Theodore Sammis | New Mexico State University (original) (raw)

Papers by Theodore Sammis

Journal of Hydrology, 1981

Sammis, T.W., 1981. Lysimeter for measuring arid-zone evapotranspiration. J. Hydro!., 49: 385-394.

Computers and Electronics in Agriculture, Dec 31, 1992

ABSTRACT Software for an automatic weather data collection and processing software was developed ... more ABSTRACT Software for an automatic weather data collection and processing software was developed based around a computer bulletin board (OPUS). At night, an external event timer stops the bulletin board, executes a series of EXE files that interrogate climate stations, processes and writes the data to files.OPUS makes meteorological data readily available in electronic form. Users can download data, convert data to select formats and then download the processed data or run external programs that use the climatic data.

Horttechnology, 2003

Accurate measurement of evapotranspiration (ET) is difficult and expensive for large, in-ground c... more Accurate measurement of evapotranspiration (ET) is difficult and expensive for large, in-ground container (pot-in-pot) plants. We engineered and used a simple and inexpensive system to determine evapotranspiration of in-ground container trees. The system was shopassembled and used a block and tackle system attached to a collapsible tripod. A unique container harness system attached to the block and tackle system was used to lift containers that were sunken in the ground. Containers were weighed with a battery-operated balance that was accurate to 1 g (0.04 oz) at its maximum load capacity of 60 kg (132.3 lb). One person operated the system, and the weight of the system exclusive of the balance was 17.5 kg (38.50 lb). Gravimetric water use data obtained with the system were

Agu Spring Meeting Abstracts, May 1, 2007

Satellite-received radiances and auxiliary ground-based information are routinely used to estimat... more Satellite-received radiances and auxiliary ground-based information are routinely used to estimate the evapotranspiration rate (ET, or LE as a latent heat energy flux density) on landscape elements. Many methods compute LE as a residual, computing the terms Rn, G, and H in the full energy-balance equation, S = Rn - G ¬ H - LE, where S is surface (canopy) heat storage (often assumed near zero), Rn is net radiation, G is heat flux into the (soil) surface, and H is the sensible heat flux. Computation of H is prone to errors in obtaining accurate radiometric temperatures, TR, of the surface and in relating TR to the true kinetic temperature of the surface heat source. The Surface Energy BAlance Land (SEBAL) method avoids the offset errors by introducing an assumption of a linear relation of TR to the surface-to-air temperature difference. This assumption, and several others, can introduce distinct errors and operational problems, which will be discussed, along with several improvements under development. The latter include direct regression solutions for LE, correcting for advection of energy and for the lapse rate of the surface (not air) temperature, and the use of auxiliary radiance-based information on vegetation water stress. Also to be discussed are potential applications of enhanced ET methods to estimate hydrologic redistributions (runon, runoff), the consequent spatial patterning of vegetation, and the implications of both for ecological studies (equilibrium canopy development, long-term acclimation of stomatal control) and ecosystem management (estimating forest water stress and its relations to stand density, forest thinning exercises, and hazards of fire and insect outbreaks).

Universities manage research projects through both internal funding and support systems for the g... more Universities manage research projects through both internal funding and support systems for the generation of external grant funds. The management of a research project is full of uncertainty and complexity. An economic evaluation of university research projects can determine the economic impact on society and can generate a return on the investment from federal and state funds. This paper presents a simple method that uses an Excel spreadsheet to estimate the economic value of research at the project level. Three sample calculations were conducted for agricultural research projects (on pecan irrigation, a new variety of bigtooth maple tree, and evaluation of new alfalfa varieties) to demonstrate the methodology. The research on new alfalfa varieties obtained the highest benefit:cost ratio (123:244). This supports the concept that variety trials have one of the highest potential paybacks of any agricultural research. An economic analysis of the benefit:cost ratio and a net present value for most applied research are easy to compute with the presented Excel calculator. When the economic analysis includes a large number of environmental values, more time and effort are needed to conduct the analysis, but an economic analysis remains possible. If used as part of research proposal submission, the economic analysis could give reviewers another method to rank research proposals and select those proposals that not only propose good science but also have a potential reasonable return on taxpayers' investments.

