Click on “Download PDF” for the PDF version or on the title for the HTML version.

If you are not an ASABE member or if your employer has not arranged for access to the full-text, Click here for options.

Correlation of soil water content determination by neutron backscatter and almond tree stem water potential for microirrigation scheduling in almonds

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

Citation:  5th National Decennial Irrigation Conference Proceedings, 5-8 December 2010, Phoenix Convention Center, Phoenix, Arizona USA  IRR10-9870.(doi:10.13031/2013.35884)
Authors:   Blake L Sanden, Ken A Shackel, Patrick H Brown
Keywords:   Neutron probe, soil water content, pressure chamber, stem water potential, irrigation scheduling, regulated deficit irrigation

During the last 15 years, the use of midday bagged leaf water potential (LWP), as measured by a portable field pressure chamber to determine overall tree stem water potential (SWP), has been advanced as the preferred method to determine orchard water stress and schedule irrigation This strategy has particular merit for deficit irrigation and disease management. However, there is a limited time window (usually 1200 to 1500 hrs) in which to take these readings, and in a coarse sandy loam soil it is possible to nearly deplete available soil moisture before this method indicates the need for an irrigation. This paper explores the site specific correlation of rootzone soil water content as determined with neutron backscatter to a depth of 1.8 m and SWP in a mature almond orchard planted to a uniform Milham sandy clay loam soil, to orchard-wide averages under microsprinklers and double-line drip applying identical amounts of water. Reasonable values of R2 suggest that calibrated soil water content readings can provide sufficient estimates of tree stress.

(Download PDF)    (Export to EndNotes)