DOI: 10.15482/usda.adc/1527912
title: The Bushland, Texas, Winter Wheat Datasets

description: This parent dataset (collection of datasets) describes the general organization of data in the datasets for each growing season (two-year period) when winter wheat (Triticum aestivum L.) was grown for grain at the USDA-ARS Conservation and Production Laboratory (CPRL), Soil and Water Management Research Unit (SWMRU), Bushland, Texas (Lat. 35.186714°, Long. -102.094189°, elevation 1170 m above MSL). Winter wheat was grown on two large, precision weighing lysimeters, calibrated to NIST standards (Howell et al., 1995). Each lysimeter was in the center of a 4.44 ha square field on which wheat was also grown (Evett et al., 2000). The two fields were contiguous and arranged with one directly north of the other. See the resource titled "Geographic Coordinates, USDA, ARS, Bushland, Texas" for UTM geographic coordinates for field and lysimeter locations. Wheat was planted in Autumn and grown over the winter in 1989-1990, 1991-1992, and 1992-1993. Agronomic calendar for the each of the three growing seasons list by date the agronomic practices applied, severe weather, and activities (e.g., planting, thinning, fertilization, pesticide application, lysimeter maintenance, harvest) in and on lysimeters that could influence crop growth, water use, and lysimeter data. These include fertilizer and pesticide applications. Irrigation was by linear move sprinkler system equipped with pressure regulated low pressure sprays (mid-elevation spray application, MESA). Irrigations were managed to replenish soil water used by the crop on a weekly or more frequent basis as determined by soil profile water content readings made with a field-calibrated (Evett and Steiner, 1995) neutron probe from 0.10- to 2.4-m depth in the field. The lysimeters and fields were planted to the same plant density, row spacing, tillage depth (by hand on the lysimeters and by machine in the fields), and fertilizer and pesticide applications. The weighing lysimeters were used to measure relative soil water storage to 0.05 mm accuracy at 5-minute intervals, and the 5-minute change in soil water storage was used along with precipitation, dew and frost accumulation, and irrigation amounts to calculate crop evapotranspiration (ET), which is reported at 15-minute intervals. Each lysimeter was equipped with a suite of instruments to sense wind speed, air temperature and humidity, radiant energy (incoming and reflected, typically both shortwave and longwave), surface temperature, soil heat flux, and soil temperature, all of which are reported at 15-minute intervals. Instruments used changed from season to season, which is another reason that subsidiary datasets and data dictionaries for each season are required. The Bushland weighing lysimeter research program was described by Evett et al. (2016), and lysimeter design is described by Marek et al. (1988). Important conventions concerning the data-time correspondence, sign conventions, and terminology specific to the USDA ARS, Bushland, TX, field operations are given in the resource titled "Conventions for Bushland, TX, Weighing Lysimeter Datasets".
There are six datasets in this collection. Common symbols and abbreviations used in the datasets are defined in the resource titled, "Symbols and Abbreviations for Bushland, TX, Weighing Lysimeter Datasets". Datasets consist of Excel (xlsx) files. Each xlsx file contains an Introductory tab that explains the other tabs, lists the authors, describes conventions and symbols used and lists any instruments used. The remaining tabs in a file consist of dictionary and data tabs. There is a dictionary tab for every data tab. The name of the dictionary tab contains the name of the corresponding data tab. Tab names are unique so that if individual tabs were saved to CSV files, each CSV file in the entire collection would have a different name. The six datasets, according to their titles, are as follows:


Agronomic Calendars for the Bushland, Texas Winter Wheat Datasets: several tabs list by date, field, and replicate number: crop growth [plant height, crop row width, leaf area index, biomass (undried and dried), ear mass (when present), growth stage, etc.]; population density; machine (combine) yield by field location; and hand (manual) harvest statistics per replicated plot (number of plants and ears, total biomass, dry grain yield, yield at standard moisture content, harvest index). There is one agronomic calendar file for each year, containing data for the two fields.


Growth and Yield Data for the Bushland, Texas Winter Wheat Datasets: several tabs list by date, field, and replicate number: crop growth [plant height, crop row width, leaf area index, biomass (undried and dried), ear mass (when present), growth stage, etc.]; population density; machine (combine) yield by field location; and hand (manual) harvest statistics per replicated plot (number of plants and ears, total biomass, dry grain yield, yield at standard moisture content, harvest index). There is one growth and yield file for each year, containing data for the two fields.


