Degree

Doctor of Philosophy (PhD)

Department

School of Plant, Environmental and Soil Sciences

Document Type

Dissertation

Abstract

Integrating effective fertilizer management with conservation practices is essential to improve farm income and promote environment friendly sugarcane production systems. A study was conducted in multiple to document the impact of nitrogen (N) source and cover cropping on sugarcane yield and quality components. The treatment consisted of different N sources: urea, knife-in urea ammonium nitrate (UAN) solution, calcium nitrate-CaNO3, ammonium sulfate-NH4SO4, and knife-in UAN. + foliar N, applied at 90 kg ha-1 and control (0 N). The cover crops included: crimson clover (Trifolium incarnatum), hairy vetch (Vicia villosa), and oilseed radish (Raphanus sativus L.) planted at 13, 17, and 1 kg ha-1, respectively. A split-plot design was used having cover crops treatments (with and without) as main plots, and N sources as subplots with four replications. This study was also used for the acquisition of sugarcane normalized difference vegetation index (NDVI) 4 weeks after N fertilization using two platforms, a GreenSeeker® handheld sensor and a DJI Phantom 4 drone equipped with MicaSense RedEdge-M™ sensor to establish and validate NDVI conversion model and sugarcane prediction models. Cane and sugar yield, juice quality components, and stalk N content and uptake were determined at harvest. Soil and leaf tissue samples were collected for soil NH4+ -N and NO3- -N and leaf-N monitoring. Across sites, sugarcane was very responsive to N application; the highest cane and sugar yield recorded was 118 Mg ha-1 and 12,600 Kg ha-1, respectively. Across sites, both UAN. and NH4SO4 treated plots achieved the highest increase in cane (115 and 117 Mg ha-1, respectively) and sugar yield (13,283 and 12,236 Kg ha-1, respectively). Ammonium was the predominant form of N in the soil compared to NO3-. This highest concentration of NH4+-N was in knife-in UAN, and NH4SO4 treated plots. The cover crops biomass removed a higher amount of nutrients from the soil than the no-cover crop. The converted aerial-NDVI can predict sugarcane yield potential using models vii established from a ground-based sensor. The use of cover crops and remote sensing technology can be used as a decision tool to improve fertilizer recommendations and management practices for sustainable sugarcane production in Louisiana.

Date

10-18-2021

Committee Chair

Tubana, Brenda

Share

COinS