Background: Nitrogen (N) addition may have strong impacts on legume growth and their biological N fixation (BNF), but how legume N acquisition sources respond to Ninputs have yet to be comprehensively assessed.
Aims:We quantified the effects of N addition on the growth and BNF of Medicago sativa and to assess the response of legume N acquisition to N addition.
Methods:We grew M. sativa in the greenhouse with NH4NO3 added at rates of 0, 2, 5, 10, 20, 50 g N m −2 yr −1 , and analysed the variables that were relative to growth and N _________________________________________________________________________