民勤黑果枸杞形态学特征与土壤因子的关系

通过对民勤绿洲外围4种不同立地类型黑果枸杞群落物种组成、生长特征、土壤因子等的调查,分析不同立地类型土壤因子对黑果枸杞生长的影响。结果表明:①不同立地类型黑果枸杞群落物种结构简单,共出现12科24属28种,存在多个单属单科单种现象,多为适应干旱盐碱化的藜科、蒺藜科植物,无乔木和高大灌木,黑果枸杞在不同立地类型中优势地位明显。②黑果枸杞群落丰富度指数砾石地高于盐碱地、覆沙地及固定或半固定沙丘地(P<0.05);多样性指数砾石地高于盐碱地,盐碱地高于覆沙地及固定或半固定沙丘地(P<0.05)。③不同立地类型黑果枸杞密度表现为:盐碱地>覆沙地>固定或半固定沙丘地>砾石地。株高表现为:固定或半固定沙丘地>盐碱地>覆沙地>砾石地。冠幅表现为:固定或半固定沙丘地>盐碱地>砾石地>覆沙地。④土壤速效钾、有效磷、全磷及有机质含量均为盐碱地显著高于其他3个立地类型(P<0.05),全钾、全氮含量在4种不同立地类型之间差异性不显著(P>0.05)。不同土层中土壤因子变化规律不同。⑤土壤水分随土层深度的增加变化趋势不同,砾石地和固定或半固定沙丘地中土壤含水率随土层深度的增加而增加,覆沙地随土层深度的增加呈现波动变化,盐碱地随土层深度的增加变化不大。⑥黑果枸杞的生长状况和形态学特征株高、冠幅等受土壤水分、土壤氮、磷、钾及有机质等土壤因子的影响和制约,且10~20 cm土层深度土壤因子影响最为密切。

Relationship between morphological characteristics of Lycium ruthenicum and soil factors in Minqin,Gansu,Northwest China

Species composition,growth characteristics,and soil factors of Lycium ruthenicum communities at four different sites in Minqin oasis were investigated to explore the effects of soil factors on L.ruthenicum morphology.The results were as follows.(1) There were 28 species belonging to 24 genera of 12 families across the four sites,with many single representative species and genera.Most plants belonging to Chenopodiaceae and Zygophyllaceae were adapted to arid-salinized soils;there were no trees and tall shrubs.(2) Species richness was significantly higher in gravel land than in salinized desert,sandy land,and fixed or semi-fixed dunes (P<0.05);species diversity in salinized desert was significantly lower than that in gravel land but higher than that in sandy land and fixed or semifixed dunes (P<0.05).(3) Growth characteristics of L.ruthenicum showed the following trends across the four sites: density-salinized desert > sandy land > fixed or semi-fixed dunes > gravel land;plant height-fixed or semifixed dunes > salinized desert > sandy land > gravel land;and crown width-fixed or semi-fixed dunes > salinized desert > gravel land > sandy land.(4) Available potassium and phosphorus,total phosphorus,and organic matter contents were significantly higher in salinized desert than in the other types (P<0.05).Available potassium content was significantly higher in sandy and gravel lands than in fixed or semi-fixed dunes (P<0.05).Available phosphorus content was significantly higher in gravel land than in sandy land and fixed or semi-fixed dunes (P<0.05).Total potassium and nitrogen contents did not significantly differ across the four sites (P>0.05).Moreover,different soil factors varied across different soil layers.(5) Changes in soil moisture content with soil depth differed across sites,exhibiting an increase with increasing soil depth in gravel land and fixed or semi-fixed dunes,a fluctuating trend in sandy land,and little difference across soil depths in salinized desert.(6) Plant height and crown width of L.ruthenicum were affected by various soil factors such as soil moisture and soil nitrogen,phosphorus,potassium,and organic matter contents,particularly at a depth of 10-20 cm.