连作对浙贝母生长及土壤性质的影响

采用大田试验,分别在浙贝母种植的头茬、二茬及四茬田里进行植物及土壤取样,分析土壤理化性质、微生物区系、关键酶等指标.结果表明:随着连作年数的增加,浙贝母连作土壤中有效氮、有效磷及有效钾的含量显著降低,但有机质含量逐年增加,土壤呈酸化趋势；根区土壤中细菌、放线菌及微生物总量呈线性减少,但真菌数量呈线性增长；重茬根区土壤的脲酶、过氧化氢酶活性显著低于头茬土,但多酚氧化酶及蔗糖酶活性出现增加现象.在连作障碍下,浙贝母叶内膜脂过氧化程度加剧,SOD、POD等抗氧化酶活性降低,地上、地下部生物量以及根长、根表面积均显著降低.说明浙贝母连作障碍是由于土壤营养元素缺乏、根际酸化、微生物区系改变、氧化胁迫加剧等多原因造成的.

Impacts of continuous cropping on Fritillaria thunbergii Miq.growth and rhizosphere soil properties

A field experiment was conducted to study the growth of Fritillaria thunbergii Miq.and the physicochemical properties,microbial flora,and enzyme activities of rhizosphere soil under 1-,2-,and 4-year cropping,aimed to reveal the possible mechanisms of continuous cropping obstacle of F.thunbergii.With the increasing duration of continuous cropping,the contents of soil available N,P,and K decreased significantly while that of soil organic matter increased,soil pH presented a decreasing trend,the total amount o...