Effects of planting Chinese medicinal materials under the moso bamboo forest on soil available medium and micro-nutrients

【Objective】To explore the effects of planting Chinese medicinal materials under the moso bamboo forest on soil available medium and micro-nutrients，and to provide scientific reference for soil nutrient resource management under bamboo forest and the promotion of forest-medicinal materials integrated management model in bamboo producing areas in southern China. 【Method】Study plots of three kinds of Chinese medicine were set up in a bamboo plantation in the source of the Lijiang River in Guilin，Guangxi. The study included four treatments with a completely randomized block design，namely the control （the bamboo forest without planting Chinese medicinal materials），planting Polygalagfallax fallax under the bamboo forest，planting Polygonatum cyrtonema under the bamboo forest，and planting Sarcandra glabra under the bamboo forest. In the second year after planting，soil samples were collected to determine the basic physical and chemical properties and the contents of available medium and micro-nutrients，and the correlations between soil properties and nutrients were analyzed，thus to clarify the changes of medium and micro-nutrients in soil of different Chinese medicinal materials planted under bamboo forest and the main influencing factors. 【Result】Planting Chinese medicinal materials under the bamboo forest decreased soil bulk density，total carbon and available phosphorus contents，and increased the contents of dissolved organic carbon and microbial biomass carbon，nitrogen and phosphorus. The effects of planting P. cyrtonema on the above indexes were relatively greater，except for microbial biomass nitrogen， the difference compared to control were significant（P<0.05， the same below）. The contents of soil exchangeable calcium and exchangeable magnesium were significantly decreased by planting P. cyrtonema and S. glabra，while the contents of soil available sulfur were significantly increased by planting P. fallax and S. glabra. Planting Chinese medicinal materials under the bamboo forest significantly increased soil available zinc content，and significantly decreased soil available molybdenum content. Planting P. cyrtonema and S. glabra significantly increased soil available manganese content，but planting three kinds of Chinese medicinal materials had no effect on soil available iron and copper contents （P>0.05， the same below）. Planting P. cyrtonema and S. glabra had greater effects on soil available micro-nutrient contents than planting P. fallax. Correlation analysis result showed that soil available medium nutrients，including calcium，magnesium and sulfur，were mainly affected by soil bulk density，available phosphorus， microbial biomass carbon and phosphorus，while soil available micronutrients， such as iron，manganese，copper，zinc and molybdenum，were not only affected by the above factors，but also related to soil pH and exchangeable calcium and magnesium. 【Conclusion】There is a great difference in the response of soil available medium and micro-nutrients to planting different Chinese medicinal materials under the bamboo forest. Planting P. cyrtonema under the bamboo forest has the greatest influence on soil nutrients，followed by planting P. fallax or S. glabra. In the practice of planting Chinese medicinal materials under the bamboo forest，it is necessary to properly supplement the medium and micro-nutrients，especially the supply of calcium and magnesium fertilizer，and adopt different fertilization strategies according to the types of Chinese medicinal materials planted.