Calibración del sensor de humedad Watermark 200SS para programación de riego en cinco tipos de suelos de Zacatecas, México

Abstract

calibration of WATERMARK 200SS sensors to optimize water use for six crops (garlic, chili, maize, oats, alfalfa, and bean) in agricultural soils of Zacatecas, Mexico, considering their hydro-physical properties and crop water requirements.

Design/methodology/approach: Five soils were characterized by bulk density, texture, organic matter content, and water retention curves (van Genuchten model). WATERMARK sensors were calibrated using polynomial models (R² > 0.96) to correlate sensor readings (centibars, cbar) with gravimetric soil moisture. Irrigation scheduling integrated: (1) soil water balance, (2) tension thresholds (0.3–1.0 atm), and (3) sensor data, applicable to drip irrigation systems (95% efficiency).

Results: Clay soils (Sample 1 and 5) exhibited higher water retention (Hₛ up to 0.231 cm³/cm³), while sandy loam (Sample 2) showed rapid drainage (α = 0.022). Sensor calibration curves achieved high accuracy (RMSE < 0.007), enabling reliable moisture estimates within optimal ranges (field capacity to permanent wilting point). Crop-specific irrigation depths were established based on soil water tension data obtained from moisture sensors.

Limitations on study/implications: The methodology requires in situ calibration for each soil type and does not account for uncontrolled spatial variability. However, it provides a practical tool for farmers in arid regions, reducing reliance on empirical irrigation practices.

Findings/conclusions: WATERMARK 200SS sensors, calibrated with localized models, effectively support precision irrigation scheduling. This methodology enhances water-use efficiency for key crops, adapting to climate stress conditions in Zacatecas.