{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,17]],"date-time":"2026-07-17T20:34:06Z","timestamp":1784320446550,"version":"3.55.0"},"reference-count":59,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2021,8,9]],"date-time":"2021-08-09T00:00:00Z","timestamp":1628467200000},"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>Precise and quick estimates of soil moisture content for the purpose of irrigation scheduling are fundamentally important. They can be accomplished through the continuous monitoring of moisture content in the root zone area, which can be accomplished through automatic soil moisture sensors. Commercial soil moisture sensors are still expensive to be used by famers, particularly in developing countries, such as Egypt. This research aimed to design and calibrate a locally manufactured low-cost soil moisture sensor attached to a smart monitoring unit operated by Solar Photo Voltaic Cells (SPVC). The designed sensor was evaluated on clay textured soils in both lab and controlled greenhouse environments. The calibration results demonstrated a strong correlation between sensor readings and soil volumetric water content (\u03b8V). Higher soil moisture content was associated with decreased sensor output voltage with an average determination coefficient (R2) of 0.967 and a root-mean-square error (RMSE) of 0.014. A sensor-to-sensor variability test was performed yielding a 0.045 coefficient of variation. The results obtained from the real conditions demonstrated that the monitoring system for real-time sensing of soil moisture and environmental conditions inside the greenhouse could be a robust, accurate, and cost-effective tool for irrigation management.<\/jats:p>","DOI":"10.3390\/s21165387","type":"journal-article","created":{"date-parts":[[2021,8,9]],"date-time":"2021-08-09T21:41:46Z","timestamp":1628545306000},"page":"5387","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":49,"title":["Designing Low-Cost Capacitive-Based Soil Moisture Sensor and Smart Monitoring Unit Operated by Solar Cells for Greenhouse Irrigation Management"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8225-5087","authenticated-orcid":false,"given":"Abdelaziz M.","family":"Okasha","sequence":"first","affiliation":[{"name":"Department of Agricultural Engineering, Faculty of Agriculture, Kafrelsheikh University, Kafr El-Sheikh 33516, Egypt"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hasnaa G.","family":"Ibrahim","sequence":"additional","affiliation":[{"name":"Department of Agricultural Engineering, Faculty of Agriculture, Kafrelsheikh University, Kafr El-Sheikh 33516, Egypt"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Adel H.","family":"Elmetwalli","sequence":"additional","affiliation":[{"name":"Department of Agricultural Engineering, Faculty of Agriculture, Tanta University, Tanta 31527, Egypt"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4167-1690","authenticated-orcid":false,"given":"Khaled Mohamed","family":"Khedher","sequence":"additional","affiliation":[{"name":"Department of Civil Engineering, College of Engineering, King Khalid University, Abha 61421, Saudi Arabia"},{"name":"Department of Civil Engineering, High Institute of Technological Studies, Mrezgua University Campus, Nabeul 8000, Tunisia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3647-7137","authenticated-orcid":false,"given":"Zaher Mundher","family":"Yaseen","sequence":"additional","affiliation":[{"name":"New Era and Development in Civil Engineering Research Group, Scientific Research Center, Al-Ayen University, Thi-Qar 64001, Iraq"},{"name":"College of Creative Design, Asia University, Taichung 41354, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Salah","family":"Elsayed","sequence":"additional","affiliation":[{"name":"Agricultural Engineering, Evaluation of Natural Resources Department, Environmental Studies and Research Institute, University of Sadat City, Minufiya 32897, Egypt"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,8,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"477","DOI":"10.1016\/S0016-7185(00)00016-6","article-title":"Globalisation, information technology and the emergence of niche transnational cities: The growth of the call centre sector in Dublin","volume":"31","author":"Breathnach","year":"2000","journal-title":"Geoforum"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"678","DOI":"10.1108\/02640470510635764","article-title":"The role of technology in the emergence of the information society in India","volume":"23","author":"Singh","year":"2005","journal-title":"Electron. Libr."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Mukhopadhyay, S.C. (2012). Smart Sensing Technology for Agriculture and Environmental Monitoring, Springer.","DOI":"10.1007\/978-3-642-27638-5"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Sahitya, G., Balaji, N., Naidu, C.D., and Abinaya, S. (2017, January 5\u20137). Designing a wireless sensor network for precision agriculture using zigbee. Proceedings of the 2017 IEEE 7th International Advance Computing Conference (IACC), Hyderabad, India.","DOI":"10.1109\/IACC.2017.0069"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"236","DOI":"10.1038\/s41598-019-57150-y","article-title":"Climate change or irrigated agriculture\u2013what drives the water level decline of Lake Urmia","volume":"10","author":"Schulz","year":"2020","journal-title":"Sci. Rep."