Identifier

etd-10312011-162534

Degree

Master of Science in Biological and Agricultural Engineering (MSBAE)

Department

Biological and Agricultural Engineering

Document Type

Thesis

Abstract

Water management represents an essential component in all agricultural activities, where significant improvements can be achieved through the implementation of field measuring devices and irrigation scheduling models. The methods that integrate these tools may be based on information regarding the soil, crop, and weather. Evapotranspiration (ET) is one of the most important components of the soil water-balance used in modeling. A number of estimation methods have been developed to determine Reference Evapotranspiration (ETo) under various types of weather conditions. In this research, an analysis was conducted between different ETo estimation methods and ETo calculated from soil water content measurements and a soil-water budget, in Northeast Louisiana during the 2010 sweetpotato growing season. Similarly, the standardize ASCE Penman-Monteith equation was then compared to ETo equations using limited weather inputs. Additionally, a Sweetpotato Irrigation Scheduler (SPIS) based on a simple soil-water balance approach was developed to improve irrigation scheduling using weather, crop, and soil data. The model’s predictions were validated, for the critical first 30 Days after Transplanting (DAT) and for the entire growing season, against field data obtained from soil water content probes. A previously developed phenology-driven Bayesian belief network model was used to establish the timing and depth of irrigation. Some difficulties where found during the assessment of ETo and the simulation of the soil-water content under unsaturated soil and dry weather conditions. These circumstances reduced the capacity of the soil to move water appropriately, slowing down some of the processes involved in the soil-water budget, causing a misrepresentation by the ETo equations and the irrigation scheduling model.

Date

2011

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Sheffield, Ronald

Included in

Engineering Commons

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