03663nam a22001817a 4500 OSt 20250321110303.0 250321b |||||||| |||| 00| 0 eng d NVSU Mahiwo Jr., Noli B. Calibration and evaluation of commercially available soil moisture sensors for automatic irrigation system/ Noli B. Mahiwo Jr. Bayombong: Nueva Vizcaya State University, 2022 xii, 78 leaves : illustrations (some colored), photos ; 28 cm. This study was conducted to calibrate and evaluate a commercially available soil moisture sensor for automatic irrigation system. Two types of sensors namely resistive and capacitive soil moisture sensors were calibrated. Tomato crop was used in evaluating the calibrated sensors in terms of soil moisture reading reliability, growth and yield, and simple cost analysis. The result of the study showed that the calibration curve for the capacitive sensor was y = 1068.5e-0.032x with r2 = 0.9424 while for the resistive sensor y = 327.27e -0.016x with r2 = 0.9778 On both equation; y represents sensor reading, x represents the percent soil moisture content, and r represents the coefficient of determination. The soil moisture reading reliability test conducted for the calibrated resistive sensor showed that during the early growth of tomatoes until its vegetative stage, the sensors reading was significantly different to the soils actual moisture. The recorded resistive sensor soil moisture reading at early growth and vegetative stage were 43.05% and 24.45%, respectively; while their corresponding actual soil moisture were 17.31% and 15.69%, respectively. For the capacitive sensor, the soil moisture reading differs significantly to the actual soils moisture on the early stage only. The recorded capacitive sensor soil moisture reading at early growth was 22.41% with an equivalent actual soil moisture of 34%. The total applied water for the manual irrigation, resistive, and capacitive sensor-based automatic irrigation were 0.11784m3, 0.10056m3 and 0.08393m3 respectively. Despite the lower water volume applied for automatic irrigation system, the analysis of variance showed no significant difference on the tomato plants growth and yield performance as compared to the manual irrigation. The ROI for the manual irrigation was 2.31%. For the capacitive and resistive sensor-based automatic irrigation the same ROI of 5.39% was computed. The payback period for the manual irrigation was 43 croppings. For the capacitive and resistive sensor-based automatic irrigation, they have an equal calculated payback period of 19 croppings. The computed BEP for the manual. capacitive and resistive sensor-based automatic irrigation were ₱45.86, ₱17.53, and ₱18.08. respectively. The capacitive sensor-based automatic irrigation was determined as the best irrigation method. The capacitive sensor soil moisture reading performs better as compared to the resistive sensor. The capacitive sensor-based automatic irrigation also has the least amount of water being applied compared to the manual and resistive sensor-based automatic irrigation having no significant effect on the tomatoes growth and yield. In terms of cost analysis, the capacitive sensor-based automatic irrigation has a higher ROI, and a lower payback period and BEP as compared to the manual irrigation making it the best recommended irrigation method to be used. Thesis (Master of Science in Agricultural Engineering - Soil and Water Management) Includes appendices and bibliographical references ddc TH 0 283 283 0 0 ddc 0 0 NVSUBAY NVSUBAY GS 2025-03-21 Donation 0 T M214c 2022 T1019 2025-03-21 11:03:49 2025-03-21 TH