In semiarid environments moisture availability is the primary factor that controls land productivity, however, no method to differentiate landscape portions with high moisture availability has yet been proposed for delimitation of crop management zones for precision agriculture. The objective of the present study was to develop a methodology to determine sites with different soil potential moisture availability to improve the delimitation of homogeneous crop management zones in semiarid environments. An altimetric survey was carried out in the field to obtain a DEM with a spatial resolution of 5 m. Subsequently, maps of slopes, area of ​​flow accumulation, sub-basins of the Topographic Wetness index (TWI) were made. A potential moisture availability (PMA) map was generated by linking the TWI map with a map of previously reclassified sub-basins and homogeneous PMA zones were delineated. Soil profiles were sampled on transects through the PMA zones, and during three growing seasons soil moisture contents were recorded. The PMA zones had homogeneous soil types and moisture contents and differed from each other in soil profile depth and available moisture contents, especially in the more humid season. Soil moisture correlated well with the antecedent precipitation index (API) during crop growth and in the PMA zones with higher altimetry, while only weak relationships were found during fallow periods and for the lowest altimetry PMA zone. The proposed methodology was useful for identifying landscape portions with differences in potential moisture availability as the spatial-temporal variability was represented. The use of the API combined with the potential moisture availability allowed a better fit in its relationship with the soil available moisture contents (AMC).

在半干旱环境中，水分可用性是控制土地生产力的主要因素，然而，尚未提出区分具有高水分可用性的景观部分的方法来划定精准农业的作物管理区。本研究的目的是开发一种方法来确定具有不同土壤潜在水分可用性的地点，以改进半干旱环境中同质作物管理区的划定。在野外进行了高度测量，以获得空间分辨率为 5 m 的 DEM。随后，制作了坡度图、流量积聚区、地形湿度指数（TWI）的子流域。通过将 TWI 地图与先前重新分类的子流域地图联系起来，生成了潜在水分可用性 (PMA) 地图，并描绘了均匀的 PMA 区域。在通过 PMA 区的样线上对土壤剖面进行采样，并在三个生长季节记录土壤水分含量。PMA 区域具有均匀的土壤类型和水分含量，并且在土壤剖面深度和可用水分含量方面彼此不同，特别是在更潮湿的季节。在作物生长期间和具有较高高度的 PMA 区域，土壤水分与前期降水指数 (API) 具有良好的相关性，而在休耕期和最低高度 PMA 区域仅发现较弱的关系。拟议的方法对于识别具有潜在水分可用性差异的景观部分很有用，因为它代表了时空变异性。API 的使用与潜在水分可用性相结合，可以更好地适应其与土壤有效水分含量 (AMC) 的关系。