Influence of Harvest Dynamics and Cut Height on Yield Components of Sage (Salvia officinalis L.)

Abstract

ABSTRACT Sage plant herbage was harvested twice at two cutting heights in various stages of development in the course of the growing season, the first harvest on nine dates at one- or two-week intervals in the spring and the second on a single date in the summer. In the spring harvest, the highest yield of fresh herbage (1159 g/m2) was achieved with the low cut, 10 to 15 cm above the soil, at the mature seed stage. In the summer harvest the yields were not affected by the date of the preceding spring harvest, but significantly higher yields were obtained from low-cut (567 g/m2) as compared with high-cut plants (182 g/m2). The essential oil yield paralleled the green herbage yield (total of both harvests: low cut 5.8 to 10.5 ml/m2, high cut 2.6 to 4.8 ml/m2). Among the plant parts, the highest essential oil content was in the primordia (1.05%), followed by leaves (0.7%), inflorescences (0.6%), and stems (0.1%). A total of 25 copies essential oil components were isolated, the most abundant being α- and β-thujone, 1,8-cineole, and viridiflorol. Contents of these constituents depended more on the plant part than on the developmental stage. The optimum time for the first harvest is the period from milk maturity to the mature seed stage and for the second 70 to 100 days later, both by cutting at 10 to 15 cm above the soil.