Identifier

etd-04272011-153235

Degree

Master of Science (MS)

Department

Plant, Environmental Management and Soil Sciences

Document Type

Thesis

Abstract

Cotton (Gossypium hirsutum L.) is an important commercial crop in the northeastern part of Louisiana. Research-based information for irrigation scheduling in cotton is lacking in this region. A two-step reference evapotranspiration (ETo) - cotton crop coefficient (Kc) approach is considered a standard method of crop water use (ETc) estimation. Therefore, a study was conducted to determine stage-specific cotton water use crop coefficients (Kc), a ratio of ETc to ETo at the LSU AgCenter Northeast Research Station in 2010. For ETc estimation, paired weighing lysimeters were used. Cotton variety ‘Stoneville 5458 B2RF’ was planted on weighing lysimeters by hands and surrounding field using a vacuum planter under similar growing conditions typical of the region on May 12. Cotton plants on lysimeters and surrounding field were irrigated throughout the season. Other crop management practices were carried out following the LSU AgCenter recommendations. To estimate ETo, an area of 102 m by 102 m seeded with Bermuda grass (Cynodon dactylon L.) was demarcated and a tower 10 m in height instrumented with weather sensors was installed in the center of demarcated area in July 2009. Daily measurements of maximum and minimum air temperature, minimum and maximum RH, wind speed, and total solar radiation were obtained and ETo was estimated using the Standardized Reference Evapotranspiration Equation (SREE) of the American Society of Civil Engineers (ASCE).An average Kc value of 0.42 for initial growth stage (0 to 25 days after planting), 0.89 for developmental (26 to 60 days after planting) and 1.41 for mid-season (61 to 132 days after planting) were observed. With the development of these Kc values, a simple internet based tool can be designed to help producers conduct a more efficient irrigation scheduling which will subsequently improve water use efficiency in this region.

Date

2011

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Labonte, Don R.

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