Evaluating the impacts of cover crops in Southeast Florida citrus groves affected by citrus greening: part I – effects on soil fertility

Abstract Soil fertility plays a crucial role in maintaining fruit production systems, particularly in Florida, where the decline of citrus production from citrus greening disease (huanglongbing, HLB) has prompted growers to explore alternative soil management practices. This study evaluates the impact of cover crops on soil nutrients, soil organic matter (SOM), soil moisture, and soil temperature in commercial citrus groves under the challenging conditions of citrus greening, and the poorly drained sandy flatwood soils that dominate the region. A three-year field trial was conducted from January 2022 to July 2024 across four commercial citrus groves in Fort Pierce, FL. In this trial, “Star Ruby” grapefruit, “Bearss” lemon, and “OLL-8” sweet orange trees grafted on various rootstocks were arranged in a randomized complete block design. Each grove served as a block and contained conventional (perennial grass) and cover crop treatment plots. Warm and cool season cover crop mixtures were planted biannually. Cover crops affected soil moisture, temperature, organic matter, and nutrient dynamics across groves and sampling periods. Increases in soil moisture (38%–52%), nitrate (37%–134%), and phosphorus (30%–48%) were observed, with high variability across seasons. Despite this variability, the potential benefits of cover crops remain significant, particularly in the context of long-term soil fertility. As citrus growers seek adaptive management strategies in response to citrus greening, cover crops show a promising long-term avenue for enhancing soil health and sustaining citrus production in Florida.