Boron fertilization of root chicory (Cichorium intybus var. sativum) in a field experiment in Kwazulu-Natal, South Africa

Abstract

Root chicory (Cichorium intybus var. sativum) production is increasing in KwaZulu-Natal Province, South Africa, especially on coarse-textured soils, prone to boron (B) deficiency. Literature on the response of chicory to B application is scarce and largely anecdotal. A field experiment was conducted to determine this response and the movement of B in the upper 60 cm of a loamy sand. Eight rates of B (from 0 to 3.5 kg ha⁻¹) were either soil- or foliar-applied, with four replications. Soil samples were taken pretrial and after each of the two harvests at 15 cm depth intervals to 60 cm for fertility analysis. Hot water soluble B was also analyzed. Results are presented as means of the two harvest periods for yield, and leaf and soil analysis. Root analysis is reported for the second harvest only. Yield effects were not significant (p > 0.05) for both seasons over all B application rates. Application method (App), and the App × B interaction were also not significant. Root chicory was tolerant to 3.5 kg B ha⁻¹. Multiple rooting, especially in the control plots, was significant compared to plots that received B and root rot incidence was also significantly higher, probably due to B deficiency. Root quality was compromised at about 0.1 mg B kg⁻¹ in the topsoil. A highly significant movement of B occurred from the topsoil to 45–60 cm measured after the final harvest. The application rate, App, and time were all significant for the averaged data from the 0–15 to 45–60 cm depths.

Keywords:

• chicory (Cichorium intybus var. sativum)
• foliar boron application
• hot water soluble boron
• soil boron application

Acknowledgments

The authors are grateful to Jon Lawrence (consulting soil scientist, Howick) for the hwsB extraction measurements and to Cathy Stevens (Biometrical Services, Cedara, Pietermaritzburg) for statistical assistance.

Funding

This project was not funded.