Please state project objectives and what work was done this quarter to address them:Objective 1: Determine how different cover crop mixtures impact soil and root health and weed cover in established commercial citrus groves.Cover crops were planted in November 2021 and included sunnhemp, daikon radish, rye, and oats. Preliminary assessment of amplicon sequencing from the August 2021 soil collection indicates that cover crop treatments had minimal impact on overall soil bacterial diversity. However, the bacterial community composition was impacted by cover crop mixtures over time in at least one grove. The negative correlation between the growth and coverage of cover crops and weeds observed in the previous measurements has continued, with the density of grasses, sedges and broad leaf weeds being significantly low in cover cropped row middles compared to the non-cover cropped control. Although the establishment and growth of cover crops are lower than the North grove location, the cover crop density in the South grove location appears to be improving over time, as noted from the comparisons of cover crop density in planted row-middles between 2019 and 2021. Objective 2: Examine the impact of eco-mowing in conjunction with cover crops on soil and root health and weed cover in established commercial citrus groves.Eco-mowing primarily occurs prior to planting the winter season cover crops, as the movement of harvest equipment in the spring has eliminated the need for mowing to terminate cover crops prior to planting. We have not seen any significant impact of eco-mowing on the soil microbial communities. Visual and quantitative root growth assessments continues to show similar root growth under cover cropping and eco-mowing with no consistent trends over time. Objective 3: Quantify the effect of cover crops and eco-mowing on tree growth and production.The final yield collection is scheduled for March/April 2022. In addition, fruit drop estimates are being conducted in February and March of 2022 prior to harvest. Previous yield data found little change with treatments in one location, and a slight increase with cover crops at the second site. Analysis of fruit quality, canopy volume, and trunk size also showed no significant differences between treatments. Final analysis of canopy volume and trunk size is in progress. However, the marginal changes are not unexpected, as trees of this age could take several years to show responses to treatments. Objective 4: Identify the economic benefits of using cover cropsThe economics team has estimated the preliminary results from the cover crops in citrus survey. The survey solicited information on growers use of cover crops, willingness to pay to for cover crops, and ranked how they valued different soil and pest attributes. Preliminary results suggest that growers in Florida are willing to pay $476 per acre per year on average to adopt cover crops in citrus production. Results also indicate that owning a no till drill or planter and access to markets are significant determinants of the price that the growers are willing to pay. The team has also worked on a preliminary cost benefit analysis on cover crop adoption using data from published budgets, secondary sources, and interviews with growers. A median yield-quality scenario, that is based on historical data from USDA-NASS and FDOC, gives break-even prices ($/pound solids) that are below the highest recorded prices, indicating that it could be profitable to use cover crops for growing oranges. Currently, the team is working on finalizing the results and finishing the drafts of the papers. Objective 5: Communicate results to growers using field days and extension materialsPreliminary results will be presented at the UF/IFAS Citrus Health Forum in February at the North Florida REC. Some relevant observations on the impact of cover cropping on weed management were presented at the Southeastern Fruit and Vegetable conference (Jan 2022) and a citrus production school growers meeting ( Feb 2022) in the current quarter. Plans are being made to hold a grower seminar in late spring to present the final results of the project. In addition, an EDIS document summarizing the findings of these trials is being drafted. Please state what work is anticipated for next quarter:Final analyses of soil and leaf samples is underway. Final analysis of microbial DNA sequencing and qPCR is also in progress, as well as correlations with soil nutrient data. Fruit drop estimates are being conducted in February and March prior to harvest. Final yield and fruit quality measurements will occur in March/April. Final analysis of canopy and trunk size measurements along with root image will be completed. Analysis and interpretation of the weed data, including density and biomass, will be conducted in the next quarter. Please state budget status (underspend or overspend, and why):With the NCE, we are now on track with our planned budget spending.