Effect of zeolite and nitrogen fertilizer application on canola yield and nitrate leaching loss from root environment

In order to study the effect of various amounts of nitrogen (N) and zeolite (clinoptilolite) on the yield of winter canola (Brassica napuse L.) and nitrogen leaching, in a light soil, a field experiment was conducted in the research farm of Tarbiat Modares University, on 2012-2013. The experiment was conducted as factorial trial in a randomized complete block design with three replications. The experimental factors contain zeolite (0, 3, 6 and 9 t.ha-1) and nitrogen (90, 180 and 270 kg ha-1 in urea form). The result showed that the highest grain yield (2452 kg/ha) obtained from N270Z9 treatment and N90Z0 produce the lowest grain yield (1569 kg/ha). Moreover using 270 kg N/ha without zeolite (N270Z0) has the highest amount of N leaching (142 kg/ha). Zeolite application has significant effect on the reduction of N leaching in each N level. It could be concluded that a combined application of zeolite (9 t.ha-1) and chemical N (270 kg ha-1) for canola production is recommended to ensure an acceptable yield and for environmental protection from excess N leaching.