Effects of nitrogen source and effective micro-organisms on vegetative growth of shrubs of selected grapefruit (Citrus paradisi Macf) cultivars

Mohamed E. Elkashif, Suhair A. Suliman, Osman M. Elamin


Grapefruit (Citrus Paradisi Macf.) is one of the most important citrus fruits in the Sudan. It can be successfully grown throughout the country where there are suitable soils and sufficient water to sustain tree growth. The objectives of this study were to find out the effects of different nitrogen sources, effective microorganisms (EM) and their combinations on the vegetative growth of shrubs of selected grapefruit cultivars. A field experiment was carried out at Umbarona, Wad Medani, Gezira State, Sudan, latitude 14.38 N, longitude 33.48 E and altitude 409 masl, in June 2012. Treatments consisted of three grapefruit cultivars: Marsh Seedless, Red Blush and Shamber. Fertilizer treatments were urea (100%), chicken manure (100%), urea with chicken manure (50% each), urea with EM, chicken manure with EM, urea (50%)+ chicken manure (50%)+ EM and unfertilized control. All fertilizer treatments were applied at the rate of 43 kg N/ha. Treatments were arranged in a split- plot design with two replicates. Grapefruit cultivars were allotted to the main plots and fertilizer treatments to the sub-plots. Data were collected on plant height (cm), stem diameter (cm), number of new branches, length of new branches (cm) and diameter of new branches (cm). Results showed that Marsh Seedless cultivar had the most vigorous vegetative growth compared to the other two cultivars. The results showed that the combination of urea, chicken manure and EM significantly gave the highest vegetative growth values, followed by chicken manure with EM, urea with chicken manure, urea with EM, urea alone, chicken manure alone and the least values of growth parameters were recorded for the unfertilized control. It is recommended to grow Marsh Seedless grapefruit cultivar and fertilize it with a combination of urea, chicken manure and EM.

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