Canola yield under different irrigation frequencies and nitrogen levels in the Brazilian Cerrado

Produtividade de canola sob diferentes frequências de irrigação e doses de nitrogênio na região do Cerrado Brasileiro

ABSTRACT

In the Brazilian Cerrado, canola is grown in the off-season. During this period, rainfall is insufficient to ensure the maximum crop yield, and irrigation is needed. Canola has a high demand for nitrogen; thus, the application of this nutrient is essential for obtaining a good crop yield. Therefore, a study was conducted at the Federal University of Grande Dourados in 2012 and 2013 using a randomized block split-plot design with four repetition treatments in the plot that consisted of three irrigation frequencies (no irrigation, weekly irrigation and irrigation three times per week). Subplots received different doses of nitrogen: 0, 30, 60, 90 and 120 kg ha^{- 1} in 2012 and 0, 60, 120, 180 and 240 kg ha^-1 in 2013. In both periods, the irrigation frequencies significantly affected plant height, dry weight, grain yield, thousand grain weight and oil content. The nitrogen levels significantly affected dry weight, thousand grain weight and oil content in 2012, as well as plant height, number of pods, dry weight, grain yield and oil yield in 2013. The highest yields were obtained when irrigation was performed three times per week, corresponding to 3,001.84 kg ha^-1 in 2012 and 2,516.7 kg ha^-1 in 2013.

Index terms:
Brassica napus L.; oil seeds; tensiometry