Causes of the global Nitrogen crisis:
Too little BNF, too much Haber Bosch. Why?
The ultimate cause is that crop legumes are generally not tolerant of soil infertility, relative to the cereals. The pulses we have domesticated require fertile soils to grow well. This generalisation applies to the temperate as well as the tropical pulses.
This greatly limits legume profitability and hence adoption, as growing cereals on poor soils is safer than growing pulses. In particular, it disadvantages poor farmers on the planet, who generally farm the infertile soils.
This in turn leads to increased use of Haber Bosch N in developed Agriculture (and greatly contributes to N pollution), and reduced legume yield in developing countries.
Solution
to domesticate a different set of legume options for infertile soils
Providing the opportunity for new food legumes in developing countries, and increased uptake of legumes (more flexibility) in developed nations.
We need research programs to domesticate legumes adapted to the poor soils (low clay content, low CEC, low fertility, low pH) but domestication programs must be market driven.
From Prof Howieson Murdoch University, Perth Western Australia
From his presentation to the International N Fixation Conference, California 2015.
John Howieson