by Allen in 1996 that data used for evapotranspiration be scrutinized by comparing daily minimum temperature (Tmin) and the daily average dew point temperature (Tdew). If the difference between Tmin and Tdew is greater than 3°C, then the site is considered to be arid (nonreference) and adjustments are recommended for temperature and dew point data. In Arizona, normal weather conditions often occur where Tmin and Tdew do not approach each other. This study examined the appropriateness of applying the conditions set forth by Allen to temperature data collected in central Arizona. Two weather stations were set up in a 35.5ha alfalfa field in central Arizona to measure dry bulb and wet bulb temperatures. Additionally, plant te...
Agronomy Journal, 2006
The Unified Animal Feeding Operation Strategy requires that field application of animal waste, a ... more The Unified Animal Feeding Operation Strategy requires that field application of animal waste, a common fertilization and disposal practice, may not exceed crop nutrient needs. Additional guidelines set forth by the Arizona Department of Environmental Quality state that animal waste applications on agricultural fields in designated Confined Animal Feeding Operations (CAFOs) must be made in a manner such that the total N applied to the field cannot exceed the uptake from the crop grown. Because alfalfa is grown year round and can take up large quantities of N, many operators of CAFOs apply animal waste to their production alfalfa fields as method of waste disposal. In this research, fresh and composted dairy manure was applied to plots in a production alfalfa (Medicago sativa L.) field to determine the impact on alfalfa yield, soil nitrogen (N), phosphorus (P), and electrical conductivity (EC) levels and the potential for nitrate (NO 3) and phosphate (PO 4) leaching. Unfertilized plots were maintained as controls. Fresh and composted manure was applied to fertilized plots after each harvest at a rate intended to replace N removed from the previous cutting. After 1.5 yr and 13 cuttings, soil analysis down to 150 cm depth showed no significant difference in soil N between treatments. At study end, NO 3-N made up 1.1% of total N in the fertilized plots but only 0.6% in control plots. Changes in soil N were not significant. Soil P content increased in fertilized plots but remained stable in control plots. Final soil PO 4 measurements were 16, 99, and 116 kg ha 21 in the control, manure-treated, and compost-treated plots, respectively. Leachate from three drainage lysimeters contained no detectable NO 3 or PO 4 from any of the treatments. LSD showed no difference in EC between the beginning and the end of study, and alfalfa yield did not vary among treatments.
Applied Engineering in Agriculture, 1997
he citrus-growing regions of the world are widely distributed between 20°and 40°of latitude. The ... more he citrus-growing regions of the world are widely distributed between 20°and 40°of latitude. The climate of these areas ranges from humid tropic to arid subtropic. In the U.S., there exists a variety of subtropical climates ranging from arid deserts to humid tropics. In the Florida peninsula, citrus grows under humid conditions with an annual rainfall of 1250 to 1550 mm. By contrast, the arid regions of Arizona and California produce citrus under irrigation where the mean annual rainfall is less than 125 mm. In these arid regions, the determination of crop water use is critical to assure good fruit quality and high yields. Much of the irrigation in the western U.S. is done using some method of scheduling, including computerized scheduling programs, to determine when to irrigate and how much water to apply. One such program that is being used in Arizona is AZSCHED, AriZona irrigation SCHEDuling program (Fox et al., 1992). AZSCHED uses a checkbook balance approach to help growers schedule irrigation on a variety of crops including cotton, wheat and several vegetable crops. A unique aspect of AZSCHED is that all crop coefficient (kc) data are heat unit-based. AZSCHED calculates heat units using the sinusoidal approach described by Snyder (1985). Heat units (HU), also termed growing degree days (GDD), are widely used to measure plant phenological events and the growth and development of crop pests. In irrigation scheduling, heat unit-based kc data allow for differences in temperatures from year to year. In Arizona, the determination of heat units is difficult because the lower temperature threshold (LTT) and the upper temperature threshold (UTT) must both be determined. This concept is further complicated in grapefruit production because there is no dormant period in Arizona. Many other researchers have attempted to delineate the LTT and UTT for citrus crops. Reuther (1967) gave an overview of the development of the citrus industry. He stated that as early as 1927, Oppenheim studied stomatal changes in grapefruit. Although Oppenheim did not specify threshold temperatures, he did report that the fruit growth slowed at 12.5°C and declined rapidly below 8°C. Furthermore, he suggested that growth and development of the tree would be inhibited at