{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,30]],"date-time":"2026-06-30T10:48:24Z","timestamp":1782816504085,"version":"3.54.5"},"reference-count":49,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2016,7,14]],"date-time":"2016-07-14T00:00:00Z","timestamp":1468454400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Fresh water is a key natural resource for food production, sanitation and industrial uses and has a high environmental value. The largest water use worldwide (~70%) corresponds to irrigation in agriculture, where use of water is becoming essential to maintain productivity. Efficient irrigation control largely depends on having access to reliable information about the actual plant water needs. Therefore, fast, portable and non-invasive sensing techniques able to measure water requirements directly on the plant are essential to face the huge challenge posed by the extensive water use in agriculture, the increasing water shortage and the impact of climate change. Non-contact resonant ultrasonic spectroscopy (NC-RUS) in the frequency range 0.1\u20131.2 MHz has revealed as an efficient and powerful non-destructive, non-invasive and in vivo sensing technique for leaves of different plant species. In particular, NC-RUS allows determining surface mass, thickness and elastic modulus of the leaves. Hence, valuable information can be obtained about water content and turgor pressure. This work analyzes and reviews the main requirements for sensors, electronics, signal processing and data analysis in order to develop a fast, portable, robust and non-invasive NC-RUS system to monitor variations in leaves water content or turgor pressure. A sensing prototype is proposed, described and, as application example, used to study two different species: Vitis vinifera and Coffea arabica, whose leaves present thickness resonances in two different frequency bands (400\u2013900 kHz and 200\u2013400 kHz, respectively), These species are representative of two different climates and are related to two high-added value agricultural products where efficient irrigation management can be critical. Moreover, the technique can also be applied to other species and similar results can be obtained.<\/jats:p>","DOI":"10.3390\/s16071089","type":"journal-article","created":{"date-parts":[[2016,7,14]],"date-time":"2016-07-14T10:25:08Z","timestamp":1468491908000},"page":"1089","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":43,"title":["Ultrasonic Sensing of Plant Water Needs for Agriculture"],"prefix":"10.3390","volume":"16","author":[{"given":"Tomas","family":"G\u00f3mez \u00c1lvarez-Arenas","sequence":"first","affiliation":[{"name":"Instituto de Tecnolog\u00edas F\u00edsicas y de la Informaci\u00f3n, Spanish National Research Council (CSIC), Serrano 144, Madrid 28006, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eustaquio","family":"Gil-Pelegrin","sequence":"additional","affiliation":[{"name":"Unidad de Recursos Forestales, Centro de Investigaci\u00f3n y Tecnolog\u00eda Agroalimentaria-Instituto Agroalimentario de Arag\u00f3n (IA2), Gobierno de Arag\u00f3n, Av. Monta\u00f1ana, 930, Zaragoza 50059, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Joao","family":"Ealo Cuello","sequence":"additional","affiliation":[{"name":"Escuela de Ingenier\u00eda Mec\u00e1nica, Ed. 351, 2011, Ciudad Universitaria- Mel\u00e9ndez, Universidad del Valle, Cali 760032, Colombia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maria","family":"Fari\u00f1as","sequence":"additional","affiliation":[{"name":"Instituto de Tecnolog\u00edas F\u00edsicas y de la Informaci\u00f3n, Spanish National Research Council (CSIC), Serrano 144, Madrid 28006, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Domingo","family":"Sancho-Knapik","sequence":"additional","affiliation":[{"name":"Unidad de Recursos Forestales, Centro de Investigaci\u00f3n y Tecnolog\u00eda Agroalimentaria-Instituto Agroalimentario de Arag\u00f3n (IA2), Gobierno de Arag\u00f3n, Av. Monta\u00f1ana, 930, Zaragoza 50059, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"David","family":"Collazos Burbano","sequence":"additional","affiliation":[{"name":"Escuela de Ingenier\u00eda Mec\u00e1nica, Ed. 351, 2011, Ciudad Universitaria- Mel\u00e9ndez, Universidad del Valle, Cali 760032, Colombia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jose","family":"Peguero-Pina","sequence":"additional","affiliation":[{"name":"Unidad de Recursos Forestales, Centro de Investigaci\u00f3n y Tecnolog\u00eda Agroalimentaria-Instituto Agroalimentario de Arag\u00f3n (IA2), Gobierno de Arag\u00f3n, Av. Monta\u00f1ana, 930, Zaragoza 50059, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2016,7,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"909","DOI":"10.1641\/0006-3568(2004)054[0909:WRAAEI]2.0.CO;2","article-title":"Water resources: Agricultural and environmental issues","volume":"54","author":"Pimentel","year":"2004","journal-title":"Bioscience"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Taher Kahil, M., Albiac, J., Dinar, A., Calvo, E., Esteban, E., Avella, L., and Garcia-Molla, M. (2016). Improving the performance of water policies: Evidence from drought in spain. Water, 8.","DOI":"10.3390\/w8020034"},{"key":"ref_3","unstructured":"European Environment Agency Water for Agriculture. 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