Effect of nitrogen and sulfur fertilizes on growth and leaf oil content of lime (Citrus aurantifolia) and orange (Citrus sinensis)

Abstract

This study was conducted in the fruit orchard of College of Agricultural studies, Sudan University of Science and Technology at Shambat, in the period of May/2006 – August/2006, to investigate the effect of urea 46% N (source of nitrogen) and sulfur 80% S fertilizers on growth parameters and oil content of balady lime and common sinnari orange in two separate experiments. The two experiments were composed of the following treatments: 100gm urea/tree, 60gm sulfur/tree and 100gm urea + 60gm sulfur (N/S) and control (C). The experimental design used in both experiments was randomized complete block design replicated four times with one tree per plot. Data was recorded at the end of the study period for the following parameters: plant height, leaves number, branches number and oil content of fresh leaves. The results of the two experiments showed that the singular and combined effects of urea and sulfur on number of leaves in lime and orange were significant compared to control. However, combination of urea and sulfur (N/S) treatment ranked top, while urea treatment (N) ranked second with significant difference from sulfur treatment (S). The results also exhibited significant differences in plant height. The combination of urea and sulfur (N/S) resulted in the best increase in means of plant height. There were no significant differences between the single effects of urea (N) and sulfur (S) on either lime or orange. The results showed highly significant differences in means of branches number between treatments in the orange experiment. While the combination of urea and sulfur (N/S) clearly increased the number of III branches compared to urea (N) and sulfur (S) treatments. In lime, the singular urea effect on branching was not significantly different from either the combination or the single sulfur effects. However, the combination increased branching significantly compared to the singular sulfur treatment. In lime, all fertilizers treatments resulted in significant increase in leaf oil content compared to the control. However, there were no significant differences between the combination (N/S) and urea (N), also between urea and sulfur treatments. The statistical analysis revealed that both urea (N) and the combination (N/S) ranked top. Sulfur treatment was in the second rank with significant differences from the control in the leaf oil content of orange.