Journal of Applied Horticulture, 2012, volume 14, issue 1, pages 77-80.
Abstract: An experiment was conducted to study the allelopathic potential of old orchard soils on the seedling growth of rough lemon. Soils from the root zone spheres of eight orchards of mango, aonla, peach, pomegranate, citrus, pear, ber, guava and virgin soil as a control was used for raising the seedlings. The rough lemon Jatti khatti seedlings of one and a half year old raised in aonla, ber and peach orchard soil as growing media showed the reduction in shoot length (40-50%), leaf number (46-63%), leaf area/ plant (62-69%) and shoot dry weight (79-83%). The root length was most inhibited by ber, aonla and peach orchard soils. The percent reduction in root dry weight (11.23- 34.48%) of the seedling was not in equal proportion to reduction in root volume (42.55- 55.86%). Root dry weight density varied between 0.55-0.96 g mL-1 and root: shoot ratio between 1.42-1.82. Whereas, in citrus, mango, pomegranate, ber and guava orchard soils, the percent reduction in root dry weight was in equal proportion to root volume and root dry weight density varied between 0.41-0.49 g mL-1 and root: shoot ratio between 0.44-0.72. The shoot and root growth of the seedlings was at par when raised in citrus and pomegranate orchard soil as growing media. Leaf N and P contents increased, whereas, Ca and Mg decreased in all the orchard soils except citrus and pomegranate orchard soils as growing media. Leaf Fe, Cu and Mn contents in all the orchard soils as growing media were in toxic range except citrus and pomegranate orchard soils. Overall, the orchard soils of deciduous fruit plants showed more allelopathic effect than the soils growing evergreen fruit plants in citrus cultivation.