Gómez-Astorga María José, Villagra-Mendoza Karolina, Masís-Meléndez Federico, Ruíz-Barquero Aníbal, Rimolo-Donadio Renato
Agricultural Engineering, CETIA Centro de Investigación y Extensión en Tecnología e Ingeniería Agrícola, Instituto Tecnológico de Costa Rica, Cartago P.O. Box 159-7050, Costa Rica.
Chemistry, CEQIATEC, Centro de Investigación y de Servicios Químicos y Microbiológicos, Instituto Tecnológico de Costa Rica, Cartago P.O. Box 159-7050, Costa Rica.
Sensors (Basel). 2024 Sep 13;24(18):5958. doi: 10.3390/s24185958.
With the increasing focus on irrigation management, it is crucial to consider cost-effective alternatives for soil water monitoring, such as multi-point monitoring with low-cost soil moisture sensors. This study assesses the accuracy and functionality of low-cost sensors in a sandy loam (SL) soil amended with biochar at rates of 15.6 and 31.2 tons/ha by calibrating the sensors in the presence of two nitrogen (N) and potassium (K) commercial fertilizers at three salinity levels (non/slightly/moderately) and six soil water contents. Sensors were calibrated across nine SL-soil combinations with biochar and N and K fertilizers, counting for 21 treatments. The best fit for soil water content calibration was obtained using polynomial equations, demonstrating reliability with R2 values greater than 0.98 for each case. After a second calibration, low-cost soil moisture sensors provide acceptable results concerning previous calibration, especially for non- and slightly saline treatments and at soil moisture levels lower than 0.17 cmcm. The results showed that at low frequencies, biochar and salinity increase the capacitance detected by the sensors, with calibration curves deviating up to 30% from the control sandy loam soil. Due to changes in the physical and chemical properties of soil resulting from biochar amendments and the conductive properties influenced by fertilization practices, it is required to conduct specific and continuous calibrations of soil water content sensor, leading to better agricultural management decisions.
随着对灌溉管理的关注度不断提高，考虑采用具有成本效益的土壤水分监测替代方法至关重要，例如使用低成本土壤湿度传感器进行多点监测。本研究通过在三种盐度水平（非盐/微盐/中盐）和六种土壤含水量条件下，在两种氮（N）肥和钾肥存在的情况下对传感器进行校准，评估了在添加了15.6和31.2吨/公顷生物炭的砂壤土（SL）中低成本传感器的准确性和功能。传感器针对九种添加生物炭以及氮、钾肥的砂壤土组合进行了校准，共计21种处理。使用多项式方程获得了土壤含水量校准的最佳拟合，每种情况下的R2值均大于0.98，证明了其可靠性。在二次校准后，低成本土壤湿度传感器给出了与之前校准相符的可接受结果，特别是对于非盐和微盐处理以及土壤湿度低于0.17 cmcm的情况。结果表明，在低频时，生物炭和盐度会增加传感器检测到的电容，校准曲线与对照砂壤土的偏差高达30%。由于生物炭改良导致土壤物理和化学性质发生变化，以及施肥方式影响土壤导电性质，因此需要对土壤含水量传感器进行特定且持续的校准，以做出更好的农业管理决策。
