Increasing demand for productive vineyard soils is driving growers to attempt new agricultural practices. Many such methods use renewable, regionally available resources. Biochar is a highly porous soil amendment created by burning organic matter under low-oxygen conditions. By using renewable soil amendments such as biochar, the health and yield of vines can be improved. The aim of the research was to determine the efficacy of using biochar to promote grapevine development. One-year-old bare-root cuttings of Valvin Muscat (NY62.0122.01) grafted onto 1103P were grown in a glasshouse in substrates containing either: (1) 30 B: 30% biochar + 70% medium, (2) 70B: 70% biochar + 30% medium, (3) 100B: 100% biochar, (4) 30C: 30% compost + 70 % medium, (5) 70C: 70% compost + 30% medium, (6) 100C: 100% compost, (7) 15B15C: 15% biochar + 15% compost + 70% medium, (8) 35B35C: 35% biochar + 35% compost + 70% medium, (9) 50B50C: 50% biochar + 50% compost, or (10) 100% medium. The pH and EC of the substrates, optical estimate of leaf chlorophyll content, leaf gas exchange, true leaf number, lateral leaf number, shoots lengths, and lateral and true leaf area were measured and root and shoot dry weight was determined. Biochar induced high pH (>8) if present in the mixes at over 35%. Biochar and compost combined at from 15 to 35% biochar and 15 to 35% compost induced more chlorophyll than the control. Photosynthetic carbon assimilation, stomatal conductance, and intercellular CO₂ concentration did not differ among treatments; however, positive correlations were found between photosynthetic carbon assimilation and optical measurement of chlorophyll concentration. Mixes with 30B, 15B15C, and 35B35C increased leaf area, but total biomass was similar to the control. Preliminary findings indicate that biochar in combination with compost can be used to promote grapevine development.

Funding Support: Missouri Wine and Grape Board