The Bushland, Texas, Winter Wheat Datasets

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 <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.

本父数据集（数据集集合）描述了在美国农业部农业研究服务局（USDA-ARS）保护与生产实验室（CPRL）土壤与水资源管理研究单元（SWMRU）（位于德克萨斯州布什兰，纬度35.186714°，经度-102.094189°，海拔1170米，高于平均海平面（mean sea level，MSL））种植冬小麦（Triticum aestivum L.）以收获谷物的每个生长季节（两年期）的数据集数据组织概况。冬小麦种植于两个大型精密称重蒸渗仪（lysimeter）上，该蒸渗仪已校准至美国国家标准与技术研究院（NIST）标准（Howell等，1995）。每个蒸渗仪位于4.44公顷方形田块的中心，田块内也种植小麦（Evett等，2000）。两个田块相邻，一个位于另一个的正北方。关于田块和蒸渗仪位置的通用横轴墨卡托投影（Universal Transverse Mercator，UTM）地理坐标，请参见标题为“德克萨斯州布什兰USDA-ARS地理坐标”的资源。冬小麦于1989-1990、1991-1992和1992-1993年秋季播种并越冬生长。三个生长季节的农艺日历按日期列出了影响作物生长、水分利用和蒸渗仪数据的农艺措施、极端天气及活动（如播种、间苗、施肥、施药、蒸渗仪维护、收获），包括肥料和农药施用情况。灌溉采用配备压力调节低压喷头的线性移动喷灌系统（中高程喷雾灌溉，mid-elevation spray application，MESA）。灌溉管理通过每周或更频繁地补充作物消耗的土壤水分实现，土壤水分含量由田间校准（Evett和Steiner，1995）的中子探针（neutron probe）在0.10至2.4米深度读取。蒸渗仪与田块采用相同的种植密度、行距、耕作深度（蒸渗仪为人工耕作，田块为机械耕作）及肥料和农药施用方案。称重蒸渗仪用于以5分钟间隔、0.05毫米精度测量相对土壤储水量，5分钟土壤储水量变化结合降水量、露水与霜冻积累量及灌溉量计算作物蒸散量（evapotranspiration，ET），ET数据以15分钟间隔报告。每个蒸渗仪配备一套仪器，用于感知风速、气温、湿度、辐射能（入射与反射，通常包括短波和长波）、地表温度、土壤热通量和土壤温度，所有数据均以15分钟间隔报告。不同季节使用的仪器有所变化，这也是每个季节需要附属数据集和数据字典的另一原因。布什兰称重蒸渗仪研究项目由Evett等（2016）描述，蒸渗仪设计由Marek等（1988）描述。关于数据-时间对应关系、符号约定及德克萨斯州布什兰USDA-ARS田间操作特定术语的重要约定，请参见标题为“德克萨斯州布什兰称重蒸渗仪数据集约定”的资源。

本集合包含六个数据集。数据集中使用的通用符号和缩写定义于标题为“德克萨斯州布什兰称重蒸渗仪数据集符号与缩写”的资源。数据集以Excel（xlsx）文件形式存在，每个xlsx文件包含一个介绍性标签页，解释其他标签页、列出作者、描述所用约定与符号及列出所用仪器。文件中其余标签页包括字典标签页和数据标签页，每个数据标签页对应一个字典标签页，字典标签页名称包含对应数据标签页名称。标签页名称唯一，因此若将单个标签页保存为CSV文件，整个集合中的每个CSV文件名称均不同。六个数据集按标题如下：

1. 德克萨斯州布什兰冬小麦数据集的农艺日历：多个标签页按日期、田块和重复编号列出：作物生长指标（株高、行距、叶面积指数（leaf area index）、生物量（鲜重和干重）、穗重（若存在）、生育期等）、种植密度、按田块位置的机械（联合收割机）产量、按重复小区的人工收获统计（植株数与穗数、总生物量、干谷粒产量、标准含水量下产量、收获指数（harvest index））。每个年份有一个农艺日历文件，包含两个田块的数据。

2. 德克萨斯州布什兰冬小麦数据集的生长与产量数据：多个标签页按日期、田块和重复编号列出：作物生长指标（株高、行距、叶面积指数、生物量（鲜重和干重）、穗重（若存在）、生育期等）、种植密度、按田块位置的机械（联合收割机）产量、按重复小区的人工收获统计（植株数与穗数、总生物量、干谷粒产量、标准含水量下产量、收获指数）。每个年份有一个生长与产量文件，包含两个田块的数据。

