DETERMINATION OF OPTIMAL LOCATION OF SOIL MOISTURE SENSING DEVICES FOR TRICKLE IRRIGATION SYSTEMS

Document Type : Original Article

Authors

1 Assoc. prof., Dept. of Agric. Eng., Fac. of Agric., Damietta Univ., Egypt.

2 Demonstrator, Dept. of Agric. Eng., Fac. of Agric., Damietta Univ., Egypt.

Abstract

Moisture sensing devices are considered the main element to reach better irrigation management especially for irrigation systems that are based on automatic control. Moisture devices location accuracy may affect the accuracy of their sent data which will lead to a poor performance under various operating conditions and consequently, affect irrigation efficiency that affects dependency on water productivity and thus, water use energy efficiency. For this purpose, a lab experiment was carried out using a fiberglass box (100 x 100 x 20 cm) and digital moisture meter (SKZ-DM300L), 2 digits accuracy to determine the optimal position of a calibrated moisture sensing device. The experiment was carried out on two soil types (sandy, and clay) under three flow rates (4.2, 5.6, and 6.2 l/h) for each soil type. Soil moisture content (SMC) average and total moisture content average were calculated for both soil types throughout four investigation periods (6, 12, 24, and 48 h) respectively, after applying the water for an hour. Standard deviation (SD) was estimated for each quarter of the total investigation depth to determine the amount of variation or dispersion of the obtained average (mean) moisture content values. For sandy soil, (15 cm) vertically (under the emission point directly) is the optimal position recommended putting a calibrated moisture sensing device use in irrigation scheduling under the lowest flow rate (4.2 l/h) whereas, (15, 15 cm) horizontally and vertically respectively, (from the emission point) is recommended for clay soil under flow rate (5.6 l/h) to obtain highly irrigation efficiency and thus, highly water productivity and water use energy efficiency.

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