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C. D. Stanley, G. A. Clark, E. E. Albregts and F. S Zazueta

Sixteen field-located drainage lysimeters (each 60 cm wide, 2.44 m long, 60 cm deep) designed specifically for determination of water requirements for fruiting strawberry production (season - Oct to April) were installed in 1986. Each lysimeter was equipped with individual micro-irrigation and drainage collection systems automated for minimal management input. Initially, computer control (using a low-cost microcomputer) was used to continuously check switching-tensiometers located in each lysimeter and apply irrigation water as needed, A drainage suction (-10 MPa) was applied continuously to simulate field drainage conditions. Manually-installed lysimeter covers were used to protect the plots from interference from rainfall when needed, Initial irrigation application treatments were set at four levels of soil moisture tension controlled by tensiometers and were measured using flow meters for each lysimeter. This paper will discuss problems that were experienced with the initial setup (difficulty in measuring actual application amounts, tensiometer and computer control, elimination of rainfall interference, uniformity of irrigation application, and salinity in the rooting zone) and the modifications (pressurized reservoir tanks, construction of motorized rain-out shelter, micro-irrigation emitters used, and fertilization program) which have been made to overcome them,

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Aparna Gazula, Eric Simonne, Michael Dukes, George Hochmuth, Bob Hochmuth and David Studstill

Collecting leachate from lysimeters installed in the field below vegetable fields may be used to quantify the amount of nitrogen released into the environment. Because limited information exists on the optimal design type and on the effect of design components on lysimeter performance, the objective of this study were to identify existing designs and their limits, assess cost of design, and test selected designs. Ideally, lysimeters should be wide enough to collect all the water draining, long enough to reflect the plant-to-plant variability, durable enough to resist degradation, deep enough to allow for cultural practices and prevent root intrusion, have a simple design, be made of widely available materials, and be cost-effective. Also, lysimeters should not restrict gravity flow thereby resulting in a perched water table. Previous study done with a group of free-drainage lysimeters (1-m-long, 45-cm-wide, installed 45-cm-deep) under a tomato-pumpkin-rye cropping sequence resulted in variable frequency of collection and volume of leachate collected (CV of load = 170%). Improving existing design may be done by increasing the length of collection, lining the lysimeter with gravel, limiting the depth of installation, and/or breaking water tension with a fiberglass wick. Individual lysimeter cost was estimated between $56 to $84 and required 9 to 14 manhours. for construction and installation. Costs on labor may be reduced when large numbers of lysimeters are built. Labor needed for sampling 24 lysimeters was 8 man-hr/sampling date. Because load may occur after a crop, lysimeter monitoring and sampling should be done year round.

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David J. Chalmers, Preston K. Andrews, Kevin M. Harris, Ewen A. Cameron and Horst W. Caspari

The design of a type of drainage lysimeter, as tested with trees of Pyrus serotina Rehder var. culta Rehder `Hosui' is described. All lysimeter operations and monitoring of irrigation and drainage volumes were managed by a “multi-tasking” controller/datalogger. It was possible to apply different irrigation levels to each of three sets of four random lysimeters. Evapotranspiration (ET) was calculated using a conservation of water equation, with differences between irrigation inputs and drainage outputs corrected for changes in soil-water content. ET ranged between 3.3 and 10.7 liters/tree per day in well-watered, noncropped trees in late Summer and Fall 1990. These rates correspond to ET of 0.13 to 0.43 liter·cm-2·day-1 and 0.96 to 3.10 liters·m-2·day-1 on trunk cross-sectional area and canopy area bases, respectively. The correlation coefficient between ET and Class A pan evaporation was >0.9 during this period. Weekly crop coefficients for the well-watered trees averaged 0.52 when calculated on a canopy-area basis. When irrigation was withheld for 18 days, the crop coefficient declined to 0.38. There were no differences in ET between trees growing in the two soil profiles, despite significant differences in soil water distribution.

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S.M. Scheiber, R.C. Beeson Jr, J. Chen, Q. Wang and B. Pearson

obtained from a commercial nursery in 0.72-L containers with six transplanted on 8 Aug. 2002 into each drainage lysimeter constructed from 246-L rigid plastic containers (Lerio Corp., Kissimmee, FL) placed in full sun. Each lysimeter had a diameter of 0

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S.M. Scheiber and Richard C. Beeson, Jr

coleus. Materials and methods ‘Yalaha’ coleus were obtained from a commercial nursery in 4-inch-diameter containers and transplanted on 9 June 2005 into drainage lysimeters and an uncovered companion field plot of deep, highly drained fine sand (Apopka

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Tim R. Pannkuk

previous work; therefore, this research would address this gap in literature. Materials and methods The experiment was conducted in Huntsville, TX, at the Sam Houston State University Plant Science Field Laboratory. Nine drainage lysimeters were constructed

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Jeffrey G. Williamson, Luis Mejia, Bradley Ferguson, Paul Miller and Dorota Z. Haman

containing ‘Emerald’ and ‘Jewel’ plants using only the ‘Emerald’ plants. The in-row plant sequence alternated between three consecutive plants of each cultivar. Twelve nonweighing, drainage lysimeters were installed during Nov. 2009 through Dec. 2009. In each

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S.M. Scheiber, Richard C. Beeson Jr and Sudeep Vyapari

sandy soils to decrease irrigation requirements. Materials and Methods Pentas lanceolata Schum. ‘New Look Red’ were obtained from a commercial nursery in 0.72-L containers and transplanted on 3 Sept. 2003 into 12 drainage lysimeters made from

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Tim R. Pannkuk, Richard H. White, Kurt Steinke, Jacqueline A. Aitkenhead-Peterson, David R. Chalmers and James C. Thomas

of the lysimeter walls ( Fig. 1 ). From the lysimeters, the cables were enclosed in a 10-cm diameter perforated corrugated drainage pipe and routed to a nearby data collection station. Volumetric soil moisture content measurements were collected using

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Hongyan Sun, Kelly Kopp and Roger Kjelgren

to separate drainage for each hydrozone in each lysimeter plot, drainage could be assigned to each hydrozone based on area and reading of soil moisture sensors at the 80-cm depth in each hydrozone. For example, in spring, when drainage was greatest