Effects of source and rate of N and foliar micronutrients on yield and fruit quality of “Shendi” navel orange in Jebel Marra

Yousif Ahmed Sharafeldin, Osman Mohammed Elamin, Mohamed Elhaj Elkashif


Experiments were conducted during 2003/04 and 2004/05 seasons in Jebel Marra Project orchard at Nyertete to study the effects of source and rate of N fertilizers, alone or in combination with foliar micronutrients fertilizer on leaf mineral nutrient content, yield and fruit quality of Shendi navel orange. The experimental design was a randomized complete block design with three replications and two trees plot-1. Nitrogen from urea or ammonium sulphate nitrate ((NH4)3SO4NO3 was applied at the rates of 0, 0.3 and 0.6 kg N tree-1 in a single dose. Micronutrients as foliar fertilizer “Bashaer” were applied at 100 ml tree-1, split in two equal doses in combination with N fertilizers. Urea at 0.6 kg N tree-1 and both rates of (NH4)3SO4NO3 significantly raised leaf N content up to the optimum level (2.6), while the control treatment was in the deficiency zone (2.2). Foliar application of “Bashaer” significantly increased leaf Mn and Zn to the optimum levels but Fe remained in the low range. Nitrogen fertilizers alone or in combination with micronutrients as foliar fertilizer resulted in significant increases in "Shendi" navel orange yield. The highest yield was obtained with (NH4)3SO4NO3 in combination with foliar application of “Bashaer”. Nitrogen fertilizers significantly reduced fruit weight but increased total soluble solids (TSS).

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