Effects of Biochar on Germination and Growth of Bok Choy at Varying Application Rates

Abstract

Biochar is increasingly recognized as a climate-smart soil amendment due to its ability to improve soil fertility, enhance water and nutrient retention, and support sustainable crop production. Bok choy (Brassica rapa) is a fast-growing, nutrient-dense leafy vegetable commonly used as an indicator crop for evaluating early growth responses to soil amendments. This study evaluated the effects of three biochar types (coconut, soursop, and teak) applied at 1%, 3%, and 5% (w/w) on the germination and early growth of bok choy, using commercial peat moss as a control. Soursop biochar at 3% significantly improved germination rates, while teak biochar at 1% and 3% produced shoot and leaf growth comparable to peat moss. Higher biochar concentrations (5%), particularly soursop and teak, tended to suppress growth. These results indicate that biochar can enhance bok choy germination and early growth when applied at moderate rates, highlighting the importance of appropriate feedstock selection and application levels for sustainable vegetable production.