temperatures higher than 30°C. Other researchers have also attempted to determine the threshold temperatures in citrus. Bain (1949) proposed temperature thresholds of 12.2°C and 36.1°C for 10-yearold "Marsh" grapefruit trees. Mendel (1969) reported the temperature thresholds were between 12.5°C and 13°C for the LTT and 37°C and 39°C for the UTT. Mendel also estimated that an annual accumulation of heat units between 1000°C and 1500°C would represent slow growth while a range of 5000°C to 6000°C would represent optimum growth. Other researchers (Newman et al., 1967; Cassin et al., 1967) also estimated LTT between 12°C and 13°C and an UTT in the mid-30°C range. Traditionally, sap flow meters have been used as a measure of direct transpiration. Steinberg et al. (1990) found that sap flow in pecan trees in a 24-h period closely corresponded to canopy transpiration (+8%). They also found that trunk and branch sap flow began concurrently. Weibel et al. (1992) compared stem flow balance, gravimetric and leaf transpiration methods to measure water loss in mangosteens. They reported close agreement in the results from the three methods. Lascano et al. (1992), Devitt et al. (1993), Dugas et al. (1993), and Ansley et al. (1994) also successfully used sap flow gauges and the stem heat balance (SHB) method.
This information has been reviewed by university faculty. cals.arizona.edu/pubs/water/az1329.pdf ... more This information has been reviewed by university faculty. cals.arizona.edu/pubs/water/az1329.pdf MEASURING WATER FLOW IN SURFACE IRRIGATION DITCHES AND GATED PIPE Measuring water in surface irrigation systems is critical for peak efficiency management. Without knowing the amount of water being applied, it is difficult to make decisions on when to stop irrigating or when to irrigate next. A good irrigation manager should know the flow rate of the irrigation water, the total time of the irrigation event and the acreage irrigated. From this, the total amount of water applied can be determined, which will help determine whether the irrigation was adequate and when the next irrigation should be. Irrigation management decisions should be made based on the amount of water applied and how this relates to the consumptive use demands of the plants and the soil water holding capacity. Units of Measuring Water There are many ways to express water volume and flow. The volume of water applied is usually expressed in acre-inches or acre-feet for row crops or gallons per tree in orchards. Flow rate terminology is even more varied. Flow rate is expressed as cfs (cubic feet per second), gpm (gallons per minute) and in some areas, miner's-inches. Below is a description of each. Acre-inch (ac-in.): An acre-inch is the volume of water required to cover an acre of land with one inch of water. One acre-inch equals about 3,630 cubic feet or 27,154 gallons. Acre-foot (ac-ft): An acre-foot is the volume of water required to cover an acre of land with 1 foot of water. One acre-foot equals about 43,560 cubic feet, 325,848 gallons or 12 acre-inches. Cubic feet per second (cfs): One cubic foot per second is equivalent to a stream of water in a ditch 1foot wide and 1-foot deep flowing at a velocity of 1 foot per second. It is also equal to 450 gallons per minute, or 40 miner's-inches. Gallons per minute (gpm): Gallons per minute is a measurement of the amount of water being pumped, or flowing within a ditch or coming out of a pipeline in one minute. Miner's inches: Miner's-inches was a term founded in the old mining days. It is just another way of expressing flow. Some areas in the West still use this measurement unit. Caution needs to be taken because there are Arizona miner's-inches, California miner's-inches and probably some that are locally used. Approximately 40 Arizona miner's-inches equals 1 cfs or 450 gpm. Pressure or Head (H): People often use the phrase "head of water." A foot of head usually implies that the water level is one foot above some measuring point. However, head can also mean pressure. For example, as the level of water rises in a barrel, the pressure at the bottom of the barrel increases. One foot of water exerts 0.43 pounds per square inch (psi) at the bottom of the barrel. Approximately 2.31 feet of water equals 1 psi. Thus, if a tank of water were to be raised 23.1 feet (2.31 x 10) in the air with a hose connected to it, the pressure in the hose at the ground would be about 10 psi. Area: The cross sectional area of a ditch is often required to calculate flow. Some ditches are trapezoids and others or more like ellipses. To find the area of a trapezoid (Fig. 1a), measure the width of the bottom (b) and the width of the ditch at the water surface (s) and add them together. Divide that number by 2 and then multiply by the height (h) of the water. If the ditch is more elliptical in shape (Fig. 1b), take the depth of the water (h), multiply it by the width of the ditch at the surface (s), divide by 4 and then multiply by PI (3.14). To calculate the cross-sectional area of a pipe, the formula is PI x r 2 , where PI is 3.14 and "r" is the radius of the pipe. NOTE: All measurements should be in feet.