Remote sensing evapotranspiration (ET) models are important for forest, phreatophyte, rangeland, ... more Remote sensing evapotranspiration (ET) models are important for forest, phreatophyte, rangeland, and agricultural water and pest management. However, most remote sensing ET models are not available in an Internet-based operational mode. Manually downloading satellite and weather data and processing this data is complicated and time-consuming, requiring as much as 2-6 hrs per satellite scene. If the ET algorithm is going to be used by the scientific community or management agencies and farmers, it is imperative that the computer processing be automated and user-friendly; the user should be able to input the dates and locations of interest and have the model output the ET results (map and ACSII data file). The objective of our research was to test the hypothesis that remote sensing algorithms that calculate daily ET based on energy balance could be automated. An Internet-based ET model using MODIS, local weather station, and forecast data was developed. The automated calculated daily ET was compared to measured eddy-covariance ET under both stressed and non-stressed conditions.

Http Dx Doi Org 10 1080 15324982 2012 680656, Jul 1, 2012

ABSTRACT Land application of wastewater conserves fresh water and recycles nutrients, but little ... more ABSTRACT Land application of wastewater conserves fresh water and recycles nutrients, but little is known of its impacts on arid and semiarid landscapes. Lagoon treated saline−sodic industrial effluent was applied from 2002–2005 to a 0.4-ha Chihuahuan Desert shrubland to assess the deposition and recovery of effluent components and changes in soil quality vis-à-vis a non-irrigated area. Effluent irrigation supplied 26% of the average annual nonstressed evapotranspiration (ET) of the native shrubs [Larrea tridentata (DC.) Coville and Prosopis glandulosa Torr. var. glandulosa], and increased both soil stress factors (sodicity, salinity, and pH) and soil fertility (N, P, and K). After 3 yr, the soil saturation extract electrical conductivity (ECe) reached as high as 6.1 dS m−1 and Cl− 76 molc m−3 at 105 cm depth under irrigated L. tridentata. After 4 yr, saturation extract sodium adsorption ratio (SARe) reached 25–35 at 7.5 cm under the irrigated shrubs and intershrub spaces. There were 27 Mg ha−1 of cumulative ionic deposits to the site comprised mostly of Na+, Cl−, and CaCO3 equivalent alkalinity, with soil analysis recovering most of the deposits (>57%) except for K+ and Na+ (8% to 13%). Subsurface leaching of and P was detected within the upper 1 m soil depth after 4 yr, and a high downward mobility of Cl− revealed the potential for deeper leaching at higher N loading rates. While long-term effects on the natural vegetation are unknown, results contribute to a limited scientific database for sustainable wastewater land application in semiarid regions.

Journal of Natural Resources and Life Sciences Education, 1996

Transactions of the Asabe, 2008

Dust exposure in and near farm fields is of increasing concern for human health and may soon be f... more Dust exposure in and near farm fields is of increasing concern for human health and may soon be facing new emissions regulations. Dust plumes of this nature have rarely been documented due to the unpredictable nature of the dust plumes and the difficulties of accurately sampling the plumes. This article presents a dynamic random-walk model that simulates the field-scale PM 10 (particle diameter <10 mm) dust dispersion from an agriculture disking operation. The major improvements over traditional plume models are that it can simulate moving sources and plume meander. The major inputs are the friction velocity (u*), wind direction in the simulation period, atmospheric stability, and source strength (mg s -1 ). In each time step of the model simulation, three instantaneous wind velocities (x, y, and z directions) are produced based on friction velocity, mean wind speed, and atmospheric stability. The computational time step is 0.025 times the Lagrangian time scale. The resulting instantaneous wind vectors transport all the individual particles. The particle deposition algorithm calculates if a particle is deposited based on the particle settling speed and vertical wind velocity when it touches the ground surface. The particle mass based concentration in 3-D can be obtained at any instant by counting the particle numbers in a unit volume and then converting to mass based on the particle size and density. Simulations from this model are verified by comparison with dust dispersion and plume concentrations obtained by an elastic backscatter LIDAR. The simulated plume spread parameters (s y , s z ) at downplume distances up to 160 m were within ±73% of those measured with a remote aerosol LIDAR. Cross-correlations between a modeled plume and LIDAR measurements of the actual plume were as high as 0.78 near the ground and decreased to 0.65 at 9 m above ground, indicating close pattern similarity between the modeled and measured plumes at lower heights but decreasing with elevation above the ground.