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1893","DOI":"10.1175\/JCLI-D-16-0460.1","article-title":"Role of fire in the global land water budget during the twentieth century due to changing ecosystems","volume":"30","author":"Li","year":"2017","journal-title":"J. Clim."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"171","DOI":"10.1016\/j.jenvman.2017.01.049","article-title":"Climate change and the economics of biomass energy feedstocks in semi-arid agricultural landscapes: A spatially explicit real options analysis","volume":"192","author":"Regan","year":"2017","journal-title":"J. Environ. Manag."},{"key":"ref_8","first-page":"413","article-title":"Water budget for the production of major crops under climate change in Egypt","volume":"5","author":"Hesham","year":"2016","journal-title":"Glob. Adv. Res. J. Agric. Sci."},{"key":"ref_9","unstructured":"Karajeh, F., Oweis, T., and Swelam, A. (2013). Water and Agriculture in Egypt, International Center for Agricultural Research in the Dry Areas (ICARDA)."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"El-Ramady, H.R., El-Marsafawy, S.M., and Lewis, L.N. (2013). Sustainable agriculture and climate changes in Egypt. Sustainable Agriculture Reviews, Springer.","DOI":"10.1007\/978-94-007-5961-9_2"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"105848","DOI":"10.1016\/j.agwat.2019.105848","article-title":"The value of information for the management of water resources in agriculture: Assessing the economic viability of new methods to schedule irrigation","volume":"227","author":"Galioto","year":"2020","journal-title":"Agric. Water Manag."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"544","DOI":"10.1016\/j.jhydrol.2019.05.045","article-title":"Soil moisture simulation using hybrid artificial intelligent model: Hybridization of adaptive neuro fuzzy inference system with grey wolf optimizer algorithm","volume":"575","author":"Maroufpoor","year":"2019","journal-title":"J. Hydrol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"666","DOI":"10.1016\/j.agwat.2009.12.009","article-title":"Precision of soil moisture sensor irrigation controllers under field conditions","volume":"97","author":"Dukes","year":"2010","journal-title":"Agric. Water Manag."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Placidi, P., Gasperini, L., Grassi, A., Cecconi, M., and Scorzoni, A. (2020). Characterization of Low-Cost Capacitive Soil Moisture Sensors for IoT Networks. Sensors, 20.","DOI":"10.3390\/s20123585"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Bogena, H., Huisman, J., Schilling, B., Weuthen, A., and Vereecken, H. (2017). Effective Calibration of Low-Cost Soil Water Content Sensors. Sensors, 17.","DOI":"10.3390\/s17010208"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"125","DOI":"10.1016\/j.earscirev.2010.02.004","article-title":"Investigating soil moisture-climate interactions in a changing climate: A review","volume":"99","author":"Seneviratne","year":"2010","journal-title":"Earth Sci. Rev."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1641","DOI":"10.1016\/j.agwat.2011.06.003","article-title":"Yield and seasonal water productivity of sunflower as affected by tillage and cropping systems under dryland conditions in the Limpopo Province of South Africa","volume":"98","author":"Mzezewa","year":"2011","journal-title":"Agric. Water Manag."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"92","DOI":"10.1016\/j.measurement.2014.04.007","article-title":"A critical review of soil moisture measurement","volume":"54","author":"Su","year":"2014","journal-title":"Measurement"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Vereecken, H., Huisman, J.A., Bogena, H., Vanderborght, J., Vrugt, J.A., and Hopmans, J.W. (2008). On the value of soil moisture measurements in vadose zone hydrology: A review. Water Resour. Res., 44.","DOI":"10.1029\/2008WR006829"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"258","DOI":"10.1016\/0022-1694(70)90066-1","article-title":"The gravimetric method of soil moisture determination Part I A study of equipment, and methodological problems","volume":"11","author":"Reynolds","year":"1970","journal-title":"J. Hydrol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"301","DOI":"10.1016\/j.sandf.2016.02.012","article-title":"Field evaluation of soft highway subgrade soil stabilized with calcium carbide residue","volume":"56","author":"Du","year":"2016","journal-title":"Soils Found."},{"key":"ref_22","unstructured":"James, L.G. (1988). Principles of Farm Irrigation Systems Design, John Wiley and Sons Limited."