套种牧草果园土壤浸提液对萝卜种子发芽和幼苗生长的化感效应

Allelopathy of Soil Extracts from Orchards Intercropping with Mulch Forage Plants

采用生物检测方法,探讨果园套种牧草,其土壤浸提液对萝卜种子发芽和幼苗生长的化感效应。结果表明:果园分别全园套种宽叶雀稗、百喜草、平托花生、圆叶决明4种牧草,其土壤浸提液均对受体萝卜种子萌发有抑制作用,而对受体萝卜根的生长有不同程度的促进作用;全园套种百喜草处理对受体萝卜根干重起抑制作用;全园套种百喜草、平托花生、圆叶决明处理对受体萝卜的幼苗生长和干重均起显著的促进作用,而全园套种宽叶雀稗处理则反之;全园套种百喜草、平托花生、圆叶决明3种牧草处理对受体萝卜的化感综合效应指数均大于套种宽叶雀稗处理,且前者起促进作用,而后者起抑制作用;用不同牧草区土壤浸提液进行砂培法培养的萝卜幼苗根系活力受到极显著抑制,对照处理的萝卜根系活力最强,为156.3μg·g-1·h-1,而宽叶雀稗处理区的根系活力最小,为64.3μg·g-1·h-1。

The soil was collected from orchards intercropping with different common cover forage plants and extracted.Radish was cultured on the soil extracts to determine the seed germination and seedling growth of radish through the bioassay method.The results indicated that the soil extracts of 4 forage plants Paspalum notatum Flugge,Arachis pintoi,Chamaecrista rotundifolia and Paspalum wettsteinii significantly inhibited seed germination of radish but stimulated to some extent the growth of radish root.The radish dry root weight was inhibited by P.notatum Flugge.The growth and dry weight of the radish seedling were all stimulated obviously on the soil extracts of P.notatum Flugge,A.pintoi and C.rotundifolia,but reduced on the soil extracts of the other species.The soil extracts of these 3 species of cover plants had a higher overall allelopathic effect in radish than that of the Paspalum Wettsteinii and were stimulatory in allelopathy,and the latter was inhibitory.Radish seedlings grown on the sandy culture with the soil extracts of all species of cover plants were highly significantly inhibited in their root activities,whereas the radish seedlings cultured without the soil extracts or the control had the highest root activities,156.3 μg·g-1·h-1,as against those cultured on the soil extract of P.wettsteinii that had the lowest root activities（64.3 μg·g-1·h-1）.