Journal of Higher Education Outreach and Engagement, 2013

Universities develop strategic planning documents, and as part of that planning process, logic mo... more Universities develop strategic planning documents, and as part of that planning process, logic models are developed for specific programs within the university. This article examines the longstanding pecan program at New Mexico State University and the deficiencies and successes in the evolution of its logic model. The university's agricultural experiment station's pecan program logic model has evolved along with increased external funding, but never has developed into a complete logic model because the outcome-impact component remains incomplete. With increased assistance from the university, the pecan industry grew and became stronger and more economically viable; however, the incomplete development of a pecan program logic model has prevented development of a complete synergy. The evaluation of outcome-impact is most efficient and accurate when at least part of the evaluation is conducted with methods independent of the growers.

Hydrology and Water Resources in Arizona and the Southwest, Apr 16, 1977

Soil water content was measured every two weeks during 1974 -1975, using a neutron probe, at sele... more Soil water content was measured every two weeks during 1974 -1975, using a neutron probe, at selected locations around the desert plant species creosote (Larria divaricata), bursage (Ambrosia deltoidea), and in an open space. The purpose of taking the measurements was to enable one to estimate the evapotranspiration rate of the desert plants by measuring soil moisture depletion. The sampling problem associated with measuring soil moisture, using neutron access tubes, is the number, location, and installation depth of the tubes.

ABSTRACT Rising fertilizer costs and diminishing water resources, have made improved efficiency o... more ABSTRACT Rising fertilizer costs and diminishing water resources, have made improved efficiency of water and nitrogen management a top research and extension priority for the deciduous crop industries. Pecan is among the deciduous crops and it uses the most amount of water among all the tree crops. Currently, there is no model to simulate pecan tree growth under water and nitrogen stress that has been calibrated and evaluated by experimental data. In this study, a pecan growth model was developed that contains a nitrogen stress function and a water stress function. The nitrogen function limits tree growth based on leaf nitrogen concentration. Leaf concentration was calculated by nitrogen concentration at the root zone and nitrogen distribution to the tree components. At the same time, evapotranspiration was reduced by nitrogen stress and interacts with the water stress function. The stress functions and their interactions were calibrated by results from a physiological mechanistic model and experimental data. The pecan tree growth model was evaluated by experimental data. The evaluation shows that the water stress function is reasonably well, while it may overestimate the nitrogen uptake. More field experiments need to be conducted to calibrate the related parameters.

Journal of the American Water Resources Association, 1982

Deep percolation rates are normally estimated from a water balance. Results are presented of a st... more Deep percolation rates are normally estimated from a water balance. Results are presented of a study undertaken to evaluate three alternative methods of estimating percolation below the root zone when howledge about the history of applied water and evapotranspiration are not available. The alternative methods are: 1) use of Darcy's equation to calculate deep percolation rate; 2) measurement of the soil temperature prof& and calculation of the deep percolation rate from the shape of the temperature depth curve; and 3) measurement of the tritium concentration in the soil water and its relationship to the history of the tritium concentration in rainfall. At the principal study site, the Darcy velocity of flow ranged from 9 cm per year determined by the temperature method, to 40 cm per year determined by the tritium method. k c y ' s equation to calculate seepage rates resulted in an estimation of deep seepage of 18 cm per year. An average deep percolation rate at the principal study site of 22 cm per year was determined using the average of all three methods. Results for other sites based on the temperature method indicated a lower seepage rate. (KEY TERMS: deep percolation; Darcy's equation; temperature profhs; tritium.)

Hydrology and Water Resources in Arizona and the Southwest, May 1, 1976

Energy budget evaluations of evapotranspiration from saltcedar were carried out on th~ flood plai... more Energy budget evaluations of evapotranspiration from saltcedar were carried out on th~ flood plain of the Rio Grande River, near Bernardo, New Mexico. The site was adjacent to the Bureau of Reclamation's lysimeter study of water use by saltcedar. The energy budget for the cloudless day of June 14, 1975, revealed that energy gains from net radiation totaled 432 cal/cm 2 , while energy losses (in cal/cm 2 ), were 14 to stored energy, 31 to convection, and 387 to evapotranspiration (ET). The energy loss to ET is equivalent to the latent energy contained in about 6.5 mm of water. The energy budget values are reasonable for a phreatophyte community in a semi-arid environment. The latent energy loss compares favorably with 401 cal/cm 2 measured by three lysimeters, although there were discrepancies in timing and amounts of loss among the individual lysimeters. The mean canopy diffusion resistance was 1.90 sec/em over a 10-hour daytime period on June 14. The mean resistance was combined with vapor pressure deficit to predict lysimeter ET on three subsequent days. The agreement was within 12 percent, which suggests that diffusion resistance may be useful for simple ET predictions.

