N. Vázquez, J. Huete, A. Pardo, M.L. Suso, V. Tobar
The objective of the study was to evaluate the use of soil moisture sensors for automatic high frequency drip irrigation in processing tomato (Lycopersicum esculentum Mill.) in the Ebro valley (Spain). Three types of high frequency irrigation scheduling methods in two soil conditions, bare soil and soil mulched with black plastic, were evaluated. Irrigation requirements were calculated according to the daily crop evapotranspiration (ET) or were based on two different soil moisture sensors, capacitance soil water sensor (Cap) and granular matrix sensor (GMS). Sensor based treatments used a soil moisture sensor buried 20 cm deep within the crop root zone to maintain soil moisture above a set level. Irrigation was applied when soil volumetric water content (Cap) or soil tension (GMS) were below the set level for each sensor. The system allowed up to 4-6 irrigation events of 30 min per day. In mulched soil, the marketable yield was higher than in bare soil (115.3 vs. 92.6 t/ha). The GMS and ET treatments resulted in the largest marketable yields (107.8 and 106.8 t/ha respectively), but GMS treatment used approximately 15% less seasonal irrigation water in mulched soil, and 25% less in bare soil, than ET treatment and the solid soluble content increased significantly. Irrigation water use efficiencies (kg marketable /m3) were higher in mulched soil than in bare soil (32.7 vs. 26.7) and treatment GMS (34.4) was higher than ET and Cap (34.4 vs. 27.1, 27.3 respectively). The results indicate that high frequency irrigation events based on soil moisture sensor control can maintain crop yield and quality while reducing irrigation water applied. However, further research is needed to adjust the set irrigation levels for sensors in different soils.
Vázquez, N., Huete, J., Pardo, A., Suso, M.L. and Tobar, V. (2011). USE OF SOIL MOISTURE SENSORS FOR AUTOMATIC HIGH FREQUENCY DRIP IRRIGATION IN PROCESSING TOMATO. Acta Hortic. 922, 229-235
DOI: 10.17660/ActaHortic.2011.922.30
irrigation scheduling, granular matrix sensor, capacitance soil water sensor, Lycopersicum esculentum

Acta Horticulturae