Abstract: We compared the yield and active ingredient content of Salvia miltiorrhiza Bge. for different soil moisture with field pipe irrigation method to investigate the impacts of irrigation on its yield and quality. Experimental results show that the contents of tanshinone ⅡA, tanshinone I, and cryptotanshinone are the highest when relative soil moisture is less than 30% (especially severe drought), but its yield is low. Its yield significantly increases after proper irrigation, the content of active ingredients in the requirements of pharmacopoeia. All the active ingredient contents are the lowest when water content of soil is too much. If its medical value and economic benefits are considered together, moderate irrigation is available when relative soil moisture is less than 30%. This can achieve the effect of no yield decrease and even yield increase. Our work can provide theoretical basis for soil water management before its harvest.

Key words: Salvia miltiorrhiza Bge., irrigation, relative soil moisture, yield, active ingredients