Semester of Graduation

August 2026

Degree

Master of Science (MS)

Department

School of Plant, Environmental, and Soil Sciene

Document Type

Thesis

Abstract

Tea (Camellia sinensis L.) is an emerging specialty crop in Louisiana and the southeastern United States; however, region-specific nitrogen (N) management recommendations remain limited. This research evaluated N fertilizer source, application rate, and nutrient leaching to identify management strategies that improve nitrogen use efficiency (NUE) and environmental sustainability during tea establishment.

Three complementary studies evaluated N source replacement, application rate, and fertilizer source effects on nutrient retention and movement. The first study evaluated the replacement of urea ammonium sulfate (UAS) with blood meal (BM) while maintaining a constant annual N application rate. Fertilizer replacement did not significantly affect leaf greenness (SPAD), plant growth, soil pH, electrical conductivity, soil organic matter, or most soil microbial indicators. These results demonstrated that BM supplied sufficient N to support tea establishment with plant and soil responses comparable to UAS.

The second study evaluated UAS and BM applied at 150, 250, and 350 lb N ac⁻¹ yr⁻¹. N application rate had limited influence on plant growth, soil chemical properties, and soil biological responses, whereas sampling date consistently exerted the strongest effect. Tea receiving 150 lb N ac⁻¹ yr⁻¹ performed similarly to plants receiving higher rates, suggesting that additional N provided little benefit during establishment.

The third study used lysimeters to evaluate N leaching across multiple soil types. UAS generally produced the greatest nitrate (NO₃⁻), ammonium (NH₄⁺), and total inorganic N losses, whereas BM reduced N leaching, indicating greater N retention and lower potential for environmental losses.

Collectively, these findings demonstrate that BM can serve as an effective alternative to UAS during tea establishment and that N application rates above 150 lb N ac⁻¹ yr⁻¹ provide limited agronomic benefit. Moderate N rates and organic N sources improved NUE by maintaining tea performance while reducing N losses under Louisiana growing conditions. Although BM is generally more expensive than UAS, its reduced nutrient losses and potential environmental benefits should be considered alongside fertilizer cost when selecting N management strategies. This research provides a foundation for developing region-specific N management recommendations for specialty tea production in Louisiana and the southeastern United States.

Date

7-17-2026

Committee Chair

Chen, Yan

LSU Acknowledgement

1

LSU Accessibility Acknowledgment

1

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