3. 德克萨斯州布什兰冬小麦数据集的称重蒸渗仪数据：蒸渗仪原始数据包括相对土壤储水量（蒸渗仪质量转换为等效水深，考虑蒸渗仪表面积）和微气候。每个年份有一个文件，包含两个蒸渗仪的数据。蒸渗仪相对土壤储水量（有时包括雨量计和风速）数据以5分钟间隔给出，其他数据以15分钟间隔给出。每个5分钟储水量数据对应一个标记，指示发生的事件（P代表降水，含降雪；Sn代表风吹雪；DW代表露水或霜冻积累；D代表排水箱排空；I代表灌溉；M代表干扰蒸渗仪质量的维护操作；CW代表蒸渗仪秤配重调整；F代表称重传感器数据丢失；NO代表由噪声引起的储水量增加，不应计为降水、露水、霜冻或灌溉）。15分钟数据包括一个或多个高度的风速、气温和相对湿度；辐射指标（如反射太阳辐照度、净辐射、反射与透射光合有效辐射等）；红外温度计测量的天底和斜视角地表温度；土壤热通量和土壤温度；以及流入悬挂于蒸渗仪上的排水箱的核心与侧壁排水。并非所有列出的参数每年均有观测。一个单独标签页给出观测参数的每日总和或平均值。为数据可视化，一个标签页包含主要每日数据的图表，另一个标签页包含15分钟数据的图表，最后一个标签页包含5分钟数据的图表，后两个标签页允许用户查看从指定年份任意一天开始的五天周期数据。

4. 德克萨斯州布什兰大型称重蒸渗仪实验的土壤含水量数据：周期性（每周或更长周期）读取的土壤体积含水量数据按年份各一个文件，合并两个蒸渗仪和田块的数据。每年每个蒸渗仪周围田间至少有四个中子探针观测管（access tube），但根据子实验需要常多于四个，观测管在任意年份均有唯一编号，每个蒸渗仪内也有两个观测管。通常包含三个数据标签页：第一个按日期和田块或蒸渗仪位置汇总土壤剖面含水量值，包含田间持水量、永久萎蔫点和管理允许耗水量以供比较；第二个数据标签页按日期、时间（若可用）、深度、观测管编号和田块位置（东北田块或蒸渗仪、东南田块或蒸渗仪、西北田块或蒸渗仪、西南田块或蒸渗仪）列出所有土壤含水量值；第三个数据标签页按观测管编号列出观测管位置的UTM地理坐标；最后一个标签页以图表形式展示每个观测管土壤水分剖面在季节内的变化。

5. 德克萨斯州布什兰冬小麦数据集的蒸散量、灌溉、露水/霜冻-水分平衡数据：每个年份一个文件，给出两个蒸渗仪的水分平衡组分数据。一个数据标签页给出每日作物蒸散量（ET）、露水与霜冻积累量、降水量（雪和雨）、灌溉量、蒸渗仪秤配重调整量及排水箱排空损失量（单位：毫米水深）；另一个数据标签页给出15分钟间隔的露水与霜冻积累量、降水量、灌溉量和ET总和；第三个数据标签页按年份日期列出每个蒸渗仪接收的灌溉量及灌溉方式（中高程喷雾灌溉（MESA）、地下滴灌（subsurface drip irrigation，SDI）、低能耗精准灌溉（low energy precision application，LEPA）拖管或高压喷灌）。

6. 德克萨斯州布什兰大型称重蒸渗仪实验的标准气象数据：每个年份一个文件，包含土壤与水资源管理研究单元研究气象站的气象数据，数据采集于2米高度，下方草地修剪至不超过12厘米并灌溉施肥以维持参考条件。通常每个高度的传感器均有重复，重复传感器的数据可通过适当回归关系用于填补主传感器的数据缺口；数据缺口也可通过气象站西侧四个大型称重蒸渗仪之一部署的传感器或附近保护与生产研究实验室（CPRL）气象站的数据填补。气象站紧邻东侧蒸渗仪田块的东侧。气象变量包括太阳辐照度、空气相对湿度（RH）、气温、风速、气压和降水量（四个称重蒸渗仪的平均降水量，及从蒸渗仪质量变化确定的每个蒸渗仪降水量）。由于大型（表面积3米×3米）称重蒸渗仪比翻斗式雨量计（tipping bucket gauge）更优，15分钟降水量数据由每个蒸渗仪的质量变化推导而来。一个数据标签页给出15分钟间隔的数据；另一个标签页给出每日降水量总和；第三个标签页给出缺失数据的图形检查；最后一个标签页允许用户通过绘制从指定年份任意一天开始的五天15分钟数据进行可视化。

土壤为普尔曼系列细质、混合、超活性、热性干旱变性软土（Pullman series fine, mixed, superactive, thermic Torrertic Paleustoll），土壤性质定义于标题为“德克萨斯州布什兰称重蒸渗仪数据集土壤性质”的资源。蒸渗仪田块的土地坡度<0.3%，地形平坦。年平均降水量约470毫米，20年蒸发皿记录显示每年A级蒸发皿蒸发量约2600毫米，风向通常为南风和西南风。气候为半干旱气候，约70%（350毫米）的年降水量发生于5月至9月，此期间蒸发皿平均蒸发量约1520毫米。

这些数据集源于旨在确定灌溉方式、时机、水量（充分或不同程度亏缺）、农艺措施、品种和气候对作物耗水量（ET）、基于参考ET的灌溉调度作物系数、作物生长、产量、收获指数及作物水分生产率影响的研究。先前出版物已描述设施和研究方法（Evett等，2016），并聚焦于冬小麦ET（Howell等，1995、1997、1998）及用于ET网络灌溉管理的作物系数（Howell等，2006；Schneider和Howell，1997、2001）。这些数据可用于开发、校准和测试作物ET、生长和产量模拟模型（Evett等，1994；Kang等，2009），并已被多所大学用于测试和校准使用卫星和/或气象数据的ET模型。