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Waller, P., and Yitayew, M. (2015). Irrigation and Drainage Engineering, Springer.","DOI":"10.1007\/978-3-319-05699-9"},{"key":"ref_24","first-page":"37","article-title":"Design, evaluation and irrigation scheduling of drip irrigation system on citrus orchard","volume":"12","author":"Asif","year":"2015","journal-title":"Pak. J. Meteorol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"391","DOI":"10.1097\/00010694-195205000-00007","article-title":"Determination of soil moisture by neutron scattering","volume":"73","author":"Gardner","year":"1952","journal-title":"Soil Sci."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"151","DOI":"10.1071\/SR02054","article-title":"The effect of a gap between the access tube and the soil during neutron probe measurements","volume":"41","author":"Li","year":"2003","journal-title":"Soil Res."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"306","DOI":"10.1016\/j.agwat.2016.06.024","article-title":"Scheduling irrigation from wetting front depth","volume":"179","author":"Stirzaker","year":"2017","journal-title":"Agric. Water Manag."},{"key":"ref_28","first-page":"11199","article-title":"Measuring Soil Electrical Resistivity Using a Resistivity Box and a Resistivity Probe","volume":"27","author":"Sheahan","year":"2004","journal-title":"Geotech. Test. J."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"39","DOI":"10.1016\/j.jhydrol.2012.01.041","article-title":"Comparison of four soil moisture sensor types under field conditions in Switzerland","volume":"430\u2013431","author":"Mittelbach","year":"2012","journal-title":"J. Hydrol."},{"key":"ref_30","first-page":"394","article-title":"Measurement of Soil Water Content with a 50-MHz Soil Dielectric Sensor","volume":"68","author":"Seyfried","year":"2004","journal-title":"Soil Sci. Soc. Am. J."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1016\/S0065-2113(06)90002-9","article-title":"Advances in Crop Water Management Using Capacitive Water Sensors","volume":"90","author":"Fares","year":"2006","journal-title":"Adv. Agron."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"986","DOI":"10.1021\/ed074p986","article-title":"The gravimetric analysis of nickel using a microwave oven","volume":"74","author":"Carmosini","year":"1997","journal-title":"J. Chem. Educ."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"574","DOI":"10.1029\/WR016i003p00574","article-title":"Electromagnetic determination of soil water content: Measurements in coaxial transmission lines","volume":"16","author":"Topp","year":"1980","journal-title":"Water Resour. Res."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Will, B., and Rolfes, I. (2014, January 18\u201320). A miniaturized soil moisture sensor based on time domain transmissometry. Proceedings of the 2014 IEEE Sensors Applications Symposium (SAS), Queenstown, New Zealand.","DOI":"10.1109\/SAS.2014.6798952"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"431","DOI":"10.1007\/s13580-016-0072-2","article-title":"Improving water and fertilizer use efficiency during the production of strawberry in coir substrate hydroponics using a FDR sensor-automated irrigation system","volume":"57","author":"Choi","year":"2016","journal-title":"Hortic. Environ. Biotechnol."},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Mander, G., and Arora, M. (2014, January 6\u20138). Design of capacitive sensor for monitoring moisture content of soil and analysis of analog voltage with variability in moisture. Proceedings of the 2014 Recent Advances in Engineering and Computational Sciences (RAECS), Chandigarh, India.","DOI":"10.1109\/RAECS.2014.6799646"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"568","DOI":"10.1016\/j.agwat.2018.11.002","article-title":"Performance evaluation of a recently developed soil water content, dielectric permittivity, and bulk electrical conductivity electromagnetic sensor","volume":"213","author":"Kargas","year":"2019","journal-title":"Agric. Water Manag."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"43","DOI":"10.3733\/ca.v054n03p43","article-title":"Soil type affects accuracy of dielectric moisture sensors","volume":"54","author":"Hanson","year":"2000","journal-title":"Calif. Agric."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1016\/j.agwat.2016.12.002","article-title":"Automatic fault detection in a low cost frequency domain (capacitance based) soil moisture sensor","volume":"183","author":"Oates","year":"2017","journal-title":"Agric. Water Manag."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"205","DOI":"10.5194\/npg-23-205-2016","article-title":"Multifractal behaviour of the soil water content of a vineyard in northwest Spain during two growing seasons","volume":"23","year":"2016","journal-title":"Nonlinear Process. Geophys."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"148","DOI":"10.1016\/j.compag.2017.12.038","article-title":"Design and implementation of a low cost photovoltaic soil moisture monitoring station for irrigation scheduling with different frequency domain analysis probe structures","volume":"148","author":"Ramadan","year":"2018","journal-title":"Comput. Electron. Agric."