The aim of this study was to develop ternary diagrams to estimate water retention in the soil θ_{-33 kPa} and θ_{-1500 kPa} corresponding to the field capacity and wilting point, respectively and available soil water (ASW) using geostatistical approach. The data were extracted from the physical-water base of irrigated areas linked to the Irriga® System belonging to the Rural Engineering Department of the Federal University of Santa Maria. The database provides information regarding the physical characterization of soils in irrigated areas in the states of Rio Grande do Sul, Paraná, Goiás, Mato Grosso, São Paulo, Minas Gerais and Bahia. The data included 11,193 observations covering texture (sand, silt and clay), water retention properties (θ_{-33 kPa} and θ_{-1500 kPa}) and structural properties (bulk density and total porosity). The measured values of the water content in the soil were displayed in the ternary diagram according to the coordinates provided by the particle size distribution determined in the soil samples. Estimates of water content (cm³ cm⁻³) using the kriging method were performed using only the particle size distribution (sand, silt and clay). To obtain the spatial distribution of soil water retention values in the texture triangle, the use of the ordinary kriging estimator was proposed. The uncertainty analysis resulted in an Root mean square error (RMSE) below 0.048 cm³ cm^-3 when comparing the interpolated water content and observed in the values of θ_{-33 kPa} and θ_{-1500 kPa}, with the subdivisions by ranges of bulk density having the lowest uncertainties, highlighting the importance of subdividing the database by classes based on structural properties. Ternary diagrams can act as useful and simplified tools to estimate these properties just by applying the particle size distribution.

这项研究的目的是开发三元图，以地统计学方法估算分别对应于田间持水量和萎点和可用土壤水（ASW）的土壤中θ- _{33 kPa}和θ- _{1500 kPa的保}水量。数据是从灌溉区域的物理水基中提取的，该灌溉水基与属于圣玛丽亚联邦大学农村工程系的Irriga®系统相关。该数据库提供有关南里奥格兰德州，巴拉那州，戈亚斯州，马托格罗索州，圣保罗州，米纳斯吉拉斯州和巴伊亚州灌溉区土壤物理特性的信息。数据包括11,193个观测值，涵盖了质地（沙，淤泥和粘土），保水特性（θ- _{33 kPa}和θ）。_{-1500 kPa}）和结构特性（堆积密度和总孔隙率）。根据土壤样品中确定的粒径分布所提供的坐标，将土壤中水含量的测量值显示在三元图中。使用克氏法估算的水含量（cm³cm ^- ³）仅使用粒度分布（沙，粉砂和粘土）进行。为了获得质地三角形中土壤保水值的空间分布，提出了使用普通克里格估计器的方法。当比较插值水含量并观察到θ- _{33 kPa}值时，不确定性分析导致均方根误差（RMSE）低于0.048 cm ³ cm ^-3。和θ- _{1500 kPa}，用体积密度范围进行的细分具有最小的不确定性，突出显示了根据结构特性对数据库进行细分的重要性。仅通过应用粒度分布，三元图就可以用作评估这些特性的有用且简化的工具。