The effects of sulfur-coated Urea and other nitrogen sources and rates on yield N uptake and nitrate content of Onion
2005
Golchin, A. | Esmaeili, M. | Lamaei, J. | Tookasi, M.
In order to study the effect of rate and source of nitrogen fertilizer on onion yield and No3-N content of onion bulb, a factorial experiment with 16 treatments and 3 replications was conducted in Zanjan Agricultural Research center for two years. The rates of nitrogen were 0, 100, 200 and 400 Kg/ha and nitrogen sources were sulfur coated urea, urea, Ammonium sulphate and Ammonium nitrate. Sulfur coated urea was applied to soil before planting but two-third of other nitrogen sources was used after planting in two splits application. The results of analysis of variance showed that the main effect of nitrogen sources of onion yield is not significant. The nitrogen concentration of onion bulb and NH4-N content of soil after harvest were not also affected by nitrogen sources. However, the main effects of nitrogen rates on all measured characteristics was significant. The highest yield of 59 ton/ha was obtain with the use of 200Kg nitrogen/ha which was not significantly different from the yield obtained from the use of 400Kg nitrogen /ha with respect to the results of this experiment split application of nitrogen fertilizers or use of slow release fertilizer can reduce nitrogen leaching and losses and decrease the cost of production. To reduce labor cost for split application of nitrogen, sulfur coated urea can be used to increase fertilizer use efficiency and protect the environment from pollution. Key Word: Onion, Yield, No3-N content, Onion bulb, Sulfur coated urea
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