The purity of product from agricultural cleaners (such as chile, cotton, bean, wheat and other cr... more The purity of product from agricultural cleaners (such as chile, cotton, bean, wheat and other crop cleaners) is needed to be measured under various conditions in order to adjust and optimize the machine at the design and improvement stages. The traditional weight-based method of measuring purity is time consuming, and requires much labor. In this study, we used image analysis to measure percent crop cover for the product output to infer the purity. Chile cleaner was used as one example machine to compare between Photoshop© and Arcview© software for the analysis of fresh and dry harvest pictures. The data collection process is more reproducible and less labor and time consuming than the traditional technique. Both software packages provided accurate estimations of purity for both fresh and dry harvest pictures. Photoshop© had better accuracy than Arcview© (mean error ratio of 0.016 vs. 0.081 for fresh harvest; and 0.035 vs. 0.114 for dry harvest). Citation: Wang J, Eaton F E, Sammis...

HortTechnology

ADDITIONAL INDEX WORDS. Experiential learning, environmental data, season extender, teaching unde... more ADDITIONAL INDEX WORDS. Experiential learning, environmental data, season extender, teaching undergraduates SUMMARY. We integrated the construction and operation of hoop houses into a general education course to provide students with basic agriculture skills such as basic agricultural construction, greenhouse crop production, and greenhouse environmental data collection, while immersing them in an experiential learning environment. Students in the class constructed three 12 · 15-ft hoop houses, installed an irrigation system and climate data acquisition system, and grew radish (Raphanus sativus 'Cherry Belle') and lettuce (Lactuca sativa 'Black-Seeded Simpson') within each hoop house. At the end of the exercise, 86% of students agreed that they knew the basic techniques of hoop house construction, and 89% agreed that they understood the practical application of building a hoop house. More instruction on calculating crop fertilizer requirements would benefit students because only 43% of students agreed or strongly agreed that they understood how to compute crop fertilizer requirements. Climate data demonstrated that air temperature within the unvented hoop houses exceeded the optimal growing temperature for lettuce and radish. We conclude that construction and operation of hoop houses provided practical agricultural skills in an experiential learning environment while revealing subject areas that warrant further instruction.

2006 Portland, Oregon, July 9-12, 2006, 2006

Dust plumes in the atmosphere, generated by cotton field preparation planting and harvesting oper... more Dust plumes in the atmosphere, generated by cotton field preparation planting and harvesting operations were measured remotely via aerosol lidar. Dust plume size, shape and movement are reported The in-plume aerosol size distributions were measured with ...

