The objectives of this research were i) to observe the movement of the wetting front in subsurface drip irrigated lettuce and broccoli, 2) to analyze variability in soil water tension (SWT) within the profile, and 3) to determine root distributions of subsurface drip irrigated lettuce and broccoli. Lettuce and broccoli plots at the Maricopa Agricultural Center during the 1992-93 and 1993-94 winter growing seasons were intensively instrumented with automated tensiometers. During both seasons, there was good agreement between mean daily SWT, and SWT measured before irrigation. During 1992-93, the maximum variation in mean SWT among tensiometers was 2.5 kPa. Among tensiometers within the zone of greatest root density, the maximum variation was only 1.5 kPa. Therefore, the range of SWT within the lettuce root zone was small, and tensiometer placement anywhere within the root zone would have been adequate. During 1993-94, the maximum variation in mean SWT among tensiometers was 7 kPa. The maximum variation among tensiometers within the zone of greatest root density was 5.3 kPa. The larger variation in mean SWT among tensiometers, compared to lettuce, is due to the greater water use of broccoli. Tensiometer placement will be more critical for higher water use crops. During both seasons roots proliferated around the drip tubing. These results substantiate the assumption that tensiometer placement anywhere within the zone of greatest root density will be adequate for irrigation scheduling of subsurface drip irrigated crops.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/221449 |
| Date | 08 1900 |
| Creators | Thompson, Thomas L., Maki, Kerri L. |
| Contributors | Oebker, Norman F. |
| Publisher | College of Agriculture, University of Arizona (Tucson, AZ) |
| Source Sets | University of Arizona |
| Language | en_US |
| Detected Language | English |
| Type | text, Article |
| Relation | Series P-100, 370100 |
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