Allelopathic Effect of "Eucalyptus camaldulensis" and "Eucalyptus grandis" on "Phaseolus vulgaris" and "Zea mays"

Research Paper (postgraduate) from the year 2012 in the subject Agrarian Studies, grade: 1, University of Hawassa, course: Journal of Agroforestry Research, language: English, abstract: Allelopathic effects of Eucalyptus are widely reported and are considered the major factor limiting the cultivation of agricultural crops intercropped with Eucalyptus stands. However, reports of the allelopathic effects of eucalyptus are mostly based on laboratory bioassay, not on field trials. The objective of the present study was to determine the effects of different leaf powder proportions of Eucalyptus species on agricultural crops as well as change in soil reaction. This research was undertaken in a pot experiment grown in the nursery of Hawassa College of Agriculture campus laid in a completely randomized design containing leaf powder prepared by drying and grinding fresh collected leaves of Eucalyptus camaldulensis and Eucalyptus grandis and containing two agricultural crops (haricot bean and maize). Results suggested that leaf powder of each tree species induced significant inhibitory effect on emergence and growth of each crops compared to the control treatments. The study revealed that application of low-dose leaf powder of either tree species had low effect on all measured parameters of both crops. Eucalyptus grandis has more inhibitory effect on both crops than Eucalyptus camaldulensis, and the negative effect of allelochemicals is more pronounced on haricot bean than maize in both tree species. Thus, it is recommended that maize and haricot bean should not be planted very close or not to Eucalyptus trees. In addition, crops seed rate should be increased to get maximum emergence.