Optimization of field cultivation of Baptisia tinctoria (L.) R. Br. by fertilizer, mulch and mycorrhiza treatments

Baptisiae tinctoriae radix (L.) R. Br. is used as phytomedicinal compound in immunostimulating Esberitox^®. Since 1992 field cultivation has lead to guaranteed quality of the drug regarding purity, hygiene and stability of compounds. To increase yield, different trials concerning mulching, fertilization and application of mycorrhiza were carried out to enhance survival of plants as well as fresh weight of roots. Mulching with tea and oak leaves is known to increase survival of plants due to their content of tannins. Mineral fertilization should lead to higher yield of fresh weight and was carried out in two different concentrations. Application of mycorrhiza to establish a beneficial symbiosis is known to cause a better adaptation of plants to stresses like nutrient deficiency, drought and pests and diseases. The trial was carried out in three successive plantations for the 3-year cycle. All treatments were carried out each year at the beginning of the vegetation period. Fresh weight and survival rates were investigated every year at the end of the season and yield calculated by multiplication of fresh weight and survival rates. Results show that application of tea and oak leaves show positive effects but with a decrease over the years. Fertilization leads to negative yields especially when doubled. Only mycorrhiza application leads to a stable increase over the 3-year cultivation. We conclude that all applications except mycorrhiza show a decreasing effect over the years when applied every year. Further trials will be carried out to investigate whether an increase could be achieved if a treatment would be applied only in the first year or if a combination of treatments would lead to better results.