MANAGING SUMMER SOIL MOISTURE THROUGH WINTER COVER CROPS IN NORTHWEST FLORIDA

Johnson, L.1; Carter, E.2
1EXT AGT II, AGRICULTURE, UF, CANTONMENT, FL, 32533-7792
2Regional Specialized Agent, UF/IFAS Northwest District, Marianna, FL, 35768

Abstract:

Unless a grower can afford irrigation, there are not a lot of options left to manage soil moisture under dryland production. A lot of benefits of cover cropping take years to become apparent, but improved soil moisture is not one of them. Keeping the ground mulched during periods of drought during summer production reduces the “evapo” part of the evapotranspiration equation, and results in increased soil moisture compared to non-covered ground. Soil moisture sensors have been deployed around northwest Florida for multiple years, where producers killed part of their cover crop so we could have side-by-side comparisons of soil moisture and subsequent crop yield with and without cover cropping. Objectives:  To demonstrate the efficacy of winter cover crops in maintaining soil moisture levels throughout the summer growing season in cotton and peanuts. Methods:  Rye, a winter cover crop, was established late Fall 2018 in a field that was planted in cotton in 2019.  A strip of land was left unplanted in the middle of the field and left fallow.  The rye cover was fertilized and maintained till the crop was rolled down and stripped tilled.  After establishment of the cotton crop, Sentek soil moisture probes were installed in two plots: in the rolled rye and fallow ground.  Soil moisture was monitored throughout the growing season.  Crop was harvested in late October. Results: Extension activities in the area have demonstrated improved soil moisture status and yield when a persistent cover crop remains on the soil surface during cotton and peanut production. These data are being used to advocate for statewide cost share for cover cropping in Florida, where proposals are currently being developed for $75/acre cost share for cover cropped land. Conclusions: Well-managed high residue cover crops can benefit growers that have no irrigation potential on sandy soils.  More work needs to be done with mixtures of cover crops and to help get more funding for growers using winter cover crops to offset soil moisture fluctuations.  

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