Agronomy Journal, 2000
Detasseling is the operation that consists of removing the tassels of the female plants prior to ... more Detasseling is the operation that consists of removing the tassels of the female plants prior to silk emergence CERES-Maize, which was designed for simulation of hybrid maize and pollen shed to prevent self-pollination. During this (Zea mays L.), cannot be applied directly to seed-producing inbred maize because of specific field operations and physiological traits of operation, several leaves are generally removed from inbred maize plants. We developed CERES-IM, a modified version the plants. Though male-sterile inbreds have also been of CERES-Maize 3.0 that accommodates these inbred-specific operaused to avoid detasseling of seed-bearing female plants, tions and traits, using a set of phenological measurements conducted most maize inbreds planted in the USA are not malein Nebraska (NE), and further tested this model with a set of field sterile and require mechanical detasseling (Wych, 1988; data from Michigan (MI). Detasseling (i.e., removal of the tassels J. Wei, personal communication, 1999). Detasseling is from the female plants) was conducted prior to silking. Male rows an important field operation that modifies the plant were removed approximately 10 d following 75% silking. The thermal canopy. The number of leaves removed by detasseling time from emergence to the end of the juvenile phase (P1) and the depends on plant morphology, the time of detasseling potential number of kernels per plant (G2) were assessed from field relative to the time of tassel emergence, pollen shed data, and were the only two coefficients allowed to vary according to the inbred line. Rate of leaf appearance of the inbreds was accurately and silk emergence, and the settings of the mechanical simulated using a measured phyllochron interval of 54 degree-days detasseling machines (Wilhelm et al., 1995b). Removal (؇Cd). Simulation of detasseling and male-row removal improved grain of the tassel alone was reported to augment maize grain yield simulation for inbreds. For a set of 35 inbred-site-year simulayields by increasing the amount of light available to the tions, the model simulated grain yield with satisfactory accuracy top leaves (Duncan et al., 1967; Hunter et al., 1969). (RMSE ϭ 429 kg ha Ϫ1). Average grain yields were 4556 and 4721 kg Leaf removal associated with detasseling induces a linha Ϫ1 for the measured and simulated values, respectively. CERESear decline in grain and stover yields proportional to IM simulations suggest that the effect of male-row removal on grain the number of leaves removed (Wilhelm et al., 1995b). yield is extremely sensitive to the precise date at which this operation Stover biomass was reduced by 4 to 18% when one to is conducted. This would explain the inconsistent effect of male-row three leaves were removed with the tassel (Wilhelm et removal on female grain yields reported in the literature. al., 1995b). Inbred maize plants differ from grain-producing hybrids in size and potential grain yield. The canopy of
Agronomy Journal, 2000
... Crop Sci. 34:7683. WHEAT Durum Grain Quality as Affected by Nitrogen Fertilization nearAnthe... more ... Crop Sci. 34:7683. WHEAT Durum Grain Quality as Affected by Nitrogen Fertilization nearAnthesis and Irrigation During Grain Fill ... Applications of that N fertilizer application near anthesis has a primary influence on N fertilizer near anthesis are more efficient at increasing ...
Un método que se usa comúnmente para determinar cuándo regar es monitorear la disminución de agua... more Un método que se usa comúnmente para determinar cuándo regar es monitorear la disminución de agua en el suelo. Cuando una planta crece, utiliza el agua del suelo alrededor de su zona de raíces. A medida que las plantas utilizan el agua, la humedad en el suelo baja hasta un nivel en el cual se requiere aplicar un riego o el cultivo comienza a estresarse por falta de agua. Si no se aplica agua, la planta continuará haciendo uso de la poca humedad que queda hasta que finalmente utilice toda el agua disponible en el suelo y muera de sed.
