Seed, Oil, and Protein Yields of Canola under Combinations of Irrigation and Nitrogen Application

Abstract

Canola (Brassica napus L.), an important oilseed crop in Iran, is intensively managed with high inputs of N and irrigation water. Understanding N and water use characteristics of canola will help improve N and water use effi ciency (WUE) and reduce production costs. Here, the eff ects of irrigation levels (IL 1 , 750; IL 2 , 450; and IL 3 , 300 mm water ha -1 ) and N rates (NR 1 , 0; NR 2 , 40; NR 3 , 80; NR 4 , 120; and NR 5 , 160 kg N ha -1 ) on canola production are evaluated during 2006 and 2007 growing seasons. Data showed that irrigation levels and N rates and their interaction had signifi cant eff ects on WUE for seed, oil, and protein as well as seed, oil, and protein yields/ha. Th e maximum values of seed, oil, and protein yields ha -1 , WUE for these traits and seed weight plant -1 were achieved at IL 2 × NR 4 treatment. Th e highest values of seed N concentration and seed N uptake were produced at IL 2 treatment. Among N rates, maximum averages of seed and straw N concentration were observed at 160 kg N/ha. Th e highest signifi cant value of straw N uptake was observed at IL 1 treatment. Also, maximum N uptake for both seed and straw was the same at 120 and 160 kg N ha -1 . Total N uptake achieved signifi cantly in IL 2 × NR 4 treatment. With decreasing irrigation water and increasing N rates, N use effi ciency decreased signifi cantly. In general, consumption of 450 mm water ha -1 season -1 and supplying 120 kg N ha -1 can produce the highest seed, oil, and protein yields ha -1 , while increasing WUE and decreasing N leaching.

Deficit Irrigation of Durum Wheat (Triticum durum Desf): Effects on Total Dry Matter Production, Light Interception and Radiation Use Efficiency Under Different Nitrogen Rates

“…With reduced nitrogen (N3 and N4) and irrigation application rates (D2 and D3), TDM decreased and the lowest values was observed under D3N4 condition. These findings are in line with those of Gan et al (2008), Ali et al (2009), Hamzei (2011 and Hamzei et al (2012). They observed that increasing nitrogen levels increase the biological yield of the crop.…”

“…In fact, N deficiency reduces vegetative and reproductive growth with a final impact on the yield (Tewolde & Fernandez, 1997). Higher rates of N may shift the balance between vegetative and reproductive growth toward excessive vegetative development, thus delaying crop maturity and reducing final yield (Howard et al, 2001;Hamzei, 2011). Water deficit remarkably decreases the nitrogen translocation ratio derived from soil and adversely affects the contributions of nitrogen in various vegetative organs to grain nitrogen (Xu et al, 2006;Hamzei, 2011).…”

“…Higher rates of N may shift the balance between vegetative and reproductive growth toward excessive vegetative development, thus delaying crop maturity and reducing final yield (Howard et al, 2001;Hamzei, 2011). Water deficit remarkably decreases the nitrogen translocation ratio derived from soil and adversely affects the contributions of nitrogen in various vegetative organs to grain nitrogen (Xu et al, 2006;Hamzei, 2011). Several water-saving methods have been developed (Belder et al, 2004;Bouman et al, 2006), among which, deficit irrigation is one of the best techniques that could improve irrigation water use.…”

Effect of Deficit Irrigation and Root-Zone Drying Irrigation Technique under Different Nitrogen Rates on Water Use Efficiency for Potato (Solanum Tuberosum L.) in Semi-arid Conditions (I)

“…correlated with the nitrogen application. Indeed, these results are in agreement with those found by Ali et al, (2009), Massignam et al, (2011) and Hamzei (2011), who observed that increased nitrogen improved the biological yield of crops. Similarly, MacDonald (2002) investigated the effect of different nitrogen doses on the yield of several varieties of durum wheat, and observed that TDM at the anthesis stage increased significantly with increasing nitrogen rate.…”

Growth of spring canola (Brassica napus) under deficit irrigation in Western Nebraska

“…With 20 cm water applied, Pavlista (2012) reported a yield of 1600 kg/ha which is near the amount reported here for LI treatment receiving 25-26 cm of water (Table 4). Hamzei (2011), and Hamzei and Soltani (2012) reported that 45 cm of applied water was needed to achieve a yield of 2565 kg/ha in Iran and a reduction of applied water to 30 cm reduced yield by greater than half. Majnooni-Heris (2014) recently reported a yield of 1790 kg/ha with 50 cm of applied water also in Iran.…”