种植年限对唐古特大黄根部土壤理化性质及纤毛虫群落的影响

Effects of Planting Years of Rheum tanguticum on Physicochemical Properties of Rhizosphere Soil and Ciliate Community

【目的】探明土壤微生态对唐古特大黄产量和品质形成的响应机制,为其科学种植与推动中草药种植产业可持续发展提供理论依据。【方法】采用双因素试验设计结合培养计数法和3级10倍稀释培养法,探究唐古特大黄生长过程中对根部土壤理化性质和土壤纤毛虫数量的影响效应,以及生长1年、2年、3年和4年(A_(1)、A_(2)、A_(3)和A_(4))的唐古特大黄根部土壤不同土层(1~20 cm、21~40 cm和41~60 cm)理化性质、养分含量和纤毛虫群落结构的变化特征。【结果】随着唐古特大黄生长年份的增加,土壤含水量呈逐渐下降趋势,A_(1)为20.40%~22.29%,A_(4)为14.39%~16.25%;全氮(1.42~3.14 g/kg)、碱解氮(37.91~88.45 mg/kg)、全磷(0.82~0.90 g/kg)和有机质(31.24~66.47 g/kg)含量的变化趋势与含水量一致,pH(7.55~8.22)、全钾(17.22~18.21 g/kg)和速效钾(81.33~175.67 mg/kg)含量则相反,即A_(4)最高。培养计数法获得的纤毛虫数量为756.67~6 473.33 ind./g,大于3级10倍稀释法(48.67~3 020.00 ind./g)。随着唐古特大黄生长年份增加,纤毛虫数量呈先减后增趋势,依次为A_(1)>A_(4)>A_(2)>A_(3),A_(3)为756.67~1 036.67 ind./g, A_(1)为1 340.00~6 473.33 ind./g;A_(1)与A_(4)间、A_(2)与A_(3)间无显著差异,而A_(1)和A_(4)与A_(2)、A_(3)间差异显著;同一年份中,随着土壤深度增加,A_(1)和A_(4)中纤毛虫数量均呈显著减少趋势,A_(2)中第1土层和第2土层间无显著差异,而与第3土层间差异极显著,A_(3)中第1土层中纤毛虫数量显著高于其他2个土层;纤毛虫数量与土壤含水量、有机质含量、全钾和速效钾含量均呈极显著正相关,相关性系数分别为0.712、0.651、0.575和0.471,与全氮含量呈显著正相关(0.219),而与土壤pH呈极显著负相关(-0.556)。【结论】唐古特大黄生长前3年对土壤纤毛虫有较强的抑制作用,随着土壤结构的稳定性和纤毛虫的耐受性增强,第4年时,纤毛虫数量又逐步恢复。唐古特大黄对根部土壤环境和土壤微型生物数量影响明显,及时补充水分和有机肥,不仅能提高唐古特大黄的产量,还有助于维持土壤微生态平衡。

【Objective】The response mechanism of soil micro-ecology to yield and quality of Rheum tanguticum is explored to provide the theoretical basis for scientifically planting R.tanguticum and sustainable development of Chinese herbal medicine cultivation industry.【Method】The effects of four different R.tanguticum growth years〔one year(A_(1)),two years(A_(2)),three years(A_(3))and four years(A_(4))〕on physicochemical properties,nutrient content and ciliate community structure of R.tanguticum rhizosphere soils with three different soil layers(1-20 cm,21-40 cm and 41-60 cm)are analysed by a double-factor experimental design combined with the culture counting method and 10-fold with three stages dilution method.【Result】The soil water content of A_(1) treatment is 20.40%-22.29%while that of A_(4) treatment is 14.39%-16.25%.The soil water content gradually decreases with increase of R.tanguticum growth year.The soil TN,AN,TP and OM content of A_(1),A_(2),A_(3) and A_(4) treatments is 1.42-3.14 g/kg,37.91-88.45 mg/kg,0.82-0.90 g/kg and 31.24-66.47 g/kg respectively and the change trend of soil TN,AN,TP and OM content is consistent with the water content.The soil pH,TK and AK content of A_(1),A_(2),A_(3) and A_(4) treatments is 7.55-8.22,17.22-18.21 g/kg and 81.33-175.67 mg/kg separately and the soil pH,TK and AK content of A_(4) is the highest.The ciliate quantity obtained by the culture counting method and 10-fold with three stages dilution me thod is 756.67-6473.33 ind./g and 48.67-3020.00 ind./g.The ciliate quantity shows a first decrease and then increase trend with increase of R.tanguticum growth year and is A_(1)(1340.00-6473.33 ind./g)>A_(4)>A_(2)>A_(3)(756.67-1036.67 ind./g).There is no significant difference in ciliate quantity between A_(1) and A_(4) and between A_(2) and A_(3) but the ciliate quantity of A_(1) and A_(4) is higher than A_(2) and A_(3) significantly.The ciliate quantity of A_(1) and A_(4) significantly decreases with increase of soil depth in the same year.There is no significant difference in ciliate quantity of A_(2) between the first soil layer(1-20 cm)and second soil layer(21-40 cm)and the ciliate quantity at first soil layer and second soil layer is higher than the third soil layer(41-60 cm)very significantly.The ciliate quantity of A_(3) at the first soil layer is significantly higher than at the second and third soil layer.The ciliate quantity is positively related to the soil moisture,organic matter,total potassium and available potassium content very significantly and the correlation coefficient is 0.712,0.651,0.575 and 0.471 respectively.The ciliate quantity is positively related to soil total nitrogen content(0.219)significantly and negatively related to soil pH(-0.556)very significantly.【Conclusion】The growth of R.tanguticum has the strong inhibition effect on soil ciliate quantity within first three years but in the fourth year the ciliate quantity recover gradually with improvement of soil structure stability and ciliate’s tolerance.The management measures of timely irrigation and applying organic fertilizer during growth of R.tanguticum not only increase R.tanguticum yield but also maintain soil micro-ecological balance because the growth of R.tanguticum has the obvious effects on environment and microorganism of the rhizosphere soil.