Yield of chamomile capitula and essential oil in competition with weeds in different spacings and sowing dates

Abstract

Chamomile is an important socioeconomic option for family farming. The crop involves manual management practices and restriction to the use of herbicides, and the knowledge regarding the interference of weeds on the yield of chamomile capitula and quality of the essential oil is still limited. In this perspective, this study aimed to assess the effect of sowing dates, plant spacings and hoeing management on the yield of capitula, content, and yield of essential oil in the environmental conditions of a region with Humid Subtropical climate without defined seasons. The experiments were conducted on four dates (18/03, 28/04, 31/06, and 30/08/2017), with plants spaced by 0.05, 0.10, 0.15, 0.20, 0.30, and 0.40 m within rows. On March 28 and May 14, 2018, the plant spacings between plants in the row were 0.05, 0.10, 0.15, and 0.20 m, including two hoeing managements (with and without weeds). The variables analyzed in the two years were the yield of dry capitula, the dry mass of chamomile plants and weeds (g m^-²), and the content and yield of essential oil in 2018. The sowing dates influenced the yield of floral capitula, the content, and yield of essential oil as a function of the duration of the cycle and occurrence of weeds. The autumn sowings resulted in a higher yield of floral capitula in both years. A linear reduction trend was also verified in the yield of floral capitula with the increase in plant spacing within the row from 0.05 to 0.20 m in the two crop years.