What do pulses contribute to the nitrogen balance in Central Queensland farming systems

Abstract

Take home message
• Nitrogen derived from atmosphere (Ndfa) in mungbean crops is strongly influenced by the amount of mineral soil nitrates that are available at planting. There is an almost linear decline in N2 fixation as soil nitrates increase in the top 60cm of the profile.
• Mungbean and chickpea crops can access and utilise soil nitrate N in the top 60cm as efficiently as cereal crops. This raises implications for nitrate N supply in crops following these pulse crops.
• Mungbeans planted in long fallow situations will create a soil nitrate N deficit as N2 fixation rates cannot replace the amount of soil nitrate being exported in grain. Circumstantial evidence suggests that chickpeas may be similar.