La estimación acertada de la cantidad de agua aplicada a una parcela es crítica para cualquier es... more La estimación acertada de la cantidad de agua aplicada a una parcela es crítica para cualquier esquema de manejo del riego. Muy a menudo, los agricultores aplican agua para hacer que la parcela y los surcos “se vean bien” (oscurecer las camas de los surcos) o continuan regando hasta que el agua llega al final de cada surco. Sin embargo, con frecuencia no tienen una idea precisa de cuanta agua han aplicado. Cuando los agricultores no toman en cuenta la eficiencia de sus sistemas de riego, pueden estar aplicando demasiada o muy poca agua. Muy poca agua ocasiona un estrés hídrico innecesario y puede resultar en reducciones de rendimiento. Demasiada agua puede causar estancamiento del agua, pérdida de nutrientes por excesiva infiltración y puede resultar en una pérdida de la cosecha.
La conversión de sistemas de riego por gravedad a sistemas por goteo requiere más que la inversió... more La conversión de sistemas de riego por gravedad a sistemas por goteo requiere más que la inversión de capital. Los agricultores y regadores deben adaptar sus estrategias de manejo para dar acomodo al nuevo sistema de riego. En particular, los sistemas por goteo no están diseñados para aplicar las grandes candidades de agua de riego que la mayoría de los sistemas por gravedad sí son capaces de aplicar. Dependiendo del diseño y distribución del sistema por goteo, este sistema puede tomar varias horas para aplicar una pulgada de agua a la parcela, mientras que la mayoría de los sistemas por gravedad pueden aplicar de 4 a 8 pulgadas en 12 horas. Debido a esta diferencia, los agricultores que utilizan sistemas por goteo necesitan monitorear muy de cerca la condición de humedad del suelo de sus campos regados por goteo y regar apropiadamente. Existen varias publicaciones sobre el uso del agua en cultivos, la calendarización del riego, el monitoreo del agua en el suelo, la medición del flu...
Proper water management involves two basic considerations: when and how much irrigation water to ... more Proper water management involves two basic considerations: when and how much irrigation water to apply. The timing of an irrigation event (the when) involves utilizing information on plant needs and soil water conditions. How much depends primarily on the soil’s water holding capacity, the depletion level and the rooting depth of the crop. Once you have calculated how much water to apply, how can you be sure that you have accurately applied that amount? Or, if you miss your target amount, how do you determine how much water you actually applied? The amount of water applied to a field is a function of time, flow and area. The time of an irrigation is easily recorded. The amount of area irrigated is also easily calculated. However, estimating flow rate in an open ditch is often guess work, at best. In this bulletin we shall discuss ways to measure water flow in an open ditch.
is an equal opportunity, affirmative action institution. The University does not discriminate on ... more is an equal opportunity, affirmative action institution. The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.
An irrigation scheduling trial was implemented on both long and short staple cotton on the Saffor... more An irrigation scheduling trial was implemented on both long and short staple cotton on the Safford Agricultural Center in 1993. It is a continuation of studies initiated in 1991, where plots were irrigated when they reached 40 %, 50% and 60% soil water depletion level as predicted by the AZSCHED software. Results for this study are given as well as a summary of the three year study. Introduction AZSCHED software has been used on the Safford Agricultural Center to schedule irrigations on all of the cotton fields using 50% depletion level to trigger irrigations.. Varying the depletion level at which irrigations are scheduled does not affect the calculated evapotranspiration (ET) values used by the software, only the timing at which the irrigations are applied. In the 1992 trial the 50% depletion level on long staple cotton yielded lower than the 40% and 60% depletion levels, so it was felt necessary to perform the experiment another time to look at long term effects. Materials and Methods The experiment was set up in the same manner as the two previous trials (references 1 and 2), the ground was prepared, rowed -off, planted and watered up. The fields were then marked off with each four rows separated from the adjacent plot with a border to prevent seepage from one plot to another. The treatments were applied to plots in a randomized complete block design. Weather data was downloaded from the AZMET bulletin board each Monday and the fields in the computer were updated for irrigations and rainfall received during the week. A print -out with the scheduled irrigations were given to the farm manager who in turn discussed the