N fertilizer application in wheat significantly increased total N, ammonium N and nitrate-N contents in paddy field, resulting in high indigenous N supply of soil (INS).

• 结果表明，麦季氮肥的施用明显提高了稻季土壤全氮、铵态氮和硝态氮的含量，造成土壤背景氮偏高。