Salinity responses and salinity-related suppression of budbreak of dripirrigated pecan [Carya ill... more Salinity responses and salinity-related suppression of budbreak of dripirrigated pecan [Carya illinoinensis (Wangenh.) K. Koch] seedlings under different irrigation water salinity (EC IRR ) levels were investigated in the pot-in-pot system. The 1-year-old pecan seedlings of rootstock 'Riverside' grafted with 'Western Schley' scions were transplanted in pots filled with sandy loam soil and grown for 2 years under the same amount of irrigation water but four irrigation EC IRR treatment levels consisting of 1.4 dS · m L1 (control), and three qualities of irrigation water obtained by using a solution of calcium chloride (CaCl 2 ) and sodium chloride (NaCl) in a ratio of 2:1 (by weight) to reach the EC IRR levels of 3.5, 5.5, and 7.5 dS · m L1 , respectively. The leachate electrical conductivity (EC d ) was highly correlated with soil salinity (EC 1:1 ) and was significantly higher when the irrigation EC IRR treatment levels increased from 1.4 (control) to 7.5 dS · m L1 . However, both EC d and EC 1:1 remained nearly constant within the same irrigation EC IRR treatment level during both years. Increasing salinity in irrigation water, particularly the EC IRR levels of 5.5 and 7.5 dS · m L1 , showed significantly low seedling height and stem diameter growth and delayed or even inhibited budbreak in the seedlings. The EC 1:1 that inhibited seedling heights, stem diameters, and budbreak was somewhere between 0.89 and 2.71 dS · m L1 (or EC IRR between 1.4 and 3.5 dS · m L1 and EC d between 2.10 and 4.86 dS · m L1 ), providing that soil water content was not a limiting factor in the root zone and irrigation water was uniformly distributed in the confined root zone to obtain uniform salt leaching. The visual symptoms of leaf scorch for irrigation EC IRR levels of 3.5, 5.5, and 7.5 dS · m L1 also indicated that somewhere between 0.89 and 2.71 dS · m L1 of the EC 1:1 , salt injury started to occur. Increasing salinity in irrigation water significantly increased chloride (Cl -) accumulation but reduced nitrogen (N) content in the scorched leaves, particularly under the irrigation EC IRR levels of 5.5 and 7.5 dS · m L1 . Leaf scorch symptoms in pecan seedlings were likely associated with Cltoxicity. No pecan seedlings under the irrigation EC IRR treatment levels of 5.5 and 7.5 dS · m L1 survived to the end of the 2-year growing period. Thus, threshold EC 1:1 was somewhere between 0.89 and 2.71 dS · m L1 beyond which plant injury increases with increasing EC 1:1 threatening the survival of pecan seedlings.

ABSTRACT Currently, the application of fertilizer and water in orchard crops follows largely stan... more ABSTRACT Currently, the application of fertilizer and water in orchard crops follows largely standardized practices with limited consideration of temporal, climatic and crop variability. This approach constrains our ability to improve management, results in loss of potential income and causes negative environmental impact. We strive to address this issue by integrating 1) new approaches to determine crop demand with spatial and temporal accuracy, with 2) advanced methods of estimating current crop status and performance with 3) the development a new site specific orchard management platform. In this poster (#1 of 2), we discuss integrated approaches to define real time crop demand' for water and nutrients with high spatial and temporal demand for water and nitrogen by deciduous perennial crops. In a partner poster we present advanced methods for crop status' determination. A series of 8 research sites were established in 2008 throughout California, New Mexico and Texas in Almond, Pistachio and Pecan. Fertilizer rate trials and nutrient monitoring (all essential elements) in plant, soil, and crop are being used to construct nutrient budgets with a high degree of spatial and temporal specificity. Water demand is being estimated with a number of redundant models and with real time monitoring of plant, soil and atmospheric parameters. Yield prediction and nutrient and water demand models are under development through the integration of multi-year yield monitoring in a large number (>1,500) individual trees. Fertilizer rate trials and irrigation treatments have been established to develop response curves and interaction required for model refinement. Preliminary results will be presented on the following: Whole tree nutrient budgeting Temporal pattern of nutrient uptake annually Within tree nutrient partitioning Yield estimation modeling Comparative analysis of soil, plant and model based determination of water demand

Applied and Environmental Soil Science, 2012

Water is a limited resource for crop production in arid areas of Southern New Mexico. The objecti... more Water is a limited resource for crop production in arid areas of Southern New Mexico. The objectives of this study were to estimate the amount and depth of water and nitrate-nitrogen (NO 3 -N) fronts, water and NO 3 -N balances, and irrigation efficiencies for two onion (Allium cepa L.) fields under furrow and drip irrigation systems. Monthly soil samples were analyzed for NO 3 -N and chloride concentration for two onion growing seasons starting September 2006 to August 2009. The average amount of NO 3 -N in the soil water estimated by chloride tracer technique varied from 97.4 to 105.2 mg L −1 for furrow and 65.2 to 66.8 mg L −1 for drip-irrigated fields for the 60-to 200-cm depth. The NO 3 -N loadings below the rooting zone ranged from 145 to 150 kg ha −1 for furrow-and 76 to 79 kg ha −1 for drip-irrigated fields. The irrigation efficiencies varied from 78 to 80% for furrow-and 83% for drip-and N application efficiencies (NAEs) were 35 to 36% for furrow-and 38 to 39% for drip-irrigated fields. Small N fertilizer applications, delayed until onion bulbing starts, and water applications, preferably through drip irrigation, are recommended to reduce deep percolation and increase nitrogen and water efficiencies.