Effect of N Sources and Effective Micro-organisms on Seedling Vegetative Growth of Selected Grapefruit (Citrus Paradisi Macf) Cultivars

Abstract

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 some grapefruit cultivars. Two experiments were carried out, the first one was a field experiment and the second one was a pot experiment. Treatments consisted of three grapefruit cultivars; Marsh, Red Blush and Shamber. Fertilizer treatments were urea only, chicken manure only, urea with chicken manure, urea with EM, chicken manure with EM, urea with chicken manure and EM and a 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 allowed 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). The results showed that Marsh cultivar gave the highest vegetative growth compared to the other two cultivars. The results showed that the combination of urea, chicken manure and effective microorganisms significantly gave the highest values, followed by chicken manure with effective microorganisms, urea with chicken manure, urea with effective microorganisms, urea alone, chicken manure alone and the least values of growth parameters were recorded for the control in both experiments. It is recommended to grow Marsh grapefruit cultivar and fertilize it with a combination of urea, chicken manure and effective micro-organisms.