Semester of Graduation

Spring 2018

Degree

Master of Science (MS)

Department

School of Plant, Environmental, and Soil Sciences

Document Type

Thesis

Abstract

Sugarcane (Saccharum spp) production is an integral part of Louisiana's economy. Proper fertilizer management, particularly nitrogen (N) and potassium (K), optimizes sugarcane production. An experiment was established in 2015 at the LSU AgCenter Sugar Research Station in St. Gabriel, Louisiana to: (1) assess the effect of N and K fertilizer sources on sugarcane yield and quality parameters, and (2) monitor the changes in inorganic N and K levels in the soil at different sugarcane growth stages. The experiment was arranged in a randomized complete block design on a Sharkey clay soil and complete randomized design on a Commerce silt loam soil with four replications. Data were collected from control (0) and treated plots with 45, 90 and 135 kg N ha-1 using controlled-release fertilizer (CRF) (Agrocote Max®, 45% N) and urea ammonium nitrate (UAN, 32% N). Potassium treatments included data from the control (0) and 90 kg ha-1 applied as 100% muriate of potash (MOP, 60% K) and 50% MOP + 50% Agrocote KCl ® (61% K). Soil (0-15 and 15-30 cm depths) and leaf samples were collected (every two weeks from fertilization), dried and analyzed for N and K content. At harvest, ten stalks were collected, shredded, and analyzed for quality parameters using a SpectraCane NIR system. Plot yields were determined using a combine harvester and a weigh-wagon. Results of this study showed positive impact of CRF on sucrose, TRS, and polarity in Sharkey clay soil with a net return profit of $218 ha-1 higher than UAN. The UAN solution performed better on Commerce silt soil with a net return of $496 ha-1 higher than CRF. Also, both N sources showed higher inorganic N concentration in 0-15 cm depth on Sharkey clay soil. The MOP+ CR-K was more beneficial than 100% MOP on Sharkey clay soil, making $155 ha-1 higher than 100% MOP. Sugarcane on Sharkey clay soil had the most K response compared to Commerce silt soil. This study shows the potential of CRF as a source of N and K in certain soil types, and the effectiveness of UAN as N source in Louisiana sugarcane production

Date

4-3-2018

Committee Chair

Tubana, Brenda

DOI

10.31390/gradschool_theses.4680

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