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The strategic incorporation of low-cost management practices, such as cover crops (CCs), to citrus production in southern Texas could add valuable ecosystem services that increase trees’ resilience to changing climatic conditions. To provide insight into how producers can manage CCs to optimize ecosystem services, we conducted a study in controlled conditions to examine the potential of adding three annual summer CCs species: common buckwheat (Fagopyrum esculentum), sunflower (Helianthus annuus L.), and sunn hemp (Crotalaria juncea L.) as monocultures growing in two representative soil types of the citrus region in Texas, and receiving one of these irrigation volumes based on calculated daily water losses [i.e., evapotranspiration (ET)] corresponding to 100, 75, 50, and 25% field capacity replenishment. Sunflower and sunn hemp produced the highest aboveground dry matter, which was on average 338 and 342% greater than buckwheat. Sunn hemp emerged faster than the other CCs, and mortality was relatively uniform across CCs, but buckwheat exhibited the highest sensitivity to drought and heat distress. Sunn hemp exhibited superior aboveground biomass accumulation, height, and chlorophyll content. All CCs performed similarly in both experimental soils, under native fertility conditions, and without the addition of mineral fertilizers. Irrigation at 75 and 100% ET levels were conducive to enhanced plant growth, which indicates that a minimum of 86.4 mm (75% ET) is required during CCs lifespan, but sunn hemp and sunflower were also capable of tolerating medium (50% ET) drought stress. Overall, our findings suggest that sunflower and sunn hemp exhibited traits desirable for incorporation as CCs to a perennial citrus production system. The primary benefit was the addition of organic matter with minimum management; however, both CCs’ performance was dependent on planting timing, successful early establishment, and favorable environmental conditions.
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This content will become publicly available on December 1, 2025
Enhanced Nutrition Programs to Rehabilitate Freeze-stressed Citrus Trees in Subtropical Regions
Citrusspp. trees are not fully dormant during the winter months in the northern hemisphere; therefore, they are susceptible to sporadic freeze events of various magnitudes that could decline tree productivity or be lethal. In Feb 2021, winter storm Uri produced freezing air temperatures for nearly 72 hours, 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 of how practices such as compost application (CA) combined with varying rates of nitrogen (N) might facilitate tree recovery. Therefore, we conducted a 2-year field experiment using two CAs as soil amendments in combination with three N rates (112, 168, and 224 kg·ha−1N) to evaluate fruit yield and internal quality, root growth, and recovery of ‘Rio Red’ grapefruits (Citrus×paradisiMacf.) and ‘Marrs’ sweet oranges (Citrus sinensis). The yields of both crops exhibited modest improvement with CA in 2022; however, it was nonsignificant. Moreover, CA elicited more beneficial effects than N rates alone when 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 two-fold dry weight increment with CA. Sweet oranges from trees in the CA treatment had 22% lower acidity compared with that of 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 with the timely application of compost, which enhanced tree fitness and ameliorated fruit productivity declines during subsequent harvests.
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- Award ID(s):
- 1914745
- PAR ID:
- 10591265
- Publisher / Repository:
- American Society for Horticultural Science
- Date Published:
- Journal Name:
- HortScience
- Volume:
- 59
- Issue:
- 12
- ISSN:
- 0018-5345
- Page Range / eLocation ID:
- 1763 to 1771
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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