},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Gonz\u00e1lez-Teruel, J., Torres-S\u00e1nchez, R., Blaya-Ros, P., Toledo-Moreo, A., Jim\u00e9nez-Buend\u00eda, M., and Soto-Valles, F. (2019). Design and Calibration of a Low-Cost SDI-12 Soil Moisture Sensor. Sensors, 19.","DOI":"10.3390\/s19030491"},{"key":"ref_43","doi-asserted-by":"crossref","unstructured":"Aguilar, J., Rogers, D., and Kisekka, I. (2015). Irrigation Scheduling Based on Soil Moisture Sensors and Evapotranspiration. Kans. Agric. Exp. Stn. Res. Rep., 1.","DOI":"10.4148\/2378-5977.1087"},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Vaz, C.M.P., Jones, S., Meding, M., and Tuller, M. (2013). Evaluation of Standard Calibration Functions for Eight Electromagnetic Soil Moisture Sensors. Vadose Zone J., 12.","DOI":"10.2136\/vzj2012.0160"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"111","DOI":"10.1071\/SR15036","article-title":"Soil-specific calibration of capacitance sensors considering clay content and bulk density","volume":"54","author":"Parvin","year":"2016","journal-title":"Soil Res."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"4014076","DOI":"10.1061\/(ASCE)IR.1943-4774.0000847","article-title":"Effect of Temperature and Salinity on the Precision and Accuracy of Landscape Irrigation Soil Moisture Sensor Systems","volume":"141","author":"Dukes","year":"2015","journal-title":"J. Irrig. Drain. Eng."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"111","DOI":"10.1016\/j.agwat.2013.10.005","article-title":"Laboratory and field assessment of the capacitance sensors Decagon 10HS and 5TE for estimating the water content of irrigated soils","volume":"132","author":"Visconti","year":"2014","journal-title":"Agric. Water Manag."},{"key":"ref_48","doi-asserted-by":"crossref","unstructured":"Nagahage, E.A.A.D., Nagahage, I.S.P., and Fujino, T. (2019). Calibration and Validation of a Low-Cost Capacitive Moisture Sensor to Integrate the Automated Soil Moisture Monitoring System. Agriculture, 9.","DOI":"10.3390\/agriculture9070141"},{"key":"ref_49","doi-asserted-by":"crossref","unstructured":"Gao, Z., Zhu, Y., Liu, C., Qian, H., Cao, W., and Ni, J. (2018). Design and Test of a Soil Profile Moisture Sensor Based on Sensitive Soil Layers. Sensors, 18.","DOI":"10.3390\/s18051648"},{"key":"ref_50","first-page":"552","article-title":"Performance analysis of photovoltaic based submersible water pump","volume":"5","author":"Lal","year":"2013","journal-title":"Int. J. Eng. Technol. IJET"},{"key":"ref_51","unstructured":"Panagiotis, K., Kazadzis, S., and EL-Askary, H. (2020). The Solar Atlas of Egypt, Egyptian Ministry of Electricity."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"175","DOI":"10.17660\/ActaHortic.1997.449.23","article-title":"Water requirements of greenhouse grown pepper under drip irrigation","volume":"449","author":"Chartzoulakis","year":"1997","journal-title":"Acta Hortic."},{"key":"ref_53","unstructured":"American Society of Agricultural Engineers (2000). Test Procedure for Determining the Uniformity of Water Distribution of Center Pivot and Lateral Move Irrigation Machines Equipped with Spray or Sprinkler Nozzles, American Society of Agricultural Engineers Standards. ANSI\/ASAE S436. 1."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"423","DOI":"10.1061\/(ASCE)0733-9437(1997)123:6(423)","article-title":"Irrigation Performance Measures: Efficiency and Uniformity","volume":"123","author":"Burt","year":"1997","journal-title":"J. Irrig. Drain. Eng."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"106454","DOI":"10.1016\/j.agwat.2020.106454","article-title":"Propagation of soil moisture sensing uncertainty into estimation of total soil water, evapotranspiration and irrigation decision-making","volume":"243","author":"Sharma","year":"2021","journal-title":"Agric. Water Manag."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"554","DOI":"10.1136\/bmj.1.3923.554-a","article-title":"Design of Experiments","volume":"1","author":"Fisher","year":"1936","journal-title":"BMJ"},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"67","DOI":"10.2136\/sssaj2005.0067a","article-title":"Frequency Dependence of the Complex Permittivity and Its Impact on Dielectric Sensor Calibration in Soils","volume":"69","author":"Kelleners","year":"2005","journal-title":"Soil Sci. Soc. Am. J."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1016\/S0022-1694(99)00017-7","article-title":"Performance of TDR calibration models as affected by soil texture","volume":"218","author":"Ponizovsky","year":"1999","journal-title":"J. Hydrol."},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"632","DOI":"10.1061\/(ASCE)IR.1943-4774.0000449","article-title":"Performance Analysis and Calibration of a New Low-Cost Capacitance Soil Moisture Sensor","volume":"138","author":"Kargas","year":"2012","journal-title":"J. Irrig. Drain. Eng."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/16\/5387\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T06:43:11Z","timestamp":1760164991000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/16\/5387"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,8,9]]},"references-count":59,"journal-issue":{"issue":"16","published-online":{"date-parts":[[2021,8]]}},"alternative-id":["s21165387"],"URL":"https:\/\/doi.org\/10.3390\/s21165387","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,8,9]]}}}