Radish cover crop growth and compaction alleviation: effects of cultivar and planting date

Authors: COFER, TREVOR - AUBURN UNIVERSITY; GAMBLE, AUDREY - AUBURN UNIVERSITY; GUERTAL, ELIZABETH - AUBURN UNIVERSITY; Balkcom, Kipling

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 9/3/2019
Publication Date: 11/11/2019
Citation: Cofer, T., Gamble, A.V., Guertal, E.A., Balkcom, K.S. 2019. Radish cover crop growth and compaction alleviation: effects of cultivar and planting date[abstract]. ASA-CSSA-SSSA Annual Meeting. CD ROM.

Interpretive Summary:

Technical Abstract: Soil compaction in the form of hardpans often restricts cash crop root growth in the Southeastern U.S., reducing plant vigor and yield potential for crops with deep taproots such as cotton. Planting forage radish (Raphanus sativus) as a cover crop has been introduced as a method to alleviate hardpans, preserve soil structure by reducing the need for deep tillage, and aid in subsoil nutrient cycling. Research is needed to assess the effectiveness of forage radish to alleviate compaction in Coastal Plain soils and provide basic information on radish management to determine appropriate planting dates and cultivars for the Southeast. Five radish cultivars (i.e., ‘Smart’, ‘Sodbuster’, ‘Nitro’, ‘Tillage’, and ‘CCS779’) were planted on three planting dates (i.e., mid-September, mid-October, and mid-November) at two locations in the Coastal Plain region of Alabama to test the effect of cultivar and planting date on radish growth and soil compaction in strip-till cotton. Plant canopy width and foliage, root, and total dry matter were measured at five sampling times during the growing season. Root diameter and root length aboveground, belowground, and in total were also measured. Plots were evaluated for soil compaction using a tractor-mounted penetrometer after cover crop termination. No differences were observed between cultivars for most growth parameters, however, planting dates were often significant—earlier planting dates consistently led to increased canopy width, dry matter production, and root growth. Radish growth was markedly different between the 2017-18 and 2018-19 growing seasons, suggesting that the date of planting and accumulated growing degree days are much more important than cultivar selection for dry matter production and root growth. Penetrometer data revealed trends that radish cover crops reduced penetration resistance near the subsequent cotton row, however, no significant differences were found between cultivar treatments or planting dates.