Date of Graduation

8-2018

Document Type

Thesis

Degree Name

Master of Science in Biological Engineering (MSBE)

Degree Level

Graduate

Department

Biological and Agricultural Engineering

Advisor/Mentor

Henry, Christopher G.

Committee Member

Watkins, Kenton B.

Second Committee Member

Reba, Michele L.

Third Committee Member

Costello, Thomas A.

Fourth Committee Member

Bowie, Charolette

Fifth Committee Member

Mane, Ranjitsinh

Keywords

Furrow irrigation; Irrigation efficiency; % of NPPPC; Row rice; Surge irrigation; Tail-water recovery

Abstract

Furrow irrigation is a very common irrigation method for growing crops like soybean, cotton and corn in Arkansas. A major portion of this irrigation water is lost as runoff from the field significantly reducing the irrigation application efficiency. There are various methods of improving irrigation efficiency and one of the methods is using tail-water recovery. A tail-water recovery system utilizes tail-water recovery ditches or pits to collect tail-water which can be re-used for irrigation. However, this method is very labor intensive and has been found to be economically non-feasible for some farms in the past research studies. In order to reduce the cost of a tail-water recovery system, a new system was designed at the University of Arkansas, a Variable Flow Tail-Water Recovery System (VFTWRS). This system eliminates the need of tail-water recovery ditches or pits. It can be operated using grid power or photo voltaic (PV) modules. Application and system efficiency tests were performed in a 16 ha rice field planted in 76 cm × 76 cm rows. Application efficiencies of VFTWRS were compared with continuous furrow and surge irrigation methods. Results have indicated that application efficiency of furrow irrigation can be increased up to 93% using this designed tail-water recovery system. Application efficiency for continuous furrow irrigation was from 47% to 83%, 32% to 88% for surge irrigation, 81% to 97% for VFTWRS on electric grid as the energy source, and 23 to 96% for VFTWRS on PV modules as the energy source. Average percent of Nebraska Pumping Plant Performance Criteria were 98% and 77% for VFTWRS on grid and VFTWRS on PV modules, respectively.

Net Present Value (NPV) and Discounted Payback Period (DPP) were analyzed for different scenarios with an interest rate of 4%. VFTWRS on grid was found to be the most economically feasible system with the highest NPV of $8,031 per hectare with a DPP of 2 years. VFTWRS on PV modules was a better alternative than VFTWRS on grid when the distance of the tail-water pump to the power source was greater than 900 m. In general, all of the designs of tail-water recovery systems which consisted of a tail-water ditch had lower NPV and higher DPP in comparison to VFTWRS operated using grid as well as PV modules.

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