Wheat response to nitrogen splitting applied to a Vertisols in different tillage systems and cropping rotations under typical Mediterranean climatic conditions

作者：Lopez Bellido Luis; Munoz Romero Veronica; Benitez Vega Jorge; Fernandez Garcia Purificacion; Redondo Ramon; Lopez Bellido Rafael J

来源：European Journal of Agronomy, 2012, 43: 24-32.

DOI：10.1016/j.eja.2012.05.002

• No tillage
• Soil nitrate
• N-15 recovery
• Grain yield
• Sunflower
• Chickpea
• Faba bean

The application of an adequate rate and splitting of nitrogen (N) is essential for the efficient use of N fertiliser and to maintain the economic sustainability of cropping systems. A 3-year field experiment was conducted on a Vertisol under Mediterranean conditions to determine the effect of tillage systems, crop rotation, and variations in N timing on the grain yield and N recovery of N-15-labelled fertiliser (N-R) in hard red spring wheat (Triticum aestivum L.). The experiment was designed as a randomised complete block with a split-split plot arrangement and 3 replications. The main plots were tillage system (no-tillage [NT] and conventional tillage [CT]), and the subplots were the preceding crop with 2-year rotations (wheat-sunflower [WS], wheat-chickpea [WC], and wheat-faba bean [WFB]). Sub-subplots were the N timing (all at the same rate of 100 kg N ha(-1)), and the fertiliser was applied 50% at sowing and 50% at stem elongation and 50% at tillering and 50% at stem elongation. The area of each basic plot was 50 m(2) (5 m x 10 m). The residual NO3-N content (0-90 cm) was significantly higher in CT than in NT, the opposite occurring with grain yield. The N-R of NT was greater than that of CT. According to the previous crop, the N-R was WS %26gt; WFB = WC. The soil nitrate content was twice as much when the preceding crop was a legume compared with sunflower and the wheat yields were as follows: WFB %26gt; WC %26gt; WS. Although the N timing did not have an effect on overall grain yield, the interactions with year, tillage system and previous crop were significant. The average recovery of N-15 fertiliser by wheat was 44.6%, with 33.7% obtained in the grain (41% in stem elongation, 32% in tillering and 27% in sowing). The habitual use of high rates of N fertiliser and the frequency of dry years in the agrosystem studied generated a progressive accumulation of residual in the soil profile. This can represent an important source of mineral N for the cereal and can reduce the need to apply N fertiliser to the crop.

• 出版日期2012-11