不同生长期太子参根际土壤的理化性质及微生物数量

摘要

The physicochemical property,enzyme activity and microbial quantity of rhizosphere soil of R.pseudostell at different growth stages were determined to provide the scientific basis for high-yield cultivation of R.pseudostell.Two peaks of soil pH are in mid-April and early-June respectively.There is no significant difference in soil moisture content.Maximum organic matter content is at mid-late flowering stage (early-May).Minimum available nitrogen content is at late flowering stage (mid-May)and maximum available nitrogen content is at tuber maturity stage (mid-July).Rapid available P content shows a first increase and then decrease trend.Maximum rapid available K content is 97.82 mg/kg at early flowering stage.The activities of catalase and acid phosphatase both dropped after over-ground part withering.The urease activity fluctuates frequently. Fungi quantity exists 3 wave crests and 2 wave valleys but actinomycetes and bacteria quantity presents 2 wave crests and 2 wave valleys.The ratios between three microbial species fluctuate greatly at tuber maturity stage.Maximum yield increase speed is at mid-late flowering stage. In conclusion,many indexes present several peaks at flourish growth stage of R. pseudostell and part indexes appear the fast increase phenomenon at harvesting stage.The active time for soil physicochemical property and tuber yield is at mid-late flowering stage but the active time for microbial quantity is at tuber maturity stage.Because R.pseudostell at different growth stages can influence physicochemical property and microbial quantity of hizosphere soil, the micro-ecological environment around hizosphere soil of R.pseudostell should be improved to effectively inhibit occurrence of root rot.%为给太子参高产栽培提供科学依据，测定了太子参不同生育时期根际土壤理化性质、酶活性和微生物数量。结果表明：土壤 pH 在4月中旬（6．05）和6月初（6．18）分别出现峰值；水分变化无显著差异；有机质含量开花中后期（5月初）含量最高；碱解氮含量在开花后期（5月中旬）含量最低，块根成熟后（7月中旬）含量最高；速效磷大致呈先增加后减少的趋势；速效钾开花初期含量高于出苗期，且是全生育期的最高值（97．82 mg/kg ）；过氧化氢酶和酸性磷酸酶活性均在地上部分逐渐凋零后降低；脲酶活性波动较大；出苗后，太子参根际土壤真菌数量出现了3次波峰，2次波谷；放线菌和细菌也分别有2次波峰和2次波谷，从三大微生物菌类比值来看，在块根成熟期的变化波动较大；产量增加速度最快的也是在开花中后期。结论：多个指标均在太子参茂盛生长期出现多个峰值，且部分指标在采收时出现徒增的现象；开花中后期是产量和根际土壤理化性质最后活跃的时期，而微生物最活跃的时期是在块根成熟期；太子参不同生长期会影响其根际土壤的理化性质及微生物数量，应加强对太子参根际微生物菌根的研究，以有效遏制根腐病的发生，改善太子参土壤根际微生态环境。