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ARS Home » Southeast Area » Stoneville, Mississippi » Crop Production Systems Research » Research » Publications at this Location » Publication #418498
Research Project: Development of Productive, Profitable, and Sustainable Crop Production Systems for the Mid-South

Location: Crop Production Systems Research

Title: Enhanced nutrient programs to rehabilitate freeze-stressed citrus in subtropical regions

Author
item DE-LEON, DESIDERIO - Texas A&M University
item NELSON, SHAD - Texas A&M University
item SÉTAMOU, MAMOUDOU - Texas A&M University
item Bhandari, Ammar
item ZAMORA, ERIK - Texas A&M University
item ZARAGOZA, AMBERLY - Texas A&M University
item DONATO, CONSUELO - Texas A&M University
item REYES-CABRERA, JOEL - Texas A&M University

Submitted to: Scientia Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/28/2024
Publication Date: 11/13/2024
Citation: De-Leon, D., Nelson, S.D., Sétamou, M., Bhandari, A.B., Zamora, E., Zaragoza, A., Donato, C., Reyes-Cabrera, J. 2024. Enhanced nutrient programs to rehabilitate freeze-stressed citrus in subtropical regions. Scientia Horticulturae. Volume 59: Issue 12. https://doi.org/10.21273/HORTSCI18233-24.
DOI: https://doi.org/10.21273/HORTSCI18233-24

Interpretive Summary: Citrus (Grapefruit and sweet oranges) are highly valued horticultural commodities. Texas is the third largest citrus-producing state in the United States (U.S.). With 7,300 hectares bearing fruit in the Lower Rio Grande Valley (LRGV), it represents an estimated crop value of 37 million dollars. The Texas citrus region experiences sporadic cold events ranging from moderate to severe. For instance, in mid-February 2021, citrus orchards in the LRGV suffered from prolonged freezing temperatures for approximately 48 hours due to winter storm Uri, where some of the orchards experienced temperatures as low as –7.2 °C. There is growing interest among citrus stakeholders in better understanding horticultural practices that increase citrus resilience to freezing temperatures. The objectives were to assess the effect of enhanced nutrition programs and compost application on freeze-affected citrus fruit yield and quality. The results indicated compost application increased root dry weight in grapefruits. The sweet orange had a higher brix with nitrogen application than the control. The basal nitrogen fertilization combined with compost application is a short-term measure to maintain grapefruit tree health and productivity following mild to moderate freeze events. The results will help the citrus industry, researchers, and stakeholders make informed decisions about developing strategies for mitigating the impact of freeze events on citrus in LRGV.

Technical Abstract: Citrus spp. trees are not fully dormant during the winter months in the northern hemisphere, thereby they are susceptible to sporadic freeze events of various magnitude that could decline tree productivity or be lethal. In February 2021, winter storm Uri produced freezing air temperatures for nearly 72 h, which created several degrees of injuries to citrus orchards in southern Texas. Producers in the area implemented combinations of multiple horticultural practices aimed at remediating injuries from the cold spell to stimulate root and tree recovery. However, there is a gap in our understanding on how practices such as compost application (CA) combined with varying rates of nitrogen (N) might facilitate tree recovery. Therefore, we conducted a 2-yr field experiment using two CA methods (broadcast and ring) as soil amendment in combination with three N rates (112, 168, and 224 kg N ha-1) to evaluate fruit yield and internal quality, root growth, and recovery of ‘Rio Red’ grapefruits (Citrus x paradisi Macf.) and ‘Marrs’ sweet oranges (Citrus sinensis). Yield of both crops exhibited modest improvement with CA in 2022, albeit it was nonsignificant. Moreover, CA elicited more beneficial effects than N27 rates alone in rehabilitating trees, and improving fruit internal quality after freezing events. Grapefruit brix was 4% higher in fruits harvested from trees treated with compost, and grapefruit roots exhibited a 2-fold dry weight increment with CA. Sweet oranges from trees in the CA treatment had 22% lower acidity compared with untreated trees. Overall, our results indicate that citrus producers in southern Texas and other subtropical citrus-producing regions might facilitate the rehabilitation of tree injuries attributed to mild to moderate freeze events with moderate financial gains by timely application of compost, which enhanced tree fitness, and ameliorate fruit productivity decline in subsequent harvests.