In the state of Louisiana surface irrigation is widely used due to the low start-up cost, typically high rainfall, and soil conditions. Irrigation scheduling is an important practice to achieve water use efficiency in agriculture. The objectives of this study were to compare three different methods to determine crop evapotranspiration (ETc) for soybeans in addition to, evaluate a computer based irrigation scheduling program using real scale fields. Weather variables, soil moisture and irrigation water use collected during the summer months of 2005 and 2006 at a production agriculture farm in northeast Louisiana were studied. The ETc estimates obtained using atmometers (ETgage); a weather station approach; an evapotranspiration algorithm from the computer based Arkansas Irrigation Scheduler (AIS). Three weeks of continuous ETc values showed that the atmometer and the weather station methods estimated similar values. The AIS method estimated lower values than the other two methods. The higher estimates by the weather station compared to the AIS are related to higher ETo values throughout the analyzed period. Similar estimation by the atmometer and the weather station methods suggest that these approaches were more suitable than the AIS method for estimating ETc at Angelina Plantation. The AIS proved to be a good scheduling tool that accurately predicts the crops irrigation needs. However, the results obtained at Angelina Plantation suggest that the farmer or irrigator programs the irrigation events modified by on-farm requirements. The AIS monitored the Maximum Allowable Depletion (MAD). Higher MAD values at the end of the crop cycle reduced the number of irrigations per field but increased the water use. Non-standard procedures implemented in leveled basins suggested a negative impact in the field drainage and made the irrigation process more labor intensive. Extra care is necessary to avoid waterlogging with level basins.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-06142007-145340 |
| Date | 14 June 2007 |
| Creators | Ocampo Briceno, Luis R |
| Contributors | Daniel L Thomas, Bill W Branch, Albert J Clemmens, Ernest L Clawson, Earl D Vories |
| Publisher | LSU |
| Source Sets | Louisiana State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lsu.edu/docs/available/etd-06142007-145340/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached herein a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to LSU or its agents the non-exclusive license to archive and make accessible, under the conditions specified below and in appropriate University policies, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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