毛竹林林下种植中药材对土壤有效态中、微量营养元素的影响

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

【目的】探究毛竹林林下种植中药材对土壤有效态中、微量营养元素的影响,为毛竹林林下种植土壤养分资源管理及我国南方竹产区林药复合经营模式的推广提供科学参考。【方法】以广西桂林漓江源区毛竹人工林林下种植的3种中药材样地为研究对象,采用完全随机区组设计,设4个处理,即未种植中药材的毛竹林对照、林下种植黄花倒水莲(Polygala fallax)、林下种植多花黄精(Polygonatum cyrtonema)、林下种植草珊瑚(Sarcandra glabra),在种植后的第2年测定土壤基本理化性质和中、微量营养元素有效态含量,分析其相关性,明确毛竹林林下种植不同中药材土壤中、微量营养元素的变化及其主要影响因素。【结果】毛竹林林下种植中药材降低了土壤容重、总碳和有效磷含量,增加了可溶性有机碳和微生物生物量碳、氮、磷含量,种植多花黄精对上述指标的影响相对较大,除微生物生物量氮外均与对照差异显著(P<0.05,下同);林下种植多花黄精和草珊瑚显著降低了土壤交换性钙和交换性镁含量,而种植黄花倒水莲和草珊瑚显著增加了土壤有效硫含量;林下种植中药材显著增加了土壤有效锌含量,显著降低了土壤有效钼含量,种植多花黄精和草珊瑚也显著增加了土壤有效锰含量,而种植3种中药材对土壤有效铁和有效铜含量无显著影响(P>0.05,下同),种植多花黄精和草珊瑚对土壤微量营养元素有效态含量的影响大于种植黄花倒水莲。相关分析结果表明,土壤中量营养元素钙、镁、硫有效态含量主要受土壤容重、有效磷及微生物生物量碳和磷影响,而微量营养元素铁、锰、铜、锌、钼有效态含量除受以上因素影响外,还与土壤pH及中量营养元素钙和镁有效态含量有关。【结论】土壤中、微量营养元素有效态含量对毛竹林林下种植不同中药材的响应存在较大差异,林下种植多花黄精对土壤养分的影响最大,种植黄花倒水莲和草珊瑚次之。在毛竹林林下种植中药材实践中需适当补充中、微量营养元素,尤其是钙镁肥的供应,且需根据种植中药材的种类采取不同施肥策略。

【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 Polygala 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.