farm needs with the chief irrigator. Water was applied to the plots as near to the dates specified as possible, but it should be noted that availability of water, or other scheduling pressures sometimes delayed application. When an irrigation was to be applied, the irrigator set the siphon pipes and allowed the water to run until the furrows were filled. At that time the siphons were stopped and the time was recorded. Thus, the amount or water applied was dictated by how much water the furrows could hold, not what the software indicated was needed to bring the soil back to field capacity. The way that the plots were managed is described in the following crop histories. Crop history Pima: Soil type: Pima clay loam variant (est. water holding capacity, 7.9 inches in 5 feet) Previous crop: Wheat Planting date: i April 1993 Rate: 25 pounds /ac Herbicide: Treflan, pre -plant incorporated Fertilizer: 108 lbs /ac of urea side dressed on 10 June 229 Insecticides: Pyrethroids applied twice, organophosphate applied once; pink boll worms and aphids Pix/Prep: None Defoliants: None Harvest dates First pick: 1 November Second pick: 23 November Crop history upland: Soil type: Grabe clay loam (est. water holding capacity, 7.9 inches in 5 feet) Previous crop: Cotton Planting date: 2 April 1993, the stand was not adequate so it was replanted 29 April and watered up 3 May Rate: 25 pounds /ac Herbicide: Treflan, pre -plant incorporated Fertilizer: 108 lbs /ac of urea side dressed on 10 June and on 16 August Insecticides: Pyrethroids applied twice, organophosphate applied once; pink boll worms and aphids Pix/Prep: None Defoliants: None Harvest dates First pick: 28 October Second pick: 23 November At harvest time the center two rows out of each plot was picked using a IH 782 two -row cotton picker and weighed using a basket scale. Results and Discussion Figure 1 shows the percent soil moisture depletion, as calculated by AZSCHED, throughout the season for the long staple trial. The bar graphs indicate when and how much irrigation water was applied. Some drops can be seen in the percent depletion curve, which are not associated with an irrigation application, these drops were caused by rainfall, which had a total of 6.4 inches during the growing season. Figure 2 shows similar information for the short staple trial. In Figure 1, it can be seen that the percent depletion exceeded it target values about 30 days on both the 40% and 50% depletion graphs during the middle of the season. And in fact, these plots may have undergone more moisture stress than the 60% depletion treatment. This probably explains why the 60% depletion plot had a higher yield than the other treatments as shown in Table 1. Table 1 shows yields and other agronomic data from the long staple trial. The 50% depletion treatment, apparently lost fruit in its high stress period between 60 and 75 days. This caused it to grow taller and mature later as shown by the data. The 60% depletion treatment had less water applied, produced no leaching and had the highest `efficiency'. In an area such as Safford, where soils and irrigation water are salty, this efficiency may come at a high cost. Leaching water through the soil profile to reduce salts is probably of more importance to growers in the area than having a highly `efficient' harvest. The 50% depletion…
One method commonly used to determine when to irrigate is to follow soil moisture depletion. As a... more One method commonly used to determine when to irrigate is to follow soil moisture depletion. As a plant grows, it uses the water within the soil profile of its rootzone. As the water is being used by the plants, the moisture in the soil reaches a level at which irrigation is required or the plant will experience stress. If water is not applied, the plant will continue to use what little water is left until it finally uses all of the available water in the soil and dies.
Timely information on crop water needs is essential for any effective irrigation scheduling strat... more Timely information on crop water needs is essential for any effective irrigation scheduling strategy. Use of historical or average weather data may suffice in the short term, but often causes significant errors in crop water use estimates when used over long periods of time. AZSCHED (AriZona Irrigation SCHEDuling) program utilizes real-time weather data from the AZMET (AriZona METeorological) database to estimate reference crop evapotranspiration (ET o ). These data are then combined with crop coefficient data (K c ) to estimate daily crop water use for 28 different crops grown in Arizona and the Southwest. AZSCHED V1.0 is already available on the Internet and has been downloaded to over 300 users. This new version allows for the use of tree crops and incorporates many new features that can be used with drip and micro sprinkler systems. This paper discusses some of the new features and how the new V2.0 system operates.