Assessing agronomic and environmental implications of different N fertilisation strategies in subtropical grain cropping systems on Oxisols

作者：Migliorati Massimiliano De Antoni^*; Bell Mike J; Grace Peter R; Rowlings David W; Scheer Clemens; Strazzabosco Alice

来源：Nutrient Cycling in Agroecosystems, 2014, 100(3): 369-382.

DOI：10.1007/s10705-014-9655-4

• Oxisols
• Nitrogen recovery
• NUE
• DMPP
• Nitrification inhibitor
• Cereals

A multi-season N-15 tracer recovery experiment was conducted on an Oxisol cropped with wheat, maize and sorghum to compare crop N recoveries of different fertilisation strategies and determine the main pathways of N losses that limit N recovery in these agroecosystems. In the wheat and maize seasons, N-15-labelled fertiliser was applied as conventional urea (CONV) and urea coated with a nitrification inhibitor (DMPP). In sorghum, the fate of N-15-labelled urea was monitored in this crop following a legume ley pasture (L70) or a grass ley pasture (G100). The fertiliser N applied to sorghum in the legume-cereal rotation was reduced (70 kg N ha(-1)) compared to the grass-cereal (100 kg N ha(-1)) to assess the availability of the N residual from the legume ley pasture. Average crop N recoveries were 73 % (CONV) and 77 % (DMPP) in wheat and 50 % (CONV) and 51 % (DMPP) in maize, while in sorghum were 71 % (L70) and 53 % (G100). Data gathered in this study indicate that the intrinsic physical and chemical conditions of Oxisols can be extremely effective in limiting N losses via deep leaching or denitrification. Elevated crop N-15 recoveries can be therefore obtained in subtropical Oxisols using conventional urea while in these agroecosystems DMPP urea has no significant scope to increase fertiliser N recovery in the crop. Overall, introducing a legume phase to limit the fertiliser N requirements of the following cereal crop proved to be the most effective strategy to reduce N losses and increase fertiliser N recovery.

• 出版日期2014-12