Progress 06/01/24 to 05/31/25

Outputs
Target Audience:The target audiences reached during this reporting period include academic and scientific researchers as well as land managers, industry partners, and the general public. Because this is the first year of data collection for the study, the project team and I have not yet formally presented project outcomes to the target audience. However, we have been communicating closely with producer stakeholders in the region during the project establishment phase to seek their input on proposed management strategies such as variety selection for cover crops and instrumentation for applying compost. Data from the first cotton cropping season of the study are expected to be presented at producer-focused workshops in the upcoming fall and spring. Changes/Problems:Except for difficulties faced in establishing the first year of cover crop treatments (described in previous section), we have no major changes or problems to report. We have not significantly altered our study or treatment approach except for minor adjustments to planting and harvest methods to ensure cover crop emergence and growth over the winter study months. What opportunities for training and professional development has the project provided?In addition to the graduate student mentored directly as part of this work, additional students have been regularly involved in field activities, soil sampling, and lab analyses conducted as part of this study, particularly during the summer months. These include undergraduate students from The University of Puerto Rico-Mayaguez and Texas Tech University, as well as a visiting Ph.D. scholar in Summer 2025 (ongoing) supported by the Sao Paulo Research Foundation in Brazil who investigated the effects of study treatments on soil water retention and cotton crop physiology. How have the results been disseminated to communities of interest?Although no formal presentations or research products were generated during the first year of study as we worked to establish treatments and collect initial soil and plant data, we have frequently discussed the study design, objectives, and ongoing activities with producer stakeholders during outreach and educational events and commodity group meetings. What do you plan to do during the next reporting period to accomplish the goals?The current reporting period represented the first year of treatment establishment. During the next reporting period, we intend to harvest cotton early and plant the cover crop immediately following crop harvest to take advantage of any early winter rainfall available to aid cover crop establishment. In addition, we intend to drill the cover crop seeds to avoid seed loss to wildlife or sun exposure. Data collected from Year 1 soil samples and additional soil samples collected at the midpoint of the cotton growing season (late summer/early fall 2025) will be presented at both scientific conferences and producer-focused workshops. The M.S. graduate student supported by this work will also begin preparing data for inclusion in their thesis and for publication of initial study results.

Impacts
What was accomplished under these goals? Agricultural producers in semi-arid regions frequently experience yield declines and even crop failures due to environmental stressors such as extreme drought and pathogen infection. Management practices such as cover cropping and compost application are often recommended as ways to help restore and improve the soil's natural ability to capture and store water for crop plants. However, barriers to adopting these practices persist such as the potential for water depletion by cover crops or limitations to compost incorporation (e.g., erosion loss of applied compost and slowed decomposition dynamics in dry, hot environments). This study was designed to test how potential synergies in cover cropping and compost management influence tradeoffs of the individual practices and together improve plant-soil interactions and cotton system stability against drought and pathogen stress. This helps producers in semi-arid regions to feasibly combine soil health management practices to optimize soil water storage dynamics and resource restoration for long-term yield outcomes and stability. Objective 1: As proposed, in Summer 2024 we established a field experimental system with cotton as the cash crop and factorial combinations of cover crop (wheat-winter pea mix) or compost application, resulting in the following four treatments: 1) +Cover crop (planted in fall/winter following cotton harvest), 2) +Compost (applied in early or mid-spring at least one month prior to cotton planting), 3) +Cover+Compost, and 4) Control (no amendment). We proposed six replicated blocks containing each treatment, but have instead established twice the number of experimental replicates to be able to maintain statistical power when more treatments are added such as deficit irrigation. In addition, we proposed an ambitious annual compost rate (20 Mg ha-1) based on previous literature, but have instead opted for an annual rate of approximately 5 Mg ha-1 based on stakeholder (i.e., cotton producers) and industry involvement to better reflect the highest rate that could be economically incorporated into a production system. An M.S. graduate student was recruited prior in Fall 2024 to work on study establishment as part of their thesis research, and they officially began their program in January 2025. Following the final cotton harvest for the trials previously located in the study area, the experimental treatments for this work officially began with baseline soil sampling and cover crop planting in December 2024. A cover crop mix consisting of 70 lbs winter wheat (TAM 204 beardless) and 30 lbs Austrian winter pea for a total rate of 100 lbs/ac was broadcast in the cover-crop treatment plots (i.e., +Cover and +Cover+Compost) in December 2024. Unfortunately, the cover crop failed to emerge throughout the winter, and we have since determined that this was due largely to a combination of limited rainfall and birds descending on the plots to feed on the seeds after the nearby sorghum trials were harvested. Cotton was planted earlier in 2025 to facilitate an earlier harvest, and we have acquired a seed drill to plant the cover crop immediately after cotton harvest instead of relying on broadcast application. Compost was successfully applied at a target rate of 5 Mg ha-1 to +Compost and +Cover+Compost plots in early April 2025, with soil samples collected prior to compost application. All soil samples collected for this study are currently undergoing the proposed analyses. Preliminary data from the baseline sampling indicates that the randomized complete block design with twelve blocks has sufficiently mitigated inherent variability between treatment locations for the study, with few treatment-associated zonal differences detected for soil parameters such as electrical conductivity or permanganate oxidizable carbon. Furthermore, plots were sampled in both late winter/early spring and in the fall of 2024 prior to study establishment to determine background levels of soil-borne crop pathogens, including Verticillium wilt. Soil assays yielded no viable microsclerotia of Verticillium spp. across the experimental area during both sampling times. In the fall assay, small amounts of Alternaria leaf spot were detected in the plots, which is common in the region during the fall months. Objective 2: We proposed a greenhouse study using soil collected from each field treatment after two years of treatment application, in which severe drought would be applied to cotton plants. Apart from planning for project activities related to this objective, no activities have been conducted yet as we focus on establishing and maintaining the experimental field system. Objective 3: We proposed a greenhouse study using soil collected from each field treatment after two years of treatment application, in which cotton plants would be exposed to viable microsclerotia of Verticillium dahliae and subjected to Verticillium wilt. Apart from planning for project activities related to this objective, no activities have been conducted yet as we focus on establishing and maintaining the experimental field system.

Publications