Effects of Tillage, Irrigation, and Fertility Management on Nitrate Leaching and Rapeseed (Brassica napus L.) ‎Quantitative and Qualitative Traits in a Sandy Soil

This study investigates the effects of different tillage systems (no-tillage, minimum and conventional), fertilizers (no fertilizer, vermicompost (V), urea (U) and combined urea and vermicompost (VU) and irrigation regimes on various quantitative and qualitative traits of rapeseed, as well as soil nitrate leaching (NL). Field trials have been conducted between 2017 and 2019 in the Research Institute of Forests and Rangelands with no significant difference observed for seed and oil yield between the minimum and conventional till systems. However, the no-till system vs. minimum and conventional till decrease these traits by 22% and 21.5%. The combined application of vermicompost and urea under optimal irrigation conditions boosts oil yield by 24%, compared to the control) of rapeseed. Furthermore, across all tillage types, the highest NL is observed where urea was applied. When compared with urea, V and UV treatments decrease the NL by 67% and 50% in no-till plots, 50% and 36% in minimum till plots, and 49% and 34% in conventional till plots, respectively. Deficit irrigation also reduces linoleic acid by 7.6%. In addition, the highest levels of oleic acid (63.9%) and linoleic acid (20.7%) are observed under residual tillage system with combined fertilizer application and the residual tillage system with vermicompost application, respectively The findings indicate that minimum till in combination with VU treatments supports reduced NL over conventional till and urea fertilization practices, while improving rapeseed quantitative and qualitative traits.