Weighing Lysimeter Data for The Bushland, Texas Winter Wheat Datasets: Lysimeter raw data for relative soil water storage (lysimeter mass converted to equivalent depth of water considering the lysimeter surface area), and microclimate. There is one file for each year, containing data for the two lysimeters. Lysimeter relative soil water storage (and sometimes rain gauge and wind speed) data are given for 5-minute periods. Other data are given for 15-minute periods. For every 5-minute storage datum there is a corresponding flag that indicates what is occurring (P for precipitation, including snow; Sn for wind-blown snow; DW for dew or frost accumulation; D for emptying of drainage tanks; I for irrigation; M for maintenance operations that disturb lysimeter mass; CW for lysimeter scale counterweight adjustment; F for loss of load cell data; and NO for storage increases that are due to noise and should not be counted as precipitation, dew, frost, or irrigation). The 15-minute data include wind speed, air temperature and relative humidity at one or more heights; radiation metrics (e.g., reflected solar irradiance, net radiation, photosynthetically active radiation reflected and transmitted, etc.); nadir and oblique view surface temperature from infrared thermometers; soil heat flux and soil temperature; and core and sidewall drainage into drainage tanks that were suspended from the lysimeter). Not all properties listed were sensed in every year. A separate tab gives daily sums or averages of the sensed properties. For data visualization there is a tab with graphs of the major daily data, another tab with graphs for 15-minute data, and a final tab with graphs for 5-minute data. The latter two allow viewing data in five-day periods beginning with any day of the year specified by the user.


Soil Water Content Data for The Bushland, Texas, Large Weighing Lysimeter Experiments: Soil volumetric water content data from periodic (weekly or longer periods) readings are presented in one file for each year, combining data for the two lysimeters and fields. There were at least four neutron probe access tubes in the field surrounding each lysimeter in any year, but there were often more than that as needed for sub-experiments. Access tubes were given unique numbers in any given year. Each lysimeter also had two access tubes in it. There are typically three data tabs. The first summarizes the soil profile water content values by date and field or lysimeter location, and it contains values of field capacity, permanent wilting point, and management allowed depletion for comparison. Another data tab lists all the soil water content values by date, time (when available), depth, access tube number, and field location (NE field or lysimeter, SE field or lysimeter, NW field or lysimeter, SE field or lysimeter). A third data tab lists by access tube number geographic coordinates (UTM) of the access tube locations. A final tab gives a graphical view of the data showing how the soil water profiles at each access tube changed over the season.


Evapotranspiration, Irrigation, Dew/frost - Water Balance Data for The Bushland, Texas Winter Wheat Datasets: In a single file for each year, water balance component data for both the two lysimeters are given. One data tab gives daily values in mm depth of water of evapotranspiration (ET), dew and frost accumulation, precipitation (snow and rain), irrigation, lysimeter scale counterweight adjustment, and amount lost when drainage tanks were emptied. Another data tab gives 15-minute sums of dew and frost accumulation, precipitation, irrigation, and ET. A third data tab lists by day of the year the values of irrigation amounts received by each lysimeter, and the method of irrigation application [mid elevation spray application (MESA), subsurface drip irrigation (SDI), low energy precision application (LEPA) drag socks, or high pressure sprinkler].


Standard Weather Data for the Bushland, Texas, Large Weighing Lysimeter Experiments: A single file for each year contains weather data from the Soil and Water Management Research Unit Research Weather Station, collected at 2-m height over grass mowed to not exceed 12-cm height and irrigated and fertilized to maintain reference conditions. Typically, sensors were duplicated at each height, and data from a duplicate sensor may be used to fill gaps in data from the primary sensor using appropriate regression relationships. Gap filling may also be accomplished using sensors deployed at one of the four large weighing lysimeters immediately west of the weather station, or from the nearby Conservation & Production Research Laboratory (CPRL) weather station. The weather station is located immediately adjacent to the east side of the east lysimeter fields. Weather variables include solar irradiance, air relative humidity (RH), air temperature, wind speed, air pressure, and precipitation (mean precipitation for the four weighing lysimeters, and precipitation determined for each lysimeter from lysimeter mass changes). Because the large (3 m by 3 m surface area) weighing lysimeters are better rain gauges than are tipping bucket gauges, the 15-minute precipitation data are derived for each lysimeter from changes in lysimeter mass. One data tab gives the data in 15-minute periods. Another data tab gives daily sums of precipitation. Another tab gives a graphical check for missing data. And yet another tab allows data visualization by graphing five days of 15-minute data beginning on a day of year chosen by the user.


The soil is a Pullman series fine, mixed, superactive, thermic Torrertic Paleustoll. Soil properties are given in the resource titled "Soil Properties for the Bushland, TX, Weighing Lysimeter Datasets".  The land slope in the lysimeter fields is &lt;0.3% and topography is flat. The mean annual precipitation is ~470 mm, the 20-year pan evaporation record indicates ~2,600 mm Class A pan evaporation per year, and winds are typically from the South and Southwest. The climate is semi-arid with ~70% (350 mm) of the annual precipitation occurring from May to September, during which period the pan evaporation averages ~1520 mm.
These datasets originate from research aimed at determining crop water use (ET), crop coefficients for use in ET-based irrigation scheduling based on a reference ET, crop growth, yield, harvest index, and crop water productivity as affected by irrigation method, timing, amount (full or some degree of deficit), agronomic practices, cultivar, and weather. Prior publications have described the facilities and research methods (Evett et al., 2016), and have focused on winter wheat ET (Howell et al., 1995, 1997, 1998), and crop coefficients (Howell et al., 2006; Schneider and Howell, 1997, 2001) that have been used by ET networks for irrigation management. The data have utility for developing, calibrating, and testing simulation models of crop ET, growth, and yield (Evett et al., 1994; Kang et al., 2009), and have been used by several universities and for testing, and calibrating models of ET that use satellite and/or weather data.