Determination of Heat Unit Based Crop Coefficient for Alfalfa in Western Arizona
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AbstractAlfalfa is the second largest production crop grown in Arizona with an estimated 150,000 acres of production in 1993. Water requirements for alfalfa have been estimated at 6 acre-feet per year. These two facts together make it imperative that data be gathered to help growers apply their irrigation water efficiently while maintaining their yields. In 1994, a study was initiated in the Parker Valley region of La Paz County, Arizona, to measure daily water use in alfalfa. Two sites were chosen for measurement: one site was a surface irrigated field located at the Quail Mesa Farm; the second site was a surface irrigated field located on the Colorado River Farm. The two sites were chosen to give a contrasting schedule of irrigation and allow for data collection at differing times throughout the year. Nine neutron probes were installed in each field, three 113 in from the head, three in the center, and three 113 in from the tail on one field at each location. Neutron probe readings were taken at 18", 30", 42", and 54" depths below the soil surface to measure soil moisture from 1' -2', 2' -3', 3'-4', 4' -5'. The soil moisture for the top foot was determined by gravimetric sampling. The data gathered by this study was used to compare with data used in AZSCHED, a computerized irrigation scheduling program. With this data, determination of alfalfa water used based on heat units after cutting was made to help growers better use their irrigation water.
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The ethnobotany and phenology of plants in and adjacent to two riparian habitats in southeastern Arizona.Asdall, Willard Van; Adams, Karen Rogers.; Mason, Charles T.; Martin, Paul S.; Davis, Owen K.; Turner, Raymond M. (The University of Arizona., 1988)Two riparian habitats in southeastern Arizona provide the setting for a study of 127 plants useful to human foragers. A view of plant part availability is based on annual phenological profiles, and on historic and prehistoric records of plant use. Food choice is limited in March and April, but high August through November. Riparian plants also offer numerous non-food resources. Trees and shrubs serve more needs in relation to number of available species than do perennial herbs (including grasses) and annuals. Southwestern ethnographic literature hints that certain native taxa (Panicum, Physalis, Populus, Salix, Typha and Vitis) might receive special care. Inherent qualities of parts, coupled with ethnographic records of preparation and use, provide a basis for speculation on which parts might survive in an ancient record. Most are expected to disintegrate in open sites. Parts sought for different needs can enter a dwelling via diverse routes that produce confusingly similar archaeological debris. Modern experiments to wash pollen from 14 separate harvests permit evaluation of plant fruit and leaves as pollen traps, to help interpret pollen recovered from ancient dwellings. High amounts of Berberis, Rumex and Ribes pollen, sometimes in clumps or as tetrads, travel on harvested fruit. Arctostaphylos, Monarda, Oxalis, Rhus, Rhamnus, Vitis and Juniperus parts carry lower amounts. Quercus and Gramineae pollen grains travel on parts of other taxa, as well as on their own fruit. The phenological profiles offer insight into group life-form activities in response to local temperature and precipitation trends. Rising and maximum temperatures coincide with intense vegetative and reproductive activity for trees, shrubs, herbaceous perennials, and annuals. Increased levels of precipitation coincide with maximum flowering and fruiting of herbaceous perennials and fall annuals. Limited data on six taxa from Utah generally agrees with observations in this study, suggesting strong genetic control in the phenology of some riparian taxa.
A recursive programming analysis of water conservation in Arizona agriculture : a study of the Phoenix active management areaLierman, Wally Kent.; Wade, James C.; Ayer, Harry W.; Cory, Dennis (The University of Arizona., 1983)Arizona agriculture faces many changes in the near future. One of the most imminent changes will come from the enactment of the 1980 Arizona Groundwater Management Act. The 1980 AGWMA is designed ultimately to curtail the use of groundwater in Arizona. Agriculture will be affected since this sector used approximately 87 percent of all water in the State in 1980. This study reports on the possible effects that a proposed pump tax and water duty policy would have on agriculture within the Phoenix Active Management Area. The PAMA is one of four such areas in the State that have been identified as needing groundwater use management. The results of this study indicate that the proposed water duty is more effective in curbing groundwater use than the proposed pump tax. Investment in more water application efficient irrigation technologies is also important in this study. However, substantial amounts of capital investment funds will be needed to begin this investment.