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How Much and When to Irrigate the Crops Using Water Content Reflectometer

Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan www.asabe.org

Citation:  Pp. 884-890 in Proceedings of the World Congress of Computers in Agriculture and Natural Resources (13-15, March 2002, Iguacu Falls, Brazil)  701P0301.(doi:10.13031/2013.8424)
Authors:   M. Montiel, E. Peña, y A. Chávez
Keywords:   field capacity, permanent wilting point, temporary wilting point, water content reflectometer

In the hereby work a methodology to determine the irrigation moment using water content reflectometer (WCR) measurement equipment is applied. Initially a traditional concepts revision on the soils humidity calculus and irrigation programming was performed. Through the general study of soils of the II-1 Module of the District 010 Culiacn, Sinaloa, Mxico, with its layers texture data, were calculated by means of the proposed methodology by IMTA, adapted from Rawls and Brakesiek, (1997), the field capacity humidity parameters (qcc) and permanent wilting point (qpmp), as well as the humidity from which advantage can be taken (HA). These values were plotted in SURFER ambiance as isoindexes for irrigation programming in a graphical system in real geographical coordinates.

The Module II-1 is integrated by 16 irrigation sections counting with an approximate surface of 30,500 hectares and a total of 3,600 users. An analysis with foundation in the plans elaborated to determine an equation for each one of the 16 Module II-1 irrigation sections was performed, with the purpose to serve as support to the section head in the irrigation programming and use of the irrigation forecast system in real time installed in the Module II-1. For the particular case of the WCR sensor use, the existence within the humidity scale was proposed, a temporary wilting point (qpmt) as main indicator in the determination of when and how much apply of watering to the crop. This value was obtained for each irrigation section, through an equation that relates the soil humidity constants. Graphs and charts summarizing the results with success as well as a brief description thereof are presented.

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